“We are very enthusiastic to evaluate Pfizer’s novel investigative selective-CDK4 inhibitor atirmociclib in combination with RLY-2608, the first mutant selective PI3Kα inhibitor,” said Don Bergstrom, M.D., Ph.D., President of R&D at Relay Therapeutics. “We believe that combining these two selective agents – atirmociclib and RLY-2608 – will avoid key off-target toxicity that comes from hitting CDK6 and wild-type PI3Kα, which has historically significantly limited use of non-selective agents. The breast cancer treatment landscape continues to evolve quickly, and we are pleased that the safety profile RLY-2608 has demonstrated to-date makes it well-positioned to be part of the next generation of therapies.”