Geron triumphs in FDA AdComm battle, securing 12-2 vote in favor of blood cancer drug imetelstat

Geron has triumphed in its latest uphill battle. Facing questions about the trade-offs of its blood cancer drug candidate imetelstat, the biotech won over an FDA advisory committee and secured a 12 to 2 vote in its favor—triggering a surge in its share price.

After decades of setbacks, Geron reported a phase 3 win at the start of last year and outlined plans to file for FDA approval of its telomerase inhibitor imetelstat. However, details of the clinical data muddied the waters, leading this week to the publication of a FDA briefing document that raised questions about whether the benefits of imetelstat outweigh the risks in myelodysplastic syndromes (MDS).

Thursday, 12 of the experts on the FDA’s Oncologic Drugs Advisory Committee voted that the benefits do outweigh the risks. 

“This trial met its primary endpoint and offers a new therapy for some patients who may have no other option, depending on their MDS classification,” Neil Vasan, M.D., Ph.D., an assistant professor at the Columbia University Irving Medical Center, said in the meeting. “I felt that the benefits of improvement in transfusion independence outweighed the risks of cytopenia in a patient population and in a blood cancer oncology community that's well versed in these adverse events and their management.”

The National Cancer Institute’s Ravi Madan, M.D., delivered one of the two negative votes. While Madan said “a significant minority of patients clearly benefited from imetelstat,” he concluded that the efficacy seen in some people failed to outweigh the toxicity experienced by most patients. The molecule “seems to be life changing” for some people, Madan added, but better tools to identify responders are needed.  

Christopher Lieu, M.D., an associate professor at the University of Colorado, grappled with many of the same issues as Madan but reached a different answer. The decision is “primarily an issue of trade-offs,” Lieu said. With imetelstat seemingly having little effect on overall survival and response rates, Lieu said the question is whether achieving transfusion independence offsets the side effects.

“To me, this becomes truly a quality of life issue. What we have heard from patients and providers is that the quality of life benefits outweigh the negative impacts of this agent. So, though I am concerned about the risks in this total trial population—in other words, not just the responders—I do believe it is more likely than not that there is a quality of life benefit here that is real,” Lieu said.

The FDA can, and on occasion does, reject drugs that received the support of advisory committees, but getting the backing of the experts typically paves the way to regulatory authorization. Geron is set to learn the FDA’s decision by June 16. Anticipating an authorization, investors sent shares in the biotech up around 85% in premarket trading Friday, pushing its value up above $3.20.