AstraZeneca ties up with little Mirati on another PD-L1 combo trial

Mirati CEO Charles Baum

AstraZeneca's ($AZN) big MedImmune subsidiary has a new partner for its closely-watched PD-L1 checkpoint inhibitor durvalumab (MEDI4736). Little Mirati Therapeutics, which is run by some high-profile cancer R&D execs, has struck a deal to pair the therapy with its HDAC inhibitor, mocetinostat, against non-small cell lung cancer.

In the pact--the latest in a long string of combination plays in the checkpoint field--Mirati will foot the bill for an early-stage proof-of-concept study to evaluate the combo in the clinic next year, with MedImmune supplying durvalumab. And MedImmune gets a chance to study the results with rights to craft the first licensing proposa--if it's promising enough.

Little Mirati Therapeutics ($MRTX), which has a $465 million market cap, used to be called MethylGene before it was moved to the U.S. a few years ago, named former Pfizer oncology R&D chief--and Schering-Plough vet--Charles Baum as its new CEO and won a listing on Nasdaq. The San Diego-based company had followed a rocky road financially when it filed its S-1 in 2013, but appears to have stabilized in recent times. Its CMO is Isan Chen, who worked as CMO at Aragon before J&J bought it out in a $1 billion deal.

Durvalumab is coming up behind the two leading checkpoint inhibitors from Bristol-Myers Squibb and Merck, with Roche hustling along a dozen different late-stage studies of its own PD-L1 therapy. The basic idea behind all of them is that a drug can dismantle the mechanism that cancer cells rely on to stay invisible to the immune system. By flagging cancer cells for destruction, these drugs offer an ideal combo approach for targeted drugs that can amp up the therapeutic impact of a checkpoint inhibitor.

"There is a growing body of evidence that mocetinostat may enhance the efficacy of immune checkpoint inhibitors such as PD-L1 antibodies," said Baum in a statement. "Mocetinostat selectively targets specific HDACs that may increase the efficacy of durvalumab in patients with non-small cell lung cancer, as well as other tumor types. We look forward to working with MedImmune on this novel combination to potentially improve outcomes for patients."

Mocetinostat is partnered with Taiho in Asia. Mirati's web site notes that the drug is currently in Phase II trials as a single agent in patients with bladder cancer and DLBCL. Mocetinostat is also in a Phase II dose confirmation study in combination with Vidaza as treatment for intermediate and high-risk myelodysplastic syndrome.

- here's the release