Bristol-Myers Squibb’s experimental HIV-1 therapy BMS-663068 has been granted breakthrough status by the US Food and Drug Administration, potentially accelerating the drug’s development pathway.

A first-in-class HIV-1 attachment inhibitor, BMS-663068 (fostemsavir) is being targeted towards heavily treatment-experienced adult patients. The drug is thought to work at an earlier point in the replication process than standard entry inhibitors to prevent the virus’ initial interaction with immune cells and subsequent invasion.

Breakthrough designation is based on data from the Phase IIb clinical study comparing BMS-663068 to boosted protease inhibitor Reyataz (atazanavir sulfate) and ritonavir in treatment-experienced patients, with a treatment backbone across all arms of raltegravir, in addition to tenofovir disoproxil fumarate. This showed similar response rates in the two treatment groups.

A Phase III trial in heavily treatment-experienced patients (defined as individuals who can no longer formulate a viable three-drug treatment regimen due to accumulation of drug resistance, past intolerabilities or antiretroviral contraindications) is ongoing, BMS noted.