Gilead aiming to put four HIV drugs in one pill

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Gilead aims to start trials in 2009 of a new four-drugs-in-one-pill product, combining all its anti-HIV drugs, the company told Bloomberg news service yesterday.

The `Quad` pill will combine tenofovir and emtricitabine (already marketed as a two-drug pill called Truvada) with a new antireretroviral drug now in phase III studies, called elvitegravir. This drug belongs to a new class of antiretroviral drugs called integrase inhibitors, and will be combined with another new drug, called GS9350, which boosts levels of elvitegravir.

Gilead hopes that if pre-licensing studies are successful, elvitegravir could receive a license for use in treatment-experienced patients in 2010.

Glossary

integrase inhibitors (INI, INSTI)

A class of antiretroviral drugs. Integrase strand transfer inhibitors (INSTIs) block integrase, which is an HIV enzyme that the virus uses to insert its genetic material into a cell that it has infected. Blocking integrase prevents HIV from replicating.

treatment-experienced

A person who has previously taken treatment for a condition. Treatment-experienced people may have taken several different regimens before and may have a strain of HIV that is resistant to multiple drug classes.

first-line therapy

The regimen used when starting treatment for the first time.

central nervous system (CNS)

The brain and spinal cord. CNS side-effects refer to mood changes, anxiety, dizzyness, sleep disturbance, impact on mental health, etc.

phase III

The third and most definitive stage in the clinical evaluation of a new drug or intervention, typically a randomised control trial with the new intervention compared to an existing therapy or a placebo, in large numbers of participants (typically hundreds or thousands). Trial results are used to evaluate the overall risks and benefits of the drug and provide the information needed for regulatory approval.

However Gilead has its eye on the market for patients new to treatment, currently dominated by another of its combination pills Atripla (co-marketed with Bristol-Myers Squibb) which contains tenofovir, emtricitabine and efavirenz (Sustiva).

Efavirenz may be less suitable for African-American patients, said Gilead president John Milligan, because it is metabolised more slowly by people of African descent, leading to a higher risk of central nervous system side-effects.

Although elvitegravir’s long-term side-effect profile is unknown, another integrase inhibitor called raltegravir has shown that it is well-tolerated in comparison to efavirenz, and just as effective at suppressing viral load. Raltegravir (Isentress), manufactured by Merck, is likely to receive US approval for first-line use during 2009.

Gilead’s hope is that a four-in-one combination pill, taken once a day, could have an edge over raltegravir, which must be dosed twice daily.