OSE Immunotherapeutics Provides Update on Clinical Results With OSE-279 in Advanced Solid Tumors

Regulatory News:

OSE Immunotherapeutics SA (ISIN: FR0012127173; Mnemo: OSE) presented an update on the positive results of OSE-279 in the Phase 1/2 clinical evaluation in advanced solid tumors at the 2024 ESMO Targeted Anticancer Therapies Congress (ESMO TAT) held in Paris, France (February 26 – 28, Abstract #368; FPN 30P).

Silvia Comis, Head of Clinical Development and Regulatory Affairs of OSE Immunotherapeutics, comments: “We are very pleased to share this positive update on the preliminary efficacy and safety results from a Phase 1/2 study assessing the therapeutic potential of our proprietary high affinity anti-PD1 monoclonal antibody OSE-279 in advanced solid tumors. These new results and additional signal of efficacy with a high anti-tumor response rate in difficult-to-treat patients, highlight the value of OSE-279 as a potential strong anti-PD1 therapy and encourage further clinical development in the future in pre-identified cancer niche indications, with still high unmet medical needs. In parallel to OSE-279 monotherapy development, new cohort testing combinations with other OSE drug candidates, including cancer vaccine, are being explored.”

The ESMO-TAT communication reported on the positive results from the Phase 1/2 clinical trial (NCT05751798) evaluating OSE-279 monotherapy in patients with advanced solid tumors, with no therapeutic option available.

The updated data show a good pharmacokinetic/pharmacodynamic (PK/PD) and manageable safety profile in line with previous anti-PD1 development and with a high signal of efficacy in the first 20 patients representing 13 different tumor types. Four confirmed ongoing partial responses (PR) with 600 mg every six weeks (q6w), with a response rate of 36%, were reported in patients with anal squamous cell carcinoma, undifferentiated pleomorphic sarcoma, oncocytic thyroid cancer, and alveolar soft part sarcoma. One still ongoing confirmed PR (81% reduction of target lesions) has been observed in a patient with hepatocellular carcinoma after one single dose of OSE-279 300 mg. Five stable diseases (SD) were reported at multiple dose levels. Treatment is ongoing in seven patients. Pharmacokinetic (PK) showed dose-proportionality and favorable exposure. Receptor occupancy (RO) was maintained. At 600 mg q6w, no dose-limiting toxicities (DLTs) were reported in 10 patients. Further to the recommendation of a Phase 2 dose (RP2D) of 300 mg q3w, the dose of 600 mg q6w has been selected as the second RP2D.