Roche pharmaceuticals has alerted the community that it is terminating its in-house research for new HIV drugs, according to a letter released to HIV treatment activists.

The company—which in the United States makes the protease inhibitor Invirase (saquinavir) and, in partnership with Trimeris, the fusion inhibitor Fuzeon (enfuvirtide)—has been studying two other types of antiretroviral (ARV) drugs. Those drugs, CCR5-based entry inhibitors and reverse transcriptase inhibitors, were all in the earliest stages of development. Roche, however, says, “We now have concluded that none would provide a true incremental benefit for patients compared to medicines currently on the market.”

In light of this setback, Roche has “decided to refocus [its] resources within virology on diseases in which [the company] can deliver substantial improvements over existing medicines,” including hepatitis C.

While Roche will continue manufacturing and selling Invirase and Fuzeon—and Viracept (nelfinavir) outside the U.S. and Canada—the company says that it will be keeping its eyes open for co-development or purchase of possible HIV drug candidates being explored by other companies.