INBRX-106 boosts response in HNSCC for Inhibrx (Nasdaq: INBX) with Phase 2 results
Filing Impact
Filing Sentiment
Form Type
8-K
Rhea-AI Filing Summary
Inhibrx Biosciences reported encouraging interim Phase 2 data for INBRX-106 in first-line head and neck squamous cell carcinoma with high PD-L1 expression. In the evaluable population, INBRX-106 plus pembrolizumab achieved a confirmed objective response rate of 44.0% (11 of 25 patients) versus 21.4% (6 of 28) with pembrolizumab alone, a 22.6% absolute improvement, including three complete responses in the combination arm and none in the control arm.
Pharmacodynamic analyses showed up to a 15-fold increase in CD8+ and CD4+ T‑cell proliferation and up to a four-fold increase in activation with the combination, compared with up to 2.5-fold and 1.5-fold increases on pembrolizumab alone. The safety profile of INBRX-106 plus pembrolizumab was generally manageable, with mostly low‑grade rash, diarrhea, fatigue and infusion reactions and no treatment-related deaths.
The company plans to start the Phase 3 portion of the HexAgon study in third-quarter 2026 and expects progression‑free survival data from Phase 2 in fourth-quarter 2026. Inhibrx also outlines expansion plans for INBRX-106 into perioperative and front‑line metastatic non‑small cell lung cancer and other checkpoint‑inhibitor‑sensitive tumors, estimating a potential addressable market of about $50 billion if the drug ultimately extends across major PD‑1/PD‑L1 indications.
Positive
- INBRX-106 delivers higher response rates versus pembrolizumab alone in Phase 2 HNSCC. The combination achieved a 44.0% confirmed objective response rate versus 21.4% with pembrolizumab monotherapy, a 22.6% absolute increase, including three complete responses in the combination arm and none in the control arm.
- Mechanistic and safety data reinforce the INBRX-106 signal. Up to a 15-fold increase in CD8+ and CD4+ T‑cell proliferation and up to a four-fold increase in activation were observed with the combination, while adverse events were generally low‑grade and no treatment‑related deaths occurred in either arm.
- Large potential commercial opportunity if efficacy generalizes beyond HNSCC. The company estimates approximately $1 billion market size for high–PD-L1 HNSCC, $25 billion for NSCLC and $25 billion for other checkpoint‑inhibitor indications, implying around $50 billion of potential market if INBRX-106 can enhance PD‑1/PD‑L1 therapy across these settings.
Negative
- None.
Insights
Interim INBRX-106 data show stronger responses than PD-1 alone and justify moving toward Phase 3.
Inhibrx presents randomized Phase 2 data in first-line PD-L1–high HNSCC where INBRX-106 plus pembrolizumab reached a 44.0% confirmed objective response rate versus 21.4% on pembrolizumab alone, including three complete responses only in the combination arm. This is an early but meaningful efficacy separation in a head‑to‑head setting.
Pharmacodynamic results support the mechanism: combination therapy produced up to a 15-fold rise in CD8+ and CD4+ T‑cell proliferation and up to a four-fold increase in activation, clearly above pembrolizumab monotherapy. Safety remained generally manageable, with mostly low‑grade immune‑type adverse events and no treatment‑related deaths reported in either arm.
The company plans to initiate the Phase 3 HexAgon portion in Q3 2026 and to read out progression‑free survival from Phase 2 in Q4 2026, which will be critical for understanding durability and potential regulatory paths. Management also highlights expansion into perioperative and front‑line metastatic NSCLC and other PD‑1–sensitive tumors, tying INBRX-106 to an estimated $50 billion aggregate checkpoint‑inhibitor market if later‑stage trials confirm benefit.
Data support INBRX-106 as a potential add-on across a large checkpoint-inhibitor market.
The interim HexAgon results are framed as proof of concept in PD-L1 CPS ≥20 HNSCC, a setting where pembrolizumab already works but leaves room for improvement. A 22.6% absolute increase in confirmed responses and three complete responses in the combination arm suggest INBRX-106 can add meaningful activity on top of PD-1 blockade.
Inhibrx estimates the high–PD-L1 HNSCC market at about $1 billion, NSCLC at roughly $25 billion, and additional checkpoint indications at another $25 billion, implying a total opportunity near $50 billion if INBRX-106 ultimately proves useful broadly. Actual realization will depend on forthcoming progression‑free survival, overall survival, and safety data from Phase 3 and subsequent studies, as well as competitive dynamics in immuno‑oncology.
8-K Event Classification
3 items: 7.01, 8.01, 9.01
3 items
Item 7.01
Regulation FD Disclosure
Disclosure
Material non-public information disclosed under Regulation Fair Disclosure, often investor presentations or guidance.
Item 8.01
Other Events
Other
Voluntary disclosure of events the company deems important to shareholders but not covered by other items.
Item 9.01
Financial Statements and Exhibits
Exhibits
Financial statements, pro forma financial information, and exhibit attachments filed with this report.
Key Figures
INBRX-106 combo confirmed objective response rate: 44.0% (11/25 patients)
Pembrolizumab monotherapy confirmed objective response rate: 21.4% (6/28 patients)
Absolute increase in confirmed responses: 22.6% increase
+5 more
8 metrics
INBRX-106 combo confirmed objective response rate
44.0% (11/25 patients)
Evaluable Phase 2 HexAgon population in first-line PD-L1 CPS ≥20 HNSCC
Pembrolizumab monotherapy confirmed objective response rate
21.4% (6/28 patients)
Control arm in Phase 2 HexAgon HNSCC study
Absolute increase in confirmed responses
22.6% increase
Difference between INBRX-106 combination and pembrolizumab alone in cORR
Complete responses in combination arm
3 complete responses
Observed only with INBRX-106 plus pembrolizumab in Phase 2 HNSCC
T-cell proliferation increase with combination
Up to 15-fold increase
CD8+ and CD4+ T‑cell proliferation versus pembrolizumab alone
Estimated HNSCC high–PD-L1 market size
$1 billion
Company estimate for HNSCC CPS ≥20 treatment market
Estimated NSCLC treatment market size
$25 billion
Company estimate for NSCLC market
Total checkpoint inhibitor market estimate
Approximately $50 billion
Combined NSCLC, HNSCC CPS ≥20 and other checkpoint‑inhibitor indications
Key Terms
confirmed objective response rate, hexavalent OX40 agonist, Head and Neck Squamous Cell Carcinoma, treatment-related adverse events, +2 more
6 terms
confirmed objective response rate clinical
"the INBRX-106 + pembrolizumab combination achieved a cORR of 44.0% versus 21.4% with pembrolizumab alone"
hexavalent OX40 agonist clinical
"The trial evaluated the safety and efficacy of INBRX-106, a hexavalent OX40 agonist, in combination with pembrolizumab"
Head and Neck Squamous Cell Carcinoma clinical
"treatment-naïve, PD-L1 positive (CPS ≥ 20) metastatic or unresectable recurrent Head and Neck Squamous Cell Carcinoma (HNSCC)"
A type of cancer that starts in the thin, flat cells that line the mouth, throat, voice box and upper airway; imagine the lining like roof shingles that, when damaged, can grow into a harmful lump. It matters to investors because its diagnosis, treatment options and regulatory approvals drive demand for drugs, tests and therapies—affecting clinical trial outcomes, market size, company valuations and the financial risk/reward of healthcare investments.
progression-free survival clinical
"The progression-free survival data from the Phase 2 portion of the HexAgon study are expected to become available in the fourth quarter of 2026"
Progression-free survival is the length of time during and after a treatment that a patient's disease does not get worse, measured from the start of treatment until the disease shows measurable signs of progression or the patient dies. Investors care because longer progression-free survival in clinical trials often signals that a drug is effective, improving chances of regulatory approval, market adoption, and revenue potential—think of it as a stopwatch showing how long a therapy can keep the illness at bay.
checkpoint inhibitor-sensitive indications clinical
"would support INBRX-106’s potential to enhance checkpoint inhibitor efficacy across checkpoint inhibitor-sensitive indications"
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 or 15(d)
of the Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): May 11, 2026
(Exact name of registrant as specified in its charter)
| (State or other jurisdiction of incorporation) | (Commission File Number) | (IRS Employer Identification No.) | ||||||||||||
(Address of Principal Executive Offices and Zip Code)
Registrant’s telephone number, including area code: (858 ) 795-4220
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:
Securities registered pursuant to Section 12(b) of the Act:
| Title of each class | Trading Symbol(s) | Name of each exchange on which registered | ||||||
Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).
Emerging growth company ☒
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☒
Item 7.01. Regulation FD Disclosure.
On May 11, 2026, Inhibrx Biosciences, Inc. (“Inhibrx” or the “Company”) issued a press release announcing clinical updates on INBRX-106 in first-line head and neck squamous cell carcinoma (HSNCC), as discussed in Item 8.01 of this Current Report on Form 8-K. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.
On May 11, 2026, Inhibrx posted an updated copy of its corporate presentation to the “Investors” tab of its website at www.inhibrx.com. The presentation is attached to this Current Report on Form 8-K as Exhibit 99.2. Inhibrx from time to time presents and/or distributes the presentation to the investment community during conferences and meetings to provide updates and summaries of its business.
The information in Item 7.01 of this Current Report on Form 8-K, including Exhibits 99.1 and 99.2 attached hereto, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.
Item 8.01. Other Events.
Interim Phase 2 Data for INBRX-106 in First-Line HNSCC
On May 11, 2026, Inhibrx announced positive interim results from its randomized, first-line Phase 2 portion of the HexAgon study. The trial evaluated the safety and efficacy of INBRX-106, a hexavalent OX40 agonist, in combination with pembrolizumab (the combination arm) versus pembrolizumab monotherapy (the control arm) in first-line patients with treatment-naïve, PD-L1 positive (CPS ≥ 20) metastatic or unresectable recurrent Head and Neck Squamous Cell Carcinoma (HNSCC).
HNSCC was selected as a proof-of-concept indication, as PD-1 monotherapy is active in this tumor type but leaves significant room for improvement. The trial design was modeled after KEYNOTE-048, focusing on patients with high PD-L1 expression (CPS ≥ 20) in order to further sharpen the ability to detect a treatment effect above checkpoint inhibition alone. A clear signal of added benefit in this study design would support INBRX-106’s potential to enhance checkpoint inhibitor efficacy across checkpoint inhibitor-sensitive indications.
The Phase 2 portion of the HexAgon study enrolled 68 patients: 33 randomized to the combination arm and 35 to the control arm. Baseline prognostic factors are largely balanced between both arms and the study is being conducted at over 80 sites in the United States, Europe and Asia. Today, the Company presented preliminary data from 53 patients (25 in the INBRX-106 combination arm and 28 in the control arm) with a data cutoff of May 7, 2026, representing the evaluable population for confirmed response, defined as patients who had either experienced confirmed disease progression or death, or completed at least two on-study tumor assessments. The remaining 15 patients in the overall population across both arms had not yet reached the maturity threshold for response confirmation or were not evaluable at the time of this data cut and were therefore not included in this analysis. Active unconfirmed responses and ongoing tumor increases/reductions are present in both arms, and these patients are expected to contribute to the final efficacy dataset in a subsequent update.
In the evaluable population, 11 out of 25 patients (44.0%) in the INBRX-106 combination arm achieved a confirmed objective response, compared with 6 out of 28 patients (21.4%) in the control arm. This represents a 22.6% absolute increase in confirmed responses. Three complete responses were observed in the INBRX-106 combination arm, reflecting tumor clearance, while no complete responses were observed with pembrolizumab alone. Complete responses in first-line HNSCC remain uncommon and are generally associated with more durable outcomes.
These clinical findings were supported by pharmacodynamic data, which showed up to a 15-fold increase in peripheral CD8+ and CD4+ T-cell proliferation and up to a four-fold increase in activation in INBRX-106 combination-treated patients compared with up to 2.5-fold and 1.5-fold increases, respectively, in those receiving pembrolizumab alone. The observation of robust systemic T-cell expansion and activation in combination-treated patients, alongside the clinical activity observed in this arm, is consistent with the expected mechanism of action of INBRX-106 as a potent T-cell costimulator.
The combination of INBRX-106 and pembrolizumab was generally manageable, with a safety profile consistent with the addition of an active immunostimulatory agent to checkpoint blockade. The most common treatment-related adverse events were rash, diarrhea, fatigue, and infusion-related reactions, which were predominantly low-grade. No treatment-related deaths were reported in either arm.
The progression-free survival data from the Phase 2 portion of the HexAgon study are expected to become available in the fourth quarter of 2026. The Company plans to begin the Phase 3 portion of the HexAgon study during the third quarter of 2026.
Based on these promising early results, the Company also aims to evaluate INBRX-106 across broader indications to potentially improve the efficacy of checkpoint inhibitors. This strategy includes initiating a study in the perioperative setting in non-small cell lung cancer (NSCLC) later this quarter. The Company believes OX40 agonism has the greatest potential to drive cure in
earlier-stage disease settings, where patients typically retain a more active and responsive immune system. In addition, the Company is beginning to plan for expansion into the front-line metastatic NSCLC setting, with studies expected to begin in 2027. Outside of combination with checkpoint inhibitors, the Company plans to explore combinations with agents that could benefit from T-cell costimulation, such as vaccines, T-cell engagers, and CAR-Ts.
Market Overview
While HNSCC with high PD-L1 expression (CPS ≥ 20) is the Company’s initial proof-of-concept indication, a clear signal of added benefit in this study design would support INBRX-106’s potential to enhance checkpoint inhibitor efficacy across checkpoint inhibitor-sensitive indications, potentially broadening into NSCLC and beyond. The Company estimates that the total market size for treating HNSCC with high PD-L1 expression (CPS ≥ 20) is valued at approximately $1 billion. The total market size for treating NSCLC is valued at approximately $25 billion, and all additional checkpoint inhibitor indications add approximately $25 billion to the market size. Together, the Company estimates this results in a total market size of approximately $50 billion, representing the potential market opportunity if INBRX-106 were to expand across all indications where checkpoint inhibitors are used. The Company’s market estimates are based on estimates from third party studies and Company estimates and involve a number of assumptions and limitations.
Forward-Looking Statements
Inhibrx cautions you that statements contained in this Current Report on Form 8-K regarding matters that are not historical facts are forward-looking statements. These statements are based on Inhibrx’s current beliefs and expectations and upon what management believes to be reasonable assumptions based on information currently available to it. These forward-looking statements include, but are not limited to, statements regarding: Inhibrx’s judgments and beliefs regarding the strength of Inhibrx’s pipeline; statements regarding the safety and efficacy of its therapeutic candidate, INBRX-106, based on topline and interim results; the potential for INBRX-106 to be used for the treatment of HNSCC; the clinical development of INBRX-106, including expected enrollment in the expansion cohort, data readouts, regulatory submissions and interactions, and the timing thereof; any presumption that topline, interim or preliminary data will be representative of final data or data in later clinical trials, including data from the remaining 15 patients in the overall population for the Phase 2 trial for INBRX-106 in first-line HNSCC; Inhibrx’s plans to evaluate INBRX-106 across broader indications and to explore combinations with other therapies; Inhibrx’s plans to expand into the front-line metastatic NSCLC setting, with studies expected to begin in 2027; Inhibrx’s plans to begin the Phase 3 portion of the HexAgon study during the third quarter of 2026; and estimates and other statistical data made by independent parties and by Inhibrx relating to potential market size related to Inhibrx’s product candidates. Actual results may differ from those set forth in this Current Report on Form 8-K due to the risks and uncertainties inherent in Inhibrx’s business, including, without limitation, risks and uncertainties regarding: topline data may not accurately reflect the complete results of a particular study or trial and remain subject to audit, and final data may differ materially from topline data; the initiation, timing, progress and results of its preclinical studies and clinical trials, and its research and development programs; its ability to advance therapeutic candidates into, and successfully complete, clinical trials; its interpretation of topline, interim or preliminary data from its clinical trials, including interpretations regarding disease control and disease response; results from preclinical studies or early clinical trials not necessarily being predictive of future results; unexpected adverse side effects or inadequate efficacy of its therapeutic candidates that may limit their development, regulatory approval and/or commercialization; the potential for its programs and prospects to be negatively impacted by developments relating to its competitors, including the results of studies or regulatory determinations relating to its competitors; the timing or likelihood of regulatory filings and approvals and regulatory developments in the U.S. and foreign countries; the successful commercialization of its therapeutic candidates, if approved; the pricing, coverage and reimbursement of its therapeutic candidates, if approved; its ability to utilize its technology platform to generate and advance additional therapeutic candidates; and other risks described from time to time in the “Risk Factors” section of its filings with the U.S. Securities and Exchange Commission, including those described in its Annual Report on Form 10-K, its Quarterly Reports on Form 10-Q, and supplemented from time to time by its Current Reports on Form 8-K as filed from time to time. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this Current Report on Form 8-K, and Inhibrx undertakes no obligation to update these statements to reflect events that occur or circumstances that exist after the date of this Current Report on Form 8-K. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.
Item 9.01. Financial Statements and Exhibits.
(d) Exhibits.
| Exhibit No. | Description | |||||||
| 99.1 | Press Release issued by Inhibrx Biosciences, Inc. on May 11, 2026 | |||||||
| 99.2 | Corporate Presentation | |||||||
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document) | |||||||
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
| Date: May 11, 2026 | ||||||||
| INHIBRX BIOSCIENCES, INC. | ||||||||
| By: | /s/ Kelly Deck | |||||||
| Name: | Kelly Deck | |||||||
| Title: | Chief Financial Officer | |||||||
Exhibit 99.1
Inhibrx Reports Interim Phase 2 Data for INBRX-106 in First-Line HNSCC; Initial Results Demonstrate Potential Costimulatory Benefit Over PD-1 Monotherapy
•Interim analyses show INBRX-106 + pembrolizumab achieved a 44.0% confirmed Objective Response Rate (cORR): In the preliminary confirmed response-evaluable population, the INBRX-106 + pembrolizumab combination achieved a cORR of 44.0% versus 21.4% with pembrolizumab alone, representing a 22.6% absolute increase in cORR.
•Superior depth of response: Responding patients in the combination arm demonstrated deeper tumor reductions overall, with the majority achieving target lesion shrinkage exceeding 50%; notably, three patients achieved a complete radiographic response.
•Up to 15-fold mean increase in systemic T-Cell expansion: Peripheral blood analysis showed robust CD8+ and CD4+ T-cell proliferation in combination-treated patients, providing mechanistic support for the observed clinical activity.
•Manageable safety profile: The combination demonstrated a manageable preliminary safety profile consistent with that expected from an immunotherapy combination.
SAN DIEGO, CA — May 11, 2026 — Inhibrx Biosciences, Inc. (Nasdaq: INBX) (“Inhibrx” or the “Company”), a clinical-stage biopharmaceutical company focused on developing novel biologic therapeutic candidates, today announced positive interim results from the randomized, first-line Phase 2 portion of the HexAgon study. The trial evaluated the safety and efficacy of INBRX-106, a hexavalent OX40 agonist, in combination with pembrolizumab (the combination arm) versus pembrolizumab monotherapy (the control arm) in first-line patients with treatment-naïve, PD-L1 positive (CPS ≥ 20) metastatic or unresectable recurrent Head and Neck Squamous Cell Carcinoma (HNSCC).
HNSCC was selected as a proof-of-concept indication, as PD-1 monotherapy is active in this tumor type but leaves significant room for improvement. The trial design was modeled after KEYNOTE-048, focusing on patients with high PD-L1 expression (CPS ≥ 20) in order to further sharpen the ability to detect a treatment effect above checkpoint inhibition alone. A clear signal of added benefit in this study design would support INBRX-106's potential to enhance checkpoint inhibitor efficacy across checkpoint inhibitor-sensitive indications.
The Phase 2 portion of the HexAgon study enrolled 68 patients: 33 randomized to the combination arm and 35 to the control arm. Baseline prognostic factors are largely balanced between both arms and the study is being conducted at over 80 sites in the United States, Europe and Asia. Today, the Company presented preliminary data from 53 patients (25 in the INBRX-106 combination arm and 28 in the control arm) with a data cutoff of May 7, 2026, representing the evaluable population for confirmed response, defined as patients who had either experienced confirmed disease progression or death, or completed at least two on-study tumor assessments. The remaining 15 patients in the overall population across both arms had not yet reached the maturity threshold for response confirmation or were not evaluable at the time of this data cut and were therefore not included in this analysis. Active unconfirmed responses and ongoing tumor increases/reductions are present in both arms, and these patients are expected to contribute to the final efficacy dataset in a subsequent update.
In the evaluable population, 11 out of 25 patients (44.0%) in the INBRX-106 combination arm achieved a confirmed objective response, compared with 6 out of 28 patients (21.4%) in the
control arm. This represents a 22.6% absolute increase in confirmed responses. Three complete responses were observed in the INBRX-106 combination arm, reflecting tumor clearance, while no complete responses were observed with pembrolizumab alone. Complete responses in first-line HNSCC remain uncommon and are generally associated with more durable outcomes.
These clinical findings were supported by pharmacodynamic data, which showed up to a 15-fold increase in peripheral CD8+ and CD4+ T-cell proliferation and up to a four-fold increase in activation in INBRX-106 combination-treated patients compared with up to 2.5-fold and 1.5-fold increases, respectively, in those receiving pembrolizumab alone. The observation of robust systemic T-cell expansion and activation in combination-treated patients, alongside the clinical activity observed in this arm, is consistent with the expected mechanism of action of INBRX-106 as a potent T-cell costimulator.
The combination of INBRX-106 and pembrolizumab was generally manageable, with a safety profile consistent with the addition of an active immunostimulatory agent to checkpoint blockade. The most common treatment-related adverse events were rash, diarrhea, fatigue, and infusion-related reactions, which were predominantly low-grade. No treatment-related deaths were reported in either arm.
“We are greatly encouraged by these early clinical results,” said Mark Lappe, Chief Executive Officer of Inhibrx. “These data, coupled with the clear evidence of T-cell expansion and superior depth of response, give us confidence that INBRX-106 could be the first costimulatory agent to fundamentally shift the efficacy ceiling of immunotherapy, and open the door to combinations with new modalities that could be enhanced by OX40 agonism.”
Next Steps
The progression-free survival data from the Phase 2 portion of the HexAgon study are expected to become available in the fourth quarter of 2026. The Company plans to begin the Phase 3 portion of the HexAgon study during the third quarter of 2026.
Based on these promising early results, the Company also aims to evaluate INBRX-106 across broader indications to potentially improve the efficacy of checkpoint inhibitors. This strategy includes initiating a study in the perioperative setting in non-small cell lung cancer (NSCLC) later this quarter. The Company believes OX40 agonism has the greatest potential to drive cure in earlier-stage disease settings, where patients typically retain a more active and responsive immune system. In addition, the Company is beginning to plan for expansion into the front-line metastatic NSCLC setting, with studies expected to begin in 2027. Outside of combination with checkpoint inhibitors, the Company plans to explore combinations with agents that could benefit from T-cell costimulation, such as vaccines, T-cell engagers, and CAR-Ts.
About INBRX-106
INBRX-106 is a hexavalent agonist targeting OX40 (CD134), a costimulatory receptor on T-cells. Utilizing Inhibrx’s proprietary single-domain antibody (sdAb) platform, INBRX-106 is designed to achieve the high-order receptor clustering necessary for robust T-cell activation and survival, a feat that has eluded traditional bivalent antibody approaches. To date, over 175 patients have been treated with INBRX-106.
About Inhibrx Biosciences, Inc.
Inhibrx Biosciences is a clinical-stage biopharmaceutical company focused on developing a broad pipeline of novel biologic therapeutic candidates. Inhibrx Biosciences utilizes diverse methods of protein engineering to address the specific requirements of complex target and disease biology, including its proprietary protein engineering platforms. Inhibrx Biosciences was incorporated in January 2024 as a direct, wholly-owned subsidiary of Inhibrx, Inc. Prior to the sale of Inhibrx, Inc. and the INBRX-101 program to Sanofi S.A., Inhibrx Biosciences acquired certain corporate infrastructure and other assets and liabilities through a series of internal restructuring transactions effected by Inhibrx, Inc. Inhibrx, Inc. also completed a distribution to holders of its shares of common stock of 92% of the issued and outstanding shares of Inhibrx Biosciences. Following such transactions, Inhibrx Biosciences’ current clinical pipeline of therapeutic candidates includes ozekibart (INBRX-109) and INBRX-106, both of which utilize multivalent formats where the precise valency can be optimized in a target-centric way to mediate what we believe to be the most appropriate agonist function. For more information, please visit www.inhibrx.com.
Forward-Looking Statements
Inhibrx cautions you that statements contained in this press release regarding matters that are not historical facts are forward-looking statements. These statements are based on Inhibrx’s current beliefs and expectations. These forward-looking statements include, but are not limited to, statements regarding: Inhibrx’s judgments and beliefs regarding the strength of Inhibrx’s pipeline; statements regarding the safety and efficacy of its therapeutic candidate, INBRX-106, based on topline and interim results; the potential for INBRX-106 to be used for the treatment of HNSCC; the clinical development of INBRX-106, including expected enrollment in the expansion cohort, data readouts, regulatory submissions and interactions, and the timing thereof; any presumption that topline, interim or preliminary data will be representative of final data or data in later clinical trials, including data from the remaining 15 patients in the overall population for the Phase 2 trial for INBRX-106 in first-line HNSCC; Inhibrx’s plans to evaluate INBRX-106 across broader indications and to explore combinations with other therapies; Inhibrx’s plans to expand into the front-line metastatic NSCLC setting, with studies expected to begin in 2027; and Inhibrx’s plans to begin the Phase 3 portion of the HexAgon study during the third quarter of 2026. Actual results may differ from those set forth in this press release due to the risks and uncertainties inherent in Inhibrx's business, including, without limitation, risks and uncertainties regarding: topline data may not accurately reflect the complete results of a particular study or trial and remain subject to audit, and final data may differ materially from topline data; the initiation, timing, progress and results of its preclinical studies and clinical trials, and its research and development programs; its ability to advance therapeutic candidates into, and successfully complete, clinical trials; its interpretation of topline, interim or preliminary data from its clinical trials, including interpretations regarding disease control and disease response; results from preclinical studies or early clinical trials not necessarily being predictive of future results; unexpected adverse side effects or inadequate efficacy of its therapeutic candidates that may limit their development, regulatory approval and/or commercialization; the potential for its programs and prospects to be negatively impacted by developments relating to its competitors, including the results of studies or regulatory determinations relating to its competitors; the timing or likelihood of regulatory filings and approvals and regulatory developments in the U.S. and foreign countries; the successful commercialization of its therapeutic candidates, if approved; the pricing, coverage and reimbursement of its therapeutic candidates, if approved; its ability to
utilize its technology platform to generate and advance additional therapeutic candidates; and other risks described from time to time in the “Risk Factors” section of its filings with the U.S. Securities and Exchange Commission, including those described in its Annual Report on Form 10-K, its Quarterly Reports on Form 10-Q, and supplemented from time to time by its Current Reports on Form 8-K as filed from time to time. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and Inhibrx undertakes no obligation to update these statements to reflect events that occur or circumstances that exist after the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.
Investor and Media Contact:
Kelly Deck, CFO
ir@inhibrx.com
858-795-4260
INHIBRX Investor Presentation Innovation Driven Outcomes Focused
2 Presentation disclaimer This presentation of Inhibrx Biosciences, Inc. (the “Company”) contains forward-looking statements. In some cases, you can identify forward-looking statements by the words “will,” “expect,” “intend,” “plan,” “objective,” “believe,” “estimate,” “potential,” “continue” and “ongoing,” or the negative of these terms, or other comparable terminology intended to identify statements about the future. These statements are based on management’s current beliefs and expectations. These statements include but are not limited to statements regarding the Company’s business strategy, the Company’s plans to develop and commercialize its product candidates, the safety and efficacy of the Company’s product candidates, the Company’s plans and expected timing with respect to clinical trials and regulatory filings and approvals, manufacturing matters, strength of intellectual property protection, and the size and growth potential of the markets for the Company’s product candidates, and any implication that pre- clinical data or preliminary or topline results will be representative of the results of later trials. This presentation also contains certain projections and estimates regarding the Company’s future financial performance, namely potential future revenue for certain of the Company’s product candidates. This information also constitutes forward-looking information and is for illustrative purposes only and should not be relied upon as necessarily being indicative of any future results. The assumptions and estimates underlying this estimated financial information are inherently uncertain and subject to a wide variety of significant business, economic competitive and other risks and uncertainties that could cause actual results to differ materially from those contained in the prospective financial information. These potential financial information and other forward- looking statements involve substantial known and unknown risks, uncertainties and other factors that may cause the Company’s actual results, levels of activity, performance or achievements to be materially different from the information expressed or implied by these forward-looking statements. Additional information regarding the Company’s risks and uncertainties are described from time to time in the “Risk Factors” section of our Securities and Exchange Commission filings, including those described in our Annual Report on Form 10-K as well as our Quarterly Reports on Form 10-Q, and supplemented from time to time by our Current Reports on Form 8-K. The Company may not actually achieve the plans, intentions or expectations disclosed in its forward-looking statements, and you should not place undue reliance on the Company’s forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements the Company makes. The forward- looking statements in this presentation represent the Company’s views as of the date of this presentation. The Company anticipates that subsequent events and developments will cause its views to change. However, while the Company may elect to update these forward-looking statements at some point in the future, the Company has no current intention of doing so except to the extent required by applicable law. You should, therefore, not rely on these forward-looking statements as representing the Company’s views as of any date subsequent to the date of this presentation. The investigational product candidates discussed in this presentation have not been approved or licensed by the U.S. Food and Drug Administration or by any other regulatory authority, and they are not commercially available in any market. This presentation also contains estimates and other statistical data made by independent parties and by the Company relating to market size and growth and other data about its industry. This data involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. In addition, projections, assumptions, and estimates of the Company’s future performance and the future performance of the markets in which it operates are necessarily subject to a high degree of uncertainty and risk. The Inhibrx logo is a registered trademark of Inhibrx Biosciences, Inc. All third-party trademarks used herein are registered trademarks of their respective owners. This presentation shall not constitute an offer to sell or the solicitation of an offer to buy securities.
3 $ Biosciences founded 2018 first IND 2020 IPO 2024 INBRX-101 acquisition by Sanofi 2010 >300 ozekibart (INBRX-109) Patients treated to date >175 INBRX-106 Patients treated to date Our mission: To discover & develop effective biologic treatments for people with life-threatening conditions ~110 employees with an experienced leadership team Key financial highlights: (as of 12/31/2025) $124.2M Cash and cash equivalents 14.6M Common stock outstanding 19.6M* Fully diluted outstanding In-house expertise: Discovery Protein engineering Cell biology Translational research Chemistry Manufacturing and controls Clinical development and operations Commercial * Includes 4.0M employee and BOD option reserve and approximately 1M pre-funded warrants and 0.1M warrants outstanding
4 Near Term Expected Milestones 1H 2026 INBRX-106 Interim ORR data for randomized, first line HNSCC (INBRX-106/Pembro vs. Pembro) 2H 2026 Ozekibart BLA submission for the treatment of metastatic or unresectable chondrosarcoma Ozekibart (INBRX-109) Ozekibart (INBRX-109) PFS data for Phase 1/2 late line CRC cohort INBRX-106 PFS data for randomized, first line HNSCC (INBRX-106/Pembro vs. Pembro) Ozekibart (INBRX-109) Potential approval of ozekibart for the treatment of metastatic or unresectable chondrosarcoma Potential meeting with FDA to discuss accelerated regulatory pathway for Ewing sarcoma, 4L CRC; Also discuss 1L CRC registrational trial design Ozekibart (INBRX-109) INBRX-106 Phase 3 portion of HexAgon initiation INBRX-106 Perioperative NSCLC study initiation 1H 2027 Ozekibart (INBRX-109) Potential first commercial launch of ozekibart for the treatment of metastatic or unresectable chondrosarcoma Phase 1 GBM study initiation Ozekibart (INBRX-109)
INBRX-106 Boosting PD-1 efficacy through next-generation hexavalent OX40 agonism
6 INBRX-106 OX40 agonism enhances anti-tumor T cell activity in combo with PD-1 blockade (1) Croft. Ann Rev Immunol 2010. (2) Salek-Ardakani, Curr Imunol Rev 2006. (3) Weinberg, Immunol Rev 2011. (4) Piconese, J Exp Med 2008 T cell activation restored/enhanced Optimized T cell activation by OX40 agonism and PD-1 blockade Dual Immunotherapy: Releasing the Brakes and Stepping on the Gas Synergistic Tumor destruction via INBRX-106 and Pembro INBRX-106 is designed to: Supercharge the immune system against the tumors 1-4 Reverse immune suppression 1-4 Complement checkpoint inhibitors (anti-PD-1/PD-L1), enhancing activity Patients must have an immune response to their tumor(s) for signal 2 and check point inhibition to be impactful. T-cell activation critical steps: The ignition Signal 1: TCR tumor antigen recognition OX40 agonism enhances proliferation, survival and memory formation for tumor specific T-cells. PD-1 signaling (in T-cells) activated via PD-L1 expressed in APCs and tumor cells dampens signal 1 and 2. PD-1 inhibition is necessary to remove this brake. The accelerator Signal 2: OX40 T-cell co-stimulation The brake Check point inhibition
7 INBRX-106 INBRX-106 is a hexavalent agonist designed to maximize OX40 signaling to drive antitumor activity IN BR X- 10 6 Bi va le nt AF647 detection OverlayGFP high-order OX40 clustering low-order OX40 clustering *Holay et al. Journal for Immunotherapy of Cancer 2025 Advantages of INBRX-106 format Hyperclustering Hexavalent Simultaneously engages multiple OX40s to drive more potent clustering/signaling Receptor hyperclustering enables more efficient co-stimulation of OX40 Key for OX40 low expressing cells such as CD8 + T-cells Hexavalent OX40 Agonist OX40 INBRX-106 High-order OX40 clustering by INBRX-106 JITC Providence Publication
8 INBRX-106 Seamless Phase 2/3 study in 1L R/M HNSCC with PD-L1 CPS ≥20 Clinicaltrials.gov (NCT06295731). Protocol version 1.0; January 31, 2024. INBRX-106 to be administered every 3 weeks. Pembro 200 mg to be administered every 3 weeks. 1L, first line; CBR, clinical benefit rate; cORR, confirmed objective response rate; CPS, combined positive score; DOR, duration of response; ECOG PS, Eastern Cooperative Oncology Group performance status; HNSCC, head and neck squamous cell carcinoma; HPV, human papillomavirus; OS, overall survival; PD-L1, programmed cell death 1 ligand 1; pembro, pembrolizumab; PFS, progression-free survival; PFS6mo, progression-free survival rate at 6 months; PRO, patient-reported outcome; R, randomization; R/M, recurrent/metastatic; TTCx, time to chemotherapy; Tx, treatment. Randomization will be stratified by: + Disease status (locoregional advanced vs metastatic) + HPV status (positive vs negative). + ECOG PS (0 vs 1) Phase 2, Open label Phase 3, Double blind Survival Follow-up Ongoing INBRX-106 + Pembro INBRX-106 + Pembro Pembro Pembro Co-primary endpoint: PFS and OS. Secondary endpoints: ORR, DOR, CBR, TTCx, safety, PROs. Primary Criteria: ORR Secondary Criteria: + DOR + CBR + PFS6m + safety Key inclusion criteria: R/M HNSCC PD-L1 CPS ≥20 HPV status confirmed No prior systemic Tx for R/M HNSCC R 1:1 R 1:1 Interim Phase 2 Readout: May 2026 INBRX-106 with pembrolizumab: costimulatory proof of concept study
9 INBRX-106 Interim HexAgon Phase 2 data in 1L HNSCC demonstrate INBRX-106 Potential costimulatory benefit over PD-1 monotherapy Improvement in cORR with superior depth of response Confirmed objective response rate (cORR): • 44.0% with INBRX-106 + pembro • 21.4% with pembro alone Superior depth of response: • 3 complete radiographic response (CRs) in INBRX-106 + pembro; no CRs observed in pembro alone • Deeper tumor reductions overall in INBRX-106 + pembro arm, with majority of responding patients achieving >50% target lesion shrinkage Pharmacodynamic evidence of potent T-Cell co-activation Increased T-Cell expansion: • Up to 15-fold mean increase in proliferation of CD8+ and CD4+ T- Cells vs. pembro alone • Up to 4-fold mean increase in activation of CD8+ and CD4+ T-Cells vs. pembro alone Consistent with the expected mechanism of action of INBRX-106 as a potent T-cell costimulator Manageable safety profile consistent with immunotherapy combination INBRX-106 + pembro demonstrated generally manageable safety profile, consistent with the addition of an active immunostimulatory agent to checkpoint blockade Data support initiation of INBRX-106 Phase 3 HexAgon (1L HNSCC) expected in 3Q 2026 and expansion into additional settings such as perioperative NSCLC and 1L metastatic NSCLC
10 INBRX-106 SD at 1st scan and PR 2nd scan ongoing not yet confirmed PR 1st scan and PD at 2nd scan 44.0% cORR Patient Number [CPS] Patient Number [CPS] 21.4% cORR INBRX-106 + Pembrolizumab Pembrolizumab Interim phase 2 data in HNSCC: INBRX-106 + Pembro vs. Pembro Ch an ge fr om B as el in e, % PR PD PR PD Safety: INBRX-106 + pembrolizumab demonstrated a clinically manageable safety profile, with adverse events consistent with the mechanism of action and no treatment-related deaths Data cutoff date: May 7, 2026; Evaluable population for confirmed response, defined as patients who had either experienced confirmed disease progression or death, or completed at least two on-study tumor assessments. This includes 2 patients, 1 per arm, who experienced PD-death prior to the first scan ** * * *Patients ongoing on study without PD event * * * * * * * * * * * * * * * * * *
11 INBRX-106 INBRX-106 is the key driver of T- cell activity in the combination group INBRX-106 drives up to 15-fold change increase in proliferation and up to 4-fold change increase in activation of T-cells Clear validation of INBRX-106 as a potent T-cell co-activator Data cutoff date: April 2, 2026. RP2D (recommended phase 2 dose) for combination is 0.1 mpk of INBRX-106. Data is representative of Hexagon U.S. cohorts only (9 Pembro and 13 Combo patients). Data represented as Mean±SEM HexAgon Phase 2 – 1L HNSCC Proliferation Activation C D 4+ T c el ls C D 8+ T c el ls INBRX-106 + pembro drives up to 15-fold change in proliferation and up to 4-fold change in activation of T-cells
12 INBRX-106 Broad Expandability: development plan to unlock opportunities in NSCLC, H&N and beyond H&N1 NSCLC PD-1 Sensitive Indications Adv/Met Curative 1L Bladder Kidney Breast Liver
13 INBRX-106 Inhibrx path to oncology market leadership 0 10 20 30 40 50 60 70 CPS > 20% TPS > 50% (Chemo Sparing) Peri-Operative All Comers (with Chemo) All PD-1 Markets W W To ta l M ar ke t S ize (U S $b n) 1 (1)Source: Evaluate estimates for PD-1s (Keytruda/Qlex, Opdivo, Libtayo) projected to 2031 based on 2025-2027 growth rates (market size for INBRX-106 independent of biosimilar entry). H&N based on company estimates, NSCLC informed by Evaluate 2031 market totals and breakouts based on company estimates. $1bn+ $25bn+ $50bn+ Demonstrate INBRX-106 Contribution of Benefit via Head & Neck Randomize INBRX-106+pembro vs. pembro monotherapy to demonstrate the efficacy of INBRX-106 Pursue significant market value in NSCLC Three studies: pembro+106 in 1L TPS > 50% (chemo-free); 1L combination with pembro/chemo (all comers); and peri- operative Expand INBRX-106 to wherever PD-1s are Effective +10-20 additional indications
14 INBRX-106 Phase 1 data: PD-L1+ CPI-R/R NSCLC INBRX-106 with pembrolizumab 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 19 19 20 21 22 23 24 25 26 PD-L1 TPS 60 20 95 10 80 80 90 2 11 20 3 75 10 10 35 1 50 1 1 10 41 100 50 60 100 90 + The NSCLC patients included were heavily pretreated (prior lines: median, 3.5; range, 1-11) and all had received prior CPI (some patients received several lines of CPI treatment) + Most patients experienced a reduction in or stabilization of target lesions. Three of the patients have had ongoing responses for more than a year. Ch an ge fr om b as el in e, % 0 -100 -80 -60 -40 -20 20 60 40 PR PD
15 INBRX-106 Phase 1 data: PD-L1+ CPI-R/R or CPI-naive HNSCC INBRX-106 with pembrolizumab 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 PD-L1 CPS 0 100 0 30 1 10 75 20 100 100 10 5 24 90 25 + The HNSCC patient population included was heterogeneous (1L+) and included CPI-naive patients and those with CPI-R/R disease + More than half of patients experienced a reduction in target lesions, including two patients who achieved durable complete responses *NPC = nasopharyngeal carcinoma -60 PR PD NPC* patient (D2) Be st c ha ng e fr om b as el in e, % Cohort CPI-naïve (F4) CPI-R/R (F1) 20 -100 -80 -40 -20 0 40 60
ozekibart (INBRX-109) Selectively inducing apoptosis in tumor cells through tetravalent DR5 agonism
17 INBRX-109 Ozekibart (INBRX-109) registrational trial results Unprecedented data in chondrosarcoma Primary endpoint met: + HR= 0.479; (95% CI: 0.33, 0.68); P<0.0001 (52% reduction in the risk of disease progression or death) + More than doubling median PFS to 5.52 months compared to 2.66 months for placebo + Ozekibart's benefit was consistent across all pre-specified subgroups Secondary endpoint: + Disease control rate (54% vs 27.5%) Patients: Conventional chondrosarcoma, Grades 2 and 3, unresectable or metastatic R 2:1 Ozekibart (INBRX-109) Placebo Every three weeks Every three weeks N=137 N=69 Randomization stratified by line of therapy, Grade and IDH1/2 mutation status Regulatory momentum Orphan designations (FDA & EMA) and Fast track (FDA) Improved disease control rate 54% vs 27.5% Median PFS more than doubled 5.52 months vs 2.66 months 52% reduction in progression or death HR 0.479; P < 0.0001
18 INBRX-109 Primary endpoint: progression-free survival by CIRR Data cutoff date: September 30, 2025. Crosses indicate censored patients. Data from the double-blind period of the study are presented. CIRR, central independent radiology review; HR, hazard ratio; mPFS, median PFS; PFS, progression-free survival. Ozekibart significantly prolonged mPFS vs placebo and led to a 52% reduction in the risk of disease progression or death Ozekibart Placebo 0.479 (0.335–0.684) <0.0001 5.52 2.66mPFS, months Stratified HR (95.02% CI) Log-rank P value Ozekibart 137 56 24 11 4 2 2 0 Placebo 69 16 2 1 0 0 0 0 No. at risk: Events / Censored, n (%) 94 (68.6) / 43 (31.4) 55 (79.7) / 14 (20.3) N=137 N=69 0 5 10 15 20 25 30 35 Time, months 0.0 0.2 0.4 0.6 0.8 1.0 Pr ob ab ili ty o f P FS 3 months 6 months 12 months Ozekibart Placebo 70.1% 21.7% 40.9% 16.9% 9.7% 47.2%
19 INBRX-109 IDH mutation status Wild type Mutant Prior treatment Yes No Histologic grade at entry 2 3 Disease status at entry Metastatic Nonmetastatic unresectable Region US Outside of US Age <65 years ≥65 years Sex Male Female Race White Other BMI <30 kg/m2 ≥30 kg/m2 ECOG PS 0 1 Progression-free survival by CIRR: subgroup analyses Data cutoff date: September 30, 2025. a N values represent the number of patients with available data for each parameter. BMI, body mass index; CIRR, central independent radiology review; ECOG PS, Eastern Cooperative Oncology Group performance status; HR, hazard ratio; CI, confidence interval; IDH, isocitrate dehydrogenase; mPFS, median progression-free survival. PFS benefit was consistent across key prespecified subgroups, including IDH mutation status & prior therapy favors Ozekibart 0 1 2 3 Ozekibart Placebo Events, n/Na mPFS, mo Events, n/Na mPFS, mo HR (95% CI) 65/93 5.5 38/47 2.7 0.493 (0.324-0.750) 29/44 5.5 17/22 2.3 0.442 (0.224-0.871) 38/58 5.3 21/28 2.7 0.546 (0.307-0.971) 56/79 7.4 34/41 2.7 0.441 (0.280-0.693) 65/96 7.2 36/48 2.7 0.485 (0.316-0.747) 29/41 5.3 19/21 1.4 0.464 (0.246-0.875) 87/122 5.5 47/56 1.5 0.424 (0.288-0.624) 7/15 5.5 8/13 5.4 0.675 (0.199-2.286) 42/65 7.6 24/32 2.0 0.517 (0.288-0.928) 52/72 4.3 31/37 2.7 0.524 (0.316-0.870) 68/104 7.4 40/52 2.6 0.398 (0.257-0.615) 26/33 5.3 15/17 2.7 0.476 (0.217-1.047) 69/96 5.4 37/42 2.7 0.545 (0.353-0.840) 25/41 7.6 18/27 2.6 0.270 (0.123-0.592) 75/114 5.5 38/47 2.7 0.546 (0.358-0.835) 19/23 7.4 17/22 2.7 0.348 (0.148-0.818) 76/112 5.6 43/53 2.6 0.499 (0.333-0.747) 18/25 4.3 12/16 2.7 0.472 (0.156-1.423) 33/51 7.6 23/29 2.7 0.404 (0.215-0.758) 60/85 5.5 32/39 2.7 0.515 (0.319-0.830)
20 INBRX-109 Patients with ≥1 AE (including unrelated AEs), n (%) 129 (94.9) 62 (92.5) Grade ≥3 53 (39.0) 17 (25.4) SAE 38 (27.9) 12 (17.9) HAE 21 (15.4) 9 (13.4) Resulting in death 5 (3.7) 1 (1.5) Patients with ≥1 treatment-related AE, n (%) 77 (56.6) 32 (47.8) Grade ≥3 14 (10.3) 1 (1.5) SAE 8 (5.9) 0 HAE 16 (11.8) 3 (4.5) Leading to interruption of study drug 8 (5.9) 2 (3.0) Leading to discontinuation of study drug 4 (2.9) 0 Resulting in death 1 (0.7) 0 Overall safety data Placebo Data cutoff date: September 30, 2025. AE, adverse event; HAE, hepatic adverse event; SAE, serious adverse event. HAEs included alanine aminotransferase increased, aspartate aminotransferase increased, bile duct stone, bilirubin conjugated increased, blood alkaline phosphatase increased, blood bilirubin increased, feces discolored, gamma-glutamyl transferase increased, hepatic failure, hyperbilirubinemia, hypertransaminasemia, and liver disorder. Double-blind period Ozekibart N=136 N=67
21 INBRX-109 Phase 1/2 colorectal adenocarcinoma in combination with FOLFIRI Safety: well-tolerated with the most common treatment-related adverse events to include diarrhea, fatigue, and nausea with the majority being low-grade and consistent with the known safety profile of FOLFIRI. 68% of patients presented with liver metastases prior to treatment and no significant liver toxicity issues were observed in these patients. + ~70% are 4th line & ~30% are 3rd line + ~80% have received prior IRI-containing regiment Disease control rate was 87% as measured by RECISTv1.1. 87% Objective response rate was 20% as measured by RECISTv1.1. 20% 45 patients evaluable for response: Median progression free survival was 5.5 months 5.5 42% of patients remained progression-free at the 6-month mark 42% Data cutoff: April 10, 2026. • LA/M, unresectable, R/R colorectal adenocarcinoma • Aged 18 to <85 years • 2-3 prior lines of systemic therapy Key inclusion criteria CRC 3-4L with FOLFIRI Ozekibart 3 mg/kg + FOLFIRI (FU, 2400 mg/m2; leucovorin, 400 mg/m2; IRI, 180 mg/m2) N=50
22 INBRX-109 Data cutoff: April 10, 2026. CR, complete response; PD, progressive disease; PR, partial response; SD, stable disease; NA, censored. Individual patient time on treatment shows sustained disease control in heavily pre- treated patients Phase 1/2 colorectal adenocarcinoma in combination with FOLFIRI 0 1 2 3 4 5 7 8 9 10 11 13 14 15 16 17 19 206 12 18 2 lines of prior therapy 3 or more lines of prior therapy Durable responder Response start Response end Progressive disease Patient died Patient censored Ongoing Progression Free Patient Prior Treatment Status: Months CR PR SD PR SD PR SD SD SD SD PR SD SD SD SD SD PR SD SD SD SD SD PR SD PR SD SD SD SD SD SD SD SD SD SD SD SD PR SD PD PD PD PD PD PD NA NA NA NA NA
23 INBRX-109 Data cutoff: April 10, 2026. PD, progressive disease; PR, partial response; a Per RECIST v1.1 20% target lesion growth indicates progressive disease. b Per RECIST v1.1 30% shrinkage of target lesions indicates a partial response contingent on the status of the non-target lesions and the presence of new lesions. 40 20 0 -20 -40 -60 -80 -100 -100 -76 -54-53 -44 -37 -34 -31-31-31 -28 -25-23-22-21-21 -17-16-16-15-14 -11-10 -7-6 -4-3-3-3-3 55 11 17 22 2526 32 PDa PRb Ch an ge fr om B as el in e, % Prior treatment status: 2 lines of prior therapy 3 or more lines of prior therapy Phase 1/2 colorectal adenocarcinoma in combination with FOLFIRI Benchmarks ORR (%) Lonsurf + bev (SUNLIGHT, 2023) 6.1 regorafenib (CORRECT, 2013) 1.0 fruquintinib (FRESCO-2, 2023) 1.5 20% Objective Response rate
24 INBRX-109 Ongoing phase 1/2 trial in Ewing sarcoma in combination with IRI/TMZ • LA/M, unresectable, R/R EWS • Aged ≥12 to <85 years • EWSR1-FLI1, -ERG or -FEV rearrangement • 1-2 prior lines of chemotherapy in metastatic setting • Prior IRI + TMZ allowed Key inclusion criteria EWS 2-3L with IRI/TMZ Ozekibart 3 mg/kg + IRI 50 mg/m2/day + TMZ 100 mg/m2/day N=50 Expected outcomes with current SoC Treatment Study Type ORR (%) PFS (months) Irinotecan + Temozolomide Phase 2 / single-arm ~15–30 3–4 HD Ifosfamide Phase 2 / rEECur ~20–25 5.7
25 INBRX-109 Updated data from expansion cohort: Ewing sarcoma in combination with IRI/TMZ Data cutoff: January 15, 2026, as presented at the ESMO Sarcoma and Rare Cancers Annual Congress. PD, progressive disease; PR, partial response; ORR, objective response rate; DCR, disease control rate Recruitment ongoing 39 patients dosed with 31 patients currently evaluable for response: N=31 Disease control rate was 87.1%, or 27 out of 31 patients, as measured by RECISTv1.1. 87.1% Objective response rate was 64.5%, or 20 out of 31 patients, as measured by RECISTv1.1. 64.5% Safety: well-tolerated with the most common adverse events were diarrhea, nausea, anemia, and fatigue, all consistent with the known safety profile of IRI/TMZ. 100 60 0 -40 -100 Ch an ge fr om b as el in e, % 80 40 20 -20 -60 -80 Progressive disease Partial response Prior IRI/TMZ Treatment No Yes
26 INBRX-109 0 7 14 21 28 35 42 49 0 20 40 60 80 100 0 20 40 60 80 100 0 7 14 21 28 35 42 49 56 63 70 77 84 0 20 40 60 80 100 y 0 2 4 6 8 10 12 7.4 1.1 0 7 14 21 28 35 42 49 56 63 70 77 0 20 40 60 80 100 Vehicle INBRX-1 TMZ INBRX-1 -25 0 25 50 75 100 0 20 40 60 80 [TMZ] (∝M) Ozekibart exhibits anti-tumor activity in GBM models as monotherapy and in combination with TMZ In vitro cytotoxicity GBM cell lines + In all tested intracranial PDX tumor mouse models, ozekibart monotherapy significantly enhanced survival + In 2 of 3 PDX models, combination treatment with ozekibart and TMZ led to a greater survival benefit than TMZ alone In vitro cytotoxicity U-87 MG INBRX-109 only (1nM) Intracranial U-87 MG Survival analysis Intracranial U-87 MG Survival analysis + Combination treatment with ozekibart and temozolomide (TMZ) induced greater in vitro cell death than TMZ alone for a majority of GBM cell lines tested (n=31) + In the intracranial U-87 MG tumor mouse model, combination treatment demonstrated superior tumor control and enhanced survival compared to TMZ alone Human GBM cell line models Human GBM patient-derived xenograft (PDX) models* Intracranial GBM44 Survival analysis Intracranial GBM38 Survival analysis Intracranial GBM39 Survival analysis *p = 0.002, INBRX-109 vs vehicle ** p – 0.004, combo vs TMZ *p = 0.03, INBRX-109 vs vehicle ** p – 0.01, combo vs TMZ *p = 0.009, INBRX-109 vs vehicle *In collaboration with Jann Sarkaria, M.D., Mayo Clinic % c el l d ea th % c el l d ea th Pr ob ab ili ty o f S ur vi va l Fo ld c ha ng e fr om b as el in e Pr ob ab ili ty o f S ur vi va l Pr ob ab ili ty o f S ur vi va l Pr ob ab ili ty o f S ur vi va l Study Day Study DayStudy Day MEDIAN SURVIVAL (d) Treatment GBM38 GBM39 GBM44 Vehicle 17 22 42 INBRX-109 25 33 58 TMZ 33 n.d. 39 Combo 42 n.d. 74 Study Day TMZ + 1 nM INBRX-109 TMZ INBRX-109 Vehicle INBRX-109 + TMZ TMZ
Investor Relations: KELLY DECK, CPA CFO 11025 N. Torrey Pines Road Suite 140 La Jolla, CA 92037 858.795.4260 ir@inhibrx.com
FAQ
What interim Phase 2 results did Inhibrx (INBX) report for INBRX-106 in first-line HNSCC?
Inhibrx reported that INBRX-106 plus pembrolizumab achieved a 44.0% confirmed objective response rate in evaluable first-line high–PD-L1 HNSCC patients, versus 21.4% with pembrolizumab alone. The combination arm also produced three complete responses, while none occurred in the monotherapy control arm.
How do the INBRX-106 Phase 2 data support its mechanism of action?
Peripheral blood analyses showed up to a 15-fold increase in CD8+ and CD4+ T‑cell proliferation and up to a four-fold increase in activation with INBRX-106 plus pembrolizumab. Patients on pembrolizumab alone showed up to 2.5-fold and 1.5-fold increases, respectively, supporting INBRX-106’s role as a potent T‑cell costimulator.
What was the safety profile of INBRX-106 combined with pembrolizumab in the HexAgon study?
The combination of INBRX-106 and pembrolizumab showed a generally manageable safety profile consistent with immunotherapy combinations. The most common treatment-related adverse events were rash, diarrhea, fatigue and infusion-related reactions, predominantly low‑grade, and no treatment-related deaths were reported in either treatment arm.
What are Inhibrx’s next clinical milestones for INBRX-106 according to the 8-K?
Inhibrx expects progression‑free survival data from the Phase 2 HexAgon study in the fourth quarter of 2026 and plans to start the Phase 3 portion in the third quarter of 2026. The company also plans a perioperative non‑small cell lung cancer study later this quarter and front‑line metastatic NSCLC studies beginning in 2027.
How large is the potential market Inhibrx targets with INBRX-106?
The company estimates the market for treating high–PD-L1 head and neck squamous cell carcinoma at about $1 billion and the non‑small cell lung cancer market at roughly $25 billion. Additional checkpoint‑inhibitor indications add about $25 billion, totaling approximately $50 billion in potential market opportunity.
What is the design focus of the HexAgon study evaluating INBRX-106?
HexAgon is modeled after KEYNOTE-048 and randomizes first-line PD-L1 CPS ≥20 metastatic or unresectable recurrent HNSCC patients to INBRX-106 plus pembrolizumab versus pembrolizumab alone. The design focuses on high PD-L1 expressers to sharpen detection of any added benefit over PD-1 monotherapy.