A blood pressure drug recalled worldwide amid fears it could cause cancer does not increase the risk of the disease in the short run.
Valsartan, which can be prescribed under the brand name Diovan, was recalled in 22 countries, including the US and UK, in July.
A change in manufacturing in China caused N-Nitrosodimethylamine (NDMA) – a potent chemical also used in rocket fuel – to trickled into the supply.
Yet, a Danish study released today found no link between NDMA exposure through valsartan and a person developing cancer over four years.
The recalled blood-pressure drug valsartan does not increase a person’s cancer risk when taken over the short term. In July 2017, certain valsartan batches were contaminated with the cancer-causing chemical NDMA at levels that ‘far exceeded regulatory exposure limits’
Researchers from the University of Southern Denmark analysed 5,150 people over 40 with no history of cancer.
The participants had taken valsartan at some point between 2012 and 2017.
Zhejiang Huahai Pharmaceuticals, a company in Linhai, east China, which manufactured the drug, changed its production process in 2012, which is thought to have led to NDMA contamination.
NDMA is one of the strongest known cancer-causing substances in animals, with health officials declaring it ‘probably carcinogenic to humans’.
Chemical exposure was calculated by identifying, via drug codes, the batches from which patients were prescribed valsartan.
National cancer registries determined the participants who were diagnosed with the disease around four years after they were prescribed the drug.
| Product name | Marketing Authorisation Holder | PL Number |
|---|---|---|
| VALSARTAN 40MG CAPSULES, HARD | DEXCEL PHARMA LIMITED | PL 14017/0192 |
| VALSARTAN 80MG CAPSULES, HARD | DEXCEL PHARMA LIMITED | PL 14017/0193 |
| VALSARTAN 160MG CAPSULES, HARD | DEXCEL PHARMA LIMITED | PL 14017/0194 |
| VALSARTAN 40MG FILM-COATED TABLETS | ACTAVIS GROUP PTC EHF | PL 30306/0109 |
| VALSARTAN 80MG FILM-COATED TABLETS | ACTAVIS GROUP PTC EHF | PL 30306/0110 |
| VALSARTAN 160MG FILM-COATED TABLETS | ACTAVIS GROUP PTC EHF | PL 30306/0111 |
| VALSARTAN 320MG FILM-COATED TABLETS | ACTAVIS GROUP PTC EHF | PL 30306/0405 |
Results, published in the BMJ, suggest 104 of the participants developed cancer after taking valsartan contaminated with NDMA.
This is compared to 198 people who developed the disease and were not exposed to the chemical. This is not a significant difference.
The researchers stress, however, the study was only carried out over several years. NDMA-contaminated valsartan may therefore be linked to cancer if a person takes the drug long term.
Rita Banzi and Vittorio Bertele, from the Center for Drug Regulatory Policies in Milan, who were not involved in the research, 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.
‘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.’
The European Medicines Agency (EMA), which raised the alarm over valsartan on July 5, said it is working to establish how long, and at what levels, patients might have been exposed to NDMA.
‘It is still too early to provide information on the longer term risk NDMA may have posed for patients. EMA has made this aspect of the review a priority and will update the public as soon as new information becomes available,’ the agency said.
Zhejiang Huahai has acknowledged there was an impurity in some of its valsartan, which it claims had sales of $50 million (£38.4m) in 2017.
The EMA added NDMA was an unexpected impurity that was not detected by routine tests carried out by valsartan’s manufacturer.
Valsartan was originally developed by Novartis and the Swiss company marketed it as Diovan, but it is now off patent and is used in a number of generic medicines supplied by various companies.
In addition to tackling high blood pressure, it is also prescribed to treat heart failure.