Sanofi preps for new pivotal trial of a blockbuster hopeful

One of the biggest pipeline setbacks Sanofi has experienced recently has been the failure of its high-profile Phase III breast cancer trial for iniparib back in January. Iniparib was the jewel in BiPar's crown when Sanofi bought it for $500 million and news of the triple-negative breast cancer trial failure rippled through the R&D world, triggering some dark second-guessing for that class of experimental medications. But Sanofi never did give up hope, pointing to sub-group data that highlighted drug activity. And now its research team is using some of the pieces from that failed study to puzzle out a new trial that will determine if a select group of patients could benefit from the drug.

In a release yesterday Sanofi highlighted their pre-planned analysis of breast cancer patients in the second- and third-line settings, which demonstrated progression-free survival rates of 4.2 months--a modest improvement compared to a 2.9 month survival rate among chemo-only patients. Sanofi also reported that in a Phase II study of platinum-sensitive ovarian cancer, iniparib, when combined with chemotherapy, demonstrated a 65 percent overall response rate among 40 evaluable patients.

"You can't use subgroup data for making a claim," Debasish Roychowdhury, Sanofi's oncology chief, told FierceBiotech during his stay at ASCO. But, he adds, the data along with fresh work on related biomarkers lays a foundation for an "important hypothesis. And that's how we are going to use this."

Roychowdhury says that once the pharma giant completes its analytical work on iniparib he hopes to launch a new pivotal trial for the drug in the second half of next year. "I think the trick is to first find the right population of patients who will benefit from this drug," he adds, noting that Sanofi investigators have been particularly encouraged by positive signs of the hazard ratio, a key clinical measure of risk related to disease progression and death.

Sanofi's work will be closely followed by other companies studying PARP inhibitors. "It's gone from a darling of the one where people are shaking their heads and wondering, 'Do we even have a validated target here?'" Pfizer's Mace Rothenberg said after Sanofi's failure.

Sanofi also unveiled new data on Zaltrap (aflibercept), with previously treated colon cancer patients on the drug plus chemo gaining survival time; 13.5 months versus 12.1 months. And Sanofi along with partner Regeneron say that's good enough to win regulatory approval. "We plan to submit regulatory applications for marketing approval to the U.S. Food and Drug Administration and the European Medicines Agency in the second half of the year," says Roychowdhury.

- check out the release on iniparib (.pdf)
- here's the release on Zaltrap (.pdf)