Rituxan for multiple sclerosis - positive clinical trial results

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February 19, 2008

Rituxan for multiple sclerosis - positive clinical trial results

 

Rituxan (rituximab) is a biologic medication that is already approved by

the FDA for the treatment of both

non-Hodgkin’s

lymphoma (NHL) and

rheumatoid

arthritis (RA). It is now being studied as a potential treatment for

 

multiple sclerosis, and results of an early-stage clinical trial,

recently published in the prestigious New England Journal of Medicine,

show that it may have great potential in treating this chronic illness.

This is not the first time that a cancer drug (Rituxan was originally

approved for NHL, a type of blood cell cancer) has later been studied in

MS. Novantrone (mitoxantrone) is one such cancer drug, originally

approved for the treatment of certain leukemias and then later for

advanced prostate cancer, which also was eventually approved by the FDA

for the treatment of MS.

In the current Phase II research, patients, 18-55 years of age with

relapsing-remitting MS, were randomized to receive either Rituxan or

placebo. Sixty-nine patients received one “course” of Rituxan, which

consisted of an intravenous infusion on days one and 15 of the study (a

total of two infusions, with two weeks in between the first and second).

Thirty-five patients received similar infusions of an inactive placebo.

All patients had MRIs to count their MS lesions before receiving any drug

and then again at weeks 4, 12, 16, 20, 24, 36 and 48. Patients who

received Rituxan had a 91 percent relative reduction in lesions (called

gadolinium-enhancing lesions) at week 24 (six months)

 

with respect to those patients who received placebo. The reduction in

lesions began by week 12 and continued throughout the six-month study. A

key secondary end-point of the study found that there was a 58 percent

relative reduction in the number of clinical relapses suffered by the

patients in the Rituxan group as compared to the patients in the placebo

group. The positive results were maintained when most of the patients

were examined again at week 48 (month 11).

The most common side effect was mild to moderate infusion-related adverse

events. These were less common with the second infusion than the first.

The symptoms included fever, chills, rigors, nausea, itching, weakness

and high blood pressure. These symptoms are similar to those seen in

patients with RA who receive Rituxan.

Rituxan inhibits the action of certain blood cells called B lymphocytes.

This is why it is used to treat B cell lymphomas. It is also why it is

used to treat RA, because B cells are known to play a role in promoting

inflammation.

 

Rheumatoid arthritis and MS are known to be diseases in which the

immune system, for whatever reasons, is overactive and most of the

treatments for these disorders suppress the activity of the immune system

in one way or another (this is why steroids are commonly used in both

conditions). Current treatments for MS are either general

immunosuppressants or they attack other blood cells called T

lymphocytes.

If Rituxan continues to show efficacy in larger Phase III clinical

trials, it would add a new method for attacking the immune system

(currently available treatments do not specifically attack B cells).

Thus, it might be used either in conjunction with or independent of other

MS drugs. Moreover, the results of the current study show that just one

course of treatment (a total of two infusions over two weeks) provided

significant efficacy for nearly one year (possibly even longer, which

might be determined over time as the study patients continue to be

evaluated). Further, this study opens an entirely new arena for other

research into the role of B cells in MS as well as the potential for

other B-cell inhibitory drugs to be either studied or developed.

It must be emphasized that Rituxan is not approved by the FDA for use in

treating MS. The current study was relatively small and was a Phase II

study, which means that it is preliminary but gives reason to proceed

with further trials that will be larger and more definitive and more

carefully designed to look for potential long-term adverse events. It is

legal for physicians to prescribe Rituxan for MS, however, it is illegal

for Genentech, the manufacturer, or Biogen (its marketing partner) to

promote or advertise Rituxan for MS (neither Genentech nor Biogen had any

involvement in this posting – I personally came up with the idea and

wrote it myself

 

because many HealthTalk members suffer from MS and I thought they might

be interested in this research). Rituxan is an expensive medication

and its lack of FDA approval would likely make insurance coverage or

other reimbursement difficult. The lack of Phase 3 data will also make

many physicians reluctant to prescribe it, however, this would be a

personal decision, made between individual patients and individual

doctors. If you find this research to be of interest, please discuss it

with your personal physician.

Reference:

New England Journal of Medicine,

“B-Cell

Depletion with Rituximab in Relapsing–Remitting Multiple

Sclerosis”