FDA to rule soon on Tekmira-created nanoparticle chemo drug

May 13 is the do-or-die date for Marqibo, a nanoparticle-delivered injectable cancer drug conceived by Canada's Tekmira Pharmaceuticals ($TKMR).

That's when the FDA is slated to decide whether or not it will approve the drug (vincristine sulfate liposomal injection) as a treatment for a form of acute lymphoblastic leukemia in patients whose cancer does not respond to other treatments, or have had relapses after previous successful ones. A mixed recommendation by an FDA panel of experts last week, however, makes the likelihood for approval up for debate.

Licensed and shepherded by Talon Therapeutics ($TLON) since 2006, Marqibo is a targeted, continuous-release cancer therapy, encapsulated by nanoparticles (sphingomyelin-based liposomes known as Optisomes, according to Talon's website), and has shown promise in both animal and early human trials. It is an injectable version of vincristine, an intravenous chemotherapy treatment. Tekmira gets milestone and royalty payments based on the drug's successful development and launch.

As FierceBiotech recently told you, 7 members of the Oncologic Drugs Advisory Committee panel voted that the clinical evidence showed the treatment's benefits outweighed its risks. Four voted no and two abstained. FDA officials will consider their recommendations when making their decision. (A solid vote for the drug would have been a lot better, of course.)

According to MedPage Today, Talon's Phase II single-arm, open-label dose escalation trial of 65 patients helped achieve a 4.6 month median overall survival time. Patients with complete remission, with or without complete blood count recovery, lived 7.7 months on average. Only 5 patients lived over a year after their last dose of the drug, however, and most patients endured severe side effects, according to the story.

Meanwhile, San Mateo, CA-based Talon is developing a Phase III trial for Marqibo. As MedPage Today notes, an FDA sign off for the drug as a last-option treatment would allow for an accelerated approval even with the drug in a Phase III trial.

- here's the Tekmira release
- check out Talon's announcement
- read the MedPage Today story