A federal panel that’s used to dealing with complex litigation expects a new heartburn drug litigation will be “nightmarishly complex.”

Plaintiffs are asking the Judicial Panel on Multidistrict Litigation (JPML) to consolidate dozens of proton pump inhibitor lawsuits into one heartburn drug litigation, to be overseen by a single federal court. The plaintiffs’ claims are over dangerous side effects like kidney disease associated with proton pump inhibitors like Nexium and Prilosec.

The panel held a hearing late last month on the request for consolidation. Panel members queried plaintiffs’ and defendants’ counsel as to how to make the proposed multidistrict litigation, or MDL, as simple and efficient as possible.

Proton pump inhibitors, or PPIs, are used to reduce the amount of acid in the stomach. Though some are FDA-approved to treat symptoms of recognized gastrointestinal conditions, they are often used to treat ordinary heartburn and indigestion.

Generally, the plaintiffs in these PPI lawsuits allege the defendants failed to issue proper warnings about the risk of kidney problems that have been associated with products like Nexium and Prilosec.

In 2014, the FDA required PPI labels to include a warning about the risk of acute interstitial nephritis. Research published more recently showed PPI treatment was associated with a 20 to 50 percent increase in the risk of chronic kidney disease.

JPML Struggles to Organize Heartburn Drug Litigation

Multidistrict litigations tend to be complex by nature. Various factors unique to this heartburn drug litigation are conspiring to make it exceptionally complicated.

For starters, the number of different drugs involved is itself fairly large, as there is a wide variety of PPIs available on the market. Many plaintiffs may have taken several medications simultaneously, further complicating their legal claims.

Each product at issue could require contentious hearings to determine the admissibility of expert witness testimony.

The large number of products could also translate to a large number of defendants. AstraZeneca is the company behind both Nexium and Prilosec. Other potential defendants could include Pfizer Inc., Takeda Pharmaceuticals and Procter & Gamble Co.

Panel members expressed concerns that forcing competitor businesses together as co-defendants could present problems with trade secret protections during discovery.

The sheer volume of cases is also expected to be enormous. PPIs are some of the most widely used drugs on the market, so the number of potential claimants could be astronomical.

The number of claims has already started to grow. When plaintiffs requested consolidation in October, there were only 15 such cases pending in 12 federal courts. By the time of last month’s hearing, around 100 cases had been filed. Plaintiffs’ attorneys say they have thousands of other potential cases under investigation.

Panel members are still considering ways to organize the heartburn drug litigation. They may group claims into more than one MDL, organizing them by single-defendant or single-product.

The question of where to host the MDL is also unresolved. Plaintiffs have proposed federal courts in Louisiana, Kansas, Illinois, California and New Jersey.

The PPI Heartburn Drug Litigation is In re: Proton-Pump Inhibitor Products Liability Litigation, MDL No. 2757 before the U.S. Judicial Panel for Multidistrict Litigation.