June 6 (Reuters) -

As U.S. District Judge Karen Marston in Philadelphia takes

the helm of litigation involving Ozempic and similar drugs,

she'll step into a lively fight where early battle lines have

already been drawn.

A former federal prosecutor who was nominated to the

bench in 2019 by Donald Trump, Marston was selected by the

Judicial Panel on Multidistrict Litigation on Thursday to take

over product liability proceedings that plaintiffs' lawyers

expect to include more than 10,000 personal injury lawsuits.

The case had been assigned in February to U.S. District

Judge Gene E.K. Pratter. She died suddenly on May 17 from

chronic obstructive pulmonary disease, the Philadelphia Inquirer

reported.

Her colleagues on the bench in the Eastern District of

Pennsylvania said in a statement that her passing was "a

tremendous loss."

Over the past three weeks, lawyers told me they continued

working without day-to-day judicial supervision to tee up a host

of issues including the all-important plaintiff fact sheet - a

form where individual litigants detail their alleged injuries

and other personal information.

"Both sides are interested in moving the litigation as

quickly as we can," plaintiffs' co-lead counsel Jonathan Orent

of Motley Rice told me. "A delay of even three or four months

can be quite significant for (clients) who are not able to work

or take care of themselves."

Marston, who did not immediately respond to a request for

comment, has already scheduled a status conference for Monday

afternoon.

A spokesperson for Novo, which is represented by outside

counsel led by Loren Brown of DLA Piper, said via email that the

company maintains the allegations are false and without merit.

Brown declined comment on the litigation.

Eli Lilly ( LLY ), repped by a team including James Hurst of

Kirkland & Ellis, has denied the allegations as well. Hurst

declined comment.

It's certainly not the first time an MDL has been reassigned

mid-stream. Last month, for example, product liability

litigation involving the blood pressure medication Valsartan was

transferred to U.S. District Judge Renee Bumb after her

colleague on the New Jersey bench, Judge Robert Kugler,

announced his retirement.

What's different here is how sudden the judge's passing was

and its abrupt -- albeit short-lived -- interruption of the

litigation. (Pratter issued a 23-page opinion in another case

just three days before her death.)

Marston can expect the multidistrict litigation to receive

extensive media attention, given the widespread use of the

medications amid the so-called obesity epidemic in the U.S.

About one in eight U.S. adults have taken a drug belonging

to the GLP-1 class of medications, my Reuters colleagues

reported in May, citing a Kaiser Family Foundation poll. The

self-injectable drugs include Novo Nordisk's diabetes drug

Ozempic and weight-loss treatment Wegovy, along with Eli Lilly's ( LLY )

Mounjaro, Trulicity and Zepbound.

Plaintiffs in court documents say the drugmakers failed to

adequately warn that their medications can potentially cause

"prolonged, life-threatening digestive dysfunction." Alleged

side-effects include gastroparesis, which prevents the stomach

from emptying properly, as well as severe vomiting, bowel

obstruction and gall bladder injuries.

The judge taking over the case will face litigation battle

lines that have already emerged.

For Marston, one looming issue will be finalizing the

plaintiff's fact sheet, which will provide individual data on

what defense counsel term "critical dispositive issues"

including claimants' alleged injuries, other medical conditions,

product identification and symptom onset.

Plaintiffs' lead co-counsel Sarah Ruane of Wagstaff &

Cartmell told me all sides are "close to ready to go" on the

form, though they don't agree on how the information should then

be used to weed out claims.

Defense counsel in court documents see the potential to use

the fact sheet responses to narrow the litigation, noting that

some claims may be time-barred, while others might involve

counterfeit or compounded products for which Novo and Eli are

not liable.

They also flag claims by plaintiffs who "lack an objective

diagnosis" of gastroparesis. Symptoms like nausea, indigestion

and bloating are "shared with numerous other conditions,"

defense lawyers say. Moreover, they argue that gastroparesis is

a "known complication" of type 2 diabetes - exactly what Ozempic

and Mounjaro are approved to treat - so how to prove the drugs

are to blame?

Plaintiffs' lawyers oppose any proposal "that would result

in the premature dismissal of claims, or in the adoption of a

single, restrictive test for proving causation" of

gastroparesis.

They reject defense suggestions that their clients should

undergo a gastric emptying study to prove their injuries,

arguing that such a test "may be inconclusive, unavailable, and,

depending on an expert's clinical judgment, unnecessary to prove

injury."

More broadly, they argue any attempt to use data points from

the fact sheet as the basis for winnowing claims via early

summary judgment invite "oversimplification" and run contrary to

the Federal Rules of Civil Procedure.

Instead, the plaintiffs team, which also includes co-lead

counsel Parvin Aminolroaya of Seeger Weiss and Paul Pennock of

Morgan & Morgan, are calling for additional discovery and

bellwether trials to test the cases.