Gilead Sciences may be best known for its HIV drug franchise and a stellar late-stage effort on the hepatitis C front, but the big biotech is also making an ambitious bid to rapidly build a portfolio of cancer drugs. And last night Gilead ($GILD) captured a bit of the ASCO limelight with positive data from a small, early-stage study of the leukemia drug idelalisib (GS-1101).
In the Phase I study of 54 patients whose cancer had relapsed after multiple treatments, the drug--a PI3K delta inhibitor picked up with the $600 million deal to acquire Calistoga--spurred a durable shrinkage of tumors in more than half of the patients with chronic lymphocytic leukemia. The median progression-free survival time was 17 months, which impressed investigators as it involved patients with some of the hardest cases to treat.
Typically, this would amount to a solid start along a very long R&D trail, but Gilead is demonstrating its usual zeal in accelerating development. Convinced that this particular type of PI3K subset inhibitor can change the standard of care for refractory patients--a sizeable percentage of the population--Gilead is hurrying to see if it can make a case for an approval on mid-stage data, ahead of a Phase III readout. The FDA has been signaling its interest in short-circuiting the regular development process, particularly for cancer, in an effort to speed up the development process.
"Drugs like idelalisib are probably going to change the landscape of the disease in the next few years," the Dana-Farber Cancer Institute's Jennifer Brown told Reuters. And Thomson Pharma has forecast peak potential sales at around $500 million.
"New therapies that can drive CLL into remission while potentially avoiding or delaying the need for chemotherapy would represent a much needed clinical advance," said Susan M. O'Brien, of the University of Texas MD Anderson Cancer Center in Houston and a principal investigator of the study. "The high overall response rate and durable disease control observed in this Phase 2 study suggest that idelalisib in combination with rituximab could become an important therapeutic option for CLL patients new to treatment."