Dive Brief:

• Merck & Co. research chief Roger Perlmutter will retire at the beginning of next year, stepping down after seven years of running the pharmaceutical company's storied research laboratories.
• Dean Li, who joined Merck in 2017 and currently serves as head of translational medicine, will succeed Perlumutter on Jan. 1, the company said Friday. Perlmutter will continue to serve as a non-executive director at Merck Research Laboratories until June 30 to aid the transition. 
• Perlmutter's legacy at Merck will be closely tied to the company's cancer immunotherapy Keytruda, a once overlooked drug that Perlmutter helped to build into one of the world's top-selling medicines and a foundational treatment for nearly 20 types of cancer, including tumors of the lung, skin, colon, kidney, head and neck. 

Dive Insight:

In June 2013, two months after Perlmutter took over the reins at Merck Research Laboratories, the drugmaker arrived at the industry's top cancer research conference with intriguing results from a small trial of an experimental compound then known as lambrolizumab. 

The drug, acquired via Merck's deal for Schering Plough in 2009, was an immunotherapy, designed to work against cancers by mobilizing the body's own defenses against tumor cells. While rival Bristol Myers Squibb had won U.S. approval for a similar drug, Yervoy, two years before, immunotherapy research in cancer was still emerging and far from established as a mainstay of cancer care. 

Under Peter Kim, Perlmutter's predecessor, Merck had hastily restarted work on the drug after it initially went overlooked in the research reorganization brought on by Merck's merger with Schering Plough. 

But it was Perlmutter who, seeing the early data in skin and lung cancer, pushed the company to aggressively expand study of the drug, renamed pembrolizumab. 

"Fairly quickly I said to people, 'You know, any one of you that's working on a project, if you want to spend a dollar on that project, you're going to have to explain to me why I shouldn't be spending it on pembrolizumab,'" Perlmutter told journalist Matthew Herper in a Forbes article published Sept. 5, 2014, the day after pembrolizumab's first U.S. approval. 

In the six years since, Merck has launched more than 1,000 studies of pembrolizumab, which is sold as Keytruda. The drug's success — it's cleared for use in 18 different types of cancer — has transformed Merck from a drugmaker known for primary care and infectious disease medicines to one that leads the most lucrative pharmaceutical market. It generated $11.1 billion in sales last year. 

Keytruda's development has tracked with the rapid expansion of immunotherapy research in cancer, inspiring work by dozens of biotech and pharmaceutical companies looking to replicate and expand on Merck's success. 

Perlmutter worked his way up through the ranks at Merck Research Laboratories between 1997 and 2001, when he left the company to head up research and development at Amgen. Over the next 11 years he helped reshape the big biotech's research pipeline, overseeing the progress of medicines like the bone drug Prolia and the cancer treatments like Imylgic and Blincyto. After more than a decade at the California biotech, he rejoined Merck as research chief in April 2013. 

At 67, Perlmutter is the oldest executive in Merck's C-suite, and one of its longest tenured members. Under his leadership, Merck also won U.S. approvals for drugs to treat HIV, hepatitis C, cytomegalovirus, diabetes, Ebola virus infections and rare cancers. 

"Roger's legacy will include a rejuvenated research and development organization, staffed by world class scientists, clinicians and professionals and led by Dr. Dean Li," said Kenneth Frazier, Merck's longtime CEO, in a statement.

While Perlmutter will stay in his role through Jan. 1, and continue to consult with Merck through June 30, he's already given some hint to where his interests post-Merck may lie. On Thursday, Insitro, a startup aiming to use machine learning to improve how drugs are discovered, announced that Perlmutter would become its first independent director.