Gilead promises generic versions of new hepatitis drug
After Gilead Sciences received FDA approval for a new drug for chronic hepatitis B virus (HBV), it said low-cost, generic versions would also soon be available. That is good news for Gilead, which has been targeted by Congressional representatives for the high cost of its Sovaldi and Harvoni hepatitis C treatments.
FDA recently approved tenofovir alafenamide, TAF (Vemlidy) 25 mg, a once-daily treatment for adults with chronic hepatitis B virus (HBV) infection with compensated liver disease. In addition, the Committee for Medicinal Products for Human Use (CHMP), the scientific committee of the European Medicines Agency (EMA), adopted a positive opinion on the company’s Marketing Authorization Application (MAA) for Vemlidy. The CHMP’s recommendation will now be reviewed by the European Commission, which has the authority to approve medicines for use in the 28 countries of the European Union, Norway and Iceland.
Meanwhile, Gilead established licensing agreements with 19 generic drug manufacturers in India, South Africa and China, as well as the Medicines Patent Pool, granting them rights to produce and sell high-quality, low-cost generic versions of Gilead HBV medicines in 112 developing countries.
Plus, since Vemlidy is already an integrated component of the company’s generic licensing agreements, with FDA approval, manufacturing partners “may begin production and distribution of a generic version of this medicine,” Gilead said in a press statement.
“Chronic hepatitis B is a life-threatening illness that affects up to 2.2 million people in the U.S.,” said Calvin Pan, MD, clinical professor of medicine, NYU Langone Medical Center, and investigator in the Vemlidy clinical trials. “Clinical trials demonstrated Vemlidy is efficacious with improved renal and bone safety parameters compared to Viread, representing an important development for people living with this chronic disease.”
Vemlidy is a novel, targeted prodrug of tenofovir that has demonstrated antiviral efficacy similar to and at a dose less than one-tenth that of Gilead’s tenofovir disoproxil fumarate (Viread) 300 mg. “Data show that because Vemlidy has greater plasma stability and more efficiently delivers tenofovir to hepatocytes compared to Viread, it can be given at a lower dose, resulting in less tenofovir in the bloodstream. As a result, Vemlidy improved renal and bone laboratory safety parameters compared to Viread,” Gilead said.
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Vemlidy’s approval is supported by 48-week data from 2 international phase 3 studies among 1,298 treatment-naïve and treatment-experienced adult patients with chronic HBV infection. Study 108 randomized and treated 425 HBeAg-negative patients with either Vemlidy or Viread, and Study 110 randomized and treated 873 HBeAg-positive patients with either Vemlidy or Viread.
Both studies met their primary end point of non-inferiority to Viread based on the percentage of patients with chronic hepatitis B with plasma HBV DNA levels below 29 IU/mL at 48 weeks of therapy.
In an integrated analysis of both studies, patients receiving Vemlidy demonstrated improvements in certain bone and renal laboratory parameters compared to those treated with Viread. Patients in the Vemlidy arm also experienced numerically higher rates of normalization of blood serum alanine aminotransferase (ALT) levels.
Vemlidy and Viread were generally well-tolerated by patients in both studies and discontinuations due to adverse events were 1% and 1.2%, respectively. The most commonly reported adverse events in both studies included headache, abdominal pain, fatigue, cough, nausea and back pain and occurred at similar rates in patients receiving either Vemlidy or Viread.
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogs. As a result, Vemlidy carries a boxed warning: Lactic acidosis/severe hepatomegaly with steatosis and post treatment severe acute exacerbation of hepatitis B.
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The most common adverse reactions (incidence ≥5%; all grades) were headache, abdominal pain, fatigue, cough, nausea and back pain.