Biomira Inc and Merck KGaA of Darmstadt, Germany, announced that the results from a large pivotal Phase III trial of Theratope vaccine for women with metastatic breast cancer did not meet the two pre-determined statistical endpoints of time to disease progression and overall survival. However, one pre-stratified subset of patients in the treatment group, women on hormonal treatment following chemotherapy, appeared to show a favourable trend to improvement in survival. Further analysis of this subset of patients is underway, as is additional analyses of the complete trial data.

Following this further analysis of the subset data, the Companies plan to discuss the results with regulatory agencies. Based on these conversations and a full evaluation of the data, the Companies will then determine how to proceed and the information will be communicated to stakeholders at that time.

"Metastatic breast cancer is a serious, life-threatening disease. This study has resulted in a wealth of information about metastatic breast cancer, and it is important that we conduct a complete review of the data so that we can determine our best course of action," said Alex McPherson, President and CEO of Biomira. "After analysis of the subset data, we intend to discuss this information with the respective regulatory agencies in the U.S., Canada and Europe as soon as possible. We hope to have the first of these discussions within the next three to five months."

"We have additional clinical trials underway and plan to continue those Theratope trials while we fully evaluate the data from the Phase III metastatic breast cancer study and determine our next steps," said Nancy Wysenski, President of EMD Pharmaceuticals Inc., Merck KGaA's wholly-owned U.S. subsidiary.

The working hypothesis for Theratope is that it stimulates an immune response to the tumour associated STn marker; this in turn may lead to a therapeutic effect. The Phase III randomized, double-blind trial was designed and powered primarily as a survival study. Enrolment in the trial totaled 1,030 women at more than 120 sites in 10 countries and, to date, is believed to be the largest trial of a therapeutic vaccine conducted in women with metastatic breast cancer. Overall, Theratope was well tolerated by patients, with the most common side effects being flu-like symptoms and local injection site reactions.

"I would like to thank the patients and clinicians who participated in this study," said David W. Miles, Senior Lecturer and Honourary Consultant in Medical Oncology at Guy's Hospital in London, England and lead clinical investigator. "It has yielded important information that warrants further investigation."

In addition to the Phase III trial for women with metastatic breast cancer, Theratope is also being studied in a Phase II study of women with metastatic breast cancer being treated with hormone therapy and a Phase II study in men and women for the treatment of colorectal cancer. The Phase II colorectal cancer study results, presented in a poster at the American Society of Clinical Oncology Meeting in May 2003, showed that patients are capable of mounting an immune response to the investigational vaccine while receiving concurrent chemotherapy. The study also showed a current median of 8.4 months for progression of their disease.

Biomira and Merck KGaA are also collaborating on the development of BLP25 Liposomal vaccine. BLP25 is being evaluated in a 171-patient Phase Iib controlled study for non-small cell lung cancer and in a Phase II pilot study for prostate cancer patients. Results from both of these trials are expected later this year or in early 2004.