Gilead has reported the results of four phase III trials of a new HIV combination therapy pairing its Descovy product with new candidate bictegravir, and says it is ready to press on with regulatory filings.
The fixed dose combination of integrase strand inhibitor bictegravir with the two active ingredients in Descovy – emtricitabine and tenofovir alafenamide – met its main objective of non-inferiority to ViiV Healthcare’s Triumeq, which contains rival integrase Tivicay (dolutegravir) as well as abacavir and lamivudine.
Two studies pitted the two drug combinations head to head, while another two found patients were able to switch from ViiV’s drug to Gilead’s with no loss of viral suppression. Detailed data from the studies will be reported later in the year.
The new data represents an opportunity for Gilead to stage a comeback in the HIV category, where it has been losing market share to ViiV due to the success of Tivicay and Triumeq, which grew more than 80% to reach £2.7bn ($3.5bn) in sales last year.
The strong uptake of ViiV’s drugs comes on the back of what is viewed as a superior profile for dolutegravir compared to Gilead’s current integrase inhibitor elvitegravir – found in its Genvoya and Stribild products – which needs to be boosted with cobicistat.
With bictegravir Gilead reckons it can get back on to firmer footing, and the company says it plans to quickly move forward with a US filing this quarter and a European application next quarter, claiming the new combination “represents an important advance in triple-therapy treatment for a broad range of HIV patients”.
Analysts at Leerink agree. They are predicting sales of $10bn thanks to the combination’s “convenience, safety and tolerability and efficacy”, and they also think Gilead will use an FDA priority review voucher to get the drug to market in the US as quickly as possible.
Gilead needs a win at the moment due to sales of its hepatitis C blockbusters starting to slide as the available pool of eligible patients gets smaller, as well as combination from other drugs developed by the likes of AbbVie and Merck & Co.
Descovy was cleared by regulators in the US and EU last year for the treatment of HIV-1 infection in adults and children aged 12 and older, and forms the backbone of Gilead’s new generation of HIV drugs. The drug is an upgrade to Truvada, which combined emtricitabine with an older and less potent tenofovir salt (tenofovir disoproxil fumarate) that is heading for patent expiry.
The combination of TAF – which is considered a best-in-class non-nucleoside reverse transcriptase inhibitor – and bictegravir are key to Gilead’s fightback against an encroaching ViiV in HIV, according to analysts at Cowen & Co.
The firm cites HIV consultants who have suggested that even if bictegravir is deemed to be equivalent to ViiV’s dolutegravir in terms of both efficacy and safety, then bictegravir plus Descovy will become their go-to regimen.