Contributing Writer

In treating cancer, two drugs often prove to be better than one. By that reasoning, Biogen Idec Inc. initiated a Phase III trial of the anti-CD80 monoclonal antibody galiximab combined with the anti-CD20 monoclonal antibody Rituxan (rituximab).

The randomized, double-blind Phase III study will enroll approximately 700 relapsed or refractory follicular non-Hodgkin's lymphoma (NHL) patients at 150 sites worldwide. Patients will receive either a combination of galiximab plus Rituxan or Rituxan and placebo. The primary endpoint of the trial is progression-free survival.

"Rituxan produces remission, but it doesn't cure," said Patrick Stiff, M.D., an investigator in the trial and director of the Cardinal Bernardin Cancer Center at Loyola University Medical Center in Chicago.

Stiff stated that about two-thirds of NHL patients go into remission after treatment with Rituxan, but "all except a very few" relapse eventually. As long as their remission lasts at least six months, they can be re-treated with Rituxan, but the number of responders decreases with each re-treatment.

The hope is that adding galiximab will produce "more remission, better remission, and longer remission," Stiff said.

In a previous Phase II trial evaluating escalating doses of galiximab combined with a standard course of Rituxan, the median event-free survival for patients receiving both drugs was 12.1 months. Similar patient populations experienced average event-free survival of about nine months with just Rituxan in single-agent trials. Side effects of the combined antibodies were similar to those observed with Rituxan treatment alone.

Stiff, who also participated in the Phase II trial, added that his patients treated with both galiximab and Rituxan who went into remission and then eventually relapsed "took a lot longer before they needed additional therapy." Although the tumors came back, their rate of re-growth "seemed to be slower" than recurring tumors in patients treated with Rituxan alone, he added.

Additionally, David Parkinson, Biogen Idec's senior vice president of oncology research and development, pointed to animal studies in which galiximab and Rituxan combined produced "more than an additive effect."

The Phase III trial is being conducted under a Special Protocol Assessment and enrolled its first patient in November. Cambridge, Mass.-based Biogen Idec estimates that enrollment will be complete in 2009, with top-line data available in 2010 and a potential launch in 2011.

As Rituxan has proven, the market potential in NHL is significant. Although Biogen Idec won't report year-end earnings until Feb. 15, marketing partner Genentech Inc. reported total Rituxan sales of $2.1 billion for 2006. This includes revenues from sales not only in relapsed or refractory NHL but in first-line treatment of both follicular and diffuse large B-cell NHL. It also includes patients with stable disease or those who achieved a partial or complete response following first-line treatment with chemotherapy. Rituxan also was approved for rheumatoid arthritis last March, but even before that the drug pulled in $1.8 billion in 2005 from its NHL indications. (See BioWorld Today, Mar. 2, 2006 and Jan. 12, 2006).

Biogen Idec has other plans for galiximab, too. Parkinson said the company will begin a trial in refractory Hodgkin's disease later this year and expects to run a trial in diffuse large B-cell NHL "in the not too distant future." Additionally, data are expected later this year from an NCI-associated trial evaluating galiximab and Rituxan in first-line NHL treatment.

As to whether or not galiximab will follow Rituxan into non-oncology indications such as rheumatoid arthritis, Multiple Sclerosis or lupus, Parkinson said some data "suggest immuno-regulatory activity" but the company has no real information in non-malignant indications at this point.

Biogen Idec's stock (Nasdaq: BIIB) traded down $1 on Thursday to close at $47.79.