Several global clinical trials to assess medicines have recruited more participants from India than required under a fair distribution of volunteers, researchers have said, urging drug regulators to probe and rule out “exploitation” of Indian participants.

The researchers have found that 26 of 424 multinational clinical trials by foreign sponsors to evaluate candidate drugs against asthma, bacterial infections, cancer and other conditions had recruited or planned to recruit 60 per cent or more of the trial volunteers from India.

“We need to be alert about the possibility of over-recruitment from India, made possible by casual or perfunctory oversight by ethics committees that approve trials,” said Gayatri Saberwal, professor of policy research at the Institute of Bioinformatics and Applied Biotechnology (IBAB), Bangalore.

The ethics committees of medical colleges and hospitals are panels of doctors, social scientists and legal experts tasked with scrutinising proposals for clinical trials and determining whether the trials are justified, the risks to the volunteers are within acceptable limits, and informed consent has been obtained from the volunteers.

“It is not always clear why global trials should have greater than 60 per cent volunteers from India,” Saberwal told The Telegraph.

Health sector analysts, however, say that India accounts for just 3 per cent of clinical trials globally while contributing 15 per cent of the global burden of high-prevalent diseases such as respiratory infections, cardiovascular disorders and diabetes.

But regulatory changes in India since 2013 have catalysed a growth in trial activity, a report on clinical trial opportunities in India released by PricewaterhouseCoopers and the US India Chamber of Commerce earlier this year had said.

The number of clinical trials initiated in India by the top 20 pharma companies rose from 175 during the three-year period 2014-2016 to 296 during 2020-2022, according to the report.

In a multinational trial, Saberwal said, the fraction of participants from one particular country should ideally not exceed 50 per cent, the actual fraction depending on how many countries the trial is conducted in. A two-country trial, for instance, should have 50 per cent participants in one country and 50 per cent in the other.

A three-country trial should have 33 per cent volunteers from each country, a four-country trial, 25 per cent from each country. Because trials might come with risks, such a distribution pattern enables a fair distribution of risks and potential benefits across volunteers from all participating countries.

Saberwal and her colleagues from the IBAB and the Centre for Ethics, Yenepoya University, Mangalore, analysed volunteer recruitment patterns in 424 multinational clinical trials with foreign sponsors — 62 completed trials and 362 incomplete trials — over the eight-year period from January 2013 to December 2020.

They found that 6 of the 62 completed trials and 20 of the 362 incomplete trials had planned to recruit or actually recruited 60 per cent or more participants from India. The researchers have published their study in the journal PLOS One.

Eighteen of the 20 incomplete trials did not concern health disorders that were “preferentially prevalent” in India. Companies in Australia, Austria, Italy, Switzerland and the US sponsored 10 of these 18 trials and non-western firms in Brazil, Russia and Malaysia sponsored the other 8 trials.

Russian companies, for instance, sponsored trials in India on asthma, while Brazilian companies sponsored trials on breast cancer and prostate cancer.

Saberwal and her colleagues have asked drug regulators to probe why some global trials had 60 per cent or more participants from India.

“It is difficult to justify trials (in India) that were sponsored by companies in Brazil or Russia since both are populous nations… it ought to be possible to find trial participants (in their own countries),” the researchers wrote in the journal.