Sunday, May 31, 2009

ASCO Conference This Week

News about results of a study on PARP inhibitors and triple negative breast cancer. This study compared Gemzar and Carboplatin with and without BSI-201 in women with triple-negative metastatic breast cancer as either the first chemo for metastatic disease, or after one or two prior chemo regimens. BiPar announded interim safety data from this trial at the San Antonio Breast Cancer Symposium, finding NO additional signigicant toxicity attributed to the experimental drug.

Quick note from Musa Mayer who is attending the Conference:

While the full presentation won't occur until tomorrow afternoon, today they released some of the findings, and I just had to tell you what I know, so far:

"Analyzes of the first 86 patients of a planned 120 patients showed that BSI-201 + G/C (Gemzar and Carboplatin) had improved CBR (clinical benefit rate, those with tumor shrinkage or stable disease), median PFS (progression-free survival) and median OS (overall survival), compared with G/C alone. The frequency and nature of adverse events (AEs) did not differ between arms."

How much of an improvement is what's impressive.

* CBR is 12% with G/C vs. 52% with G/C+BSI-201.

* Median PFS is 87 days with G/C and 211 days with G/C+BSI-201 with a HR (hazard ratio) of 0.30. In case these numbers don't mean anything to you, this amounts a 70% improvement in progression-free survival.

* Median OS: patients in the G/C arm had a median survival of 169 days, but patients on the G/C arm of the study had a median survival of more than 254 days, for a HR of 0.24. That means that patients exposed to the experimental drug lived 76% longer.

If these findings hold up in the completed study and in a full-scale Phase III trial of sufficient size to be definitive--and that's a big if, of course--this magnitude of benefit will be beyond any breast cancer drug we've seen in the 15+ years I've been following drug development. However, this is a small number of patients, not even the full number enrolled in the study, and the study itself isn't sufficiently powered to show a definitive difference.

The results of the entire study, with all 120 patients along with some studies of PARP expression will be presented tomorrow afternoon--you'll be hearing about it on the news. I'm excited!

Great news, Musa! Thanks for sharing.

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