In phase III studies, fatigue, headache, and influenzalike illness, associated with PR, were the most common adverse events. The only deaths reported were in three patients treated with simeprevir after they stopped taking the drug, but were not considered related to the drug. During the first 12 weeks of treatment, dyspnea was also higher among those on simeprevir (12% vs. 8%), but so far, the cause has not been determined, according to the FDA reviewer. Hyperbilirubinemia was also higher among those on simeprevir (49% vs. 26%), mostly grade 1 and 2 abnormalities.
In the first 12 weeks in the phase III studies, rashes (including photosensitivity) were reported in 28% of those on simeprevir, vs. 20% of those on PR only. Pruritus was also more common among those on simeprevir (22% vs. 15%); 1% of patients discontinued treatment because of a rash.
Janssen is investigating the appropriate dose in people of Eastern Asian descent. Exposure in these patients is higher, and rashes, photosensitivity, and other adverse events are increased with greater drug exposures, according to the FDA. A 100-mg daily dose of simeprevir has been approved in Japan (the only country where the drug has been approved to date). The drug is also being reviewed for approval in the European Union.
Among people with chronic HCV infections in the United States, genotype 1 is the most common, accounting for 75% of cases, according to the FDA.
The FDA usually follows the recommendations of its advisory panels and is expected to make a decision on this application by Nov. 27. Members of FDA panels have been cleared of conflicts related to the product under review; occasionally, a panelist is given a waiver, but not at this meeting.