Acting Commissioner Ned Sharpless has competition.

Since Scott Gottlieb unexpectedly stepped down from his position as U.S. Food and Drug Administration (FDA) commissioner, curiosity over who will take his place has risen. One of the top candidates is, not surprisingly, Acting Commissioner Ned Sharpless, who previously was director of the National Cancer Institute. Sharpless was recommended by Gottlieb, and he still has his backing, along with several other former FDA heads (Robert Califf, Margaret Hamburg, Andrew von Eschenbach and Mark McClellan) and many patient groups.

On the other hand, many top officials have continued to leave the agency under Sharpless’ watch, including the director of the Office of Antimicrobial Products within the Center for Drug Evaluation and Research and the senior adviser to the commissioner. Both officials left for positions in industry.

There are two other top choices, according to the Wall Street Journal: Stephen Hahn, CEO of MD Anderson Cancer Center, and Alexa Boer Kimball, a dermatologist and President and CEO of Harvard Medical Faculty Physicians at Beth Israel Deaconess Medical Center.

A permanent FDA head must be appointed with 210 days of the departure of Gottlieb, according to the Federal Vacancies Reform Act. That means the Trump administration must select his replacement by early November.