Washington

Harold Varmus, director of the US National Institutes of Health (NIH), announced last week that he will resign at the end of the year to become president of the Memorial Sloan-Kettering Cancer Center in New York.

Varmus's six years in office have seen a remarkable expansion in NIH's budget — from just over $10 billion to almost $16 billion — and something of a renaissance in the scientific reputation of the institute's intramural programmes.

He claims that “the whole enterprise is a happier and a stronger place” than when he arrived, partly because of the budget but also because of the people he has recruited.

Varmus's letter of resignation to President Bill Clinton called on the president “to consider other active medical scientists” in the search for a successor.

Varmus, who won the Nobel prize for physiology and medicine in 1989 with Michael Bishop for his work on retroviral oncogenes, says his top priority in New York will be “bringing basic science together with the clinical researchers”. He intends to strengthen some areas of research, including cancer genetics, and to collaborate with other New York medical centres.

During his tenure at NIH, Varmus developed a knack for preventing difficult issues, such as embryo research, from disrupting the agency's ties with the Congress. He also maintained excellent relations with Capitol Hill after Republicans assumed control of both houses of Congress in 1995.

Ruth Kirschstein, NIH deputy director and a long-time NIH administrator, will take over as acting director while a search committee seeks a nominee to replace Varmus.

With the presidential elections due next November, it may prove difficult for Clinton and Donna Shalala, the health secretary and Varmus's immediate boss, to find a suitable replacement. Any appointee would have to be confirmed by the Republican-controlled Senate, and be prepared to work for a new health secretary in a new administration, Democrat or Republican.

This may make the position unattractive to an outsider in the Varmus mould, and early speculation has focused on top scientific administrators already at NIH who have good political connections with both parties. These include Tony Fauci, director of the National Institute of Allergy and Infectious Diseases, and Richard Klausner, head of the National Cancer Institute.