A Phase Ib Study of Alpelisib (BYL719), a PI3Kα-Specific Inhibitor, with Letrozole in ER+/HER2- Metastatic Breast Cancer
- PMID: 27126994
- PMCID: PMC5085926
- DOI: 10.1158/1078-0432.CCR-16-0134
A Phase Ib Study of Alpelisib (BYL719), a PI3Kα-Specific Inhibitor, with Letrozole in ER+/HER2- Metastatic Breast Cancer (V体育2025版)
Abstract
Purpose: Alpelisib, a selective oral inhibitor of the class I PI3K catalytic subunit p110α, has shown synergistic antitumor activity with endocrine therapy against ER+/PIK3CA-mutated breast cancer cells. This phase Ib study evaluated alpelisib plus letrozole's safety, tolerability, and preliminary activity in patients with metastatic ER+ breast cancer refractory to endocrine therapy VSports手机版. .
Experimental design: Twenty-six patients received letrozole and alpelisib daily V体育安卓版. Outcomes were assessed by standard solid-tumor phase I methods. Tumor blocks were collected for DNA extraction and next-generation sequencing. .
Results: Alpelisib's maximum-tolerated dose (MTD) in combination with letrozole was 300 mg/d. Common drug-related adverse events included hyperglycemia, nausea, fatigue, diarrhea, and rash with dose-limiting toxicity occurring at 350 mg/d of alpelisib. The clinical benefit rate (lack of progression ≥6 months) was 35% (44% in patients with PIK3CA-mutated and 20% in PIK3CA wild-type tumors; 95% CI, 17%-56%), including five objective responses. Of eight patients remaining on treatment ≥12 months, six had tumors with a PIK3CA mutation. Among evaluable tumors, those with FGFR1/2 amplification and KRAS and TP53 mutations did not derive clinical benefit. Overexpression of FGFR1 in ER+/PIK3CA mutant breast cancer cells attenuated the response to alpelisib in vitro CONCLUSIONS: The combination of letrozole and alpelisib was safe, with reversible toxicities V体育ios版. Clinical activity was observed independently of PIK3CA mutation status, although clinical benefit was seen in a higher proportion of patients with PIK3CA-mutated tumors. Phase II and III trials of alpelisib and endocrine therapy in patients with ER+ breast cancer are ongoing. Clin Cancer Res; 23(1); 26-34. ©2016 AACR. .
©2016 American Association for Cancer Research. VSports最新版本.
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