ImClone Systems Inc. has regained the worldwide rights tointerleukin-6 mutein (IL-6m) from its corporate partnerErbamont N.V.

Thursday's announcement by ImClone of New York essentiallyends the four-year collaboration between the two companies,which was based solely on the development of ImClone'svariant of naturally occurring interleukin-6, which researchErbamont had funded. However, Erbamont still holds about 5percent of the outstanding shares of ImClone's stock (whichtotal approximately 9.4 million), said Samuel Waksal,president and chief executive officer of ImClone(NASDAQ:IMCL).

Originally, Erbamont had been responsible for scaling upmanufacture of the recombinant protein, as well as forconducting preclinical and clinical studies, obtaining thenecessary regulatory approvals, manufacturing and marketing.ImClone was to be paid a royalty on sales as well as paymentsfor various milestones.

But all rights now go back to ImClone, with the exception thatErbamont will receive royalties on product sales to compensatefor costs to date, explained Waksal.

Now that ImClone has reacquired IL-6m, it is anxious to getinto clinical trials -- for treating the decrease in circulatingblood platelets (thrombocytopenia) associated with chemo- andradiation therapy. "We wanted to speed up development,"Waksal told BioWorld.

"We were concerned about getting the product into the clinic."In fact, he explained that his company is "ready to beginclinicals this fall" and is preparing an investigational new drugapplication (IND).

"There were a number of preclinical studies in animals,including primates, investigating thrombocytopenia induced bychemotherapy drugs. They all showed that IL-6m is able toinduce a significant increase in peripheral platelets. It also hasa significantly greater activity than the native IL-6," Waksalsaid.

The mutein is a non-glycosylated variant of native IL-6, andalso contains a 22-amino acid deletion. These changes "give themolecule more activity and make it very easy to produce inbacterial systems." There are minimal steps necessary forrefolding the protein, which make it "very easy from amanufacturing point of view," he added.

In fact, because Erbamont had been taking steps toward scalingup production of IL-6m, the actual material that ImClone takesinto the clinic will initially come from Erbamont's GMPproduction facility. Thereafter, ImClone expects to produce IL-6m in its Branchburg, N.J., facility.

ImClone's stock was unchanged Thursday at $5.75 a share.

-- Jennifer Van Brunt Senior Editor

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