New Fusion Inhibitors in Early Development for HIV

"Protein Design Labs and Progenics PharmaceuticalsAnnounce Humanization Agreement for Anti-CCR5 Antibody"

PRNewswire - Wednesday May 19, 1999


Protein Design Labs, Inc. and Progenics Pharmaceuticals,Inc. today announced an agreement for the humanization by PDL of PRO 140,Progenics' novel anti-CCR5 monoclonal antibody that potently blocks HIVreplication in the laboratory. The agreement provides that Progenics willpay PDL a licensing and signing fee, will make additional payments uponthe achievement of certain milestones, and will pay royalties upon salesof the antibody, if any. The financial terms were not disclosed.

"PRO 140 is a potent and specific inhibitor of HIVwith a novel mechanism of action. We believe that the CCR5 co-receptor representsan important new target for HIV treatment strategies and are eager to furtherexplore the therapeutic potential of this new compound," said PaulJ. Maddon, M.D., Ph.D., Chairman and Chief Executive Officer of Progenics."Our objective in working with PDL is to develop an antibody whichretains PRO 140's demonstrated antiviral activity, but which is more suitablefor chronic use in humans. We are working to begin clinical testing withPRO 140 next year and are confident that this collaboration will help usto achieve that goal."

Dr. Maddon went on to say, "We examined several technologiesavailable for development of non-immunogenic antibodies and concluded thatPDL's technology and expertise are best suited to our requirements. Ourdecision was based on PDL's demonstrated ability to humanize antibodieswhile retaining the antibodies' desired characteristics."

PRO 140 is the most potent of six HIV inhibitory monoclonalantibodies against CCR5 isolated by Progenics scientists using Progenics'ProSys technology. PRO 140 blocks the fusion of viral and target cell membranes,an early step of the HIV replication cycle, and one that is not addressedby current therapies for AIDS. Importantly, PRO 140 effectively inhibitsHIV entry at concentrations that have no apparent effect on the normal functionof CCR5, which mediates the activation and trafficking of immune systemcells. The results of these studies were published in the May 1999 issueof the Journal of Virology (Vol. 73, No. 5).

"PDL's patented humanization technology has been demonstratedto produce safe, effective and non-immunogenic antibodies that have beenused in numerous acute and chronic disease settings," said Cary Queen,Ph.D., PDL Senior Vice President and Vice President, Research. Three humanizedantibodies, including one created at PDL, are currently marketed in theU.S. and more than 30 other humanized antibodies are now in clinical developmentat pharmaceutical and biotechnology companies worldwide.

Progenics' lead HIV product, PRO 542, has completed PhaseI clinical trials, and a follow-on HIV product, PRO 367, is expected tocommence Phase I/II in 1999.