Carcinogen-containing valsartan products that were recalled in about two dozen countries over the past few months didn’t significantly raise cancer risk in the short term, according to a Danish registry study published online Sept. 12 in The BMJ.
In July, some valsartan products—which are used to treat hypertension and heart failure—were found to be contaminated with N-nitrosodimethylamine (NDMA), a probable human carcinogen. Regulatory agencies around the globe promptly recalled the affected lots of the heart drug, but it was determined the contaminated drugs were in circulation since 2012, lead author Anton Pottegard, PhD, and colleagues wrote.
Therefore, the researchers looked at 5,150 Danish patients without a history of cancer who were taking any valsartan products from 2012 through June 2017. Using unique drug IDs from the National Prescription Registry, they determined which individuals had ever used drugs that were contaminated with NDMA.
Compared to those never exposed to NDMA, people taking valsartan with the carcinogen showed a 9 percent increased risk of developing any cancer over a median follow-up of 4.6 years—a statistically insignificant difference after accounting for various confounders. There was no evidence of a dose-response relationship.
“Although our results are generally reassuring, uncertainty remains regarding both individual cancer outcomes and long-term cancer risk,” the authors wrote in a blog accompanying the study. “For individual cancers, we observed increases in risk of colorectal and uterine cancer, however, with wide confidence intervals that included the null.”
Given the immediate public health concern, Pottegard et al. noted they were able to expedite the publication process of their study. It took collaboration from the Danish Medicines Agency, the Danish Health Data Authority and the editors of The BMJ to publish the results within three months of the quality issue being exposed, they said.
“This study alone cannot dispel doubts about the potential risk for patients in the longer term, but it helps inform decision making around this episode,” wrote Rita Banzi and Vittorio Bertele, both with the Mario Negri Institute for Pharmacological Research in Milan, in a related editorial. “It also illustrates the usefulness of national registries for examining the relations between risk factors and health problems and how research can give a prompt response whenever public health concerns emerge.”