Add one more medication to the HIV treatment arsenal: The quad-drug Stribild, geared specifically for people who haven’t yet been treated for the infection, just got the OK from the Food and Drug . The new Stribild therapy (elvitegravir, cobicistat, emtricitabine, tenofovir disoproxil fumarate) for adult HIV patients is a once-daily orally administered drug, the first HIV therapy to include an integrase inhibitor, such as elvitegravir. Stribild’s approval and the recent FDA authorization of Gilead’s Truvada (tenofovir, emtricitabine) for use as a prophylactic in individuals at high risk for contracting HIV (homosexual men, healthcare workers, individuals with an HIV-positive partner) have come at a crucial time for the company, which must prepare for competition from generic HIV therapies in the near future. Gilead hopes that Stribild’s improved side effect profile, compared to current therapies, can help the company maintain its market share.
In clinical trials, the efficacy of Stribild therapy has been shown to be comparable to Atripla (emtricitabine, tenofovir, efavirenz) in HIV treatment-naïve patients after 48 weeks of therapy. Furthermore, patients on Stribild had decreased incidences of neurological side effects, such as insomnia, abnormal dreams, and dizziness, compared to patients taking Atripla. Stribild therapy was more often associated with nausea than Atripla, and Stribild appeared to affect kidney function (elevated serum creatinine), but the levels remained within the normal range. Therefore, any improvement in Stribild’s side effect profile, when compared to Atripla, seems minimal. But as the average length of treatment of HIV patients increases in developed countries, the need for available therapies with limited side effects becomes more relevant within the competitive landscape of HIV disease management.
Stribild therapy was recommended to the FDA by an overwhelming 13-1 majority of the Antiviral Drugs Advisory Committee for use in treatment-naïve HIV patients in May of this year. In a press release by Gilead following the recommendation, company officials stressed that developing Stribild therapy was crucial in order to address the true unmet need in the market today – the need for treatment regimen that included a minimal side effect profile. Current anti-HIV therapies are plagued with adverse effects, but there is uncertainty about the ability of Stribild therapy to significantly improve a patient’s quality of life.
Stribild’s approval is likely to increase Gilead’s stock price, which is currently $57, but investors could be concerned when they consider Gilead’s long-term future. Gilead is the current leader in HIV therapies, but the company faces a threat from a growing generics market as Gilead’s current therapies go off patent. In order to address the threat of generics, Gilead seems to be dividing the HIV therapy market based on a region’s income. High-income countries are able to place more emphasis on the side effect profile of a regimen, since patients can afford effective therapy due to insurance reimbursement. Conversely, low-income countries are still trying to obtain an effective means of treating HIV. On August 2nd, Gilead announced a partnership with known generics manufacturers Mylan Laboratories, Ranbaxy Laboratories and Strides Arcolab to transfer information related to the manufacture of emtricitabine, a core ingredient in Atripla, Stribild and Truvada for markets in developing and low-income countries.
This move to actively participate in technology transfer within the generics market is likely to cannibalize the sales of Atripla within these markets; however, the move might have done more to boost the brand image of Gilead and assuage non-profit AIDS organizations. Despite developing countries having millions of patients requiring lifelong treatment with first-line therapies such as Atripla, Gilead seems content to focus by catering to the markets within developed countries like the US.
Gilead may have to proceed with caution in its marketing of Stribild within the US. Earlier this month, Democratic members of Congress sent Gilead a letter expressing their concern over the anticipated pricing of Stribild therapy, which was estimated to be $27,000–$34,000 per year. This would make Stribild more expensive than Atripla therapy ($22,000). Gilead’s desire to quickly recoup the costs associated with developing Stribild is understandable, but the company may be better served by introducing Stribild at a lower price than Atripla therapy. The side effect profile of Stribild is only marginally better than Atripla, so a decreased cost could provide more incentive for patients to switch therapies when Stribild eventually gains approval for treatment-experienced patients. If Gilead can shepherd patients over to Stribild therapy, the company might be able to retain them when generic HIV therapies enter the market. The anticipated difference in cost between branded and generic HIV therapies might prove too great ($20,000 compared to $2,000), and the side effect improvement may not be significant enough for insurance providers to be willing to reimburse Stribild at prices similar to current therapies. The anticipated pricing of Stribild indicates that Gilead may anticipate this scenario and hopes to make a profile while it can before generics enter the market.
As Gilead positions itself to reap the rewards of its investment in the development of Stribild, it must avoid emphasizing the divide between high and low-income countries. Patients in low-income countries can look forward to long overdue, effective treatment thanks to generic HIV therapies. Time will tell how high-income markets respond to this new therapy. Stribild will generate a profit for Gilead, but insurance companies and governments could limit its magnitude.