Medarex Reports Interim Data from Ongoing Ipilimumab Combination Phase 1 Studies in Prostate Cancer at American Association for Cancer Resear...(M Santegoets Ph.D. from the Department o...),Health

and Pathology of Vrije Universiteit Medical Center located in

Amsterdam, Netherlands. The data suggested an ipilimumab dose-related

association with increased T-cell activation, as well as associated

anti-tumor activity from the initial 12 patients that was previously

reported at the June 2007 American Society of Clinical Oncology (ASCO)

meeting.

In the Phase 1 clinical trial, 28 patients with metastatic HRPC have

been enrolled, including 12 patients in the dose-escalation cohort

(0.3, 1, 3 or 5 mg/kg ipilimumab) and 16 patients in the expansion

cohort (3 mg/kg ipilimumab). The dose of GVAX immunotherapy for

prostate cancer used in this combination trial is comparable to that

currently being evaluated in Cell Genesys' ongoing Phase 3 program. The

treatment combination was generally well-tolerated. Adverse events

associated with this regimen are consistent with data previously

reported from this study.

-- "CTLA-4 blockade for hormone refractory prostate cancer: dose-dependent

induction of CD8+ T cell activation and clinical responses" (Abstract

#2539)

Preliminary data from an ongoing Phase 1 study of escalating doses of

ipilimumab in combination with GM-CSF (sargramostim) were presented by

Lawrence Fong, Ph.D., from the University of California, San Francisco,

San Francisco. Of the six patients treated at 3 mg/kg ipilimumab, three

experienced confirmed decreases in prostate-specific antigen (PSA)

serum levels of over 50%, and one of these patients experienced a

partial response in hepatic metastases.

In the Phase 1 clinical trial, 26 patients with HRPC received treatment

with a 28-day cycle of daily doses of 250 mg/m2 of GM-CSF for 14 days

in combination with
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