Ticarcillin plus clavulanic acid in the treatment of patients with cancer.

Since the combination of ticarcillin with clavulanic acid is active against many otherwise resistant organisms that commonly affect patients with cancer, a therapeutic trial with ticarcillin disodium plus clavulanate potassium for treating infections in cancer patients was conducted. A total of 127 evaluable patients were treated with this antibiotic. Of these, 63 percent were women with breast carcinoma, 28 percent were patients with leukemia, and the remainder were patients with sarcomas and lung cancer. The median duration of therapy was 7.7 days. There were 63 documented infections, with bacteriologic documentation in 39 episodes. Because of the high incidence of gram-positive infections and after the failure of ticarcillin plus clavulanate potassium in two of these episodes, vancomycin was added to the regimen. The overall response rate was 75 percent. In microbiologically proved infections, the response rate was 79 percent. Thirteen of 17 gram-negative infections responded (76 percent), including four of four episodes caused by Pseudomonas aeruginosa. The only failures in this group were two episodes with Klebsiella species, one episode with Escherichia coli, and one episode with Enterobacter species. Of the gram-positive infections treated without vancomycin, five of eight (63 percent) responded and only two episodes due to Staphylococcus aureus and one due to JK diphtheroid bacteria failed. All episodes treated with the combination of ticarcillin plus clavulanate potassium and vancomycin responded. Seven of eight (88 percent) polymicrobial infections and 73 percent of those infections without identified organisms responded as well. The overall response rates for septicemia, pneumonia, soft tissue infections, and urinary tract infections were 71, 50, 71, and 83 percent, respectively. Of five microbiologically proved superinfections, three were fungal, and one each was due to Klebsiella species and S. aureus. No toxicity was observed. For 12 organisms, the minimal inhibitory concentration was lower for ticarcillin plus clavulanate potassium than for ticarcillin alone; in six it was identical. Five organisms were resistant to both, and three that were resistant to ticarcillin were sensitive to ticarcillin plus clavulanate potassium. Ticarcillin plus clavulanate potassium is a safe drug with an expanded spectrum of activity. More therapeutic trials need to be conducted to better define its role in the therapy of serious infections in cancer patients.