Novartis recently announced results of an exploratory retrospective biomarker analysis finding that different genetic mutation profiles in tumours harbouring PIK3CA mutation did not affect treatment benefit with Piqray (alpelisib) plus fulvestrant in patients with hormone receptor-positive, human epidermal growth factor receptor-2 negative (HR+/HER2-) advanced or metastatic breast cancer following progression on or after an endocrine-based regimen. Selected as an oral presentation at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting, the retrospective analysis of data from the phase-III Solar-1 study found that the clinical benefit of the Piqray and fulvestrant combination was maintained regardless of genetic alterations in most biomarkers, including ESR1 and genes implicated in resistance to CDK4/6 inhibitors, a statement from Novartis notified.
The Solar-1 biomarker retrospective analysis at ASCO highlighted that patients with ESR1 gene alterations achieved 12 months of median Progression-Free Survival (mPFS) when treated with Piqray and fulvestrant compared to 6.5 months for those treated with fulvestrant alone. Even patients with FGFR1 and FGFR2 gene alterations, which have been associated with resistance to CDK4/6 inhibitors, had benefit when treated with Piqray plus fulvestrant (12.7 months and 9.6 months mPFS, respectively), compared to those treated with fulvestrant alone (3.8 months and 2.8 months mPFS, respectively). The benefit seen with the Piqray and fulvestrant combination was independent of additional genetic alterations, including TP53, CCND1, MAP3K1 and ARID1A; genes in the MAPK pathway, genes implicated in CDK4/6 inhibitor resistance such as RB11.