Eli Lilly ($LLY) and Merck ($MRK) are expanding their oncology partnership to study a combination of the former's top cancer prospect with the latter's blockbuster immunotherapy. Lilly is planning to sponsor a Phase I study combining its abemaciclib, a late-stage CDK 4/6 inhibitor, with Merck's Keytruda, which blocks the protein PD-1 to marshal an immune attack on tumor cells. The idea is to see whether the two drugs in tandem can make a difference in a variety of cancer types, and Lilly plans to embark on a Phase II effort if early signs are positive. Abemaciclib, which received the FDA's breakthrough therapy designation in October, is in late-stage development as a treatment for breast and lung cancers. Merck's therapy, another breakthrough designee, is approved in melanoma and lung cancer. Release