Biogen Idec Inc., experienced in developing products against the CD40 ligand protein, formed a collaboration with Celltech Group plc to develop drugs around that target for a slew of autoimmune diseases.

The deal brings together the antibody-generating power of Celltech, of Slough, UK, and the patent position of Biogen Idec, of Cambridge, Mass., in a "pooling of interests," said Richard Bungay, director of corporate communications at Celltech.

"From Celltech's perspective, Biogen Idec holds the dominant intellectual property position around the CD40 ligand target," he told BioWorld Today. "So that was important for us to access."

With that access, Celltech will begin the early work. The terms stipulate that Celltech will identify and engineer antibodies against CD40 ligand, paying for the research and continuing to do so through Phase I studies. Upon Phase I completion, Biogen Idec has an option to co-invest in further development.

Biogen Idec's opting in would mean the companies "share costs and ultimately commercial return" from that point forward, Bungay said. However, should Biogen Idec not pick up its option, Celltech could take any products forward itself, keeping worldwide rights, although Biogen Idec would be in line for sales-based royalties. Further financial details were not disclosed.

The focus of the deal - the CD40 ligand - is a regulator of antibody-mediated immune responses. Blocking the interaction between CD40 ligand on T cells and CD40 on B cells is thought to reduce antibody overproduction and might help restore normal immune responses in many autoimmune diseases, including lupus, rheumatoid arthritis, inflammatory bowel disease and multiple sclerosis.

The deal is not Biogen Idec's first time down the CD40 path. It developed Antova, a humanized anti-CD40 ligand antibody, into Phase II trials for several indications in the late 1990s, but eventually stopped development in 1999 after witnessing thromboembolic events. The Phase II studies had been exploring the product in Factor VIII inhibitor syndrome, multiple sclerosis, islet cell transplantation, kidney transplantation, systemic lupus erythematosus and immune thrombocytopenic purpura (ITP). At the time, Biogen did not disclose which studies showed the clotting events, but admitted it was in more than one indication. (See BioWorld Today, Oct. 25, 1999.)

IDEC Pharmaceuticals Inc. also has dabbled in the area, back before it was acquired by Biogen. It once had a CD40 ligand product in development for ITP, Bungay said.

Celltech recently released details of its initiated Phase III trial of CDP870 in Crohn's disease. That product uses Celltech's PEGylated antibody fragment technology to target TNF-alpha, and it also is being developed in rheumatoid arthritis. The drug had been partnered with New York-based Pfizer Inc., but Celltech took back full rights after Pfizer said it wanted to renegotiate the financial terms of the deal. (See BioWorld Today, Nov. 14, 2003, and Jan. 7, 2004.)

Biogen Idec also has a Crohn's product, Antegren, and recently disclosed positive Phase III data in that indication. The study, known as ENACT-2 (Evaluation of Natalizumab as Continuous Therapy-2), enrolled 428 patients, each receiving 12 infusions of either 300 mg of Antegren or placebo in a one-year time period. The patients enrolled in the trial had responded to therapy in the ENACT-1 trial conducted over a three-month period in patients with very active Crohn's disease. The trial hit its primary endpoint of maintenance, which was defined as a sustained Crohn's Disease Activity Index (CDAI) score of less than 220, as well as no use of rescue intervention throughout six months. Researchers observed no notable difference in side effects between the two groups. Side effects included headaches, nausea and abdominal pain. The drug is partnered with Elan Corp. plc, of Dublin, Ireland. (See BioWorld Today, Jan. 30, 2004.)

Biogen Idec's stock (NASDAQ:BIIB) dropped $1 Thursday to close at $42.18. Celltech's stock (NYSE:CLL) rose 15 cents to close at $14.50.