Antibiotics May Negatively Impact Patients on Certain Cancer Drugs

(HealthDay News) — For patients with metastatic renal cell carcinoma (mRCC) receiving immune checkpoint inhibitors, treatment with broad-spectrum antibiotics (ATBs) can reduce progression-free survival, according to research presented at the American Society of Clinical Oncology’s annual Genitourinary Cancers Symposium, held from Feb. 16 to 18 in Orlando, Fla.

Lisa Derosa, M.D., from the Gustave Roussy Cancer Institute at the Paris-Sud University in Villejuif, France, and colleagues examined the effect of ATB use in mRCC patients treated with immune checkpoint inhibitors in a retrospective analysis of patients treated in prospective trials. Eighty patients were enrolled who were treated with anti-PD-1/PD-L1 monotherapy (67 patients), anti-PD-1 plus CTLA-4 (10 patients), or anti-PD-L1 plus bevacizumab (three patients). Twenty percent of patients were treated with ATB, mostly beta-lactamases and fluoroquinolones.

The researchers found that patients treated with ABT had decreased progression-free survival compared with those not receiving ATB (2.3 versus 8.1 months; P < 0.001). After multivariate adjustment for age, gender, International Metastatic Renal-Cell Carcinoma Database Consortium risk groups, tumor burden, and proton pump inhibitors, the statistically significant correlation persisted. Objective response rate was lower in those treated with ATB (P < 0.002). There was a negative trend toward overall survival for patients treated with ATB, although it was too early to draw conclusions (median follow-up of less than six months).

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“These early findings show that doctors prescribing cancer immunotherapy should pay closer attention to antibiotic use,” Derosa said in a statement.

Several authors disclosed financial ties to the pharmaceutical industry.

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