On July 18, the U.S. Food and Drug Administration (FDA) approved a combination tablet (Vosevi) to treat adults with chronic hepatitis C virus genotypes 1–6 without cirrhosis or with mild cirrhosis. This fixed-dose, combination tablet contains two previously approved drugs—sofosbuvir and velpatasvir (available in combination as Epclusa)—and a new drug, voxilaprevir. The tablet is the first treatment approved for patients who have been previously treated with the direct-acting antiviral drug sofosbuvir or other drugs for hepatitis C virus that inhibit a protein called NS5A.
“Direct-acting antiviral drugs prevent the virus from multiplying and often cure [hepatitis C virus]. Vosevi provides a treatment option for some patients who were not successfully treated with other [hepatitis C] drugs in the past,” said Edward Cox, MD, Director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research.
About Hepatitis C
Hepatitis C is a viral disease that causes inflammation of the liver that can lead to diminished liver function or liver failure. According to the Centers for Disease Control and Prevention, an estimated 2.7 to 3.9 million people in the United States have chronic hepatitis C. Some patients who suffer from chronic hepatitis C virus infection over many years may have jaundice (yellowish eyes or skin) and develop complications, such as bleeding, fluid accumulation in the abdomen, infections, liver cancer, and death.
There are at least six distinct hepatitis C virus genotypes, or strains, which are genetically distinct groups of the virus. Knowing the strain of the virus can help inform treatment recommendations. Approximately 75% of Americans with hepatitis C virus have genotype 1; 20% to 25% have genotypes 2 or 3; and a small number of patients are infected with genotypes 4, 5, or 6.
POLARIS-1 and POLARIS-4
The safety and efficacy of the combination tablet was evaluated in two phase III clinical trials—POLARIS-1 and POLARIS-4—that enrolled approximately 750 adults without cirrhosis or with mild cirrhosis.
The first trial compared 12 weeks of treatment with the tablet vs with placebo in adults with genotype 1 who had previously failed treatment with an NS5A inhibitor drug. Patients with genotypes 2, 3, 4, 5, or 6 all received the combination tablet.
The second trial compared 12 weeks of the combination with the previously approved drugs sofosbuvir and velpatasvir in adults with genotypes 1, 2, or 3 who had previously failed treatment with sofosbuvir but not an NS5A inhibitor drug.
Results of both trials demonstrated that 96% to 97% of patients who received the combination tablet had no virus detected in the blood 12 weeks after finishing treatment, suggesting that patients’ infection had been cured.
Treatment recommendations for the combination are different depending on viral genotype and prior treatment history.
Safety and Adverse Events
The most common adverse reactions were headache, fatigue, diarrhea, and nausea.
The combination tablet is contraindicated in patients taking the drug rifampin.
Hepatitis B virus reactivation has been reported in hepatitis C/hepatitis B coinfected adult patients who were undergoing or had completed treatment with hepatitis C direct-acting antivirals, and who were not receiving hepatitis B antiviral therapy. Hepatitis B virus reactivation in patients treated with direct-acting antiviral medicines can result in serious liver problems or death in some patients. Health-care professionals should screen all patients for evidence of current or prior hepatitis B virus infection before starting treatment with the combination tablet.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.