Colitis Reported From Drug Combination in Hepatitis C Treatment

Combination of sofosbuvir and simeprevir may have an unexpected side effect in HCV therapy.

In an article published October 9, 2015 in the journal ACG Case Reports, researchers Sarkar and colleagues identified a potential new adverse event of colitis with sofosbuvir/simeprevir combination therapy in patients with chronic hepatitis C (HCV) genotype 1.

Although colitis is not mentioned in the package insert of either drug, both sofosbuvir and the combination of sofosbuvir and simeprevir have been associated with diarrhea.

According to the package insert of each drug, the incidence of diarrhea is approximately 6% in patients taking sofosbuvir, and 16% in patients using combination sofosbuvir and simeprevir therapy.

Importantly, in the case report, the patient who experienced colitis did not have any history of inflammatory bowel disease, and developed new-onset diarrhea with blood in the stool after 2 weeks of treatment with the direct-acting antiviral combination.

While colitis is not listed in the package insert of either drug, patients taking sofosbuvir and simeprevir should be aware of the potential for colitis, and the potential signs of colitis.

Although the combination of sofosbuvir and simeprevir is approved for the treatment of genotype 1 hepatitis C virus infection, the combination was never evaluated in a phase 3 study. Rather, the combination was evaluated in a single phase 2 study known by the acronym COSMOS.

Although it is not uncommon for new adverse events to be identified after early trials are complete, the fact that sofosbuvir and simeprevir were never evaluated in a phase 3 clinical trial increases scrutiny on any adverse events that may occur.

References

• Sarkar S, Mitchell KA, Lim JK, Oikonomou I, Jakab S. Colitis Following Initiation of Sofosbuvir and Simeprevir for Genotype 1 Hepatitis C. ACG Case Rep J. 2015;3(1):42-44.
• Page MR. COSMOS Hepatitis C Trial Results Announced. http://www.specialtypharmacytimes.com/news/cosmos-hepatitis-c-trial-results-announced. Accessed October 2015.