Proteolix, Inc. Presents Phase 1b/2 Clinical Data for Carfilzomib in Advanced Solid Tumor Patients at the 2009 American Society of Clinical Oncology Annual Meeting

Promising Anti-cancer Activity Observed in Relapsed Patients

ORLANDO, Fla., and SOUTH SAN FRANCISCO, Calif. , May 30 /PRNewswire/ -- Proteolix, Inc. today reported on clinical advances for its carfilzomib solid tumor program in an oral presentation at the 2009 Annual Meeting of the American Society of Oncology (ASCO) in Orlando, Florida. Data from a Phase 1b study and an ongoing Phase 2 clinical trial of carfilzomib in relapsed patients with advanced solid tumors demonstrate promising single-agent anti-cancer activity. Carfilzomib is the first in a new class of selective, irreversible proteasome inhibitors being developed by Proteolix for the treatment of hematologic malignancies and solid tumors.

"In these clinical studies, carfilzomib demonstrated promising activity as a highly selective and potent inhibitor of the proteasome for treatment of solid tumor patients. The compound's unique characteristics enable the drug to be well tolerated with consecutive day dosing, which in turn appears to improve anti-cancer activity. Early results among patients with late-stage or metastatic solid tumors who have failed multiple prior treatments are encouraging, with a number of patients achieving stable disease or better lasting for several months," said Peter J. Rosen, M.D., Medical Director of the Tower Cancer Research Foundation and Emeritus Professor, UCLA.

Data from the Phase 1b/2 clinical trials of relapsed solid tumor patients were presented by Dr. Rosen at the 2009 Annual Meeting of the American Society of Clinical Oncology (ASCO) in an oral presentation titled "Phase II results of Study PX-171-007: A Phase Ib/II study of carfilzomib (CFZ), a selective proteasome inhibitor, in patients with selected advanced metastatic solid tumors" (Abstract #3515).

The Phase 1b dose-escalating clinical trial enrolled patients with a variety of relapsed solid tumors established a dosing schedule of 20 mg/m2 on days 1 and 2, followed by 36 mg/m2 on days 8, 9 and 15, 16 over a 28-day cycle. The ongoing Phase 2 clinical is intended to assess the safety and efficacy of single-agent carfilzomib in patients with recurrent or advanced solid tumors. Enrolled patients are stratified according to disease type, including non-small cell lung cancer, small cell lung cancer, ovarian cancer and renal cancer. The open-label, multi-center clinical trial is a two-stage design, with pre-determined criteria for continuation after an initial cohort of patients have been treated.

In the Phase 1b trial, carfilzomib demonstrated activity in advanced solid tumors, with partial responses observed in renal cancer and small cell lung cancer patients. A total of 55 patients are currently evaluable for response in the Phase 1b and Phase 2 clinical studies.

Carfilzomib was generally well tolerated. The most common adverse events include fatigue headache, nausea, diarrhea, constipation and anemia. Notably, there were no incidents of Grade 3/4 neuropathy, a common side effect associated with the approved proteasome inhibitor, bortezomib. To date, 65 patients in the Phase 1b and Phase 2 clinical trials have received 154.5 cycles of carfilzomib.

"We are genuinely excited by growing clinical evidence for carfilzomib as a promising new protease inhibitor in hematologic and solid tumor malignancies. Carfilzomib is well tolerated and active across a number of different tumor types in patients with advanced cancers," said Michael Kauffman, M.D., Ph.D., Chief Medical Officer of Proteolix. "We are committed to expeditiously demonstrating the treatment benefits of carfilzomib in multiple treatment settings. We expect to complete the first stage of our Phase 2 trial in advanced solid tumors and our late-stage clinical studies of carfilzomib in multiple myeloma, and we are actively planning a Phase 3 clinical trial in relapsed multiple myeloma patients."

About Carfilzomib

Carfilzomib is the first in a new class of selective, irreversible proteasome inhibitors. Carfilzomib produces specific and sustained inhibition of the proteasome, leading to apoptosis in cancer cells with minimal off-target effects. In Phase 1 and Phase 2 clinical trials, carfilzomib has demonstrated single-agent activity in hematologic malignancies and solid tumors, including multiple myeloma, Waldenstrom's macroglobulinemia, mantle cell lymphoma, and renal cell carcinoma.

Proteolix is conducting a comprehensive clinical development program evaluating carfilzomib for the treatment of multiple myeloma, including an ongoing accelerated approval study in heavily pre-treated relapsed/refractory patients and a Phase 2 clinical trial in relapsed patients stratified by prior treatment with bortezomib. Both Phase 2 clinical trials are being conducted by Proteolix in collaboration with the Multiple Myeloma Research Consortium (MMRC). A Phase Ib clinical trial of carfilzomib in combination with lenalidomide and dexamethasone in patients with relapsed multiple myeloma is also ongoing. In addition, Proteolix is conducting a single-agent Phase 2 clinical trial of carfilzomib in patients with recurrent or advanced solid tumors. For the latest information regarding ongoing carfilzomib clinical trials, please visit www.clinicaltrials.gov.

About Proteolix

Founded in December 2003, Proteolix, Inc. is a privately-held biotechnology company, headquartered in South San Francisco, dedicated to discovering, developing and commercializing novel therapeutics that target protein degradation pathways for cancer and autoimmune diseases. Proteolix's lead product, carfilzomib, is the first in a new class of selective, irreversible proteasome inhibitors. Proteolix is also developing a pipeline of novel proteasome inhibitors, including a selective, oral proteasome inhibitor and a selective immunoproteasome inhibitor. For additional information on Proteolix, please visit www.proteolix.com.

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