Additional Preclinical and Clinical Data Indicate Abegrin(TM) May Offer Three-Pronged Approach to Cancer Therapy
Monday April 10, 9:36 am ET
- MedImmune to Initiate Phase 3 Study with Metastatic Melanoma Patients in 2006 -
GAITHERSBURG, Md., April 10 /PRNewswire-FirstCall/ -- MedImmune, Inc. (Nasdaq: MEDI - News) announced today that it has collected additional preclinical and clinical data showing that Abegrin (formerly known as Vitaxin®) may provide a three-pronged approach to treating solid tumors. The new data provides additional insight into the drug's mechanism of action, which is believed to inhibit tumor growth, bone metastases and angiogenesis. These data support the encouraging overall survival results produced in a previously announced Phase 2 trial with metastatic melanoma patients, and provide the impetus for MedImmune to move ahead with a confirmatory Phase 3 trial for Abegrin in patients with melanoma.
"We were encouraged by results of our Phase 2 study which suggested that Abegrin may prolong survival in melanoma patients," said Dirk Reitsma, M.D., vice president, clinical development, oncology. "We have since acquired additional supportive preclinical and clinical data, expanding our insight into how Abegrin works. We are excited to begin planning a confirmatory Phase 3 study in a tumor type for which there are limited effective treatment options, and anticipate initiating this trial late in 2006."
Data from several preclinical studies and two Phase 1 translational clinical trials with Abegrin were presented recently at the 2006 annual meeting of the American Association for Cancer Research (AACR) in Washington, DC (April 1-5, 2006) and the Canadian Melanoma Conference in Banff, Alberta, Canada (March 2-5, 2006). These studies incorporated the use of biomarkers, imaging techniques, and pharmacologic and pharmacodynamic endpoints to help determine the optimal dose of Abegrin. MedImmune researchers were interested in gaining additional insight into how much alpha-v beta-3 is found in particular tumors; how drug gets to the tumors (and how much drug gets there); how tumor cells respond pharmacologically to Abegrin; and how blood levels of Abegrin correlate to tumor saturation.
Results from the preclinical studies for Abegrin indicated that its mechanism of anti-tumor action may involve both direct and indirect effects on a tumor's ability to grow or spread. Data from these studies also suggest that the majority of Abegrin's anti-tumor activity is likely mediated through antibody-dependent cellular cytotoxicity (ADCC), and that the antibody does not shrink tumors but does appear to slow progression. In addition, evaluation of dose response in four in vivo tumor models demonstrated that peak preclinical activity was achieved at comparable levels to those achieved in the Phase 2 study, at a single dose of 8 mg/kg weekly.
The Phase 1 translational studies have been conducted to describe tumor tissue saturation and biological activity of Abegrin. In the first trial, conducted by the National Cancer Institute in patients with refractory solid tumors, dynamic computed tomographic (CT) scans were used to assess changes in tumor perfusion and blood flow. As published in Clinical Cancer Research in November 2005, the data indicated that treatment with Abegrin decreased blood flow through the tumors, and that there was possible clinical activity in renal cell cancers at several dose levels. The objective of the second Phase 1 trial, which is still ongoing in patients with advanced melanoma, is to identify the dose of Abegrin that saturates the targeted tumor tissue and tumor blood vessels. Preliminary results from this study support prior findings that saturation occurs at the 8 mg/kg dose level.
About Abegrin
Abegrin is a monoclonal antibody that targets the alpha-v beta-3 integrin, which is a protein expressed on the surface of newly forming blood vessels, certain tumor types and on a number of other cell types, including macrophages and osteoclasts. Based on preclinical models, the alpha-v beta-3 integrin has been implicated in a number of disease processes, including the growth and metastasis of tumors and bone degradation. A Phase 2 study involving 112 patients with stage IV metastatic melanoma showed a 12.7-month median survival for patients treated with Abegrin alone and a 9.4-month median survival for patients treated with Abegrin plus dacarbazine (DTIC), compared to an earlier Phase 3 study in which patients treated with DTIC had a median survival of 7.9 months.(1) MedImmune is also currently conducting a Phase 2 trial in patients with androgen-independent prostate cancer that has metastasized to bone. The company completed enrolling 126 patients in this trial in April 2005. |
