- In patients with PIK3CA-mutated, HR+/HER2- advanced breast cancer, the addition of alpelisib to fulvestrant extended median overall survival (OS) by 8 months.
- The difference was not statistically significant, but judged clinically relevant by the investigators.
Why this matters
- PIK3CA mutations occur in approximately 40% of patients with HR+/HER2- breast cancer. In the phase 3 SOLAR-1 trial the PI3Kα-specific inhibitor alpelisib (ALP) extended progression-free survival (PFS) from 5.7 to 11.0 months when added to fulvestrant (FUL).
- The overall survival data were immature at the time and are now being reported.
- 572 women were randomized 1:1 to receive ALP (300 mg PO QD) or placebo (PBO), +FUL (500 mg IM on D1 and D15 of C1 then D1 of each 28-d cycle).
- Median follow-up for OS was 30.8 months.
- Funding: Novartis.
- Median OS was 39.3 months with ALP+FUL (95% CI, 34.1-44.9) and 31.4 months with PBO+FUL (95% CI, 26.8-41.3).
- Median time to chemotherapy was 23.3 months versus 14.8 months.
- In patients with lung and/or liver metastases, median OS was 37.2 versus 22.8 months.
- Safety profile was consistent with previously reported results.
- The authors judge the 8 month difference in OS as clinically relevant, although statistical significance was not reached.
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