Clinical trial data that saw some of the world’s most widely used cancer drugs approved by the US drugs regulator remains secret, despite a pharmaceutical industry commitment to transparency made in 2014.
The authors of a study published in the journal JAMA Oncology on Friday said the lack of transparency should be concerning to Australia.
Led by Flinders University, researchers audited 304 pharmaceutical company clinical trials that underpinned the US Food and Drugs Administration (FDA) approving 115 anticancer medicines over the past 10 years.
Just 136 of those trials (45%) had individual de-identified patient data available for sharing. Only 64 (21%) of the trials had the data publicly available, with the others requiring requests to the pharmaceutical company that could take months to be approved.
For three of the top-selling anticancer drugs – nivolumab, pembrolizumab and pomalidomide – 90% of the trial data was unavailable. These medicines generated more than US$25bn (AU$36bn) in profit in 2021. Of the top 20 pharmaceutical companies by global revenue, 18 sponsored trials in the study sample.
The leader of study, Natansh Modi, who is a PhD candidate in the clinical cancer epidemiology lab at Flinders University, said most of the participants in clinical trials are caucasian and male. But medicines can have different effects and efficacy depending on ethnicity, pregnancy, gender and other attributes.
In order to see how these often life-saving drugs affect people from different groups, data needs to be drawn from multiple similar studies of the drug to improve the overall sample size, and so stronger findings can be determined. These pooled studies are known as systematic reviews or meta-analyses.
If the trial data isn’t available to independent researchers, this can’t be done, which has implications for health equity, Modi said.
“It means we can’t always answer questions like: ‘Is this medicine safe to use in females, or is it safe and effective in Asians or in elderly individuals?’” he said.
“Pharmaceutical companies are not going to provide this data to other pharmaceutical companies because of competition, so this work has to be done by independent researchers. But it can’t be done without the data and transparency.”
Modi said the most common reason provided by pharmaceutical companies for the lack of transparency was that longterm follow-up data was still being collected.
“Ongoing follow-up is of course needed, but it should not hinder the release of the initial data that shows the efficacy of the drug in the first place,” he said.
The Top 10 anticancer medicines (by global revenue) audited in the study have been approved by Australia’s drugs regulator, the Therapeutic Goods Administration (TGA), and are listed on the pharmaceutical benefits scheme (PBS).
“Taxpayers pay money for the subsidisation of medicines in Australia,” Modi said. “If the taxpayers are subsidising these medicines that the pharmaceutical industry is giving to patients, it is only fair that the TGA mandate that data be available for independent researchers to use so that it can be of benefit to as many people as possible.”
Dr Ash Hopkins, a senior author of the study, said of the top-selling anticancer medicines, nivolumab, pembrolizumab and pomalidomide had the lowest transparency, with data shared from less than 10% of trials for those drugs.
“The 2020-2021 PBS expenditure report shows that pembrolizumab and nivolumab are the number one and two expenditures and that all of the top 10 drugs in our study are in the top 25 of Australia’s anticancer expenditures,” Hopkins said.
In 2014, the Pharmaceutical Research and Manufacturers of America and the European Federation of Pharmaceutical Industries and Associations acknowledged the importance of data sharing and endorsed a commitment to sharing anonymised trial data for approved medicines upon request by qualified researchers.
A 2018 audit found just 15% of clinical trials were available for sharing two years after publication – with no sharing occurring for oncology trials.
Hopkins said renewed pressure needed to be placed on pharmaceutical companies and drugs regulators to help restore public confidence in evidence-based medicine.
“Covid-19 has been a global case study exemplifying that we need to increase public trust in drug and vaccine development,” he said.