Preliminary Pre-Planned Interim Analysis Shows Negative Effect on Progression-Free Survival

THOUSAND OAKS, Calif. (March 22, 2007) - Amgen (NASDAQ: AMGN) today announced that it has discontinued Vectibix(TM) (panitumumab) treatment in the PACCE trial evaluating the addition of Vectibix to standard chemotherapy and Avastin(R)(bevacizumab) for the treatment of first-line metastatic colorectal cancer (mCRC). The PACCE trial investigated a treatment regimen that used dual biologics combined with oxaliplatin- or irinotecan-based chemotherapy. This regimen is not currently used in clinical practice.

The decision to discontinue Vectibix treatment in the trial was based on a preliminary review of data from a pre-planned interim efficacy analysis scheduled after the first 231 events (death or disease progression). This analysis revealed a statistically significant difference in progression-free survival in favor of the control arm. An unplanned analysis of overall survival also demonstrated a statistically significant difference favoring the control arm. Additional analyses are ongoing, and Amgen plans to present the results at an upcoming scientific forum.

"Patient safety is Amgen´s top priority. For this reason, we have decided to discontinue Vectibix treatment in the PACCE trial while we complete additional analyses of these preliminary results. We had hoped that adding Vectibix to the current U.S. standard-of-care for patients newly-diagnosed with mCRC would improve outcomes without excessive added toxicity. Unfortunately, it appears that adding Vectibix to Avastin, when used in combination with oxaliplatin- or irinotecan-based chemotherapy, increased toxicity, without improving efficacy," said Roger M. Perlmutter, M.D., Ph.D., executive vice president of Research and Development at Amgen.

Amgen has notified the FDA and study investigators that patients who are still receiving treatment in the PACCE study should discontinue Vectibix treatment. Patients will have the option of continuing per protocol treatment without Vectibix.

In January 2007, Amgen informed all investigators and regulatory authorities about safety information arising from a planned interim safety analysis of the PACCE trial. A review of the interim analysis showed an increased incidence of grade 3 severe events of diarrhea, dehydration and infections in the Vectibix-treated patients. In addition, an increased incidence of pulmonary embolism was observed in patients who received Vectibix compared with those who did not (4 percent and 2 percent, respectively). One (