Plexxikon commences patient dosing in PLX3397 Phase 1 clinical trial

Oct 9 2009

Plexxikon Inc. today announced that dosing of cancer patients with PLX3397 has started in a Phase 1 clinical trial. PLX3397 is a novel, oral investigational drug for treating multiple diseases, including metastatic cancer and rheumatoid arthritis. PLX3397 is a highly selective kinase inhibitor that down-modulates macrophages, osteoclasts and mast cells—all cells derived from the immune system—as well as certain tumor cells that promote tumor growth and metastases to the bone. By targeting these cells and consequently, certain cytokines, PLX3397 has been shown to be effective in reducing circulating tumor burden, bone erosion and pain associated with such erosion, in preclinical cancer models. Similarly, PLX3397 has demonstrated reduced inflammation and joint disease in several models of inflammation and autoimmune disease. PLX3397 is the first drug candidate in Plexxikon’s portfolio of compounds targeting these cell types that should enable the company to develop differentiated drugs for treatment of a wide range of diseases. Plexxikon expects to advance a second drug candidate from this portfolio to the clinic in 2010 to more specifically address other disease indications.

The Phase 1 study is a dose escalation trial, which will enroll up to 50 patients with certain cancers, including metastatic disease. Patients with solid tumors will receive PLX3397 orally in cycles of 28 days. The primary objective of this trial is to assess the safety, tolerability and pharmacokinetic profile of PLX3397. An additional follow-on Phase 1b study is planned in patients with rheumatoid arthritis. Pending completion of the Phase 1 studies, Plexxikon plans to explore further clinical development potentially both in cancer and rheumatoid arthritis patients. More information about the trial for metastatic disease is available at www.clinicaltrials.gov.

“PLX3397 is the sixth IND candidate to be generated by Plexxikon, further validating our platform as a discovery engine. It represents the first molecule among a portfolio of compounds with distinct and rational profiles selective for these targets,” stated K. Peter Hirth, Ph.D., chief executive officer of Plexxikon. “Given the high degree of selectivity of our kinase inhibitors and potential improved safety profile, we may now address a wide range of diseases with significant unmet needs, including cancer and rheumatoid arthritis. In addition, the brain penetrability of PLX3397 potentially makes this an attractive drug for brain cancer and neuro-inflammatory diseases, such as Alzheimer’s Disease and multiple sclerosis.”

Source: Plexxikon