FDA accepts Inhibrx (NASDAQ: INBX) BLA for first chondrosarcoma therapy
Filing Impact
Filing Sentiment
Form Type
8-K
Rhea-AI Filing Summary
Inhibrx Biosciences reported that the U.S. FDA has accepted for filing its Biologics License Application for ozekibart (INBRX-109) to treat patients with unresectable or metastatic conventional chondrosarcoma and has set a PDUFA goal date of April 14, 2027.
The BLA is backed by the registrational ChonDRAgon study, where ozekibart cut the risk of disease progression or death by 52% versus placebo (hazard ratio 0.479) and more than doubled median progression-free survival to 5.52 months vs 2.66 months. Disease control rate and pain and function measures also favored ozekibart.
If approved, ozekibart would be Inhibrx’s first commercial product and the first FDA‑approved systemic therapy for this cancer. The drug showed a generally manageable safety profile, with hepatotoxicity mitigated through patient selection and close monitoring.
Positive
- FDA acceptance of the ozekibart BLA with a April 14, 2027 PDUFA date is a pivotal regulatory milestone that could lead to Inhibrx’s first commercial product in a disease with no approved systemic therapies.
- The registrational ChonDRAgon trial showed ozekibart delivered a 52% reduction in risk of progression or death and more than doubled median PFS to 5.52 vs 2.66 months, with supportive secondary endpoints and a generally manageable safety profile.
Negative
- Ozekibart’s mechanism carries a risk of hepatotoxicity, including one fatal event early in the study; although mitigation measures reduced incidence to 11.8% vs 4.5% on placebo, regulatory review will closely scrutinize liver safety.
- Despite strong data, regulatory approval is not guaranteed; the FDA’s final decision on the BLA, due by the April 14, 2027 PDUFA date, remains a key uncertainty for the program and Inhibrx’s first-product timeline.
Insights
FDA BLA acceptance and strong PFS data make this a pivotal, thesis-shaping milestone for Inhibrx.
The FDA’s acceptance of Inhibrx’s BLA for ozekibart with a April 14, 2027 PDUFA date moves the program into formal review. For a rare cancer with no approved systemic options, this represents a major step toward potential commercialization.
Clinically, the ChonDRAgon trial showed ozekibart reduced the risk of progression or death by 52% (hazard ratio 0.479) and more than doubled median progression-free survival to 5.52 months vs 2.66 months. Disease control rate and patient-reported outcomes on pain and physical function also improved, supporting the robustness of benefit.
Safety appears manageable, with hepatotoxicity mitigated by excluding severe liver impairment and intensive early-cycle monitoring, leading to an 11.8% incidence of hepatic adverse events versus 4.5% on placebo, mostly low grade. The filing notes ongoing expansion cohorts in Ewing sarcoma and colorectal cancer, but the key near-term catalyst is the FDA decision by April 14, 2027.
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
PDUFA goal date: April 14, 2027
Risk reduction in progression or death: 52%
Median PFS ozekibart: 5.52 months
+5 more
8 metrics
PDUFA goal date
April 14, 2027
FDA review timeline for ozekibart BLA
Risk reduction in progression or death
52%
Ozekibart vs placebo in ChonDRAgon trial
Median PFS ozekibart
5.52 months
Patients with advanced conventional chondrosarcoma
Median PFS placebo
2.66 months
Comparator arm in ChonDRAgon
Disease control rate ozekibart
54%
Key secondary endpoint vs placebo
Disease control rate placebo
27.5%
Comparator for disease control
Hepatic adverse events ozekibart
11.8%
Treatment-related hepatic events after mitigation
Hepatic adverse events placebo
4.5%
Treatment-related hepatic events in placebo arm
Key Terms
Biologics License Application, PDUFA goal date, progression-free survival, orphan drug designation, +2 more
6 terms
Biologics License Application regulatory
"the U.S. Food and Drug Administration (FDA) has accepted for filing its Biologics License Application (the “BLA”)"
A biologics license application is a formal request submitted to regulatory authorities seeking approval to market a new biological medicine, such as vaccines or treatments made from living organisms. It is a comprehensive review process that evaluates the safety, effectiveness, and manufacturing quality of the product. For investors, receiving approval signals that a biological therapy can be sold to the public, potentially leading to revenue growth and market success.
PDUFA goal date regulatory
"has assigned a Prescription Drug User Fee Act (PDUFA) goal date of April 14, 2027"
The PDUFA goal date is the target deadline set by the U.S. Food and Drug Administration for completing its review of a new drug or biologic application. Investors watch it like a court date for a product: the outcome (approval, rejection, or request for more information) can sharply change a company’s revenue prospects and stock price, and the date gives a predictable event around which markets and planning can focus.
progression-free survival financial
"met its primary endpoint of a statistically significant and clinically meaningful median progression-free survival (PFS)"
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.
orphan drug designation regulatory
"the FDA granted orphan drug designation to ozekibart for chondrosarcoma"
Orphan drug designation is a special status given to medicines developed to treat rare diseases affecting only a small number of people. This status often provides benefits like faster approval processes and financial incentives, making it more attractive for companies to develop these drugs. For investors, it signals potential for exclusive market rights and reduced competition, which can impact the drug’s profitability.
Fast Track designation regulatory
"the FDA granted Fast Track designation to ozekibart for the treatment of patients"
A "fast track designation" is a process that speeds up the review and approval of a product or project, allowing it to reach the market or be completed more quickly than usual. For investors, it can signal that a product may become available sooner, potentially leading to earlier revenue or benefits, and indicating a priority status that might influence company performance and market opportunities.
death receptor 5 (DR5) agonist antibody technical
"a precision-engineered, tetravalent death receptor 5 (DR5) agonist antibody designed to exploit tumor-biased cell death"
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): June 15, 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 June 15, 2026, Inhibrx Biosciences, Inc. (the “Company”) issued a press release announcing that the U.S. Food and Drug Administration (the “FDA”) has accepted for filing its Biologics License Application (the “BLA”) seeking approval of ozekibart (INBRX-109) for the treatment of patients with unresectable or metastatic conventional chondrosarcoma. The FDA has not identified any filing review issues at this time and has assigned a Prescription Drug User Fee Act (PDUFA) goal date of April 14, 2027. 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.
On June 15, 2026, the Company announced that the FDA has accepted for filing its BLA seeking approval of ozekibart for the treatment of patients with unresectable or metastatic conventional chondrosarcoma. The FDA has not identified any filing review issues at this time and has assigned a PDUFA goal date of April 14, 2027.
Item 9.01. Financial Statements and Exhibits.
(d) Exhibits.
| Exhibit No. | Description | |||||||
| 99.1 | Press Release issued by Inhibrx Biosciences, Inc. on June 15, 2026 | |||||||
| 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: June 15, 2026 | ||||||||
| INHIBRX BIOSCIENCES, INC. | ||||||||
| By: | /s/ Kelly Deck | |||||||
| Name: | Kelly Deck | |||||||
| Title: | Chief Financial Officer | |||||||
Exhibit 99.1
Inhibrx Announces U.S. FDA Acceptance of BLA for Ozekibart in Patients with Conventional Chondrosarcoma
•No filing review issues identified by FDA with PDUFA goal date set for April 14, 2027
•If Approved, Ozekibart Would Be the First and Only FDA-Approved Treatment for Unresectable or Metastatic Conventional Chondrosarcoma
SAN DIEGO, June 15, 2026/PRNewswire/ – Inhibrx Biosciences, Inc. (Nasdaq: INBX) (“Inhibrx” or the “Company”), a clinical-stage biopharmaceutical company focused on developing novel biologic therapeutic candidates, today announced that the U.S. Food and Drug Administration (FDA) has accepted for filing its Biologics License Application (BLA) seeking approval of ozekibart (INBRX-109) for the treatment of patients with unresectable or metastatic conventional chondrosarcoma. The FDA has not identified any filing review issues at this time and has assigned a Prescription Drug User Fee Act (PDUFA) goal date of April 14, 2027.
“The FDA’s acceptance of our BLA for ozekibart is a monumental milestone for Inhibrx and, more importantly, for the chondrosarcoma community,” said Mark Lappe, Chief Executive Officer of Inhibrx. “Chondrosarcoma is an aggressive and devastating bone cancer and there are currently no approved therapies for patients suffering from this disease. We look forward to working closely with the FDA during this review process to potentially bring this first-in-class targeted therapy to patients as quickly as possible.”
The BLA is supported by positive results from the ChonDRAgon study, a randomized, blinded, placebo-controlled, registrational trial of ozekibart in patients with metastatic or unresectable conventional chondrosarcoma, which met its primary endpoint of a statistically significant and clinically meaningful median progression-free survival (PFS) for patients treated with ozekibart compared to placebo. Ozekibart achieved a 52% reduction in the risk of disease progression or death compared to placebo (stratified Hazard Ratio [HR] 0.479; 95% CI: 0.33, 0.68; P<0.0001), more than doubling median PFS to 5.52 months versus 2.66 months for placebo. Importantly, ozekibart is the first investigational therapy to demonstrate a significant PFS benefit in a blinded, randomized trial for chondrosarcoma, a disease with no approved systemic options.
If approved, ozekibart would become the first commercial product for Inhibrx and the first-ever approved systemic therapeutic for patients with unresectable or metastatic conventional chondrosarcoma.
About Chondrosarcoma
Chondrosarcoma is a rare type of cancer that primarily develops in the cartilage cells of bones, most commonly affecting the pelvis, hip, and shoulder. It stands as the second most common primary bone malignancy. When the disease becomes unresectable or metastatic, the prognosis is historically poor because the tumors are largely unresponsive to traditional oncology treatments, leaving surgical resection as the only effective management strategy for localized disease.
About ozekibart (INBRX-109)
Ozekibart is a precision-engineered, tetravalent death receptor 5 (DR5) agonist antibody designed to exploit the tumor-biased cell death induced by DR5 activation. In January 2021, the
FDA granted Fast Track designation to ozekibart for the treatment of patients with metastatic or unresectable conventional chondrosarcoma, and, in November 2021, the FDA granted orphan drug designation to ozekibart for chondrosarcoma.
In June 2021, Inhibrx initiated the ChonDRAgon study, a randomized, blinded, placebo-controlled, registrational trial of ozekibart in metastatic, unresectable conventional chondrosarcoma. The trial enrolled a total of 206 patients across 67 different sites worldwide. The primary objective of the trial was the evaluation of the efficacy of ozekibart as measured by median PFS, assessed by central real-time independent radiology review per RECIST 1.1. Secondary objectives were the evaluation of overall survival, median PFS by investigator assessment, quality of life, objective response rate, duration of response, disease control rate, safety and tolerability, pharmacokinetics and anti-drug antibodies to ozekibart.
Key enrollment criteria in order for patients to qualify for inclusion in the trial were grade 2 or 3 unresectable or metastatic conventional chondrosarcoma. Patients received either ozekibart or placebo every three weeks at a randomization of 2:1, stratified by the line of therapy, grade and IDH1/2 mutation status.
Patients randomized to the placebo arm were allowed to crossover to receive ozekibart upon confirmation of progression as reported by central independent radiology review.
The ChonDRAgon study met its primary endpoint of a statistically significant and clinically meaningful median progression-free survival (PFS) for patients with advanced or metastatic chondrosarcoma treated with ozekibart compared to placebo. Ozekibart achieved a 52% reduction in the risk of disease progression or death compared to placebo (stratified Hazard Ratio [HR] 0.479; 95% CI: 0.33, 0.68); P<0.0001), more than doubling median PFS to 5.52 months versus 2.66 months for placebo. Importantly, ozekibart is the first investigational therapy to demonstrate a significant PFS benefit in a randomized trial for chondrosarcoma, a disease with no approved systemic options.
The benefit of ozekibart was consistent across all pre-specified subgroups, including patients with IDH-wild-type and IDH-mutant tumors. Other key secondary endpoints, including disease control rate (54% vs 27.5%), and delay to deterioration in pain and physical function, further supported the clinical benefit observed with ozekibart.
Ozekibart was generally well tolerated, with a manageable safety profile. The most common treatment-related adverse events were fatigue, constipation, and nausea. Hepatotoxicity, a known risk for this mechanism of action, occurs during the first treatment cycle and is in patients with underlying hepatic impairment. One hepatotoxicity-related fatal event occurred early in the study, prior to the implementation of mitigation measures. Over the course of the ChonDRAgon study, this risk was effectively mitigated by excluding patients with severe liver impairment and by implementing close monitoring during early treatment cycles, allowing for prompt management of liver enzyme elevations. This approach resulted in a low overall incidence of treatment-related hepatic adverse events, 11.8% compared to 4.5% in the placebo arm, the majority of which were Grade 1 or 2 in severity.
In addition to the registrational trial in chondrosarcoma, Inhibrx is advancing ongoing expansion cohorts, evaluating ozekibart in combination with irinotecan-based regimens in Ewing sarcoma and colorectal cancer. Encouraging early signals support further exploration of ozekibart’s potential in these difficult-to-treat tumor types with high unmet medical need.
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 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, ozekibart, based on topline and interim results; the potential for ozekibart to be used for the treatment of colorectal cancer, Ewing sarcoma and solid tumor indications; the clinical development of ozekibart, including expected enrollment in the expansion cohort, data readouts, regulatory submissions and interactions, and the timing thereof; the potential commercial development of ozekibart, including becoming the first commercial product for Inhibrx; ozekibart becoming the first-ever FDA approved systemic therapeutic for patients with unresectable or metastatic conventional chondrosarcoma; and any presumption that topline, interim or preliminary data will be representative of final data or data in later clinical trials. 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; an accelerated development or approval pathway may not be available for ozekibart or other therapeutic candidates and any such pathway may not lead to a faster development process; it may not realize the benefits
associated with orphan drug designation, including that orphan drug exclusivity may not effectively protect a product from competition and that such exclusivity may not be maintained; 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
FAQ
What did Inhibrx Biosciences (INBX) announce about ozekibart and the FDA?
Inhibrx announced that the U.S. FDA accepted its Biologics License Application for ozekibart to treat unresectable or metastatic conventional chondrosarcoma. Acceptance triggers a formal review and establishes a PDUFA goal date of April 14, 2027 for a potential approval decision.
What are the key efficacy results for ozekibart in chondrosarcoma reported by INBX?
In the ChonDRAgon trial, ozekibart achieved a 52% reduction in risk of disease progression or death versus placebo, with a hazard ratio of 0.479. Median progression-free survival more than doubled to 5.52 months vs 2.66 months, supported by improved disease control and patient-reported outcomes.
Why is the ozekibart BLA important for Inhibrx (INBX) and patients?
If approved, ozekibart would be Inhibrx’s first commercial product and the first-ever FDA-approved systemic therapy for unresectable or metastatic conventional chondrosarcoma. Patients currently have no approved systemic options, relying mainly on surgery for localized disease.
What is the safety profile of ozekibart described by Inhibrx Biosciences?
Ozekibart was described as generally well tolerated, with common adverse events like fatigue, constipation and nausea. Hepatotoxicity occurred mainly early; after excluding severe liver impairment and adding close monitoring, hepatic adverse events were 11.8% vs 4.5% on placebo, mostly low grade.
What is the design of the ChonDRAgon study supporting the ozekibart BLA?
ChonDRAgon is a randomized, blinded, placebo-controlled registrational trial in 206 patients with metastatic or unresectable conventional chondrosarcoma across 67 sites. Patients received ozekibart or placebo every three weeks (2:1 ratio), with progression-free survival as the primary endpoint.
Does Inhibrx (INBX) plan to develop ozekibart beyond chondrosarcoma?
Yes. In addition to the registrational chondrosarcoma trial, Inhibrx is running expansion cohorts testing ozekibart with irinotecan-based regimens in Ewing sarcoma and colorectal cancer. The company reports encouraging early signals, supporting further exploration in these difficult-to-treat tumors.