Inhibrx combo posts 48% responses in Phase 2 HNSCC
Inhibrx Biosciences, Inc. (INBX) reported positive randomized Phase 2 data from its HexAgon study of INBRX-106 plus pembrolizumab in first-line PD-L1–positive metastatic or unresectable recurrent HNSCC.
Rhea-AI Filing Summary
Inhibrx Biosciences, Inc. (INBX) reported positive randomized Phase 2 data from its HexAgon study of INBRX-106 plus pembrolizumab in first-line PD-L1–positive metastatic or unresectable recurrent HNSCC. Among 63 evaluable patients at an August 19, 2026 cutoff, the combination achieved a confirmed objective response rate of 48.3% versus 26.5% for pembrolizumab alone, including complete responses in 13.8% of combination patients and none on monotherapy.
Median progression-free survival was 9.6 months for the combination versus 4.9 months for pembrolizumab, with six‑month PFS rates of 72.4% and 42.8%, respectively. In HPV+ patients, cORR was 80.0% vs 33.3%, with 30.0% complete responses and 90.0% six‑month PFS for the combination versus 0% complete responses and 33.0% six‑month PFS for pembrolizumab. The combination’s safety profile was generally manageable, with mostly low‑grade rash, fatigue, and diarrhea.
Based on these results, Inhibrx plans to expand the randomized Phase 2 portion of HexAgon by approximately 50 additional HPV+ OPSCC patients (CPS ≥ 1) to support a potential accelerated regulatory pathway, then initiate a Phase 3 confirmatory trial after alignment with the FDA. INBRX-106 is also being studied in a Phase 1/2 perioperative NSCLC trial with an initial data readout targeted by mid‑2027 and is being positioned for broader use in highly immunogenic tumors and in combination with therapeutic cancer vaccines.
Positive
- INBRX-106 plus pembrolizumab showed stronger efficacy than pembrolizumab alone, with 48.3% cORR vs 26.5% and median PFS of 9.6 vs 4.9 months in first-line PD-L1–positive metastatic or unresectable recurrent HNSCC.
- Efficacy in HPV+ patients was particularly high, with 80.0% cORR, 30.0% complete responses, and 90.0% six‑month PFS for the combination vs 33.3% cORR, 0% complete responses, and 33.0% six‑month PFS for pembrolizumab alone.
- Regulatory and pipeline expansion steps are defined: Inhibrx plans to add about 50 HPV+ OPSCC patients to Phase 2 to support a potential accelerated approval pathway and then initiate a Phase 3 confirmatory trial, while also running a Phase 1/2 perioperative NSCLC study targeting an initial readout by mid‑2027.
Negative
- None.
Filing Explained
The September 8 8-K reports an interim Phase 2 primary-endpoint analysis using an
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, or exhibit attachments filed with this report.
Key Figures
Confirmed objective response rate (all evaluable patients): 48.3% vs 26.5%
Complete response rate (all evaluable patients): 13.8% vs 0%
Median progression-free survival: 9.6 months vs 4.9 months
+5 more
8 metrics
Confirmed objective response rate (all evaluable patients)
48.3% vs 26.5%
INBRX-106 plus pembrolizumab vs pembrolizumab alone in first-line PD-L1–positive metastatic or unresectable recurrent HNSCC
Complete response rate (all evaluable patients)
13.8% vs 0%
INBRX-106 plus pembrolizumab vs pembrolizumab alone
Median progression-free survival
9.6 months vs 4.9 months
INBRX-106 plus pembrolizumab vs pembrolizumab alone at August 19, 2026 cutoff
Six-month PFS rate (all evaluable patients)
72.4% vs 42.8%
INBRX-106 plus pembrolizumab vs pembrolizumab alone
HPV+ confirmed objective response rate
80.0% vs 33.3%
HPV+ patients, INBRX-106 plus pembrolizumab vs pembrolizumab alone
HPV+ complete response rate
30.0% vs 0%
HPV+ patients, INBRX-106 plus pembrolizumab vs pembrolizumab alone
HPV+ six-month PFS rate
90.0% vs 33.0%
HPV+ patients, INBRX-106 plus pembrolizumab vs pembrolizumab alone
Planned Phase 2 expansion size
Approximately 50 patients
Additional HPV+ OPSCC patients (CPS ≥ 1) to be added to the HexAgon Phase 2 portion
Key Terms
confirmed objective response rate, progression-free survival, hexavalent OX40 agonist, HPV+ Oropharyngeal Squamous Cell Carcinoma, +2 more
6 terms
confirmed objective response rate medical
"demonstrated a confirmed objective response rate (cORR) of 48.3% for INBRX-106"
progression-free survival medical
"As of the data cutoff, median PFS was 9.6 months for INBRX-106"
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.
hexavalent OX40 agonist medical
"INBRX-106, a hexavalent OX40 agonist, in combination with pembrolizumab"
HPV+ Oropharyngeal Squamous Cell Carcinoma medical
"expand the randomized Phase 2 portion ... by approximately 50 additional HPV+ Oropharyngeal Squamous Cell Carcinoma"
accelerated regulatory pathway regulatory
"to support a potential accelerated regulatory pathway"
An accelerated regulatory pathway is a government process that shortens the usual review and approval steps for drugs, devices, or diagnostics that show promise for treating serious or unmet medical needs, allowing approvals based on earlier or smaller sets of data. For investors, it can bring a product to market faster and create earlier revenue potential, but it also raises higher clinical and regulatory risk because long‑term evidence may still be required after approval.
perioperative medical
"Phase 1/2 study of INBRX-106 in the perioperative setting of non-small cell lung cancer"
Pertaining to the entire span around a surgical operation — before, during and after the procedure — covering preparation, anesthesia, monitoring and recovery. Investors watch perioperative care because it shapes how often hospitals use devices, drugs and services, affects complication rates and patient stay length, and therefore influences revenue, costs and reimbursement risk; think of it like the full service cycle around a car repair that determines how long the shop is busy and what customers pay.
FAQ
What did INBX report for the Phase 2 HexAgon trial of INBRX-106 in HNSCC?
Inhibrx reported that INBRX-106 plus pembrolizumab achieved a 48.3% confirmed objective response rate vs 26.5% for pembrolizumab alone, and median progression-free survival of 9.6 months vs 4.9 months in first-line PD-L1–positive metastatic or unresectable recurrent HNSCC.
How did INBRX-106 perform in HPV+ HNSCC patients for INBX?
In HPV+ patients, the INBRX-106 combination arm showed a cORR of 80.0% vs 33.3% for pembrolizumab alone, with 30.0% achieving complete responses vs 0% on monotherapy, and 90.0% six‑month PFS vs 33.0% for pembrolizumab.
What safety profile did INBRX-106 show in the HexAgon study for INBX?
The combination of INBRX-106 and pembrolizumab was described as generally manageable. The most common treatment-related adverse events were rash, fatigue, and diarrhea, which were predominantly low grade.
What expansion plans does INBX have for the HexAgon trial of INBRX-106?
Inhibrx plans to expand the randomized Phase 2 portion of HexAgon by approximately 50 additional HPV+ OPSCC patients (CPS ≥ 1) to support a potential accelerated regulatory pathway, then align with the FDA and initiate a Phase 3 confirmatory study.
Beyond HNSCC, what other indications is INBX targeting with INBRX-106?
Inhibrx is conducting a Phase 1/2 perioperative NSCLC study of INBRX-106, with initial results targeted by mid‑2027, and plans to evaluate INBRX-106 in other highly immunogenic tumors and in combination with therapeutic cancer vaccines.
What was the data cutoff date and sample size for the primary analysis reported by INBX?
The primary endpoint analysis used a data cutoff of August 19, 2026 and included 63 evaluable patients from 68 randomized, with 29 in the INBRX-106 plus pembrolizumab arm and 34 in the pembrolizumab monotherapy arm.
AI-generated analysis. How Rhea-AI works. Not financial advice.
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): September 8, 2026
(Exact name of registrant as specified in its charter)
| (State or other jurisdiction of incorporation) | (Commission File Number) | (IRS Employer Identification No.) | ||||||||||||
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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:
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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 September 8, 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 (HNSCC), 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.
The information in Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.1 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.
Updated Phase 2 Data for INBRX-106 in First-Line HNSCC
On September 8, 2026, Inhibrx announced the primary endpoint results from the randomized and controlled Phase 2 portion of its HexAgon study, which is evaluating 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 HNSCC. Baseline prognostic factors were largely balanced between the two arms, and the study is being conducted at more than 80 sites in the United States, Europe and Asia. The Phase 2 portion of the HexAgon study included a total of 68 randomized patients, 63 of whom were evaluable for the primary endpoint analysis, including 29 patients in the combination arm (10 of which were HPV+) and 34 patients in the control arm (nine of which were HPV+).
The primary endpoint analysis, which had a data cutoff of August 19, 2026, demonstrated a confirmed objective response rate (cORR) of 48.3% for INBRX-106 plus pembrolizumab compared with 26.5% for pembrolizumab alone. Four patients (13.8%) in the combination arm achieved a complete response compared with no complete responses in the control arm. Median progression-free survival (PFS) continues to mature. As of the data cutoff, median PFS was 9.6 months for INBRX-106 plus pembrolizumab compared with 4.9 months for pembrolizumab alone, with six-month PFS rates of 72.4% and 42.8%, respectively.
The efficacy signal was particularly pronounced in patients with HPV+ disease, where the combination arm demonstrated an 80.0% cORR compared with 33.3% for pembrolizumab alone. Notably, 30.0% of the HPV+ patients treated in the combination arm achieved a complete response, compared with no complete responses in the control arm. Also, 90.0% of patients receiving INBRX-106 plus pembrolizumab remained progression-free at six months compared with 33.0% who were receiving pembrolizumab alone. As of the data cutoff, median PFS in the combination arm in patients with HPV+ disease had not yet been reached compared with 4.6 months for pembrolizumab alone.
The combination of INBRX-106 and pembrolizumab was generally manageable. The most common treatment-related adverse events were rash, fatigue, and diarrhea, which were predominantly low grade.
Based on these results, Inhibrx plans to expand the randomized Phase 2 portion of the HexAgon trial by approximately 50 additional HPV+ Oropharyngeal Squamous Cell Carcinoma (OPSCC) patients (CPS ≥ 1), to support a potential accelerated regulatory pathway. Following the Phase 2 expansion, the Company plans to align with the U.S. Food and Drug Administration on this framework and initiate the Phase 3 portion of the HexAgon trial, which is intended to serve as the confirmatory study. These results also position OX40 agonism as a promising treatment approach beyond recurrent/metastatic disease, with potential to extend durable, T-cell driven antitumor activity into earlier-stage HPV+ OPSCC.
Beyond HNSCC, Inhibrx is evaluating the potential of INBRX-106 in other highly immunogenic tumor types. The Company is currently conducting a Phase 1/2 study of INBRX-106 in the perioperative setting of non-small cell lung cancer (NSCLC), with initial results targeted by mid-2027. This readout is expected to provide important clinical insights to inform future development, demonstrating the potential for INBRX-106 to extend well beyond head and neck cancer into not only perioperative lung cancer, but broader solid tumor indications.
The Company also plans to explore the potential of INBRX-106 in combination with therapeutic cancer vaccines. The clinical activity and T-cell responses observed with INBRX-106 in HPV+ disease demonstrate its ability to amplify antigen-driven T-cell responses, providing strong scientific justification for cancer vaccine combination strategies.
Corporate Presentation
On September 8, 2026, Inhibrx posted an updated copy of its corporate presentation to the “Investors” tab of its website at www.inhibrx.com. A copy of this corporate presentation is filed as Exhibit 99.2 and is incorporated herein by reference. 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.
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 or other indications; the clinical development of INBRX-106, including expected enrollment in an expansion cohort, data readouts, initiation of additional clinical trials, regulatory submissions and interactions, and the timing thereof; the potential accelerated approval; any presumption that topline, interim or preliminary data will be representative of final data or data in later clinical trials; and Inhibrx’s plans to evaluate INBRX-106 across broader indications and to explore combinations with other therapies. 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; an accelerated development or approval pathway may not be available for INBRX-106 or other therapeutic candidates and any such pathway may not lead to a faster development process; 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 September 8, 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: September 8, 2026 | ||||||||
| INHIBRX BIOSCIENCES, INC. | ||||||||
| By: | /s/ Kelly Deck | |||||||
| Name: | Kelly Deck | |||||||
| Title: | Chief Financial Officer | |||||||
Exhibit 99.1
Inhibrx’s INBRX-106 Nearly Doubles Response Rate and Achieves Interim Median PFS of 9.6 months in Phase 2 HNSCC Study
First OX40 agonist to demonstrate clinical benefit in a randomized study
•INBRX-106 plus pembrolizumab delivers a 48.3% cORR and 72.4% of patients remain progression free at 6 months, compared with 26.5% and 42.8% for pembrolizumab alone
•Results are most pronounced in HPV+ patients, with cORR (80.0% vs 33.3%), CR rate (30.0% vs 0%), and PFS6 improvement (90.0% vs 33.0%) vs pembrolizumab alone
•Inhibrx will expand the Phase 2 study by approximately 50 HPV+ patients and may serve as a potential pathway to accelerated approval
•Positive results support large expansion opportunities into highly immunogenic tumors and combination with cancer vaccines
SAN DIEGO, CA — September 8, 2026 — Inhibrx Biosciences, Inc. (Nasdaq: INBX) (“Inhibrx” or the “Company”), a clinical-stage biopharmaceutical company focused on developing a broad pipeline of novel biologic therapeutic candidates, today announced the primary endpoint results from the randomized and controlled Phase 2 portion of the HexAgon study, which is evaluating 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). Baseline prognostic factors were largely balanced between the two arms, and the study is being conducted at more than 80 sites in the United States, Europe and Asia. The Phase 2 portion of the HexAgon study included a total of 68 randomized patients, 63 of whom were evaluable for the primary endpoint analysis, including 29 patients in the combination arm (10 of which were HPV+) and 34 patients in the control arm (nine of which were HPV+).
The primary endpoint analysis, which had a data cutoff of August 19, 2026, demonstrated a confirmed objective response rate (cORR) of 48.3% for INBRX-106 plus pembrolizumab compared with 26.5% for pembrolizumab alone. Four patients (13.8%) in the combination arm achieved a complete response compared with no complete responses in the control arm. Median progression-free survival (PFS) continues to mature. As of the data cutoff, median PFS was 9.6 months for INBRX-106 plus pembrolizumab compared with 4.9 months for pembrolizumab alone, with six-month PFS rates of 72.4% and 42.8%, respectively.
The efficacy signal was particularly pronounced in patients with HPV+ disease, where the combination arm demonstrated an 80.0% cORR compared with 33.3% for pembrolizumab alone. Notably, 30.0% of the HPV+ patients treated in the combination arm achieved a complete response, compared with no complete responses in the control arm. The durability of the benefit was also particularly striking, with 90.0% of patients receiving INBRX-106 plus pembrolizumab remaining progression-free at six months compared with 33.0% who were receiving pembrolizumab alone. As of the data cutoff, median PFS in the combination arm in patients with HPV+ disease had not yet been reached compared with 4.6 months for pembrolizumab alone.
The combination of INBRX-106 and pembrolizumab was generally manageable. The most common treatment-related adverse events were rash, fatigue, and diarrhea, which were predominantly low grade.
“What is most exciting to us is the depth and durability of the responses we are seeing with INBRX-106, particularly in HPV+ disease,” said Mark Lappe, co-founder and Chief Executive Officer of Inhibrx. “These results strengthen our conviction in OX40-mediated T-cell costimulation and give us a strong rationale to expand the program, not only into HPV+ disease, but also to explore the potential of INBRX-106 in other highly immunogenic tumors and in combination with cancer vaccines.”
Based on these results, Inhibrx plans to expand the randomized Phase 2 portion of the HexAgon trial by approximately 50 additional HPV+ Oropharyngeal Squamous Cell Carcinoma (OPSCC) patients (CPS ≥ 1), to support a potential accelerated regulatory pathway. Following the Phase 2 expansion, the Company plans to align with the FDA on this framework and initiate the Phase 3 portion of the HexAgon trial, which is intended to serve as the confirmatory study. These results also position OX40 agonism as a promising treatment approach beyond recurrent/metastatic disease, with potential to extend durable, T-cell driven antitumor activity into earlier-stage HPV+ OPSCC.
Beyond HNSCC, Inhibrx is evaluating the potential of INBRX-106 in other highly immunogenic tumor types. The Company is currently conducting a Phase 1/2 study of INBRX-106 in the perioperative setting of non-small cell lung cancer (NSCLC), with initial results targeted by mid-2027. This readout is expected to provide important clinical insights to inform future development, demonstrating the potential for INBRX-106 to extend well beyond head and neck cancer into not only perioperative lung cancer, but broader solid tumor indications.
The Company also plans to explore the potential of INBRX-106 in combination with therapeutic cancer vaccines. The clinical activity and T-cell responses observed with INBRX-106 in HPV+ disease demonstrate its ability to amplify antigen-driven T-cell responses, providing strong scientific justification for cancer vaccine combination strategies.
The Company will host a live webcast presentation today, September 8, 2026, at 5:00 a.m. Pacific Time to further discuss the results. The webcast will also include a slide presentation of the data, which is also incorporated into the Company’s investor deck accessible at https://inhibrx.com/inhibrx-biosciences-inc-investors/.
About the Conference Call
Investors may join via the web: https://app.webinar.net/4712m15mpwW or may listen to the call by dialing (1-888-880-3330). Please refer to Inhibrx Biosciences, Inc. or the conference ID 6981384 when calling in. The webcast will also include a slide presentation of the data, which is also incorporated into the Company’s investor deck accessible at https://inhibrx.com/inhibrx-biosciences-inc-investors/. Following the webcast, the presentation may be accessed through a link on the “Events and Presentations” section of Inhibrx’s website. The webcast will be available for 60 days following the event. Inhibrx will also update its corporate presentation within the “Investors” section of its website at www.inhibrx.com.
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.
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 or other indications; the clinical development of INBRX-106, including expected enrollment in an expansion cohort, data readouts, initiation of additional clinical trials, regulatory submissions and interactions, and the timing thereof; the potential accelerated approval; any presumption that topline, interim or preliminary data will be representative of final data or data in later clinical trials; and Inhibrx’s plans to evaluate INBRX-106 across broader indications and to explore combinations with other therapies. 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; an accelerated development or approval pathway may not be available for INBRX-106 or other therapeutic candidates and any such pathway may not lead to a faster development process; 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
P R OP R IE TAR Y AN D C ON FID E N TI A L; N OT FOR D IS TR IB U TION INBRX-106 Investor Overview September 2026
2 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, the potential accelerated approval, potential revenue realization, 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 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. These forward-looking statements involve substantial known and unknown business, economic, competitive and other 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 and there can be no guarantee as to the accuracy or reliability of such assumptions. While the Company believes these third-party sources to be reliable as of the date of this presentation, it has not independently verified, and makes no representation as to the adequacy, fairness, accuracy or completeness of, any information obtained from third-party sources. While the Company believes its own internal research is reliable, such research has not been verified by any independent source. 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. Presentation disclaimer
3 INBRX-106 • ORR: 80% vs 33% • CR Rate: 30% vs 0% • PFS Data: NR vs 4.6 months • PFS6 Rate: 90% vs 33% • Expansion of Phase 2 to include 50 additional HPV+ patients may serve as potential path to accelerated approval by end of ‘28/early ‘29. HPV+ HNSCC is an open $4B+ market INBRX-106 executive summary Combination with pembro demonstrates superiority to pembro mono in 1LR/M HNSCC Potentially practice-changing efficacy profile in HPV+ patients Large expansion opportunity in highly immunogenic tumors Potential for new paradigm of treatment with cancer vaccines INBRX-106 is the first clinically active OX40 agonist and T-cell costimulatory therapy • ORR: 48.3% vs 26.5% • Depth of Response • CR Rate: 13.8% vs 0% • PFS: 9.6 months vs 4.9 months • PFS6 Improvement: (72.4% vs. 42.8%) • These data are supported by superior t-cell proliferation (up to 15-fold increase) and activation (up to 4-fold increase) vs pembrolizumab alone • Bladder, NSCLC, Melanoma, MSI High/TMB High, TNBC present $50B+ commercial opportunity • Ongoing neoadjuvant lung cancer study serves as proof of concept for broad expandability with pembrolizumab across highly immunogenic tumors • Potential $50B+ market • HPV+ HNSCC data and over 20 years of academic research support the strong mechanistic rationale of INBRX-106 +cancer vaccines (OX40 agonism potency when foreign antigen is presented)
4 INBRX-106 T-cell activation critical steps: 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 Dual Immunotherapy: Releasing the Brakes and Stepping on the Gas Patients must have an immune response to their tumor(s) for signal 2 and check point inhibition to be impactful 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 Optimized T cell activation by OX40 agonism and PD-1 blockade 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
5 INBRX-106 0 500 1000 1500 2000 2500 0.01 1 100 10000 M ea n Va lu e Conc AB (ng/ml) Bivalent OX40 Agonist (Roche Analog) Hexavalent INBRX-106 Underwhelming activity among the 1st generation of bivalent OX40 therapeutics leads to INBRX-106 hexavalent OX40 JITC Providence Publication Hyper- clustering 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) Bivalent OX40 Agonists Insufficient T-cell activation Suboptimal target engagement Bivalent IgG formats fail to drive high-order OX40 clustering required for co-stimulatory signaling Weak clustering impairs signaling and stalls proliferation Limitations of bivalent attempts Hexavalent OX40 Agonist Advantages of INBRX-106 format High-order OX40 clustering leads to stronger signal potency 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 High-order OX40 clustering by INBRX-106 Low-order OX40 clustering by bivalent OX40 agonist Next Generation
6 INBRX-106 Head-to-head study serves as proof of concept, validating INBRX-106 Initial Study Design of HexAgon: Seamless Phase 2/3 study in 1L R/M HNSCC with PD-L1 CPS ≥20 Randomization stratified by: Disease status (locoregional advanced vs metastatic), HPV status (positive vs negative), ECOG PS (0 vs 1). In KEYNOTE-048, pembrolizumab achieved an ORR of 23.3% in the PD-L1 CPS ≥ 20 HNSCC population 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. Phase 3, Double blind Survival Follow-up INBRX-106 + Pembro Pembro Co-primary endpoint: PFS and OS Secondary endpoints: ORR, DOR, CBR, TTCx, safety, PROs R 1:1 Primary Criteria: ORR Secondary Criteria: + DOR + CBR + PFS6m + Safety Phase 2, Open label INBRX-106 + Pembro Pembro Key inclusion criteria: R/M HNSCC PD-L1 CPS ≥20 HPV status confirmed No prior systemic Tx for R/M HNSCC R 1:1 Original Goals of HexAgon-HN Design - Contribution of components - Randomized add-on (106 + pembro vs pembro) cleanly isolates the benefit added by 106, aligns with regulatory expectations - Seamless Phase 2/3- fastest path to market
7 INBRX-106Baseline characteristics Baseline characteristics (randomized population)* 106 + Pembro N=33 Pembro N=35 Total N=68 Median age, y (min, max) 62.0 (35, 80) 66.0 (44, 89) 64.5 (35, 89) Age ≥65y, n (%) 13 (39.4) 21 (60.0) 34 (50.0) Male, n (%) 30 (90.9) 28 (80.0) 58 (85.3) ECOG PS 1, n (%) 17 (51.5) 18 (51.4) 35 (51.5) Distant metastatic disease, n (%) 18 (54.5) 21 (60.0) 39 (57.4) HPV positive, n (%) 10 (30.3) 9 (25.7) 19 (27.9) PD-L1 CPS ≥50, n (%) 24 (72.7) 23 (65.7) 47 (69.1) Prior systemic therapy, n (%)** 21 (63.6) 19 (54.3) 40 (58.8) Arms overall well-balanced *Median follow-up: 8.02 months (INBRX-106 + Pembrolizumab) vs. 6.31 months (Pembrolizumab). ** Systemic therapy received in the curative setting
8 INBRX-106 Most common TRAEs 106+Pembro All 106+Pembro ≥G3 Pembro All Pembro ≥G3 Rash maculo-papular 10 (32.3) 3 (9.7) 4 (11.8) 0 Rash 10 (32.3) 1 (3.2) 0 0 Fatigue 9 (29.0) 1 (3.2) 4 (11.8) 1 (2.9) Diarrhea 9 (29.0) 3 (9.7) 2 (5.9) 0 ALT increased 8 (25.8) 2 (6.5) 3 (8.8) 1 (2.9) AST increased 7 (22.6) 1 (3.2) 3 (8.8) 1 (2.9) Infusion related reactions 7 (22.6) 1 (3.2) 0 0 Safety & tolerability *Safety population = patients who at least received one dose of study treatment **Data comparison of HexAgon to KN-048 is not from head-to-head study; cross-trial comparisons are limited by differences in study designs, populations, regimens and follow-up The most frequent related adverse events are rash, fatigue, and diarrhea which were mostly grade 1 and 2 Overall safety — HexAgon-HN vs published KEYNOTE-048 pembrolizumab-monotherapy arm** Patients with ≥1, n (%) (safety population)* INBRX-106 + Pembro N=31 Pembro (HexAgon) N=34 KN-048 Pembro mono N=300 TEAE, any grade 31 (100) 29 (85.3) 290 (96.7) SAE, any grade 12 (38.7) 12 (35.3) 123 (41.0) Grade ≥3 AE, any/related 18 (58.1) / 15 (48.4) 16 (47.1) / 4 (11.8) 164 (55) Grade 5 AE 0 2 (5.9) 25 (8) Tx discontinuation 11 (35.5) 5 (14.7) 15 (5.0) Most common TRAEs in HexAgon-HN ≥20%
9 INBRX-106INBRX-106+pembro drives up to 15-fold change in proliferation and up to 4-fold change in activation of T-cells vs. pembro mono 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. 0 1 2 3 4 5 Pembro INBRX-106 +Pembro M ax F ol d Ch an ge fr om Ba se lin e – % o f A ct iv at ed M em or y Ce lls 0 5 10 15 20 25 Pembro INBRX-106 +Pembro M ax F ol d Ch an ge fr om Ba se lin e – % o f A ct iv at ed M em or y Ce lls 0 5 10 15 20 25 Pembro INBRX-106 +Pembro M ax F ol d Ch an ge fr om Ba se lin e – % o f A ct iv at ed M em or y Ce lls 0 1 2 3 4 5 Pembro INBRX-106 +Pembro M ax F ol d Ch an ge fr om Ba se lin e – % o f A ct iv at ed M em or y Ce lls HexAgon Phase 2 – 1L HNSCC • 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 Proliferation Activation CD 8+ T c el ls CD 4+ T c el ls
10 INBRX-106Primary endpoint: Addition of INBRX-106 to pembro improves cORR Best % change in target lesion sum of diameters from baseline, RECIST v1.1. cORR = confirmed CR/PR on 2 consecutive occasions ≥4 weeks apart. Data from ongoing DB - CCOD 19 Aug 2026 * Evaluable population = Patients who have at least one post-baseline scan or have died or progressed INBRX-106 + Pembrolizumab Pembrolizumab ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ -100 -80 -60 -40 -20 0 20 40 ★ ★ ★ ★ ★ ★ ★ ★ -100 -80 -60 -40 -20 0 20 40 ■ CR ■ PR ■ SD ■ PD ★ Ongoing, progression-free 48.3% cORR — INBRX-106 + Pembro (n=29*) 95% CI 29.4–67.5 26.5% cORR — Pembro (n=34*) 95% CI 12.9–44.4 Δ +21.8 points Difference in cORR favoring INBRX-106 + Pembro
11 INBRX-106INBRX-106 improves overall durability & PFS across all patients *Median PFS still maturing; CCOD 19 Aug 2026 Bars show months of PFS follow-up, ranked longest to shortest, colored by best overall response. Data from ongoing DB - CCOD 19 Aug 2026. Note: Survival estimates are calculated using the Kaplan-Meier method. INBRX-106 + Pembrolizumab Pembrolizumab ■ CR ■ PR ■ SD ■ PD ★ Ongoing, progression-free 72.4% PFS at 6 months — INBRX-106 + Pembro 42.8% PFS at 6 months — Pembrolizumab ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ 0 2 4 6 8 10 12 14 16 18 20 ★ ★ ★ ★ ★ ★ ★ ★ 0 2 4 6 8 10 12 14 16 18 20 9.6 mo* Median PFS 4.9 mo Median PFS
12 INBRX-106Improved response & duration observed in HPV-negative patients *Median PFS still maturing; CCOD 19 Aug 2026. Note: Survival estimates are calculated using the Kaplan-Meier method. INBRX-106 + Pembrolizumab, HPV-negative Pembrolizumab, HPV-negative ■ CR ■ PR ■ SD ■ PD ★ Ongoing, progression-free 7.5 mo* Median PFS 5.1 mo Median PFS 63.2% PFS at 6 months, HPV-negative 31.6% cORR, HPV-negative (n=19) 46.8% PFS at 6 months, HPV-negative 24.0% cORR, HPV-negative (n=25) ★ ★ ★ ★ ★ ★ ★ 0 2 4 6 8 10 12 14 16 18 20 ★ ★ ★ ★ ★ 0 2 4 6 8 10 12 14 16 18 20
13 INBRX-106Increased benefit was observed in HPV+ patients Best % change in target lesion sum of diameters from baseline INBRX-106 + Pembrolizumab, HPV+ Pembrolizumab, HPV+ ■ CR ■ PR ■ SD ■ PD ★ Ongoing, progression-free 80.0% cORR, HPV+ INBRX-106 + pembro (n=10) 95% CI 44.4–97.5 33.3% cORR, HPV+ Pembrolizumab (n=9) 95% CI 7.5–70.1 Δ +46.7 points Difference in cORR, HPV+ INBRX-106+pembro vs. pembro mono 95% CI –2.7, 80.3 ★ ★ ★ ★ ★ ★ ★ ★ -110 -90 -70 -50 -30 -10 10 30 50 ★ ★ ★ -100 -80 -60 -40 -20 0 20 40
14 INBRX-106 ★ ★ ★ ★ ★ ★ ★ ★ 0 2 4 6 8 10 12 14 16 18 20 ★ ★ ★ 0 2 4 6 8 10 12 14 16 18 20 Enhanced durability & PFS observed in HPV+ patients *Median PFS still maturing; CCOD 19 Aug 2026. Bars show months of PFS follow-up, ranked longest to shortest, colored by best overall response. Data from ongoing DB - CCOD 19 Aug 2026. Note: Survival estimates are calculated using the Kaplan-Meier method. INBRX-106 + Pembrolizumab Pembrolizumab ■ CR ■ PR ■ SD ■ PD ★ Ongoing, progression-free 90% PFS at 6 months, HPV+ INBRX-106 + Pembro 33% PFS at 6 months, HPV+ Pembrolizumab Not reached* Median PFS 4.6 mo Median PFS
15 INBRX-106 Foreign viral antigen (E6/E7) driving a strong Signal 1, activated by OX40 co-stimulation on antigen-experienced T-cells Compelling Clinical Activity Attractive commercial opportunity: Potentially first dedicated HPV+ approval, differentiated from EGFR bispecifics (active mainly in HPV negative) Profound response-rate difference supports a potentially accelerated path to market The HPV+ signal is what the INBRX-106 mechanism predicts Opportunity to own HPV+ market Sound, mechanistic rationale High unmet need Potential for fast revenue realization Up to a 15-fold increase in peripheral CD8⁺/CD4⁺ T-cell proliferation and up to a 4-fold increase in activation (HexAgon-HN, interim Ph2) over ~2-fold pembrolizumab alone. 80% vs 33% cORR, HPV+ (106+Pembro vs Pembro) 90% vs 33% PFS6, HPV+ (106+Pembro vs Pembro) • HPV-driven tumors express viral E6/E7 neoantigens; these are foreign, high-quality targets that OX40 co- stimulation (INBRX-106's MoA) amplifies. • The enhanced results observed in HPV+ HNSCC are consistent with the expected underlying biology.
16 INBRX-106 The new study amendment adds an additional 50 HPV+ patients to the existing HexAgon design Expansion of Phase 2 HexAgon-HN with potential for an accelerated path to market in HPV+ Potential accelerated path by end of 2028/ early 2029 based on ORR as a surrogate likely to predict long-term clinical benefit (PFS & OS), and established precedent with petosemtamab and ficerafusp alfa Already part of the seamless design: serves as the confirmatory study for full approval Potential, based on preliminary signal magnitude in a serious, unmet-need indication Potential for breakthrough therapy designation Potential for accelerated approval Phase 3: confirmatory Opens the door to possibilities for accelerated development Phase 2 (additional 50 HPV+) Open label INBRX-106 + Pembro Pembro R 1:1 Phase 3 (n=TBD) Double blind, seamless INBRX-106 + Pembro Pembro R 1:1 Key inclusion criteria: R/M HNSCC HPV+ OPSCC PD-L1 CPS≥1
17 INBRX-106 ~$1B ~$2B ~$1B Set to pursue a breakthrough pathway in 1L R/M HPV+ CPS ≥1 HNSCC Source: SEER Explorer, CDC, Clarivate Disease Landscape Report ~$4B+ U.S. market opportunity including stage I-III setting 2.6% Rapidly Growing Market US Epidemiology Estimates Valuation Drivers US Sales Potential High morbidities in current therapies Clinicians actively seeking de-escalation therapy in HPV+. Significant radiation- and surgery-related morbidities — e.g., impaired speech, feeding tube High share; higher systemic usage Significant unmet need for a therapy specifically studied in the HPV+ population; where current EGFR bi-specifics do not perform well Premium pricing Ground-breaking results and limited patient population would provide opportunity for premium pricing. Premium priced therapies currently on guidelines Long duration High response rate, and deep and durable responses on INBRX-106 point to longer duration on therapy ~30,000 2029 US Incidence (De Novo Stage I-IV + Recurrent) HPV+ HNSCC Patients in the US ~8,000 Stage I-III Surgical ~16,000 Stage I-III Non- Surgical ~6,000 1L R/M US Annual Growth in HPV+
18 INBRX-106 INBRX-106: multiple attractive expansion opportunities Source: 1. Evaluate estimates for PD-1s projected to 2031 based on 2025-2027 growth rates (market size independent of biosimilar entry). 2. Virally antigen estimated based at 3x HPV based on topline epidemiology from CDC or IARC (de Martel) projected WW. 3. Company estimate, full impact of V940 data release 8/19/26 not yet propagated through reports. Highly Immunogenic Tumors • NSCLC • Melanoma • Renal Cell Carcinoma • TNBC • Bladder • MSI-H / dMMR • TMB-High Virally Antigen-Driven • HPV+ H&N • HPV+ beyond H&N (e.g., Anus/ Rectum, Cervix, Vagina, Vulva, Penis) • Non-HPV, commonly reported virally- linked cancers: EBV, HBV, HCB, HTL1-1, HHV-8 Individualized Neoantigen Cancer Vaccines Major Ph 2/3 programs: • Moderna/Merck: (V940): Melanoma, NMIBC, NSCLC • BioNTech/Genentech (Autogene Cevumeran): CRC, PDAC $50 B+1 $15 B+2 $50 B+3 Ongoing clinical trial in peri-operative NSCLC and IST in peri-operative TNBC serves as fast proof of concept for broad expandability to other immunogenic tumors Seek potential combinations with individualized neoantigen cancer vaccines Expand Phase 2 portion of HexAgon-HN trial to increase HPV+ patients for potential accelerated approval Ongoing studies & development plan WW Market Opportunity: Highest impact expected in early stage disease Increased opportunity for OX40 agonism due to increased ongoing antigen-driven T-Cell stimulation
19 INBRX-106 Highly immunogenic tumors, peri-operative NSCLC expansion: pCR is a fast, validated readout of long-term benefit 1. Wakelee et al., KEYNOTE-671, N Engl J Med 2023 • Pathologic complete response (pCR) at surgery: • Available in months, not years • Highly correlated with improved survival and can generate a second, independent proof-of-activity signal well ahead of any survival endpoint • pCR in peri-operative NSCLC opens a multibillion-dollar market opportunity and will serve as proof of concept for expandability to other highly immunogenic tumors, broadening the platform thesis beyond HNSCC KEYNOTE-671 0.58 Event-free survival HR (95% CI 0.46–0.72)¹ 18.1% Pathologic complete response Pembro+chemo Neoadjuvant study – Ongoing Ph1/2 study expected to read-out by mid-2027 Stage II–IIIB NSCLC, ECOG 0–1, surgical candidates Participants (N~40) Neoadjuvant (4 cycles) Adjuvant (13 cycles) Surgery Primary endpoints + pCR + Safety Platin doublet + pembro + INBRX-106 Pembro + INBRX-106
20 INBRX-106 INBRX-106 HPV+ ORR data and 20+ years of academic research1 support synergy of OX40 agonism and potential vaccine effectiveness 1. Appendix includes a curated set of 18 high impact publications • Extensive preclinical evidence: OX40 agonism enhances vaccine efficacy/anti-tumor activity • INBRX-106 HPV⁺ HNSCC high ORR validates that OX40 co-stimulation amplifies immunity response to APC-presented antigen • mRNA vaccine recreates HPV+ like tumor antigenicity by design INBRX-106 Hexavalent agonist antibody ± anti-PD-1 checkpoint release + Tfh-B cell help Germinal Center Stronger CD8 effector-memory responses Stronger CD4 Th1 / effector-memory responses Improved antibody response Vaccines provide tumor-driven antigens that T-Cells recognize Anti-Tumor OX40 ⁺T-cell is highly responsive to OX40 agonism OX40 T-cell co- activation Enhanced anti- tumor activity Signal 1 Signal 2
21 INBRX-106 Combinability may enable INBRX-106 to capitalize on recent breakthrough of individualized neoantigen cancer vaccines IPV* Clinical validation INBRX-106 POC validation Individualized vaccine Primes neoantigen-specific T cells Inhibrx-106 OX40 agonism Amplifies T-cell antigenic response expansion and durability Strategic opportunity Moderna's V940 (intismeran autogene) + pembrolizumab has established clinical validation in adjuvant melanoma In-patient T-cell Co-stim: CD8+ prolif. (fold ↑) Phase 2 0.51 RFS hazard ratio 0.38 DMFS hazard ratio • Favorable exploratory OS trend • Phase 3 positive top-line readout created $25B+ market value overnight • Chronic MHC-presented HPV antigen sustains an OX40+ T-cell phenotype a personalized vaccine can recreate • Strong Preclinical Evidence: OX40 agonism-vaccine synergy. Antigen specific T-cell expansion, survival, memory, humoral response Clinical PoC: HPV+ OPC — ORR INBRX-106 + pembrolizumab 15× Pembrolizumab 2× ~80% 33% INBRX-106 + pembrolizumab Pembrolizumab Potential best-in-class outcomes *IPV-Individualized Patient Vaccine
22 INBRX-106 • ORR: 80% vs 33% • CR Rate: 30% vs 0% • PFS Data: NR vs 4.6 months • PFS6 Rate: 90% vs 33% • Expansion of Phase 2 to include 50 additional HPV+ patients may serve as potential path to accelerated approval by end of ‘28/early ‘29. HPV+ HNSCC is an open $4B+ market INBRX-106 conclusion Combination with pembro demonstrates superiority to pembro mono in 1LR/M HNSCC Potentially practice-changing efficacy profile in HPV+ patients Large expansion opportunity in highly immunogenic tumors Potential for new paradigm of treatment with cancer vaccines INBRX-106 is the first clinically active OX40 agonist and T-cell costimulatory therapy • ORR: 48.3% vs 26.5% • Depth of Response • CR Rate: 13.8% vs 0% • PFS: 9.6 months vs 4.9 months • PFS6 Improvement: (72.4% vs. 42.8%) • These data are supported by superior t-cell proliferation (up to 15-fold increase) and activation (up to 4-fold increase) vs pembrolizumab alone • Bladder, NSCLC, Melanoma, MSI High/TMB High, TNBC present $50B+ commercial opportunity • Ongoing neoadjuvant lung cancer study serves as proof of concept for broad expandability with pembrolizumab across highly immunogenic tumors • Potential $50B+ market • HPV+ HNSCC data and over 20 years of academic research support the strong mechanistic rationale of INBRX-106 +cancer vaccines (OX40 agonism potency when foreign antigen is presented)
P R OP R IE TAR Y AN D C ON FID E N TI A L; N OT FOR D IS TR IB U TION Appendix
24 INBRX-106 18 selected preclinical studies spanning protein, DNA/viral-vector, whole-cell and RNA vaccine platforms, plus first-in-human proof of biology OX40 agonism enhances vaccine efficacy: broadly supported in scientific literature for 20+ years Foundational mechanism & platforms Therapeutic cancer vaccines Cancer (cont.) & RNA-era platforms HUMAN PROOF OF BIOLOGY Curti / Weinberg 2013, Cancer Research (first-in-human OX40 agonist study): patients receiving reporter-antigen immunizations showed increased T-cell and B-cell responses to the vaccine antigens — direct clinical evidence that pharmacologic OX40 agonism augments vaccine responses. Gramaglia 2001 · J Immunol · PMID 11739496 Soluble antigen vaccine: ~10× antibody titers and durable CD4 memory. Laderach 2004 · Immunology · PMID 15270726 DNA prime / poxvirus boost: higher CD4 responses; +4-1BB further raises CD8. Ruby 2007 · Eur J Immunol · PMID 17183611 Greater CD8 memory survival and recall — durability, not just expansion. Redmond 2007 · J Immunol · PMID 18025166 Restores CD8 effector function and granzyme B after antigen priming. Sanchez 2012 · PMID 22186790 Adenovirus vaccine + OX40: improved protection against viral challenge. Welten 2017 · PMID 28265272 Peptide booster vs MCMV: stronger CD4/CD8 responses; lower viral titers. 1 2 3 4 5 6 Murata 2006 · J Immunol · PMID 16393983 GM-CSF whole-cell vaccine: overcomes CD8 tolerance to endogenous tumor antigen. Murphy 2012 · Clin Cancer Res · PMID 22781551 Glioma lysate + Fc-OX40L: ~50–100% cures with rechallenge protection. Murphy / Fecci 2013 · PMID 24293627 Same regimen; regression dependent on CD4 T, NK and B cells. Linch 2016 · PMID 26729864 HER2 DC-targeted vaccine + αOX40/αCTLA-4: reverses anergy, improves survival. Jahan 2018 · Neuro-Oncology · PMID 29016879 GVAX + αOX40 in glioma: median survival 22 → 36 days; better CD8:Treg balance. Jahan 2019 · PMID 31069135 GVAX + αPD-1 + αOX40: long-term survival in all treated mice. 7 8 9 10 11 12 Peng 2019 · Clin Cancer Res · PMID 31371342 gp100 peptide / DC vaccination: greater antigen- specific CD8 expansion and memory. Du 2022 · J Cancer Res Clin Oncol · PMID 35748951 Whole-cell vaccine + CpG/αOX40/cGAMP: slower growth, more intratumoral T cells. Sun 2023 · J Transl Med · PMID 37700338 In-situ vaccine (radiation + CpG + OX40): local and abscopal tumor control. Li 2020 · Vaccines · PMID 32210183 Rabies vector expressing OX40L: more Tfh and germinal-center B cells. Duhen 2022 · Front Immunol · PMID 36238275 SARS-CoV-2 protein and saRNA vaccines: higher, longer-lasting antibody and CD4/CD8 responses. Lu 2025 · JCI Insight · PMID 40178907 Zika saRNA + OX40/4-1BB: immunity extended to day 84; lower viral load on delayed challenge. 13 14 15 16 17 18 19