US-based biotechnology company Gilead Sciences has released the results of a Phase III trial, PHOTON-1, designed to evaluate the investigational once-daily nucleotide analogue ‘sofosbuvir’ for the treatment of chronic hepatitis C virus (HCV) infection in patients co-infected with human immunodeficiency virus (HIV).

Currently, PHOTON-1 is being carried out at sites in the US and Puerto Rico to assess the efficacy and safety of 12 or 24 weeks of sofosbuvir 400mg once-daily plus weight-based RBV among HCV treatment-naïve patients with genotype 1, 2 or 3 HCV infection who are also HIV-positive.

About 114 genotype 1 HCV treatment-naïve patients participated in the trial, out of which 76% (87 people) were given an all-oral, interferon-free regimen of sofosbuvir plus ribavirin (RBV) for 24 weeks, which has seen a sustained virologic response 12 weeks after end of the therapy (SVR12).

According to the company, the patients who get SVR12 are considered cured of HCV infection an about one-third of people living with HIV in the US are co-infected with HCV.

"This regimen may have the potential to help us overcome the clinical challenge of treating HCV/HIV co-infection."

Existing HCV medicines are related with suboptimal cure rates among co-infected patients and can cause significant interactions with HIV drugs.

Mount Sinai School of Medicine’s professor of liver diseases Douglas Dieterich said there is a clear need for HCV treatment regimens that are more effective and safer for patients who are co-infected with HIV.

"In this study, sofosbuvir-based all-oral therapy achieved high SVR rates in a hard-to-treat patient population," Dieterich said.

"This regimen may have the potential to help us overcome the clinical challenge of treating HCV/HIV co-infection."

The trial also evaluated 12 weeks of sofosbuvir plus RBV among genotype 2 and 3 HCV treatment-naïve patients with HIV.

Among genotype 2 patients receiving sofosbuvir, 88% (n=23/26) achieved SVR12, while 67% (n=28/42) of genotype 3 patients achieved SVR12.

The company said all patients in the trial who did not achieve SVR12 had viral relapse after cessation of therapy, with the exception of two participants who were non-adherent to study drugs.

The adverse events were reported in 3% of patients who received 24 weeks of therapy and in 4% of patients who received 12 weeks of therapy.

According to the company, the most common side effects observed in the study were consistent with the safety profile of RBV and included fatigue, nausea, headache and insomnia.