The use of protein as a carrier of methotrexate for experimental cancer chemotherapy. IV. Therapy of murine melanoma B16 by human serum albumin-methotrexate derivative.

The influence of methotrexate bound to human serum albumin (HSA-MTX) and of free methotrexate (MTX) on B16 melanoma growth, dissemination and survival time of tumor-bearing animals was investigated. It was found that the growth of tumor was slower after therapy with the HSA-MTX derivative than after free MTX treatment. The reduction in tumor size recorded on day 21 after tumor transplantation was more significantly pronounced after HSA-MTX derivative therapy than in case of free MTX treatment. Contrary to our expectation there was no proportional difference in life span prolongation after therapy with these drugs. Comparing metastatic dissemination, the number and size of pulmonary metastatic colonies after HSA-MTX administration was more significantly reduced than after free MTX therapy.