Phase II clinical evaluation of intravenous 4'-(9-acridinylamino) methanesulfon-m-anisidide in colorectal cancer

Thirty-five patients with measurable metastatic colorectal cancer received 4'-(9-acridinylamino)methanesulfon-m-anisidide (AMSA) on a 3-day intravenous schedule repeated every 3 weeks. There were 17 previously untreated patients and 18 patients who had disease progression on several regimens containing 5-fluorouracil. Good-risk patients received an initial daily AMSA dose of 40 mg/m²; poor-risk patients received an initial daily dose of 30 mg/m². There were no complete or partial remissions. Ten patients achieved disease stabilization, 24 had disease progression and one patient was lost to follow-up. The most common toxicity associated with AMSA therapy was myelosuppression, with a greater effect on neutrophils than platelets. Median (range) lowest neutrophils and platelet counts x 10³/mm³ were 1.2 (0-5.0) and 209 (50-413), respectively. Myelosuppression was pronounced in patients with abnormalities of liver function. Other toxicities were negligible, although one patient developed an episode of cardiac arrhythmia which may have been secondary to AMSA therapy.