FDA Commissioner Scott Gottlieb and two of his top aides took to the internet Friday to urge drug sponsors to continue treatment for especially needy clinical trial patients after their studies end and before the new treatment is officially approved.

In what amounts to an open letter to drug companies, Gottlieb, CDER Director Janet Woodcock and CBER Director Peter Marks said the agency’s expanded access program has offered a lifeline to more than 13,000 patients who otherwise might be without hope.

“Although we often focus on EA as providing access to patients who cannot enter clinical trials, EA can also be considered as a mechanism for those who have participated in a trial in order to allow them to continue receiving a drug that may have provided benefit,” the trio said in a public email. “We would generally support such efforts,” including in the case of trials that have shown benefit for only a few individual patients.

Gottlieb, Woodcock and Marks point out that offering patients expanded access “rarely impacts development timelines” and it’s “very rare” to see expanded access cause problems for a drug’s development. A review of more than 300 FDA regulatory decisions between 2010 and 2016 showed no negative impact of offering expanded access on any application.