Tysabri & the Immune System

A board to discuss the newly-released drug Tysabri, (formerly known as Antegren) as a treatment for Multiple Sclerosis

Postby coolycat » Mon Mar 07, 2005 9:15 pm

Arron wrote:Hi cooly, thanks for the information. it's reassuring... kind of... 8O :)


LOL, I know what you mean :wink:

You're welcome. Of course, I can't be sure since I wasn't present for the conversation.
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No MS Drug Safety Issues Noted

Postby better2gether » Thu Mar 10, 2005 1:38 am

March 9, 2005

No MS Drug Safety Issues Noted


The FDA found that Tysabri appeared more effective than existing drugs but reviewers were unsure of its long-term effects.

By Ricardo Alonso-Zaldivar and Denise Gellene, Times Staff Writers


WASHINGTON — The Food and Drug Administration raised no red flags about safety in its review of multiple sclerosis drug Tysabri, according to documents released Tuesday.

The intravenous medicine was pulled from the market last week by co-developers Biogen Idec Inc. and Elan Corp. after one patient died from a rare brain disease and a second patient developed the illness.

A team of FDA reviewers, according to agency documents, concluded the drug offered significant benefit to patients and deserved accelerated approval based on less than two years' worth of data, the amount typically required for an MS drug.

MS, which affects as many as 400,000 Americans, is a chronic nervous system disease that leaves about half its victims permanently disabled. The disease is marked by periods of flare-ups, or relapse, and good health, or remissions. Patients undergo long-term treatment with a range of medications.

In hundreds of pages of documents that offered the first detailed look at the FDA's handling of the drug, reviewers noted that Tysabri appeared more effective than existing drugs, reducing relapses in patients by 66%, based on one year's data. The reviewers said it was "reasonably likely" that the drug would provide long-term benefits.

Nonetheless, the agency's drug reviewers acknowledged they were unsure about Tysabri's long-term effects.

"The clinical meaningfulness of a decrease in the incidence of relapses at one year is uncertain," the reviewers wrote.

FDA reviewers found that Tysabri had an acceptable safety profile, though they noted that health risks "beyond one year are not known."

Infections, including urinary and respiratory, were seen with Tysabri, but they were "generally routine and did not have a complicated course," the reviewers said.

Stanford University professor Dr. Lawrence Steinman, an MS specialist, had warned there was a clear risk of infection for patients taking such drugs, because they tend to suppress the body's immune system.

Steinman had helped discover the active agents in the drug, but later became concerned about potential side effects, and is working on a competing drug. He noted that the infection rate of Tysabri patients in one trial was 2.1%, compared with 1.3% in the placebo group.

"There were hints of an increase in the infection rate," said Steinman. "The FDA should have dug deeper."

But FDA officials have stressed that, before the drug's approval, no patients had developed the rare viral infection that prompted the drug's withdrawal.

Known as PML, or progressive multifocal leukoencephalopathy, the central nervous system disease usually strikes AIDS patients and others with severely compromised immune systems. Two cases of PML have been detected among an estimated 8,000 patients who have taken Tysabri.

Both patients were taking part in a long-term clinical study that involved taking Tysabri with another MS drug, Avonex. Some academics suspect it was the combination of drugs that left patients vulnerable to PML.

The FDA, in the documents, asked Biogen and Elan for follow-up studies, but none asked for a closer look at how Tysabri and Avonex, Biogen's brand name for interferon, affected patients' immune systems.

"Not one of these issues talks about a combination effect immunologically with interferon," said Norman J. Kachuck, associate professor of neurology at the USC School of Medicine, who administered Tysabri to patients as part of the clinical trials. "If the FDA missed anything," he said, it should have asked for more "studies looking at the interaction of these two medicines."

At the same time, Kachuck said, there was no evidence in the data that patients' immune systems were being severely compromised. "We did not see activation of tuberculosis or herpes, two major chronic infections that you look for."

After one patient died, Biogen Idec and Elan voluntarily withdrew their drug. Tysabri had been available a scant three months in the United States, since its Nov. 23 approval by the FDA. In Europe, regulators decided to wait for more data.

The companies are trying to determine what went wrong to see whether Tysabri can safely be returned to market.

http://www.latimes.com/business/la-fi-b ... &cset=true
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Re: No MS Drug Safety Issues Noted

Postby HarryZ » Thu Mar 10, 2005 6:59 am

Better.

The common point in many of these articles on Tysabri seems to be that no danger was seen with the drug in the one year trial data. But some MS docs have stated that one year data simply wasn't enough to properly determine a reliable safety level.

And now Biogen is paying the price for that.

Harry
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Re: No MS Drug Safety Issues Noted

Postby flora68 » Thu Mar 10, 2005 8:58 am

HarryZ wrote:Better.

The common point in many of these articles on Tysabri seems to be that no danger was seen with the drug in the one year trial data. But some MS docs have stated that one year data simply wasn't enough to properly determine a reliable safety level.

And now Biogen is paying the price for that.

Harry


You know, Harry, it isn't just some "MS docs" who'd hesitate to prescribe an under-tested, fresh off the drawing board new medication, especially if the issue isn't one of imminent life-or-death.

I've been privileged to work for a brilliant and very wise family doc for many years. One of the many things I've learned from her is that, while amazing new breakthrough drugs (for everything but MS!) come along pretty often, a significant number have to be pulled from the market because of dangers or other problems that don’t show up until the drug is in general use for a year or so. Many of her colleagues have expressed the same cautious approach to brand new medications.

For example, she still doesn’t prescribe Crestor, because in her opinion there are some unresolved questions about its safety, and there are alternatives with a better safety profile. But if a mutual patient’s cardiologist prescribes it for them, that’s fine with her, because she generally defers to the specialist’s opinions. But she still won’t start anyone on Crestor, and doesn't plan to until and unless she’s convinced that it’s really ready-for-prime-time.

She says that when assessing risk, a doctor has to be able to see the difference between life-and-death issues and quality-of-life issues. Furthermore, if she'd wanted her patients to be guinea pigs, she'd have been a vet... :wink:
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Postby OddDuck » Thu Mar 10, 2005 10:08 am

Hi, flora!

Sounds like you know an imminently wise and wonderful physician, in my humble opinion!

Deb
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Postby flora68 » Thu Mar 10, 2005 5:37 pm

OddDuck wrote:Hi, flora!

Sounds like you know an imminently wise and wonderful physician, in my humble opinion!

Deb


Deb, you're right. If I could design my own ideal doctor, it'd definitely be her. :)
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Re: No MS Drug Safety Issues Noted

Postby HarryZ » Thu Mar 10, 2005 5:55 pm

Flora,

Don't let that doc of yours out of your sight...ever!! You are fortunate to have someone with those kind of credentials.

Yes, I suppose I should have included general physicians in my message because they are a Godsend for many MS patients. Marg had such a doc in Toronto a few years ago when we lived there. She was the one who prescribed Prokarin for Marg and helped her get out of a terrible rut that she was in with her MS. Unfortunately, we have not been able to find someone like that here in London, ON.

Harry
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Re: No MS Drug Safety Issues Noted

Postby flora68 » Thu Mar 10, 2005 7:20 pm

HarryZ wrote:Flora,

Don't let that doc of yours out of your sight...ever!! You are fortunate to have someone with those kind of credentials.

Yes, I suppose I should have included general physicians in my message because they are a Godsend for many MS patients. Marg had such a doc in Toronto a few years ago when we lived there. She was the one who prescribed Prokarin for Marg and helped her get out of a terrible rut that she was in with her MS. Unfortunately, we have not been able to find someone like that here in London, ON.

Harry


I'm deeply grateful for my dear sweet family doc (who's also my boss and longtime best friend), and I'm very happy that she has no plans to ever move away, and neither do I. But I'd follow if I could...

Harry, is there any chance that Marg's wonderful old doc could recommend a like-minded physician in your area? It's a long shot, I know, but you never know unless you ask. My doc is often asked to recommend "someone just like you" to patients who are relocating. She's always flattered to be asked, and sometimes actually does have someone to recommend.
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Re: No MS Drug Safety Issues Noted

Postby HarryZ » Thu Mar 10, 2005 8:27 pm

Flora,

There are some excellent family docs in London but the BIG problem is that none of them are taking on any more patients. There is a chronic shortage of family docs in London and the problem has existed for the past few years. We are trying, through contacts, to obtain one but so far have been unsuccessful.

Thanks for your consideration though...it is appreciated.

Harry
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Postby coolycat » Fri Mar 11, 2005 1:00 pm

Harry,
You live in London?
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Postby HarryZ » Fri Mar 11, 2005 2:39 pm

Coolycat,
coolycat wrote:Harry,
You live in London?


London, Ontario Canada....1/2 way between Detroit and Toronto.

Harry
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Postby coolycat » Fri Mar 11, 2005 3:57 pm

HarryZ wrote:Coolycat,
coolycat wrote:Harry,
You live in London?


London, Ontario Canada....1/2 way between Detroit and Toronto.

Harry


Oh! London, Ontario Canada!!

I thought you meant London, England.
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Postby HarryZ » Fri Mar 11, 2005 5:58 pm

Coolycat,

Oh! London, Ontario Canada!!

I thought you meant London, England.


That assumption has happened often and most of the time I add the
ON (Ontario) to it in order to avoid that very issue. I forgot and of course, it happened again :D

Harry
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