Anna Edney / Bloomberg News

WASHINGTON — Harold Fuller has run out of options to keep his HIV at bay.

Fuller, 56, of Brooklyn, has lived with the virus for 20 years. Earlier in his illness, he stayed ahead of HIV’s ability to mutate by changing medicines every two years. For the past five years, though, Fuller has had to take the same pills because of a lack of new treatments.

“I’ve been on medication since 1995, and after a while everything stops working,” Fuller said in an interview. His doctor, he said, “has no clue what to do.”

With most HIV research focused on prevention and on developing drugs for the newly infected, a growing number of long-term patients like Fuller have found themselves caught in a medical no-man’s land with diminishing options to fight off the life-threatening virus. That may be about to change.

In a bid to give long-term sufferers more treatment options, the Food and Drug Administration is making it easier to develop new HIV drugs. New FDA guidelines close to approval are designed to cut the research time needed for regulatory clearance by eliminating previously mandated follow-up studies that can take almost a year to complete and cost millions of dollars.

The goal is to “open up the pipeline,” Jeffrey Murray, deputy director of the FDA’s antiviral products division, said in an interview.

Many pharmaceutical companies have refocused their infectious-disease research budgets away from the mature $17 billion global HIV market in favor of investments to tap the smaller yet faster-growing market for hepatitis C drugs. Now, the updated guidelines are making the market for new treatments for longtime HIV sufferers more appealing.

Margo Heath-Chiozzi, vice president for global regulatory strategy in virology at New York-based Bristol-Myers Squibb Co., said the changes makes sense.

The revised guidelines, unveiled in June, eliminate an almost yearlong follow-up study of therapies for HIV sufferers who have developed resistance to existing treatments. That’s an incentive for companies such as Bristol-Myers to invest in new drugs. Bristol-Myers is currently developing three new HIV drugs, two of which may help people resistant to existing drugs.