That was the essence of an email alert that landed in my inbox from sanofi-aventis just now:
“A randomized Phase III trial evaluating BSI-201 (iniparib*) in patients with metastatic triple-negative breast cancer (mTNBC) did not meet the pre-specified criteria for significance for co-primary endpoints of overall survival and progression-free survival.”
After the brouhaha of the positive phase II data published in the NEJM the other week, this is another example of we should be careful getting over-excited by early data until confirmatory larger scale study results are available.
However, while the agent flopped in newly diagnosed disease, in the relapsed/refractory setting there was a silver lining of hope:
“The results of a pre-specified analysis in patients treated in the second- and third-line setting demonstrate an improvement in overall survival and progression-free survival, consistent with what was seen in the Phase II study.
The overall safety analysis indicates that the addition of BSI-201 did not significantly add to the toxicity profile of gemcitabine and carboplatin.”
Iniparib was thought to offer the best chance of success with PARP inhibitors because the others have so far been shown to be
- more potent
- more challenging to combine given the toxicities involved.
Clearly it is a fine line between potency and toxicities with this particular class.
Trials are ongoing with other tumour types including lung cancer, but there may still be an opportunity for approval in triple negative breast cancer in the 2nd and 3rd line settings.
It will be interesting to see how the subset analysis pans out and whether those women who had the BRCA1 or 2 mutation fared better than those who did not.