[Sex distribution in clinical studies in uro-oncology-status quo in Germany]

While there are approved biomarker-based drugs in uro-oncology, no sex-specific drug approvals have been granted to date, despite corresponding subgroup results.

To assess the sex distribution in uro-oncologic clinical trials in Germany, focusing on enrollment rates and treatment-related toxicity.

A survey was conducted among the Working Group for Urological Oncology (AUO) of the German Cancer Society. The following parameters were collected from phase II/III studies conducted between 2015 and 2023 on urothelial carcinoma (UC) and renal cell carcinoma (RCC): number of male/female study participants with Common Terminology Criteria for Adverse Events (CTCAE) grade I-II or III-V, dose modifications, and study discontinuations. Sex-specific enrollment rates were compared with epidemiological benchmarks. Statistical analyses were performed using Fisher's exact test and odds ratios.

Across nine responding study centers, 106 patients were enrolled, of whom 20.8% were female. Compared with (inter)national benchmarks, female enrollment rates seemed lower (RCC: 21.1% vs. 34.1% and 26.6%; UC: 20.7% vs. 27.0% and 27.3%). This trend was consistent across all RCC and UC disease stages, except for locally advanced/metastatic UC, where the proportion of females was higher (36.4% vs. 32.5% and 25.8%). Female patients tend to discontinue participation more frequently (54.5% vs. 33.3%; p = 0.09; OR = 2.4). Differences in adverse events and dose modifications were not statistically significant.

In Germany, a sex imbalance is evident in RCC and UC clinical trials regarding enrollment and discontinuation rates, often to the disadvantage of female patients. Stratification by sex at trial enrollment or more extensive pharmacokinetic analyses could support sex-adjusted treatment regimens.