Pictilisib PI3Kinase inhibitor (a phosphatidylinositol 3-kinase [PI3K] inhibitor) plus paclitaxel for the treatment of hormone receptor-positive, HER2-negative, locally recurrent, or metastatic breast cancer: interim analysis of the multicentre, placebo-controlled, phase II randomised PEGGY study.

Vuylsteke, Peter;Huizing, M;Petrakova, K;Roylance, R;Fehrenbacher, L;et.al.
(2016) Annals of Oncology — Vol. 27, n° 11, p. 2059-2066 (2016)

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  • Vuylsteke, PeterUCLouvain
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  • Huizing, M
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  • Petrakova, K
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  • Roylance, R
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  • Fehrenbacher, L
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Abstract
Approximately 40% of hormone receptor-positive, HER2-negative breast cancers (BCs) are associated with activating mutations of the phosphatidylinositol 3-kinase (PI3K) pathway. Pictilisib, a potent and highly specific class I pan-PI3K inhibitor, demonstrated preclinical activity in BC cell lines and may potentiate the effect of taxanes, benefiting patients with or without aberrant activation of the PI3K pathway. PEGGY (NCT01740336), a randomised, placebo-controlled phase II trial, examined whether pictilisib augments the anti-tumour activity of paclitaxel in patients with hormone receptor-positive, HER2-negative locally recurrent or metastatic BC (mBC). We report results from the protocol-specified interim analysis. One hundred and eighty-three eligible patients were randomised (1:1) to receive paclitaxel (90 mg/m2 weekly for 3 weeks in every 28-day cycle) with either 260 mg pictilisib or placebo (daily on days 1-5 every week). The primary end point was progression-free survival (PFS) in the intention-to-treat (ITT) population and patients with PIK3CA-mutated tumours. Secondary end points included overall response rate (ORR), duration of response, and safety. In the ITT population, the median PFS was 8.2 months with pictilisib (n = 91) versus 7.8 months with placebo (n = 92) [hazard ratio (HR) for progression or death, 0.95; 95% confidence interval (CI) 0.62-1.46; P = 0.83]. In patients with PIK3CA-mutated tumours, the median PFS was 7.3 months for pictilisib (n = 32) versus 5.8 months with placebo (n = 30) (HR, 1.06; 95% CI 0.52-2.12; P = 0.88). ORR was similar between treatment arms. The safety profile of pictilisib was consistent with previous reports, with no new safety signals. Proportions of patients with grade ≥3 adverse events (AEs), serious AEs, and dose reductions/discontinuations due to AEs were higher with pictilisib. PEGGY did not meet its primary end point, revealing no significant benefit from adding pictilisib to paclitaxel for patients with hormone receptor-positive, HER2-negative locally recurrent or mBC. NCT01740336.
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Vuylsteke, P., Huizing, M., Petrakova, K., Roylance, R., Laing, R., Chan, S., Abell, F., Gendreau, S., Rooney, I., Apt, D., Zhou, J., Singel, S., & Fehrenbacher, L. (2016). Pictilisib PI3Kinase inhibitor (a phosphatidylinositol 3-kinase [PI3K] inhibitor) plus paclitaxel for the treatment of hormone receptor-positive, HER2-negative, locally recurrent, or metastatic breast cancer: interim analysis of the multicentre, placebo-controlled, phase II randomised PEGGY study. Annals of Oncology, 27(11), 2059-2066. https://doi.org/10.1093/annonc/mdw320 (Original work published 2016)