Additional PARPs Under Investigation for Breast Cancer

Transcript:

Joyce O’Shaughnessy, MD: Let’s talk about what’s coming soon. We’re probably going to be looking at a second PARP inhibitor that’s going to be approved, we hope, fairly soon. This is based on the EMBRACA data, which just came out at the 2017 San Antonio Breast Cancer Symposium. Could you tell us about that?

Nadine Tung, MD: Sure. EMBRACA used talazoparib, a different PARP inhibitor. Otherwise, it was a very, very similar randomized phase III trial. It really included the same population that Tiffany just talked about with the OlympiAD trial. These are patients with metastatic breast cancer. They are HER2-negative, with the germline BRCA mutation. They all had received no more than 2 lines of chemotherapy in the metastatic setting. Again, they were randomized to either a single-agent monotherapy PARP inhibitor (talazoparib) or standard (not platinum) chemotherapy. So the design was nearly identical. The results were very, very similar. Again, there was a significant improvement in progression-free survival. The median progression-free survival improved by about 3 months. Again, the hazard ratio—0.54. Still, like in OlympiAD, there were no improvements in overall survival—although I think there’s hope that the curves will separate. So we’ll see. We saw very, very similar efficacy. Again, we also saw a better quality of life than with standard chemotherapy.

The toxicity was different. I don’t know whether you want to hold off on talking about that, but the toxicity profiles were a little different. Investigators saw a little bit of alopecia. Twenty-five percent of patients had alopecia. That may be significant. There was also a bit more myelosuppression. So I think the toxicity was a little bit different. The efficacy really looked similar. There are other PARP inhibitors being studied, but EMBRACA is really the most far along, in terms of the phase III data that we heard about in San Antonio. So I think that that’s the next one. There are other PARP inhibitors being evaluated in the early setting, which I think we may talk about later. There is olaparib, in the adjuvant setting, and some other ones, which are moving all the way up into the neoadjuvant setting. But I think talazoparib is the most well established, and I would be looking for an FDA approval soon.

Transcript Edited for Clarity