British Biotech issued its statement yesterday to coincide with the presentation of the results at the American Society of Clinical Oncology. Its first announcement, last November, of results with just 94 patients provoked a massive buying of the company's shares.
Marimastat is scientifically interesting because it acts against a different target compared to existing cancer drugs, according to Dr Fran Balkwill, a principal scientist with the Imperial Cancer Research Fund (ICRF). It acts to "wall" off solid tumours by interfering with the way they develop a blood supply to feed themselves and inhibits metastasis - the spread of cancer cells from the original tumour to other sites in the body. The drug also has the advantage that it can be taken orally, at home, rather than injected in hospital.
But Dr Balkwill added that Marimastat was unlikely to be a cure for cancer. "Obviously, ICRF hopes that this will be an effective cancer treatment but it will be a matter of years rather than months before anyone knows for certain."
Dr Balkwill cautioned that the company may be trying to get the drug to market quickly, before the best long-term use for it was known. "They maybe have chosen Phase III clinical trials that give quick results."
She suggested that the best use might be to give patients chemotherapy or radiotherapy to treat their tumour and then put them on low-dose long- term Marimastat maintenance.
It might not be best, as the company is proposing in the next stage, to give Marimastat at the same time as chemotherapy. Marimastat may interfere with the chemotherapy getting to the tumour itself.
But patients as well as the company will benefit if the drug is successful and comes to market even for suboptimal use, Dr Balkwill said, because long-term trials will ultimately be done to indicate the best use.
The company has not yet compared the drug's action against existing treatments: that will come with Phase III - randomised trials involving 300 patients with pancreatic cancer (which is very rapidly lethal) to assess whether the new drug is better than what is already available.Reuse content