OSTX: OSTX granted FDA Type C meeting to review 2.5‐year OS data for OST‐HER2; interim 3‐yr OS due early Sept

AI Summary

OS Therapies (OSTX) says the FDA granted a Type C Statistical Methods meeting to review 2.5‐year overall survival (OS) data from its Phase 2b OST‐HER2 trial in fully resected, pulmonary metastatic osteosarcoma; the meeting is expected mid‐September 2026. The company expects to announce interim 3‐year OS data in early September 2026, and outcomes of the meeting will inform comparator choice, RMAT designation, a possible FDA rolling review and timing for a BLA under Accelerated Approval by year‐end 2026. The firm also notes OS was sustained between the 2‐ and 2.5‐year timepoints and has a parallel MHRA statistical advice meeting scheduled in September.

Positives

FDA granted Type C Statistical Methods meeting to review 2.5‑year OS data (meeting mid‑Sept 2026)
Interim 3‑year overall survival data expected early September 2026
Company reports OS unchanged between 2‑ and 2.5‑year timepoints and Phase 2b met 12‑month EFS primary endpoint

Negatives

FDA meeting will evaluate use of pooled non‑concurrent historical controls versus concurrent natural history data, posing potential interpretive/regulatory risk
Key regulatory steps (RMAT, rolling review, BLA submission and potential PRV/CNPV decisions) remain contingent on meeting outcomes and upcoming data
Approval timeline and benefits depend on successful regulatory acceptance of statistical approach and interim 3‑year results