Roughly three dozen plaintiffs have joined the existing litigation against Actos maker Takeda Pharmaceuticals, alleging that the type-2 diabetes drug radically increases the risk of developing bladder cancer in patients.

The new Actos lawsuits echo existing bladder cancer lawsuits filed against Takeda. These Actos bladder cancer lawsuits allege that the drug’s makers were aware, or reasonably should have been aware, of serious health problems linked to their drug.

The Actos lawsuits further allege that drug manufacturers not only failed to act on this information, but actively downplayed the risk, endangering patients.

The Actos lawsuit cites various studies and government actions to support the allegation that Actos is dangerous, including some dating back to 2005, which found a link between Actos and bladder cancer, including the PROactive Study (PROspective PioglitAzone Clinical Trial In MacroVascular Events), conducted under the supervision of the U.S. Food and Drug Administration (FDA).

Though the PROactive Study was intended to look at heart issues, it found an increased incidence of bladder cancer among Actos users more than similar populations. By 2011, sufficient evidence had mounted of a link between Actos and bladder cancer for several different countries, including Germany and France, to ban or restrict the use of Actos. That same year, the FDA issued a Drug Safety Announcement regarding the risk of Actos.

Despite this, Actos remained a best-selling drug, raking in billions in sales, and making up more than a quarter of Takeda’s revenue stream. The Actos lawsuits assert that several older, safer drugs exist to treat type-2 diabetes, making Actos unnecessarily dangerous.

The Actos bladder cancer lawsuits have taken the form of a multidistrict litigation (MDL) or mass tort. MDLs are a sort of group lawsuit, where tens, hundreds, or even thousands of individual complaints are grouped together into a single coordinated legal action.

MDLs are similar to class action lawsuits. In both class action lawsuits and MDLs, a group of plaintiffs allege that they have suffered similar harm at the hands of the same defendant. The main difference is that in class action lawsuits, the lawsuit starts out as a group lawsuit, while MDLs are later combined into single coordinated legal action.

The Actos Bladder Cancer MDL is In re: Actos Product Liability Litigation, MDL No. 2299, in the U.S. District Court for the Western District of Louisiana.