Comparing the Effectiveness of Marimastat to No Treatment (Placebo) in Women with Metastatic Breast Cancer That Was Responding or Stable Following Chemotherapy
Eastern Cooperative Oncology Group through the NCI-sponsored Cancer Cooperative Group Program
Purpose of the Study
Marimastat is an anticancer drug that may stop the growth of breast cancer cells by stopping blood flow to the tumor. This study evaluated the effectiveness of Marimastat in delaying the progression of cancer in women whose breast cancer has spread and that is responding or stable after chemotherapy, compared to the effects of a placebo (a capsule with no active ingredient but looks like the study drug).
Marimastat did not prolong the time patients in the study remained alive without their disease getting worse. In the group receiving marimastat, the cancer in 84 percent of patients got worse and five percent of patients died without their disease progressing. In the placebo group, 88 percent got worse and three percent died without disease progression. Half the patients in the marimastat group were still alive at 24.7 months, compared with 26.6 months in the placebo group. Cancer had not progressed at 4.7 months following the treatment in half the patients in the the marimastat group. This compares to 3.1 months those receiving placebo were free from progression. These differences were not considered statistically significant. In addition, serious musculoskeletal side effects were experienced by the patients receiving marimastat. These side effects were associated with inferior survival, 22.5 months compared with 28.2 months in the placebo group which experienced less severe musculoskeletal toxicity.
Marimastat was not effective in preventing progression of disease, and should not be further evaluated for advanced breast cancer.
Number of Participating Patients
Patients were at least 18 years old and their breast cancer had not spread to the brain. They had not been treated previously with trastuzumab, marimastat, or batimastat.
This was a double-blind, randomized study, which means that neither the medical staff nor the patients knew to which treatment group they were assigned. Patients were randomly selected to be in one of two groups. In one group, patients received 10 mg. of marimastat by mouth twice a day. Patients in the placebo group received a capsule that looked identical, but had no active ingredients, by mouth twice a day. Treatment continued until the patient’s breast cancer progressed or until side effects became too severe to continue therapy.
The most common side effects experienced in the study were musculoskeletal. These ranged from mild aches and pains that did not restrict activity, to pain that restricted activity or resulted in inflamed joints and tendons. Severe or moderately severe musculoskeletal side effects were experienced by 63 percent of patients taking marimastat, compared with 22 percent of patients taking the placebo. In the marimastat group, 50 percent of patients had to interrupt treatment because of these side effects; eight percent had to discontinue treatment permanently. Patients with moderately severe or severe musculoskeletal side effects had poorer survival (22.5 months) compared with those in the placebo group (28.2 months).
Additional Information at ClinicalTrials.gov