Update: Tysabri and Melanoma

[Guest guest]

The Tysabri rebuttal is below. But the first paragraph in this article is very interesting.Sharonhttp://www.nationalmssociety.org/news/news-detail/index.aspx?nid=256Jul 02, 2008Previous Report of Two Cases of Melanoma (Skin Cancer) Reported in People Taking Tysabri for MS Updated with Company Rebuttal

Originally Reported on February 7, 2008 - See Update Below, July 2, 2008

Physicians in Boston have reported two cases of melanoma (skin

cancer) that developed in women in their practice who were administered

Tysabri® (natalizumab, Biogen Idec and Elan Pharmaceuticals) to treat

their multiple sclerosis. T. Mullen, MD, and two colleagues (Beth

Israel Deaconess Hospital, Boston) reported the cases in the New

England Journal of Medicine (2008;358[6]:647-8). The melanomas

developed early in the course of treatment, but it cannot be confirmed

from these case reports that Tysabri caused them. However, the authors

advise against treating individuals with Tysabri when there is a

personal or family history of melanoma or in patients with atypical

moles or ocular nevus (spot at the back of the eye).

Background: Tysabri is a laboratory-produced monoclonal antibody

that is approved for patients with relapsing forms of MS to delay the

accumulation of physical disability and reduce the frequency of

clinical exacerbations. It is designed to hamper movement of

potentially damaging immune cells from the bloodstream, across the

"blood-brain barrier" into the brain and spinal cord.

Details: Dr. Mullen’s team reports that a 46-year-old woman

developed a melanoma shortly after receiving her first dose of Tysabri,

and an ocular nevus developed into a melanoma after several doses in a

45-year-old woman with a family history of melanoma . A case of

melanoma also appeared in the AFFIRM study – which involved 942

individuals with relapsing MS, who received either Tysabri or inactive

placebo by intravenous infusions every four weeks for more than two

years – in a patient with a history of malignant melanoma.

It cannot be confirmed from these reports that there is a causal

link between Tysabri administration and the occurrence of melanoma.

However, given these occurrences, the authors recommend that Tysabri

not be administered to people with a history or family history of

melanoma.

“These reports raise concern and they underscore the importance of

carefully tracking patients on powerful medications like Tysabri,” said

Dr. R. Richert, executive vice president of research and clinical

programs at the National MS Society. “This drug is relatively new to

the market, and as experience grows we are bound to learn more about

its benefits as well as possible adverse events,” Dr. Richert added.

JULY 2, 2008 UPDATE:

In a letter to the editor published in the July 3, 2008 issue of the

New England Journal of Medicine (2008; 359[1]:99-100), Dr. A.

Panzara and other representatives of Biogen Idec, Inc., pointed out

that individual case reports, such as were reported by Dr. Mullen and

colleagues, do not provide an adequate basis for proving cause and

effect. The authors reviewed safety data from several clinical trials

of Tysabri involving thousands of people and found that the incidence

of melanoma was similar in those who received Tysabri (0.07%) compared

to those who received inactive placebo (0.10%). In addition, a review

by the authors of the company’s post-marketing safety surveillance data

did not indicate in increased risk of melanoma in over 21,000 treated

patients (as of December 2007).

Tysabri is a registered trademark of Biogen Idec and Elan.