Janssen has launched its HIV therapy Rezolsta in the UK, which combines its own Prezista with Gilead’s Tybost.
Prezista (darunavir) is the UK’s most prescribed protease inhibitor, while Tybost (cobicistat) is an established boosting agent also used with Bristol-Myers Squibb’s Reyataz (atazanavir) and Gilead’s own elvitegravir.
The launch follows an EMA approval based on trial data suggesting that Rezolsta was effective over 48 weeks, with only 5% of patients discontinuing the treatment due to adverse events. Adding Tybost helps the drug retain a high genetic barrier to resistance of Prezista.
“The availability of this new formulation means that, for the first time, patients will be able to take a protease inhibitor and boosting agent once a day, in a single tablet, in combination with other required antiretroviral medicines,” says Professor Anna Geretti from the Institute of Infection and Global Health at the University of Liverpool.
“Reducing the pill burden in this way could increase patient adherence to treatment.”
Studies have suggested that although adherence to HIV treatment is essential in order to prevent low drug levels in the blood allowing the virus to become resistant to drugs, 39% of patients show less than 90% adherence to their regimen.
It is estimated that there are 100,000 people living with HIV in the UK and approximately 6,000 new diagnoses confirmed each year. Protease inhibitors like Prezista combat the virus by blocking an enzyme that it uses to help replicate.
Both drugs in the Rezolsta combination have previously faced manufacturing issues. Tybost hit a stumbling block on its road to the market in the US when the FDA raised concerns about of deficiencies in their marketing applications related to manufacturing, while Janssen recalled over 11,000 bottles of Prezista in 2011 due to contamination.
In its statement Janssen says that it will continue to make Prezista available as a single agent so that “patients and their physicians can decide which HIV treatment regimen is best for them”.