The response rate in patients who previously received ipi has been 10% lower all along. But, most clinicians see this as a breakeven proposition since ipi itself has a 10% response rate, meaning that patients who try it be first and then move onto PD1 have an aggregate likelihood of response that is the same as PD1 upfront. And, since ipi responses seem more likely to be durable than PD1 responses, this is seen by many as a reasonable sequence of therapies to consider in the near future. Nonetheless, it would be nice for doctors to have a choice in terms of when to use a PD1 antibody and not have that forced by the FDA label.
Keith T. Flaherty, M.D.
Director, Henri and Belinda Termeer Center for Targeted Therapies