When Idec Pharmaceuticals Corp. and partner SmithKline Beecham selected IDEC-151 clenoliximab as their lead anti-CD4 antibody to treat rheumatoid arthritis, the choice was predicated on IDEC-151 being superior to the former antibody (IDEC-CE9.1) in terms of a reduced depletion of immune system cells following treatment (see BioCentury, March 9, 1998).

Ten months later, SmithKline (Philadelphia, Penn.) has delayed the start of Phase IIb studies with the antibody in RA, which were expected to begin by the end