FRIDAY, March 3 (HealthDay News) — Two experts are questioning whether a woman who died of a rare infection after participating in a trial for the multiple sclerosis (MS) drug Tysabri should have been included in the study in the first place.

The patient was suspected of having MS but showed no symptoms, and was later found not to have had MS. Now, a commentary in the March 4 issue of The Lancet paints a cautionary tale of what went wrong, and asks whether the woman should have received Tysabri at all, when other safe and effective agents were at hand.

The piece, penned by Stanford University neurologists Dr. Annette Langer-Gould and Dr. Lawrence Steinman, adds fuel to the debate over Tysabri (natalizumab), which has been linked to three cases of a rare, dangerous infection called progressive multifocal leukoencephalopathy (PML). Two of those cases proved fatal.

Researchers quickly halted the trial last February after the PML cases emerged. At the same time, Biogen Idec and Elan Corp., the drug’s makers, heeded a U.S. Food and Drug Administration advisory and withdrew Tysabri from the market, just three months after its fast-track approval for cases of especially tough-to-treat MS.

However, research published this week in the New England Journal of Medicine found the drug to be safe and effective, at least for the short term. And after a yearlong investigation, an FDA advisory committee recently announced that it will meet Tuesday and Wednesday to consider the company’s request to return the drug to the market.

In the Lancet commentary, Steinman and Langer-Gould criticize how the original trial was conducted.

“When you test a drug that is potentially dangerous and, in this case, carries a risk of one per 1,000 of fatality or serious injury, one ought to be careful that the subjects in the study have a fair risk-benefit balance,” explained Steinman, a professor of neurobiology and neurological sciences who helped develop Tysabri.

In fact, the woman who died, Anita Louise Smith, had been diagnosed with MS, even though she had no symptoms. In the end, it was determined that Smith did not have MS. “But that can happen,” Steinman said. “MS is a notoriously difficult disease to diagnose.”

However, student loan calculator whether or not an asymptomatic patient such as Smith should have been included in the trial to begin with points to the crux of the problem, according to Steinman.

“One needs to reexamine the justifications for putting someone on an experimental MS drug when they have no disability,” he said, adding that the criteria for including patients in such a trial needs to be re-evaluated.

Steinman does believe the FDA should let Tysabri go back on sale. “If I were the FDA commissioner, I would let it back — with warnings about the risk,” he said. “I would leave it up to physicians and their patients to make the decision.”

However, Steinman believes the drug will — and should — be used mainly for patients who are not doing well, and not for patients in the early phases of MS.

“It’s hard to justify looking a person in the eye and saying that ‘You have all these approved drugs that are safe — or [you have] this drug, which might be more effective. However, it carries a chance that you can die from it or have a really serious neurologic injury,’” he said.

Langer-Gould, who treated the MS patient who survived PML, believes the risk of developing the infection while receiving Tysabri is greater than reported. But, she explained, “all you need to have is three more cases, and the estimate becomes one in 500.”

In addition, Langer-Gould doesn’t think Tysabri is significantly more effective than other, safer MS drugs. “This drug does nothing more than [add] a 4 percent reduction in disability, which is nothing,” she said.