Merck has received FDA approval for its Idvynso, a combination regimen that brings its novel islatravir to market for the first time, offering an alternative to HIV patients and serving as the cornerstone of what could be a lucrative HIV franchise for the company, reports Fierce Pharma.
Idvynso is a once-daily, two-drug oral pairing of Merck’s doravirine and islatravir. Doravirine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that has been commercialised since 2018 as part of Merck’s Pifeltro and Delstrigo, while islatravir is a newer nucleoside reverse transcriptase translocation inhibitor (NRTTI) that represents the “anchor medicine” in a number of other HIV combos the company is advancing.
The doravirine and islatravir combo’s debut is specifically targeted at patients who are switching from other HIV treatments and will be available in pharmacies after 11 May, Merck said in its press release.
The FDA signed off on the drug last week as an HIV treatment to replace current antiretroviral regimens among adults who are virologically suppressed and who have no history of virologic treatment failure or treatment substitutions due to doravirine resistance.
A pair of phase 3 studies tested the drug in those on a baseline antiretroviral therapy and those who manage their HIV with Gilead’s leading Biktarvy.
The studies showed that Idvynso was non-inferior to both comparators while offering a “generally comparable” safety profile, Merck said. The trials formed part of a new drug application the company filed in July, with the new approval coming a week before the 28 April decision date the FDA had previously set.
In one study, those who switched from Biktarvy to Indvynso saw “minimal changes” in weight and body composition, Merck reported in October. Those are two common concerns that can often be central for those with HIV, said Queen Mary University of London’s Chloe Orkin, MD, at the time.
“As the only two-drug, non-INSTI, tenofovir-free regimen, Idvynso expands therapeutic diversity beyond the currently available oral treatment options,” said Eliav Barr, MD, chief medical officer at Merck Research Laboratories.
“As the health needs of adults with HIV change over time, Idvynso gives clinicians a new choice for treatment.”
Idvynso enters an HIV treatment market populated by integrase strand transfer inhibitors (INSTIs), a popular antiretroviral drug class that includes molecules used in Gilead’s Biktarvy and GSK’s Dovato, to name a few.
However, INSTIs have been associated with resistance mechanisms that can leave users at risk of unsuppressed HIV.
With benefits in convenience and tolerability coupled with a low risk of drug-drug interactions, Merck is confident that its Idvynso could make for a go-to choice for the one in five patients who switch HIV regimens each year, company executives said.
That said, Idvynso is contraindicated when co-administered with specific drugs such as certain enzyme inducers, as specified by Merck in its release.
Still, much more is to come for the new entrant to the HIV market, as Merck has long been busy testing out islatravir across several patient populations.
Last year, the company reported that its doravirine-islatravir combo met the bar in a phase 3 trial evaluating its benefits across treatment-naïve patients, demonstrating non-inferiority to once-daily oral Biktarvy.
Elsewhere, as well as being studied with other investigational Merck HIV treatments, islatravir has been paired with Gilead’s lenacapavir as a potential once-weekly combo therapy. That cocktail has already proved that it can sustain viral suppression in patients who switched from another therapy.
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Optimism as phase 3 trials launch for new monthly anti-HIV pill