Eli Lilly and Co. said Tuesday morning that senior vice president John H. Johnson, president of the company's oncology unit, has resigned.

Indianapolis-based Lilly said in a press release that personal and family considerations led to Johnson's decision to leave the company. However, according to Bloomberg News, Johnson has been hired by as CEO of East Brunswick, N.J.-based biotechnology company Savient Pharmaceuticals Inc. 

Johnson’s resignation from Lilly Oncology is effective Friday. A successor will be named in the coming weeks, Lilly said.

Savient, a drug development firm that failed to find a buyer last year, named Johnson, 52, to help market its newly approved gout drug, Krystexxa. He will start at Savient on Jan. 31. Savient President Paul Hamelin, who had been leading the company, will leave after a transition period.

Lilly’s oncology research received a boost when the company purchased New York-based ImClone Systems Inc. for $6.5 billion in 2008, the largest acquisition in Lilly’s history. Johnson, ImClone’s CEO at the time, was brought on to lead Lilly’s oncology business. Previously, he headed Johnson & Johnson’s biopharmaceuticals unit.

“Given his previous post at ImClone, John has played a key role leading the integration efforts since Lilly’s acquisition,” Lilly President and CEO John Lechleiter said in a prepared statement. “He has always been a champion of serving patients and has guided the Lilly Oncology pipeline to an all-time high—one of the largest clinical-stage pipelines of potential cancer medicines in the industry.”

However, results of Lilly’s oncology efforts have been mixed lately.

In December, the company suspended a late-stage clinical trial of a medicine for skin-cancer patients after 12 patients in the study died.

And, in October, a study found that Lilly and Merck KGaA’s Erbitux drug failed to help colon cancer patients, which may leave doctors less likely to combine the drug with a certain type of chemotherapy. However, the drug was found to delay the spread of breast cancer by about two months in a study of women with a certain type of aggressive tumor.