Clinical trials are research studies designed to evaluate a new drug or combination of drugs. Plexxikon and its partners are currently conducting clinical trials in a number of disease indications.

Additional information about our clinical trials is available at www.clinicaltrials.gov, which gives an overview of the clinical trials process and lists a central database of all clinical trials in the U.S.

For more information about clinical trials of Zelboraf^TM (vemurafenib, also formerly known as PLX4032):

In the U.S.:

Phone: 1-888-662-6728, Monday-Friday, 9am - 5pm (ET)

Email: genentechclinicaltrials@druginfo.com

Web: www.clinicaltrials.gov

Outside the U.S.:

Web: www.roche-trials.com

For more information about clinical trials of PLX3397 or PLX5622:

Phone: 1-510-647-4000, Monday-Friday, 9am - 5pm (PT)

Email: plexxikondrug@plexxikon.com