ImClone Systems Inc. on Thursday said it has become eligiblefor several million dollars of milestone payments after clearinga key test in the development of its BEC-2 cancer vaccine.

In a presentation this week at the American Association forCancer Research in San Diego, the company said BEC-2 inducedin one patient out of five patients who could be evaluated along-lived immune response against the GD3 cancer antigen.

The New York company said it was the first time an anti-idiotype antibody had been shown to induce animmunoglobulin G response to a non-protein cancer antigen inhumans without the use of an adjuvant. The response was ahigh-titer, long-lived response, said Samuel Waksal, presidentand chief executive.

According to Waksal, the IgG response kicked in a set ofundisclosed multimillion dollar milestone payments over thenext two years from E. Merck, which formed a collaborationwith ImClone (NASDAQ:IMCL) in 1990 to develop and marketBEC-2.

BEC-2 is designed to prevent or delay the onset of recurrenttumors in patients with cancers exhibiting the GD3 antigen. GD3itself doesn't elicit an immune response.

The New York company's pilot trial was in patients withadvanced malignant melanoma. No anti-melanoma effects wereseen in the patients.

The results were consistent with animal data, which showedthat immunization with BEC-2 without adjuvants induces animmune response to GD3 in a minority of subjects. In animaltrials, adjuvants could increase the response to close to 100percent, the researchers said.

ImClone has three ongoing Phase I studies of BEC-2: a doseescalation study in Stage III/IV melanoma patients, a study inpatients who have had a human-anti-mouse antibody responseto antibody therapy or imaging, and a study combining BEC-2and BCG adjuvant. The company is about to begin a Phase Itrial of BEC-2 and BGC in small cell lung carcinoma.

The stock was up 50 cents to $11.25 after gaining 63 cents onWednesday. -- KB

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