- Seattle Genetics is moving forward with two Phase 1 studies of its blood cancer drug after regulatory authorities okayed new protocols that addressed some looming safety concerns.
- The Food and Drug Administration put those studies, which tested vadastuximab talirine in younger patients with acute myeloid leukemia (AML), on partial hold in late December because four patients died from hepatotoxicity in a third, Phase 1/2 trial also testing the drug for the AML indication, though in patients who had received allogeneic stem cell transplants.
- That Phase 1/2 trial received a full clinical hold, and will not be rebooted. The early-stage studies, however, got the go-ahead after Seattle Genetics provided more data and revised trial structures that emphasized safety. The trials also underwent an evaluation from an independent committee.
A bad safety profile can damage optimism for even the most promising of drugs. Eli Lilly's Zyprexa (olanzapine), Merck's Vioxx (rofecoxib) and Pfizer's torcetrapib are just a few notable examples.
Seattle Genetics' stock was down about 1% on Monday despite the news of lifted holds, likely reflecting continued worries on safety.
The company did not provide further details on how it amended the Phase 1 trials in a March 6 statement.
But in light of the scrapped Phase 1/2 trial, it is now preparing for a Phase 2 study testing its cancer medication in combination with the current standard of care for AML patients — known as 7+3 chemotherapy, which puts patients on a regimen of cytarabine and usually either daunorubicin or idarubicin. The mid-stage trial also targets younger patients who haven't previously received treatment, and is slated to begin sometime this year.
The FDA's clinical holds didn't affect two other vadastuximab talirine studies, including one Phase 3 trial evaluating the drug as a frontline treatment for older patients with AML, a group that has generally triggered fewer safety concerns. Seattle Genetics' CEO Clay Siegall revealed during a fourth quarter earnings call that the holds didn't negatively influence enrollment in the late-stage study.
In spite of the challenges present in AML treatment, drugmakers have signaled interest in the disease due in part to a growing market demand. A BCC Research report from September, for example, anticipated the global market for hematology cancer medications would grow to $38.2 billion by 2020, with a compound annual growth rate of 9.7% from 2015 through that later date.
Deals for AML treatments and companies have garnered big price tags as well, such as Jazz Pharmaceuticals' acquisition of Celator for $1.5 billion last May.