MSD UK has launched a once-daily version of its blockbuster HIV treatment Isentress (raltegravir) in the UK.

Taken as two 600mg pills, it can be used - in combination with other antiretrovirals - to treat HIV-1 infection in adults and paediatric patients.

Louise Houson, managing director at MSD UK, said: “As a company, we have been involved with the global response to HIV for 30 years.

“Throughout that time, progress has only been possible through partnership with thousands of people living with HIV in scientific studies and trials and today we recognise their contribution with huge gratitude. The European Commission’s marketing authorisation of once-daily raltegravir 600 mg exemplifies MSD’s commitment to innovate and invent to make a real-life difference.”

The launch follows European approval in July for patients who are treatment-naïve or whose virus has been virologically suppressed by a twice-daily, 400mg dose of Isentress.

That approval came on the back of the phase III ONCEMRK trial, which involved 800 treatment-naïve HIV-1 infected patients and compared the 1,200mg once-daily dose of Isentress 600mg to a 400mg twice a day regimen.

It found 89% of those on the once-daily dose achieved viral suppression of HIV-1 RNA compared to 88% of patients receiving raltegravir 400mg twice a day, with both groups also getting emtricitabine plus tenofovir disoproxil fumarate.

Dr Andrew Ustianowski, infectious diseases consultant at the Pennine Acute Hospitals NHS Trust, said: “We hope and believe that people living with HIV can lead a full and healthy life - but this requires long-term regular and effective anti-retroviral medication.

“Once-daily medications are an important contributor to aiding some individuals in taking their treatment well, and therefore the new once-daily raltegravir formulation is a welcome and important development for our patients.”

First launched in the UK in 2008 as a first-in-class integrase inhibitor, Isentress’ launch as a once-daily treatment will allow it to compete with ViiV’s newer, and once-daily, integrase inhibitor Tivicay (dolutegravir).

Though Isentress’ sales have been slipping in recent years it remains an important product for the firm, racking up $1.4bn in global revenues last year.