Kansas City, Mo. ? The guilty plea by the pharmacist who diluted cancer medication is likely to bolster drug companies’ defense that Robert R. Courtney is solely responsible, a legal scholar said.

Pharmaceutical giants Eli Lilly Co. and Bristol-Myers Squibb are defendants in roughly 200 lawsuits filed in Jackson County by the druggist’s former patients.

At a hearing here Thursday, the companies will seek dismissal of the lawsuits, which allege they should have done more to stop their medicine from being diluted.

Courtney, 49, pleaded guilty last week to 20 counts of tampering with and adulterating or misbranding the drugs Gemzar and Taxol, made by Lilly and Squibb, respectively. Earlier, he said he did it because he owed about $1 million in taxes and a pledge to his church.

“The drug companies can point to the pharmacist and say he caused this,” said Nicolas Terry, law professor and director of the center for health law studies at Saint Louis University. “If someone intends to do harm, there’s little that someone else can do to prevent it.”

But Michael Ketchmark, an attorney handling 173 of the lawsuits, said Courtney’s admission makes his case stronger, because Lilly and Squibb had been arguing he couldn’t prove any dilutions beyond the eight listed in the pharmacist’s indictment.

In the guilty plea, Courtney admitted to diluting medications 158 times for 34 patients.

“Missouri law poses a duty on a drug manufacturer to warn about any tampering of their products that they know about or should have known about,” Ketchmark said. “The whole question focuses on whether (Lilly and Squibb) knew or should have known. The answer is a resounding yes.”

He said Lilly and Squibb each buy 165 million records per month tracking drug sales, giving them all they needed to determine what Courtney was doing.

Besides the sales database, he said Lilly knew that Courtney was allegedly diluting drugs in early 2000, but failed to tell anyone.

Lilly sales representative Darryl Ashley first noticed a discrepancy in those drug-sales records and triggered the investigation that led to Courtney’s arrest last August.

Lilly has denied that it knew about the dilutions, saying the sales discrepancy merely alerted Ashley to take a closer look.

A spokesman for New York City-based Squibb declined to comment.

Jeff Newton, spokesman for Indianapolis-based Lilly, said the lawsuits are baseless.

“The issue here is Robert Courtney and the horrible thing he did,” Newton said. “We’re already a heavily regulated industry, and I don’t think additional regulation is the answer here. What he did is a very isolated incident.”

Terry said the companies’ argument is “not bulletproof, but it will reduce the settlement value of the case.”

Ketchmark said his clients aren’t after cash settlements. They want the drug companies to make it harder for pharmacists to tamper with their drugs, he said.

Even so, a dismissal of the claims against deep-pocketed Lilly and Squibb would significantly decrease the money available to compensate the hundreds who say they are victims and to pay fees for Ketchmark and other attorneys.

Only Courtney’s pharmacist’s insurance would remain as a target of the lawsuits, which also name the druggist and his business as defendants. Most of Courtney’s $10 million estate is to be used in criminal court for restitution.