WASHINGTON – Treatment of hepatitis C infection with a direct-acting antiviral drug strongly linked with a rapid, 14% drop in the incidence of all nonhepatic cancers, based on analysis of data from more than 30,000 U.S. patients.
The data also showedcompared with infected patients who had been treated with an interferon-based regimen during the period immediately preceding the availability of DAAs in late 2013. This included a 45% cut in lung cancers, a 49% cut in bladder cancer, a 62% relative risk reduction in leukemia, and a 29% drop in prostate cancer, , said at the annual Digestive Disease Week.®
The relative reductions in nonhepatic cancer incidence appeared soon after DAA treatment. The data Dr. Charlton reported reflected a median follow-up of 1 year for DAA-treated patients and 2.6 years for the hepatitis C–infected patients who had received interferon and did not get a DAA. A major difference between these two regimens is their efficacy, with DAA regimens producing sustained virologic response rates of 90% or better, while the interferon regimens produced substantially lower eradication rates.
“The most obvious hypothesis” to explain the observed effects is that “hepatitis C is a potent carcinogen,” possibly acting by inhibiting immune surveillance for new cancers in infected people, Dr. Charlton said in a video interview.
The study he reported used insurance-claims data from more than 146 million U.S. residents during 2007-2017 in the IQVIA
The primary analysis calculated a hazard ratio for the development of any nonhepatic cancer after adjustment for a number of demographic and clinical covariates including age, smoking history, and weight, and also applied propensity-score weighting to the data. The Kaplan-Meier analysis of the data showed clear separation of the cancer-free survival curves of the two subgroups by 6 months of follow-up, and then showed steady further separation over time suggesting an ongoing carcinogenic effect from continued hepatitis C infection in patients who had received the less effective antiviral regimen. The analysis was able to reveal this effect because it had data from many thousands of treated hepatitis C patients, far more than had been enrolled in the pivotal trials for the DAAs, noted Dr. Charlton, professor and director of the Center for Liver Diseases at the University of Chicago.
The Centers for Disease Control and Preventionthat 3.5 million Americans have a chronic hepatitis C infection. Dr. Charlton believed the number today might be more like 1-2 million remaining chronic U.S. cases because of the strong impact of DAA treatment. These chronic infections largely remain because hepatitis C is mostly silent and many clinicians fail to act on screening . The new findings provide even greater incentive for more rigorous screening and treatment, Dr. Charlton suggested.
“As if you needed another reason to get rid of hepatitis C, lowering your cancer risk is now added to the list,” he said.