Taselisib shows promise in relation to other PI3K inhibitors for HR+/HER2- breast cancer patients.
By Zachary McLellan, Analyst
22 May 2016
I am an oncology analyst at Datamonitor Healthcare based in the New York office. I joined Datamonitor in June 2015 while...
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Results from taselisib’s (Roche/Chugai) open-label Phase II trial compare favorably with other phosphoinositide 3-kinase (PI3K) inhibitors in development for hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) breast cancer. Taselisib’s confirmed response rate of 41.7% in PIK3CA-mutated patients is an improvement upon Novartis’ isoform-specific PI3K inhibitor alpelisib, which saw a response rate of only 25% in its Phase II trial. In a much larger Phase III trial, Novartis’ pan-PI3K inhibitor, buparlisib, had an overall response rate of 18% and a clinical benefit rate of 47% in PIK3CA-mutated patients. Mutations in the PI3K pathway represent the largest mutation subtype in HR+/HER2- breast cancer patients, however taselisib will need to demonstrate superior efficacy to Novartis’ PI3K inhibitors in larger studies in order to successfully compete for patient share within this subgroup. Taselisib is currently being investigated in combination with fulvestrant in the pivotal Phase III SANDPIPER trial, which is due to complete in June 2018 (ClinicalTrials.gov identifier: NCT02340221).
Early-phase efficacy data for PI3K inhibitors in HR+/HER2- breast cancer
|taselisib (Roche/Chugai)||(NCT01296555) (Phase I/II)||CRR = 41.7%|
|alpelisib (Novartis)||CBYL719A2201 (NCT01923168) (Phase II)||RR = 25%|
|buparlisib (Novartis)||BELLE-2 (NCT01610284) (Phase III)||ORR = 18%, CBR = 47%|
|CBR = clinical benefit rate; CRR = confirmed response rate; ORR = overall response rate; RR = response rate|
|Source: Baselga et al., 2015; Dickler et al., 2016; Mayer et al., 2015|
Abstracts from the 52nd Annual meeting of the American Society of Clinical Oncology (ASCO) were released May 18th. Datamonitor Healthcare and Biomedtracker’s Pre-ASCO 2016 Report provides supplemental analyses on key abstracts and companies to watch during this year’s meeting.
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