Infinity Pharmaceuticals isn’t ready to pull the plug on its lead cancer drug candidate after it failed last month in a clinical trial. The Cambridge, MA-based biotech company (NASDAQ: INFI) says it sees a way forward with the drug, IPI-504, as long as it switches to a lower dose, and by giving it to patients with a genetic makeup that makes them appear more likely to benefit.
Those ideas emerged from a study of 57 advanced lung cancer patients who got retaspimycin (IPI-504) in a clinical trial, which was presented over the weekend at the American Society of Clinical Oncology meeting in Orlando, FL. Researchers found that among patients who were heavily pre-treated, 14 percent (4 of 28) had their tumors partially shrink if they had a normal form of a tumor growth gene called EGFR. No responses like that were seen among patients with a mutated form of the gene, or with unknown status, researchers said. The drug was well-tolerated, with the most common side effects being nausea and fatigue.
Infinity is hopeful this will inject new life into the drug, which is designed to block hsp90. This compound is a leader in a new class of therapies that are made to block a molecular chaperone that is thought to help cancer cells survive even when under stress from things like chemotherapy. Infinity suffered a big setback last month when a clinical trial was halted early after interim results showed patients with gastrointestinal stromal tumors who were taking the drug had a higher risk of death than those in a control group. The key lessons, says Infinity president and chief scientist Julian Adams, are to back off from the maximum dose that patients can tolerate, and to select patients in advance who, based on their genetics, are most likely to benefit.
“There’s a false belief that more is better with cancer drugs,” Adams says. “Especially with more targeted therapies, it’s not true.”
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