Date: Sat, 01 Mar 2008 14:12:34 GMT
MIME-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: quoted-printable

Physicians in Boston have reported two cases of melanoma (skin cancer) th=
at developed in women who were administered Tysabri=C2=AE (natalizumab) t=
o treat their MS. John T. Mullen, MD, and two colleagues at Beth Israel D=
eaconess Hospital, Boston reported the cases in the New England Journal o=
f Medicine.

The melanomas developed early in the course of treatment, but it cannot b=
e confirmed from these reports that Tysabri caused them. However, the aut=
hors advise against treating individuals with Tysabri when there is a per=
sonal or family history of melanoma or in patients with atypical moles or=
ocular nevus, which is a spot on the eye that can develop into melanoma.=


Tysabri is a laboratory-produced monoclonal antibody that is approved for=
individuals with relapsing forms of MS to delay the accumulation of phys=
ical disability and reduce the frequency of clinical exacerbations. It is=
designed to impede movement of potentially damaging immune cells from th=
e bloodstream, across the "blood-brain barrier" into the brain and spinal=
cord.

Dr. Mullen's team reports that a 46-year-old woman developed a melanoma s=
hortly after receiving her first dose of Tysabri. In a 45-year-old woman =
with a family history of melanoma, an ocular nevus developed into a melan=
oma after several doses. A case of melanoma also appeared in the AFFIRM s=
tudy (which involved 942 individuals with relapsing MS, who received eith=
er Tysabri or placebo by IV infusion every four weeks for more than two y=
ears) in a patient with a history of malignant melanoma.

From these reports, a causal link between Tysabri and the occurrence of m=
elanoma cannot be determined. However, given these events, the authors re=
commend that Tysabri not be administered to people with a history or fami=
ly history of melanoma.
"Neurologists who have patients who report a family history of melanoma o=
r have unusual moles should send them to a dermatologist first. Don't jus=
t start them on drugs [Tysabri]," said Dr. John Thomas Mullen, co-author =
of the report and a surgical oncologist at Beth Israel. The report also s=
tated that Tysabri may have a dampening effect on the immune system that =
encourages the formation of the potentially deadly skin cancer.

"This new report warrants another dose of cautious observation for Tysabr=
i," adds MSF Medical Advisor Ben Thrower, M.D. "Potential Tysabri patient=
s should be screened for any history of melanoma, as mentioned. One could=
argue that any prior abnormal tissue growth may make Tysabri use riskier=
for that patient. The thought is that maybe Tysabri interferes with tumo=
r cell surveillance and one would have to question whether this applies t=
o all cancer types. In our practice, Tysabri is only considered in patien=
ts with active MS, who have failed both interferon and glatiramer acetate=
This new report indicates that Tysabri is probably not ready for consid=
eration as a first-line option for RRMS."