It was in late-June 2013, when pioglitazone, a diabetes drug was suspended in India fearing a possible link to urinary bladder cancer.
A little over a month later, the drug was back in circulation, this time, with a box-warning in “bold red letters”, outlining risk-factors and stating conditions in which it can be prescribed. But, the incident was enough to seed fear in the minds of people who had been prescribed the drug.
It’s been more than 18 months since the flip-flop on pioglitazone, but discussions on the drug continue to simmer.
This, despite recent studies including one by Takeda (the company that developed pioglitazone) claiming that primary analysis did not find an association between the drug and urinary bladder cancer.
So can people who consume pioglitazone take some comfort from these studies or should they be cautious? Though doctors are divided on its merits, they agree that caution should never be thrown to the winds, not with this or any medicine. After reviewing pioglitazone data, Takeda said, “The completed 10-year findings demonstrate that there is no statistically significant increased risk of bladder cancer among patients ever exposed to pioglitazone.” These findings were submitted to global regulators including those in the US, Europe and Japan, last August.
Subsequently, another study published in Diabetologia said: “In summary, our large international analysis does not support a causal effect of pioglitazone on bladder cancer, thus contradicting previous studies deemed to have proven this relationship.” It however added, “To fully resolve this controversy, future analyses are needed, involving longer follow-up of exposed persons and using methods to minimise allocation bias.”
Consultant endocrinologist Shashank Joshi says that the international studies are in line with a forthcoming local study by him and fellow-diabetologist Vijay Paniker. The findings are reassuring for people taking the medicine, says Joshi, adding that studies on the drug need to continue and the warning on the drug may not be off just yet.
“Every drug needs pharmaco-vigilence,” clarifies Joshi, since every drug has its effects and side-effects, so caution is advised, but there’s no need to panic.
Diabetologist V Mohan, who had raised concern in the first place, prescribes the drug infrequently, and it is not his first line of treatment. Post-marketing surveillance on drugs and their effects on patients need to continue in the interest of the patient, he says, be it anti diabetes, cancer, etc. But CM Gulati, Editor of the drug journal MIMS , is not convinced with the innovator or any other study. The innovator has a vested interest, he says, adding that studies abound to prove a point one way or the other.
It is critical if regulators reverse their decisions, but that has not happened in France or Germany where the drug is banned or used with restrictions, he points out.
In the US, patients are offered medication guides explaining drug details in lucid language. In India, even the warning is “useless”, says Gulati, since much of the population cannot read or write and doctors don’t explain drug details to patients.