Zenapax (Daclizumab)

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Zenapax (Daclizumab)

Postby Dunmann » Tue Mar 28, 2006 11:36 am

Hopes raised for effectiveness of Multiple Sclerosis drug

A national research team led by the University of Cincinnati's Bibiana Bielekova, MD, report new insights into how anti-rejection drug helps MS patients
Discovery of the mechanism of a drug being tested for the treatment of multiple sclerosis (MS) has revealed that it's not only more effective than first thought, but might also help in the management of other autoimmune diseases, organ transplant rejection and even cancer.

A research team led by the University of Cincinnati's Bibiana Bielekova, MD, report new insights into the role of the MS drug daclizumab (Zenapax) in the March 27 online version of the Proceedings of the National Academy of Sciences. The article will appear in print April 11.

The exact cause of MS is unknown, but one theory is that it may it be triggered by exposure to a viral infection or environmental influences. The disease takes different courses in different people and can go into remission for many years, recurring occasionally or progressing quickly into degeneration of all motor functions that control muscles, strength, vision and balance. The very progressive form of the disease can end in death.

Scientists have long thought that in MS the specific white cells (T-cells) that fight off infection actually turn on the body they are supposed to protect, attacking the myelin sheath that protects the nerves.

"Without the insulating cover, the nerve axons short-circuit, much like a damaged electric cord might," says Dr. Bielekova, director of UC's Waddell Center for Multiple Sclerosis. "Also, many nerve cells (neurons) do not survive without myelin sheath."

It was also believed that since activated T-cells need a growth factor called interleukin 2 for their function, drugs that can block the interaction of interleukin-2 and T-cells could be used to control MS.

Daclizumab is being tested against MS because it has already proved useful in preventing rejection of transplanted organs, "and we thought it works by inhibiting T-cell activation," Bielekova says.

Earlier research by Dr. Bielekova and her group showed that daclizumab benefits MS patients, especially those who have highly inflammatory MS. This latest study, sponsored by the National Institutes of Health (NIH), involved 22 MS patients.

"We monitored T-cell function in patients who were injected with the drug, expecting to see that the drug inhibited T-cell function," says Dr. Bielekova.

"We didn't see that at all. To our surprise the T-cells were functioning normally."

But something unexpected was happening–the numbers of T-cells circulating in the blood of patients taking daclizumab were declining by about 10 percent. Simultaneously, the number of immune cells known as "regulatory natural killer cells," which are very rare in normal human blood, increased.

Regulatory natural killer cells are known to proliferate in special conditions, such as pregnancy or bone marrow transplantation.

"Not only did the number of regulatory natural killer cells increase in patients treated with daclizumab," says Dr. Bielekova, "but that expansion correlated with the treatment outcome--the more these cells expanded, the better the MS patients did during the trial. And the longer the patients were on the therapy, the more regulatory natural killer cells they had and the better they responded to treatment."

"The best news is that natural killer cells are actually very efficient immune cells that fight viruses or cancers," says Dr. Bielekova, "so it appears that daclizumab doesn't damage the immune system. It only shifts the emphasis of the immune reaction from T-cells to natural killer cells. However, larger studies need to be performed to evaluate the safety of long-term daclizumab therapy."

The current results, however, suggest that daclizumab might also help in the management of autoimmune diseases, organ transplant rejection and perhaps even cancer, she says.

Having found one drug pathway that appears to be important for the treatment of MS, Dr. Bielekova says, "The hope is that we can learn how to enhance this pathway by drugs that can be taken orally, rather than injected." As a result of these findings by Dr. Bielekova's research team, daclizumab is now being tested as a possible MS treatment in a phase-2 trial across the United States, including UC, and Europe.

Dr. Bielekova is a member of the Neuroscience Institute, a collaborative of nine academic departments at UC College of Medicine, University Hospital and independent physician practice groups. The institute is dedicated to patient care, research, education and the development of new medical technologies.

###

The study was conducted at the Neuroimmunology Branch (NIB) of the National Institute of Neurological Disorders and Stroke (NINDS) of the National Institutes of Health (NIH). Coauthors include Marta Catalfamo, PhD, of the National Cancer Institute (NCI); Susan Reichert-Scrivner, MS, Amy Packer and Magdalena Cerna, NINDS; Thomas Waldmann, MD, NCI; Henry McFarland, MD, NINDS, Pierre Henkart, PhD, NCI; and Roland Martin, MD, NINDS.

The NIH applied for two patents related to this discovery that have been bought by drug companies. Dr. Bielekova and three coauthors. Dr. Waldmann, Dr. McFarland and Dr. Martin, are each receiving patent royalty payments from the NIH.

Here's the original link:
http://www.eurekalert.org/pub_releases/ ... 032806.php
Dunmann.
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Postby bromley » Tue Mar 28, 2006 1:13 pm

Great post Dunmann.

Drugs such as Dacluzimab and Rituximab look very promising. Not only do they appear to provide clinical benefits for the pateint but they also help the researchers in understanding how this disease develops and what drives it etc.

Ian
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Postby scoobyjude » Tue Mar 28, 2006 7:22 pm

I'm not sure that I am understanding this article correctly. Is it saying that daclizumab does not suppress T cells but rather just modifies the immune system in other ways? Does that mean it would be less likely for it to have problems like Tysabri where because the immune system was so suppressed other viruses were able to take hold? I just want to make sure I'm understanding this right before I get excited.
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Postby Arron » Thu Mar 30, 2006 1:53 pm

our coverage of this important story can be found here:

http://www.thisisms.com/modules.php?nam ... le&sid=261
Disclaimer: Any information you find on this site should not be considered medical advice. All decisions should be made with the consent of your doctor, otherwise you are at your own risk.
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Postby Arron » Thu Mar 30, 2006 1:55 pm

scoobyjude, it seems like that is the case, with the usual caveats (remember Tysabri showed no PML problems in many years of clinical and animal trials and thousands of dosings, so one can never *truly* be sure until the drug is on the market for dozens of years...) The link in our front page coverage shows the impact on the immune system of the first small daclizumab trial.

it appears that daclizumab doesn't damage the immune system. It only shifts the emphasis of the immune reaction from T-cells to natural killer cells. However, larger studies need to be performed to evaluate the safety of long-term daclizumab therapy
Disclaimer: Any information you find on this site should not be considered medical advice. All decisions should be made with the consent of your doctor, otherwise you are at your own risk.
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Postby scoobyjude » Thu Mar 30, 2006 3:22 pm

Sounds pretty good then. Hope it proves safe and effective.
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to scoobs

Postby jimmylegs » Sat Apr 01, 2006 11:14 am

hi judie did u see my answer re: regimen on the intro string?
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Natural Killer Cells, Cortisol and Beta-Endorphins

Postby Shayk » Sun Apr 02, 2006 8:43 am

I think it's worth noting that even though these natural killer cells apparently increase during pregnancy, which would also put into play more questions about the role of hormones as a factor in MS, hormones are still not out of the picture IMO. :wink:

The following links are not about MS at all, but they are about the stress hormone "cortisol". Cortisol seems to decrease NKCs. This abstract
In addition to demonstrating the significant influence of cortisol on natural killer cell function, these studies provide a model system for elucidation of molecular mechanism(s) whereby glucocorticoids repress cellular immune function, especially with respect to natural killer cells.


So, high cortisol levels in people with MS could, theoretically it seems from my non-scientisit perspective, be a potential reason people with MS might have fewer NKC cells than might be ideal.

On another note, it seems from this abstract the possibility exists that beta-endorphins (a factor with LDN I think) increase NKCs.
NK cell activity is positively regulated by immune interferon (IFN-gamma); among hormones, glucocorticoids are potent in vitro and in vivo inhibitors, whereas ACTH and beta-endorphin in many experimental circumstances enhance NK cytotoxicity.


It will be extremely interesting to see how daclizumab plays out and it strikes me that it is an important research development.

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