Glivec shows promise in stromal tumors

Novartis' chronic myeloid leukemia drug Glivec (imatinib mesylate),which is currently under fast-track review in the USA and the European Union (Marketletter March 5), may have potential in other incurable forms of cancer, according to a report in the New England Journal of Medicine (April 5 issue).

In a single-case study reported in the journal, a 50-year-old woman with a rapidly-progressive metastatic gastrointestinal stromal tumor that was resistant to chemotherapy was treated with Glivec (code-named ST1571) and had a complete metabolic response within one month of starting therapy. This response has continued through 11 months of treatment. Researchers from Finland and the USA, in reporting the effects of this tyrosine kinase inhibitor, also noted that the toxicity of ST1571 therapy was minimal and consisted mainly of mild dyspepsia and a slightly increased frequency of bowel movement.

In addition to its activity in BCR-ABL-positive leukemias, ST1571 may be active in solid tumors that rely on the expression of c-kit, ABL or platelet-derived growth factor receptor. Among the solid tumors, gastrointestinal stromal ones may be especially responsive to ST1571 because they uniformly express c-kit. The reseachers say "our patient's favorable response to ST1571 supports the concept that specific inhibition of tyrosine kinase is a clinically-useful therapeutic intervention for tumors in which aberrant tyrosine kinase signaling is critical."