Diabetes drug linked to increased risk of bladder cancer

May 31, 2012 in Cancera drug used to treat type 2 diabetes - is associated with an increased risk of bladder cancer, finds a study published on BMJ today. The results show that more than two years daily exposure to pioglitazone doubles the risk of bladder cancer. However, the authors stress that, in absolute terms, the risks are low – up to 137 extra cases per 100,000 person years.

No increased risk was seen for a similar drug (rosiglitazone). Pioglitazone and rosiglitazone belong to a class of drugs called thiazolidinediones that help to control blood sugar levels in patients with type 2 diabetes. Both drugs are known to increase the risk of heart failure but, after carrying out a safety review, the European Medicines Agency decided to keep pioglitazone on the market. However, there is now some evidence suggesting that pioglitazone may be associated with an increased risk of bladder cancer. So a team of researchers based in Canada set out to determine if the use of pioglitazone was associated with an increased risk of bladder cancer in people with type 2 diabetes. Using data from the General Practice Research Database (GPRD), which contains anonymised patient records from more than 600 UK general practices, they studied 115,727 patients newly treated with diabetes drugs from 1988 to 2009. Cases of bladder cancer were identified and matched to up to 20 healthy control patients. Results showed that 470 patients were diagnosed with bladder cancer during the average 4.6 years of follow-up (a rate of 89 per 100,000 person years). The rate of bladder cancer in the

general UK population aged at least 65 years is 73 per 100,000 person years. The analysis involved 376 cases, matched to 6,699 controls. If patients had ever taken pioglitazone they were at an 83% increased risk of bladder cancer. This corresponds to 74 per 100,000 person years. This increased to 88 per 100,000 person years for patients who had taken the drug for two years or more and increased further to 137 per 100,000 years for patients who had taken 28,000mg or more. These findings remained consistent in several further analyses designed to check the results. The authors conclude that their results "provide evidence that pioglitazone is associated with an increased risk of bladder cancer, whereas no increased risk was observed with the thiazolidinedione rosiglitazone." They suggest that such associations may have been underestimated in previous observational studies and say doctors, patients and regulatory agencies "should be aware of this association when assessing the overall risks and benefits of this therapy." In an accompanying editorial, Dominique Hillaire-Buys and Jean-Luc Faillie from the Department of Medical Pharmacology and Toxicology in Montpellier, France say "it can confidently be assumed that pioglitazone increases the risk of bladder cancer. It also seems that this association could have been predicted earlier." Considering that the benefit of pioglitazone in reducing cardiovascular events is questionable, they suggest that "prescribers who are ultimately responsible for therapeutic choices can legitimately question whether the benefit-risk ratio of pioglitazone is still acceptable for their patients with diabetes."Neglected Diseases – How Should We Pay for R&D?. May 31, 2012, 5:00 PM. By Betsy McKay It's no secret that only a fraction of the money spent on biomedical research goes toward developing vaccines and drugs for malaria, tuberculosis and other diseases that afflict people primarily in poor countries. There's little incentive to invest in medicines for which few can pay – even if those diseases are some of the world's biggest killers.

What to do about that is less clear.Last week, the World Health Assembly – the decision-making body of the World Health Organization – debated whether to obligate every country to donate at least .01% of its gross domestic product to R&D to combat these so-called neglected diseases.But the U.S., European Union and Japan opposed the idea. Instead, the assembly agreed to continue discussions and bring forth proposals next year.Some health advocates expressed dismay. Humanitarian aid organization Doctors Without Borders/Médecins Sans Frontières accused the U.S. and the other countries of "trying to "block progress.""We're disappointed," said Judit Rius Sanjuan, U.S. manager of the organization's Access Campaign to make medicines more available in developing countries. "We have been waiting more than 10 years."Why did Washington object? The Health Blog caught up with Nils Daulaire, director of the Office of Global Health Affairs at the Department of Health and Human Services and U.S. representative on the WHO's Executive Board. He presented the U.S. position last week.In short: The U.S. supports the diagnosis, but not the prescription, Daulaire said."We are strongly in favor of significantly increased R&D investment in diseases of the poor," he said – particularly because the U.S. already contributes 45% of the total investment in global R&D annually (and 70% of all government investment world-wide). The U.S. has spent about $12.7 billion over the past decade on R&D, through the National Institutes of Health, Centers for Disease Control and Prevention, U.S. Agency for International Development (USAID) and other agencies.But contributions should be voluntary, not prescribed in a binding treaty, he said. Such a requirement would amount to a global tax."It is an established U.S. government position that we do not support the concept of international taxes," he said. "Taxes are the responsibility and bailiwick of national governments."Nor should contributions go into one centralized financing mechanism, he said, which wouldn't necessarily foster the type of innovation needed to overcome these diseases."There are numerous other possibilities that are more of a voluntary nature and more pluralistic, not a single centrally directed and potentially very bureaucratic fund," Daulaire said.It's true that R&D needs to be better coordinated, so researchers in different parts of the world don't spend money duplicating efforts or so research gaps are addressed. But we at the Health Blog wonder how the NIH would feel about turning over a chunk of its research money to an international fund.Some other countries also expressed reluctance to shell out that much, he said. Indeed, some would be asked for sizable sums: big emerging market countries Brazil, Russia, India, China and South Africa together would owe about $1.4 billion a year, he estimates.Instead, Daulaire said, R&D money should be used to build research capabilities around the world, including in the developing world."Can you do something big and important without an international treaty or tax?" he said. "We believe yes – it's manifest in the Global Fund to Fight AIDS, Tuberculosis and Malaria. It has never had a treaty or tax associated with it."