Idec Pharmaceuticals Corp. announced Wednesday thatSmithKline Beecham will invest up to $30 million in developingIdec's "primatized" anti-CD4 antibody for treating rheumatoidarthritis.
SKB (NYSE:SBE) will provide the funds as milestone paymentsto Idec for preclinical and preliminary human clinical studies.Idec (NASDAQ:IDPH) of San Diego will also produce enoughclinical-grade antibody to support these efforts.
SKB will then take the product through large-scale, advancedclinical trials and the regulatory approval processes.
The two companies intend to co-promote the product in the U.S.and Canada. SKB of Philadelphia will retain exclusive rights tothe product in Europe and certain other areas of the world, andIdec will receive royalties on product sales.
About 2.5 million people suffer from rheumatoid arthritis inthe U.S. alone, and SKB has already invested in the field.
"This is an area of growing importance to SmithKline Beecham,with the successful introduction earlier this year in the UnitedStates of Relafen for the treatment of arthritis," said JanLeschly, chairman of SmithKline Beecham Pharmaceuticals.
Company spokesman Jeremy Heymsfeld added, "Arthritis isone of our key areas of interest and one of our research focalpoints."
Idec's anti-CD4 antibodies are "primatized"; that is, they arehuman/monkey derivatives. This distinguishes them fromother chimeric antibodies under development, which arehuman/mouse constructs.
Idec scientists have created the new type of antibody byimmunizing macaque monkeys with the human CD4 antigen.They then harvested the antibody-producing blood cells, fromwhich they isolated the anti-CD4 antibody gene. Theresearchers then combined the portion of the macaqueantibody gene that codes for the variable regions with geneticmaterial for human antibody constant regions.
Idec has filed patent applications on its primatized antibodiesin both the U.S. and Europe.
Richard Krawiec, Idec's director of corporate communications,explained that the macaque, which is an Old World monkey, isgenetically distant enough from humans that it can produceantibodies against human antigens, yet genetically close enoughthat these antibodies are "virtually indistinguishable fromhuman antibodies in their variable regions.
"They have the same physical structure as human antibodies,"Krawiec said.
By using this approach, Idec hopes to alleviate the human anti-mouse antibody (HAMA) response to mouse-derived antibodiesthat effectively precludes their use as therapeutic agents. Todate, academic and corporate researchers have tried to getaround this limitation by creating chimeric, or humanized,antibodies, which contain only a minimal number of actualmouse-derived amino acid residues. But even these may elicitsome anti-mouse immune response, whereas an antibodycontaining macaque sequences shouldn't. This, of course, hasyet to be shown.
Idec is currently evaluating its primatized antibodies inadvanced preclinical studies in non-human primates, Krawiectold BioWorld.
Krawiec said that both Centocor Inc. and Burroughs-Wellcomeare conducting clinical trials for rheumatoid arthritis withchimeric (mouse/human) anti-CD4 antibodies.
Centocor's arthritis trials are currently in Phase II, said RichardKoenig, Centocor's director of corporate communications, and itis too early for data on whether the humanized antibody elicitsan anti-mouse response. He added that Centocor is also testingits anti-CD4 antibody in earlier-stage trials on patients withmultiple sclerosis, psoriasis and Crohn's disease.
Idec is also hoping to use its anti-CD4 antibody for treatingother autoimmune diseases, such as systemic lupuserythematosus, psoriasis, inflammatory bowel disease andmultiple sclerosis.
Krawiec said that data from many different animal modelshave shown that anti-CD4 antibodies effectively suppress theoveractivity of T cells that is common to these chronicautoimmune diseases.
As part of its deal with Idec, SKB's venture capital venturesubsidiary, SR One, agreed to purchase $2.4 million worth ofIdec's common stock through open-market purchases and topurchase from the company warrants that cover futurepurchases of newly issued shares directly from Idec.
Half of the open-market purchases will be completed beforeApril 15, 1993, and the second half will follow the allowanceby the FDA of an investigational new drug (IND) application forIdec's primatized anti-CD4 antibody.
The warrants will be purchased for $3 per share, will cover thepurchase of up to 400,000 shares of Idec common stock at $12per share, and will be automatically exercised if the closingprice of Idec stock exceeds $15 per share for 90 days. SR One'sopen-market purchases will be done in compliance with theprovisions of Rule 10b-18 under the Securities Exchange Act of1934.
Idec shares closed up $1 per share to $8.25 on Wednesday.
-- Jennifer Van Brunt Senior Editor
(c) 1997 American Health Consultants. All rights reserved.