Gilead Sciences’ (NASDAQ:GILD) bictegravir faces tough HIV space dominated by Viiv’s Tivicay (dolutegravir), but a fixed dose combination comprising tenofovir alafenamide (TAF) could give it an edge, said experts.
Viiv’s Triumeq, a fixed dose triple combination of integrase inhibitor Tivicay, with two nucleoside reverse transcriptase inhibitor (NRTI), abacavir/lamivudine, has become the HIV treatment of choice since its August 2014 approval. While experts are favorable toward Tivicay’s current use, they noted flaws in Triumeq’s triple combo offering, notably the abacavir component that needs hypersensitivity reaction screening prior to use. In contrast, a bictegravir combination with TAF – a newer NRTI – has led to initial enthusiasm because of TAF’s tolerability profile vs abacavir. However, Triumeq would still likely remain favorable for pediatric patients given abacavir’s lack of potential cardiac toxicity issues in children, one expert noted.
Tivicay’s favorable activity and resistance profile has boosted its combination with NRTIs as the frontrunner for treatment naïve patients. Global Triumeq sales reached GBP 730m in 2015 and GBP 737m in 1H16. Sales are estimated to reach USD 5.76bn in 2022, according to BioPharm Insight data. Bictegravir will be a second to market second generation integrase inhibitor, and analysts have noted potential market barriers for Gilead’s drug given Tivicay’s dominance.
Physicians also said, that in addition to Tivicay and bictegravir, the field will be anticipating the use of Viiv’s injectable integrase inhibitor, cabotegravir in the next few years, which will remain a niche but path breaking drug.
The Phase II study (NCT02397694) is evaluating 75mg bictegravir in combination with Gilead’s Emtriva [or FTC] (emtricitabine) and Vemlidy [or TAF] (tenofovir alafenamide) vs 50mg Tivicay with /FTC/TAF in 98 treatment naïve patients, according to ClinicalTrials.gov. Analysts expect Phase II data at the Conference on Retroviruses and Opportunistic Infections (CROI) from February 13-16 in Seattle and predict bictegravir sales to reach USD 2.6bn by 2021.