RESUMO
Dose-limiting toxicities remain a major barrier to drug development and therapy, revealing the limited predictive power of human genetics. Herein, we demonstrate the utility of a more comprehensive approach to studying drug toxicity through longitudinal study of the human gut microbiome during colorectal cancer (CRC) treatment (NCT04054908) coupled to cell culture and mouse experiments. 16S rRNA gene and metagenomic sequencing revealed significant shifts in gut microbial community structure during treatment with oral fluoropyrimidines, which was validated in an independent cohort. Gene abundance was also markedly changed by oral fluoropyrimidines, including an enrichment for the preTA operon, which is sufficient for the inactivation of active metabolite 5-fluorouracil (5-FU). Higher levels of preTA led to increased 5-FU depletion by the gut microbiota grown ex vivo. Germ-free and antibiotic-treated mice had increased fluoropyrimidine toxicity, which was rescued by colonization with the mouse gut microbiota, preTA+ E. coli, or CRC patient stool with high preTA levels. preTA abundance was negatively associated with patient toxicities. Together, these data support a causal, clinically relevant interaction between a human gut bacterial operon and the dose-limiting side effects of cancer treatment. Our approach is generalizable to other drugs, including cancer immunotherapies, and provides valuable insights into host-microbiome interactions in the context of disease.
RESUMO
OBJECTIVES: The aim was to determine the safety and efficacy of gemcitabine plus cisplatin for patients with relapsed ovarian carcinoma and to compare ex vivo drug sensitivity profiles with clinical outcomes. PATIENTS AND METHODS: Previously treated patients with ovarian carcinoma received cisplatin (30 mg/m(2)) plus gemcitabine (600-750 mg/m(2)) on Days 1 and 8 of each 21-day cycle. Seventeen of the 27 patients underwent ex vivo analyses for correlation with clinical response. RESULTS: Of 27 patients, there were 7 (26%) complete and 12 (44%) partial responses, for an overall response rate of 70% (95% CI: 53-87%). Toxicities included neutropenia Grade III in 51.9%, Grade IV in 29.6%; anemia Grade III in 18.5 %; thrombocytopenia Grade III in 66.7 %, Grade IV in 29.6%; nausea and vomiting Grade III in 14.8 %; peripheral neuropathy Grade III in 3.7%; and alopecia Grade IV in 11.1% of patients. The median time to progression for objective responders was 7.9 months with a range of 2.1 to 13.2 months. There were no treatment-related deaths. Ex vivo results correlated with response, time to progression, and survival, remaining significant when adjusted for platin-resistance and number of prior therapies. Adjustment for platin-free interval decreased the significance but did not, in and of itself, predict significantly for progression-free survival. CONCLUSIONS: Cisplatin plus gemcitabine is active for patients with relapsed ovarian cancer. Toxicities, primarily hematologic, are manageable with dose modifications. Responses observed in heavily pretreated and platin-resistant patients indicate activity in drug-refractory patients. The results of the ex vivo analyses correlate with clinical outcomes.