On April 21, 2026 Inhibrx Biosciences, Inc. (Nasdaq: INBX) ("Inhibrx" or the "Company"), a clinical-stage biopharmaceutical company focused on developing novel biologic therapeutic candidates, reported updated interim data from its Phase 1/2 study evaluating ozekibart (INBRX-109) in combination with FOLFIRI in patients with locally advanced or metastatic, unresectable colorectal cancer (CRC).

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As of April 10, 2026, the cutoff date, the CRC cohort continued to demonstrate a compelling signal of activity in a heavily pretreated patient population. Of the 45 evaluable patients, approximately 70% received ozekibart as a fourth-line therapy, and 80% had previously progressed on irinotecan-based regimens. The following data were observed as of the cutoff date:

Objective Response Rate (ORR): Efficacy was assessed in 45 evaluable patients, resulting in an ORR of 20% per RECIST v1.1 criteria. Historically, the current standard of care has yielded limited response rates (ORR of 1-6% per RECIST v1.1 criteria). Nearly half of responses were durable with a duration of response exceeding 6 months. Responses were observed irrespective of RAS/RAF mutation status.

Progression-Free Survival (PFS): The median PFS for the evaluable population was 5.5 months. Notably, 42% of patients remained progression-free at the 6-month landmark, with 9 patients remaining on therapy, suggesting that a significant portion of patients achieve durable disease control that extends well beyond the median PFS.

Disease Control Rate (DCR): The overall disease control rate (partial responses and stable disease as best response) remained robust at 87%, further supporting the potential of ozekibart to control tumor growth in a heavily pre-treated population.

Safety and tolerability: Ozekibart in combination with FOLFIRI continues to maintain a manageable safety profile. The most common treatment-related adverse events (TEAEs) were diarrhea, fatigue, and nausea, which were largely Grade 1 or 2 and consistent with the known side effects of FOLFIRI. Despite the majority of the patients (68%) presenting with liver metastases at baseline, no significant liver toxicity was observed.
"The meaningful response rate and PFS, together with a manageable safety profile in this heavily pre-treated population, are highly encouraging and support our plans to advance into first line, where the potential for deeper and more durable responses may be even greater," said Mark Lappe, Chief Executive Officer of Inhibrx Biosciences. "It also highlights the opportunity for broader expansion of ozekibart into other indications, which we continue to explore."

Inhibrx plans to meet with the U.S. Food and Drug Administration (FDA) in the second half of 2026 to discuss plans to initiate a first-line registrational trial in CRC. The Company also plans to discuss with the FDA the potential for accelerated regulatory pathways for ozekibart in fourth-line colorectal cancer and in refractory Ewing sarcoma. Additionally, the Company submitted a Biologics License Application (BLA) to the FDA for ozekibart in conventional chondrosarcoma in April 2026.

The Company will host a live webcast presentation today, April 21, 2026, at 1:30 p.m. Pacific Time to further discuss the results.

About the Conference Call

Investors may join via the web: View Source or may listen to the call by dialing (1-888-880-3330). Please refer to Inhibrx Biosciences, Inc. or the conference ID 9536529 when calling in. 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. Following the presentation, Inhibrx will also update its corporate presentation within the "Investors" section of its website at www.inhibrx.com.

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 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. In October 2025, Inhibrx announced 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.

(Press release, Inhibrx, APR 21, 2026, View Source [SID1234664640])

On April 21, 2026 Fennec Pharmaceuticals Inc. (NASDAQ:FENC; TSX: FRX), a specialty pharmaceutical company, reported that four abstracts evaluating PEDMARK (sodium thiosulfate injection) were accepted as part of the 2026 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting program, taking place May 29-June 2, 2026 in Chicago, IL.

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PEDMARK is currently approved for pediatric patients one month of age and older with localized, non-metastatic solid tumors, and is also recognized by the National Comprehensive Cancer Network with a 2A recommendation for use in adolescent and young adult patients.

Poster Presentation Details:

Title: Effects of Delayed Sodium Thiosulfate on Cisplatin-Induced Ototoxicity in Pediatric and Adolescent Patients with Cancer: Results from the Japanese Children’s Cancer Group STS-J01 Study
Poster Session: Pediatric Oncology
Date and Time: June 1, 2026, 1:30 PM – 4:30 PM CT
Abstract Number: 10052
Lead Author: Eiso Hiyama, MD, professor in the Department of Pediatric Surgery at Hiroshima University Hospital in Hiroshima, Japan

Title: Randomized Phase 1 Trial of Cisplatin-Based Chemotherapy With or Without Sodium Thiosulfate for Men with Metastatic Germ Cell Tumor (GCT)
Poster Session: Genitourinary Cancer—Prostate, Testicular, and Penile
Date and Time: May 31, 2026, 9:00 AM – 12:00 PM CT
Abstract Number: TPS5131
Lead Author: Koral Shah, MD, Hematology/Oncology chief fellow, City of Hope

Abstract-Only Publication Details:

Title: Real-World Feasibility and Tolerability of PEDMARK for Otoprotection in Young Adults Receiving Cisplatin for Solid Tumors.
Abstract Number: e24189
Lead Author: Veronica Alana Vestal, MD, Comprehensive Cancer Center of University of Puerto Rico

Title: Audiometric Outcomes for Intravenous Sodium Thiosulfate for Cisplatin-Induced Ototoxicity Prevention in Adults with Head and Neck Cancer
Abstract Number: e18110
Lead Author: James Johns, MD, Icahn School of Medicine at Mount Sinai, New York

The full abstracts will be available on the ASCO (Free ASCO Whitepaper) website on May 21, 2026, at 5:00 p.m. ET.

About Cisplatin-Induced Ototoxicity
Cisplatin and other platinum-based chemotherapies are widely used to treat solid tumors and have been vital in improving survival rates. Unfortunately, these life-saving treatments often result in permanent, irreversible hearing loss, also known as ototoxicity.1

Hearing loss from cisplatin treatment is not rare. Studies show that between 60-90% of patients treated with cisplatin may develop hearing loss, depending upon the dose and duration of chemotherapy2. Many of those treated with cisplatin will require lifelong hearing aids or cochlear implants, which can be helpful for some, but do not reverse the hearing loss and can be costly over time.3 Treatment-induced hearing loss can reduce quality of survivorship as it impacts many aspects of life, such as speech and language skills, academic performance, social-emotional development, career potential and the ability to live independently.4,5 While audiologic monitoring is recommended to help manage ototoxicity, it is currently underutilized in certain cancer patient populations.

PEDMARK (sodium thiosulfate injection)
PEDMARK is the first and only U.S. Food and Drug Administration (FDA) approved therapy indicated to reduce the risk of ototoxicity associated with cisplatin treatment in pediatric patients 1 month of age and older with localized, non-metastatic, solid tumors. It is a unique formulation of sodium thiosulfate in single-dose, ready-to-use vials for intravenous use in pediatric patients. PEDMARK is also the first and only therapeutic agent with proven efficacy and safety data with an established dosing regimen, across two open-label, randomized Phase 3 clinical studies, the Children’s Oncology Group (COG) Protocol ACCL0431 and SIOPEL 6.

Additionally, PEDMARK is recommended for the adolescent and young adult (AYA) population by the National Comprehensive Cancer Network, or NCCN, with a 2A endorsement.

Approximately 500,000 patients in the U.S. are diagnosed annually with cancers that could be treated with a platinum-based chemotherapy.6,7 The incidence of ototoxicity depends upon the dose and duration of chemotherapy, and many of those treated will require lifelong hearing aids. Until the FDA approval of PEDMARK, there were no preventative agents for this hearing loss. Patients with hearing loss resulting from cancer treatment have a statistically significant worse quality of life compared with peers who have no hearing loss.89

PEDMARK has been studied by co-operative groups in two Phase 3 clinical studies of survival and reduction of ototoxicity, COG ACCL0431 and SIOPEL 6. Both studies have been completed. The COG ACCL0431 protocol enrolled childhood cancers typically treated with intensive cisplatin therapy for localized and disseminated disease, including newly diagnosed hepatoblastoma, germ cell tumor, osteosarcoma, neuroblastoma, medulloblastoma, and other solid tumors. SIOPEL 6 enrolled only hepatoblastoma patients with localized tumors.

Indications and Usage
PEDMARK (sodium thiosulfate injection) is indicated to reduce the risk of ototoxicity associated with cisplatin in pediatric patients 1 month of age and older with localized, non-metastatic solid tumors.

Limitations of Use
The safety and efficacy of PEDMARK have not been established when administered following cisplatin infusions longer than 6 hours. PEDMARK may not reduce the risk of ototoxicity when administered following longer cisplatin infusions, because irreversible ototoxicity may have already occurred.

Important Safety Information
PEDMARK is contraindicated in patients with history of a severe hypersensitivity to sodium thiosulfate or any of its components.

Hypersensitivity reactions occurred in 8% to 13% of patients in clinical trials. Monitor patients for hypersensitivity reactions. Immediately discontinue PEDMARK and institute appropriate care if a hypersensitivity reaction occurs. Administer antihistamines or glucocorticoids (if appropriate) before each subsequent administration of PEDMARK. PEDMARK may contain sodium sulfite; patients with sulfite sensitivity may have hypersensitivity reactions, including anaphylactic symptoms and life-threatening or severe asthma episodes. Sulfite sensitivity is seen more frequently in people with asthma.

PEDMARK is not indicated for use in pediatric patients less than 1 month of age due to the increased risk of hypernatremia or in pediatric patients with metastatic cancers.

Hypernatremia occurred in 12% to 26% of patients in clinical trials, including a single Grade 3 case. Hypokalemia occurred in 15% to 27% of patients in clinical trials, with Grade 3 or 4 occurring in 9% to 27% of patients. Monitor serum sodium and potassium levels at baseline and as clinically indicated. Withhold PEDMARK in patients with baseline serum sodium greater than 145 mmol/L.

Monitor for signs and symptoms of hypernatremia and hypokalemia more closely if the glomerular filtration rate (GFR) falls below 60 mL/min/1.73m2.

Administer antiemetics prior to each PEDMARK administration. Provide additional antiemetics and supportive care as appropriate.

The most common adverse reactions (≥25% with difference between arms of >5% compared to cisplatin alone) in SIOPEL 6 were vomiting, nausea, decreased hemoglobin, and hypernatremia. The most common adverse reaction (≥25% with difference between arms of >5% compared to cisplatin alone) in COG ACCL0431 was hypokalemia.

Please see full Prescribing Information for PEDMARK at: www.PEDMARK.com.

(Press release, Fennec Pharmaceuticals, APR 21, 2026, View Source [SID1234664656])

On April 21, 2026 Zymeworks Inc. (Nasdaq: ZYME), a biotechnology company managing a portfolio of licensed healthcare assets while developing a diverse pipeline of novel, multifunctional biotherapeutics, reported results from the dose-escalation part of the Phase 1 study for ZW191, a folate receptor alpha (FRα)-targeting antibody-drug conjugate (ADC), at the 2026 American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting.

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The data from Part 1 of the ongoing global Phase 1 study (ZWI-ZW191-101), highlight a compelling combination of anti-tumor activity and manageable safety in patients with advanced, heavily pretreated solid tumors, including ovarian and endometrial cancers.

"We are highly encouraged by the initial clinical data for ZW191, which reinforce the strength of our ADC platform and its ability to generate differentiated therapeutics," said Sabeen Mekan, M.D., Senior Vice President and Chief Medical Officer at Zymeworks. "The breadth and durability of responses, along with activity across varying levels of FRα expression, support further development of ZW191 as a potential best-in-class agent for patients with ovarian and endometrial cancers."

Part 2a, the dose-optimization portion of the study evaluating patients with ovarian cancer at doses of 6.4 mg/kg and 9.6 mg/kg, has completed enrollment, with participants recruited globally across North America, Europe, and Asia-Pacific. The data from Part 2a will determine the recommended dose for any future registration studies.

Key Findings

In platinum resistant ovarian cancer patients, ZW191 demonstrated a cORR of 56% across all dose levels, with tumor regression observed in 68% of patients and disease control achieved in 94%. Notably, ZW191 demonstrated compelling anti-tumor activity in the 6.4-9.6 mg/kg dose range regardless of FRα expression, with a cORR of 61% observed in ovarian and 57% in endometrial cancers, with disease control observed in 100% of patients. These findings highlight the potential for ZW191 to benefit a broad patient population, including those with low or heterogeneous target expression.

In endometrial cancer, ZW191 showed a cORR of 40% across all dose levels and 57% in the 6.4-9.6 mg/kg cohort, with disease control rates of 80% and 86%, respectively. Responses were observed regardless of FRα expression levels, suggesting potential activity across a broad patient population.

Across ovarian and endometrial cancer cohorts, responses were observed early, with a median time to response of 1.4 months. Median duration of response was not reached at the time of data cutoff, and median progression-free survival was 7.6 months.

ZW191 was well tolerated and safely administered up to 11.2 mg/kg. Severe (grade ≥3) treatment-emergent adverse events (TEAEs) occurred in 55% of patients treated with ZW191, most of which were grade 3. The most common grade ≥3 events were neutropenia (24%), anemia (20%), and thrombocytopenia (12%). Grade 4 events were infrequent, and one grade 5 event was reported at the highest dose level and was not treatment-related. Serious TEAEs occurred in 35% of patients, and 20% discontinued due to adverse events. Overall, the safety profile was manageable with no unexpected signals.

"These data demonstrate the potential of ZW191 to deliver meaningful clinical benefit in patients with heavily pre-treated gynecological tumors with limited options," said Patricia LoRusso, DO, PhD (hc), FAACR and lead author. "The combination of encouraging response rates and manageable safety profile supports further development of this therapy, particularly in ovarian and endometrial cancers where new treatment options are urgently needed."

ZW191’s differentiated profile, including a high drug-to-antibody ratio and novel payload, support its potential to address key limitations of current therapies and expand the reach of FRα-targeted treatment approaches across multiple tumor types.

About ZW191

ZW191 is an antibody-drug conjugate engineered to target a protein called folate receptor-⍺ found in ~75% of high-grade serous ovarian carcinomas,1 over 50% of endometrial cancers,2,3 and ~70% of lung adenocarcinomas4. ZW191’s differentiated design strongly supports its ability to internalize into FR⍺-expressing cells with the potential to release bystander active topoisomerase-1 inhibitor (ZD06519), a novel proprietary payload developed by Zymeworks to kill tumor cells.

(Press release, Zymeworks, APR 21, 2026, View Source [SID1234664672])

On April 21, 2026 Starpharma (ASX: SPL, US OTC: SPHRY), an innovative biotechnology company with two decades of experience in advancing dendrimer technology from the lab to the patient, reported that the company has met with the United States Food and Drug Administration (US FDA) in a Type C guidance meeting and received positive feedback on the proposed clinical development strategy and design of the first-in-human (FIH) phase 1 clinical study for its DEP HER2 radiotherapy candidate ("DEP HER21").

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DEP HER2 is a HER2 receptor-targeting dendrimer conjugate with a lutetium-177 radionuclide payload. Starpharma is developing DEP HER2 for the treatment of locally advanced or metastatic HER2-overexpressing gastric/gastro-oesophageal junction cancers and other HER2 expressing advanced cancers in patients who have received prior HER2-targeted therapy.

Key highlights for investors

• FDA alignment on FIH phase 1 study design and overall clinical development approach for DEP HER2
• FDA feedback supports plans to initiate the FIH phase 1 study
• FDA confirms that patients with advanced HER2-expressing cancers who have exhausted available HER2-directed therapies represent a population with significant unmet medical need
• FIH phase 1 study remains on track to enter the clinic in H2 CY 2026

Unmet need

Overexpression of HER2 is a key driver in aggressive breast and gastric cancers, and there are limited treatment options available to patients after progression, resistance, or toxicity from current HER2-directed therapies. Starpharma is developing DEP HER2 to address these clinical challenges.

The FDA confirmed that patients with advanced HER2-expressing cancers who have exhausted available HER2-directed therapies represent a population with significant unmet medical need, meaning that there is potential to pursue Fast Track designation and other accelerated development pathways for DEP HER2 in the future.

Clinical pathway

Starpharma plans to conduct a FIH phase 1 study in Europe initially in up to 15 patients to evaluate safety and tolerability, and to characterise pharmacokinetics, biodistribution and organ radiation dosimetry of DEP HER2 in patients with advanced HER2-positive cancers.

The FDA confirmed that the clinical data generated outside of the US, together with the currently available DEP HER2 preclinical data package, including a recently completed formal toxicology study, should be adequate to support future US-based clinical studies under an Investigational New Drug (IND) application.

The FDA provided clear guidance on chemistry, manufacturing and controls (CMC) expectations for DEP HER2, and agreed with Starpharma’s current approach to the manufacture and characterisation of Starpharma’s novel dendrimer-based radioligand therapy.

Professor Tony Lahoutte, MD, PhD, a physician and Head of the Department of Nuclear Medicine at University Hospital (UZ) Brussel, and Head of Molecular Imaging and Therapy Research (MITH) at the Vrije Universiteit Brussel (VUB) in Belgium, advised Starpharma on the DEP HER2 radiotherapy clinical development strategy. He attended the FDA meeting as a representative of Starpharma, contributing expert clinical nuclear medicine input to the discussion of our radiopharmaceutical study design.

Following the meeting with the FDA, Prof. Lahoutte commented:

"The FDA’s feedback provides important confirmation that Starpharma’s first-in-human phase 1 design and overall clinical strategy for DEP HER2 are in line with regulatory expectations. From a nuclear medicine and radiopharmaceutical perspective, the proposed approach to patient selection, dosimetry and safety evaluation is appropriate. DEP HER2 combines a HER2-targeting moiety with Starpharma’s novel, dendrimer-based delivery platform. The planned clinical study is well positioned to demonstrate the benefit of the dendrimer technology in targeted radioligand therapy, and to support further clinical development of the product for this high unmet-need population with HER2-expressing cancers."

Next steps

Starpharma is currently undertaking the activities required to commence the FIH phase 1 study and remains on track to begin in H2 CY 2026. Clinical site selection is complete, and the company is progressing radiopharmacy preparations, site onboarding and required ethics and regulatory approvals.

Cheryl Maley, Starpharma’s Chief Executive Officer, commented:

"DEP HER2 is a key strategic asset for Starpharma, supported by comprehensive preclinical data and a clinically validated platform technology. We are particularly excited by the encouraging data generated to date, which have shown important benefits in targeted delivery for radiotherapeutics.

"This FDA feedback is an important milestone, providing regulatory clarity and validation for the proposed clinical development pathway and marking the exciting transition from preclinical to clinical development. The guidance provides confidence that our current preclinical package, together with the data generated in the forthcoming first-in-patient study, would support a subsequent IND application and clinical development in the US. "

By exemplifying the value of DEP technology in the high-growth area of radiotherapy in a clinical setting, Starpharma aims to broaden the therapeutic applications and commercial opportunities of its dendrimer platform, whilst continuing to deliver meaningful outcomes for patients."

(Press release, Starpharma, APR 21, 2026, View Source [SID1234664556])

On April 21, 2026, Erasca, Inc. (the "Company") reported to have narrowed the time period for the anticipated Phase 1 monotherapy data readout for the Company’s pan-RAS molecular glue ERAS-0015 from the AURORAS-1 and JYP0015M101 clinical trials to no later than mid-May of 2026, from the prior guidance of the first half of 2026. The Company is evaluating ERAS-0015 in the AURORAS-1 Phase 1 trial in patients with RAS-mutant solid tumors, and the Company’s licensor, Guangzhou Joyo Pharmatech Co., Ltd. (Joyo), is evaluating ERAS-0015 in the JYP0015M101 trial in China in patients with advanced solid tumors harboring specific RAS mutations.

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(Press release, Erasca, APR 21, 2026, View Source [SID1234664609])