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NewsAugust 2026 was a big month for breast cancer treatment. A supplemental NDA was submitted for gedatolisib in PIK3CA-mutant HR+/HER2− advanced breast cancer, while ETX-19477 — a first-in-class PARG inhibitor — earned FDA fast track designation. Meanwhile, two regulatory decisions for giredestrant are on the horizon before year's end.
August 2026 brought a flurry of regulatory activity in breast cancer. Celcuity submitted a supplemental NDA for gedatolisib (Revtorpyk) — a pan-class I PI3K/mTOR inhibitor — in combination with fulvestrant with or without palbociclib, targeting adults with PIK3CA-mutant, HR+/HER2− advanced breast cancer. This builds on gedatolisib's July 2026 FDA approval in PIK3CA wild-type disease. The filing is backed by phase 3 VIKTORIA-1 data showing the gedatolisib triplet cut the risk of progression or death by 50% vs. alpelisib/fulvestrant (median PFS: 11.1 vs. 5.6 months).
On another front, ETX-19477 — a first-in-class oral PARG inhibitor — received FDA fast track designation for BRCA-mutated HR+/HER2− metastatic breast cancer. Early phase 1 data from the ERADIC8 trial showed a 57% objective response rate and 100% disease control rate in eligible patients.
Looking ahead, two giredestrant decisions are expected before year-end: one for adjuvant use in early-stage ER+/HER2− breast cancer (PDUFA: Nov 30) and another for ESR1-mutated advanced disease in combination with everolimus (PDUFA: Dec 18).
By the Numbers
Why it matters: These advances signal a rapidly evolving breast cancer treatment landscape, with novel mechanisms like PARG inhibition entering the clinic and established agents expanding into new molecular subgroups — offering more targeted options for patients with limited alternatives.
