Gilead Sciences has once again proven that independent biotechs can innovate with the best of Big Pharma. The Silicon Valley companyâ€™s wizardry at weaving multiple drugs into a single weft enabled it to overthrow GlaxoSmithKline as king of HIV in 2007. Yesterday, at the 16th annual Congress of Retroviruses and Opportunistic Infections (CROI), the biotech announced that the first-ever four-drug HIV combo cleared Phase I hurdles and will start Phase II by mid-year. Dubbed â€œThe Quad,â€ this masterwork of molecular bundling turns three different classes of anti-HIV drugs, plus a booster, into a once-daily capsule.
If approved, the Quad would likely improve patient adherence to HIV treatment, which typically calls for a â€œcocktailâ€ of three drugs, each with its own dosing requirements. Better adherence, in turn, decreases the risk of viral resistance and drug failure. The Quad would also likely shake up the marketâ€”not a first for the Foster City, CA, biotech, which was founded in 1987 during the darkest days of the AIDS epidemic.
After launching Viread (tenofovir) and Emtriva (emtricitabine)â€”two nucleoside/nucleotide reverse transcription inhibitorsâ€”Gilead pioneered fixed-dose HIV combinations in 2004 by combining the two molecules, and called it Truvada. Two years later, in a rare melding of two pharma competitors, the biotech partnered with Bristol-Myers Squibb to produce the first-ever three-drug HIV regimen in a one-a-day pillâ€”a medical advance that was unimaginable a decade earlier. Atripla, which combines Truvada with BMSâ€™s Sustiva (efavirenz), a non-nucleoside reverse transcriptase inhibitor, became the new gold standard for first time patients, with 2008 sales of $1.6 billion, up 74 percent from 2007. Truvada remains the market leader for the third year in a row, with sales up 33 percent to $2.1 billion.
The Quad appears to be the first-ever four-drug combo in any category. (There are three-drug fixed-doses in TB and malaria.) The product builds on the success of Truvada by adding to it Gileadâ€™s two newest experimental drugs: elvitegravir, a second-in-class integrase inhibitor, and GS 9350, a compound with the ability to boost levels of integrase inhibitors (and probably protease inhibitors, still the most widely used class in HIV cocktails).
The simultaneous development of all three drugs may lead to interesting clinical and commercialization challenges. Elvitegravir is currently going head-to-head with Isentress, Merckâ€™s breakthrough integrase inhibitor, in a Phase III non-inferiority trial in treatment-experienced patients. The Quad must pass the Phase II non-inferiority test against Atripla, which will position either the Truvada/boosted elvitegravir or the Truvada/Sustiva combo to lead the market in a few years. Itâ€™s worth noting that data suggest that black patients are at greater risk of Sustivaâ€™s notorious central nervous system side-effects because they metabolize the drug more slowly. The right clinical results could give integrase inhibitors the edge over this first-line non-nucleoside, making the Quad a must-have for millions of Africans with HIV.
But at what price? That question will test Gileadâ€™s talent at mixingâ€”and mixing it upâ€”with the feisty global AIDS treatment movement. Meanwhile, the biotech continues to enjoy outlandish sales growth (36 percent in 2008, to $5 billion), elevating this Bay Area dynamo to the top of the list of biotechs in this season of Big Pharma takeovers.