HIV Pipeline Prospects Getting Healthier

HIV treatment and prevention are dominated by high-cost, oral, branded specialty medications, but pipeline developments could improve the quality of life for patients.  

Andros

Currently, 27 approved antiretroviral drugs in six different therapeutic classes treat the disease, says Vickie Andros, PharmD, director of clinical services, Curant Health.

Top five HIV drugs by market share:

• Truvada (Gilead), a two-drug combination tablet taken as one pill, once daily and used with other medicines to treat HIV-1 infection in people who weigh at least 35 kg (77 lbs.). It is also indicated for use as pre-exposure prophylaxis (PrEP) in HIV-negative adults at high risk of acquiring HIV infection.

• Atripla (Gilead), a one-pill, three-drug combination, once-daily treatment that can be used alone as a complete regimen, or in combination with other anti-HIV-1 medicines, to treat HIV-1 in patients who weigh at least 40 kg (88 lbs.).

• Viread (Gilead), single drug dosed as one pill, once daily for use in combination with other antiretroviral agents for the treatment of HIV-1 infection in pediatric patients ages 2-12. 

• Genvoya (Gilead), a one pill, four-drug combination pill, taken once daily and used as a complete regimen to treat HIV-1 in patients who weigh at least 35 kg.

• Norvir (AbbVie), single-drug tablets and oral solution are each used with other antiviral medicines to treat people with HIV-1 infection. The oral powder version is used with other antiviral medicines to treat children with HIV-1 infection.

Truvada, Atripla, and Viread contain tenofovir disoproxil fumarate (TDF). The patent on TDF expired December 2017, allowing generic TDF to come to market. In January 2018, FDA approved Strides Shasun's wholly owned subsidiary Strides Pharma Global Pte. Ltd., generic version of Viread, for which the patent expired on January 25, 2018. The drug is indicated to be used in conjunction with other antiretroviral agents and Strides is marketing the product now.  

Promising developments

Truvada, Atripla, and Viread contain tenofovir disoproxil fumarate (TDF). The patent on TDF expired December 2017, allowing generic TDF to come to market. In January 2018, the FDA approved a generic version of Viread from Strides Pharma Global Pte. Ltd. The drug is indicated to be used in conjunction with other antiretroviral agents and Strides is marketing the product now.  

While this would generally result in cost-savings, the effect of new generic TDFs may be limited by the introduction of tenofovir alafenamide (TAF)-an orally bioavailable prodrug (a drug that goes from inactive drug to active drug once it is metabolized in the body) of tenofovir.

Three TAF-based products are now on the market, all of which are manufactured by Gilead: Genvoya, Descovy, and Odefsey. TAF drugs are expected to replace TDF drugs over the next few years, according to Nadina Rosier, Health and Group Benefits Practice Leader at Willis Towers Watson.

Genvoya was approved in 2015 and is already among the top five drugs by market share in 2016, according the Express Scripts 2016 Annual Drug Trend Report.

TAF is expected to replace TDF with similar effectiveness and an improved safety profile, according to Rosier.

Another reason for optimism in the HIV area occurred in November 2017, when the FDA approved Juluca (Janssen Therapeutics, ViiV Healthcare), the first two-drug regimen to treat certain adults with HIV-1 infections. Typically,  three or more drugs are included in HIV treatment.

Rosier

“The importance of this approval is that having fewer drugs in a treatment regimen can help reduce toxicity while potentially reducing cost and improving adherence,” says Nadina Rosier, Health and Group Benefits Practice Leader at Willis Towers Watson.

Pipeline drugs

At press time, FDA approved Gilead Sciences Biktarvy (bictegravir 50 mg/emtricitabine 200 mg/tenofovir alafenamide 25 mg, BIC/FTC/TAF), a once-daily single-tablet regimen for the treatment of HIV-1 infection.

There are several other drugs are in the pipeline, with a couple expected to be approved this year:

• A two-drug regimen of long-acting, injectable cabotegravir (ViiV Healthcare) and long-acting injectable rilpivirine (Janssen Sciences Ireland UC) in virally suppressed adults with HIV-1 infection. ViiV announced the beginning of a phase 3 study on these drugs in November 2017. 

• PRO 140 from biotech company CytoDyn Inc., which belongs to a new class of HIV/AIDS therapeutics called viral-entry inhibitors that are intended to protect healthy cells from viral infection.

There are also two New Drug Applications for doravirine, an investigational non-nucleoside reverse transcriptase inhibitor, for the treatment of HIV-1 infection in adults, accepted by the FDA for review in February 2018.

ViiV Healthcare also announced positive phase 3 results from the BRIGHTE study of fostemsavir, a first-in-class attachment inhibitor, in heavily treatment-experienced patients with HIV.

Rosier says approximately 25,000 HIV patients are resistant to at least one drug, and about 10,000 people have multidrug resistant-HIV.

Theratechnologies’ ibalizumab, an investigational humanized monoclonal antibody is being developed for the treatment of multidrug resistant HIV-1 infection. It potentially prevents HIV from infecting CD4+ immune T cells while preserving normal immunological function. Ibalizumab is currently under priority review by the FDA, which plans to complete the review by April 3. 

Erin Bastick, PharmD, RPh, is staff pharmacist at Southwest General Health Center, Middleburg Heights, Ohio.