Bibi, Arifa

171 Background: Treatment effects vary by volume of disease and timing of metastatic presentation in patients with mCSPC. Therefore, we updated the existing body of evidence to assess the comparative efficacy of systemic therapy in mCSPC by prognostic subgroups to inform clinical practice guidelines. Methods: This living systematic review was conducted using the living interactive evidence (LIvE) synthesis framework. Phase III clinical trials assessing contemporary systemic therapy in mCSPC and reporting overall survival (OS) by four prognostic subgroups were included. Prognostic subgroups included synchronous high volume (SHV), synchronous low volume (SLV), metachronous high volume (MHV), and metachronous low volume (MLV) disease. Mixed treatment comparisons were made using a network-meta-analytic approach in each subgroup. P-scores were used to assess relative treatment rankings in congruency with pairwise estimates. Higher scores indicated better efficacy. Results: This study included a total of nine trials with eight unique treatment options. In patients with SHV disease, darolutamide+docetaxel+ADT (DARO+D+ADT) significantly improved OS when compared to D+ADT (HR: 0.69; 0.57-0.85), enzalutamide (E)+ADT (HR: 0.67; 95% CI: 0.46-0.99), and apalutamide (APA)+ADT (HR: 0.65; 95% CI: 0.43-0.96). In patients with SLV disease, E+ADT (HR: 0.62; 95% CI: 0.42-0.91) and AAP+ADT (HR: 0.66; 95% CI: 0.49-0.89) significantly improved OS when compared to ADT. Although E+D+ADT trended toward improvement compared to other treatments, the results were not statistically significant. In patients withMHV disease, no statistically significant differences were observed among mixed treatment comparisons. However, OS with DARO+D+ADT trended toward improvement when compared to D+ADT (HR: 0.69; 95% CI: 0.39-1.23), APA+ADT (HR: 0.72; 95% CI: 0.23-2.33), E+ADT (HR: 0.67; 95% CI: 0.24-1.86), and E+D+ADT (HR: 0.59; 95% CI: 0.26-1.34). In patients with MLV disease, E+ADT significantly improved OS compared to ADT (HR: 0.51; 95% CI: 0.32-0.79), and D+ADT (HR: 0.48; 95% CI: 0.27-0.85). APA+ADT significant improved OS compared to ADT (HR: 0.22; 95% CI: 0.09-0.54), and D+ADT (HR: 0.21; 95% CI: 0.08-0.55). No other statistically significant differences were observed among mixed treatment comparisons. Conclusions: Current evidence suggests that triplet systemic therapy may be preferred in SHV, E systemic triplet and E hormonal doublet in SLV, DARO systemic triplet and APA hormonal doublet in MHV, and APA or E hormonal doublets in MLV mCSPC. [Table: see text]

6636 Background: Equitable regional enrollment in clinical trials is critical to addressing global inequities in health care outcomes. Therefore, we quantified disparities in regional recruitment in global cancer trials. Methods: Phase II/III clinical trials in prostate (PC), breast (BC), colorectal (CRC) and lung cancer (LC), and reporting regional recruitment were identified from Medline. Global regions were defined as North-(NA) and South- America (SA), Europe (EU), Africa (AF), Asia (AS), and Australia (AU). For multi-regional trials, enrollment incidence ratios (EIR) which compare region-wise trial enrollment against global estimates of region-wise specific cancer incidence obtained from Global Burden of Disease 2019 database. Trial-level EIRs were pooled using random-effects meta-analysis. A pooled EIR of < 1.0 indicates underrepresentation of a particular region in clinical trial enrollment compared to the actual burden of the specific cancer in that region. Statistical analyses were conducted in R v4.1.2. Results: Of the total 2125 trials identified, 1681 (79.1%) trials with 691,800 participants reported information regarding regional recruitment. Among those, only 1400 (65.9%) trials reported proportions of patients from pre-defined regions. A total of 1231 (57.9%) trials were single-regional recruiting patients from EU (589; 47.8%), NA (329; 26.7%), AS (295; 23.9%), AU (10; 0.8%), AF (4; 0.3%), and SA (4; 0.3%). There was significant underrepresentation of patients from AS (EIR: 0.47; 95% CI: 0.41-0.54) in cancer clinical trials. This was consistent across different cancers: PC (0.49; 0.35-0.71), BC (0.63; 0.43-0.94), CRC (0.63; 0.43-0.94), LC (0.39; 0.30-0.50). Similarly, there is a trend of under-representation of patients from AF (0.67; 0.43-1.04). Consistently, patients from were under-represented in PC (0.43; 0.24-0.77) and LC (0.26; 0.09-0.79) trials. Patients from NA (1.27; 1.08-1.51), EU (1.64; 1.57-1.72), and AU (5.41; 3.90-7.51) were significantly over-represented in multi-regional cancer clinical trials. The results are provided in table. Conclusions: There is suboptimal reporting of region-wise enrollment in cancer clinical trials. Representation of Africa and Asia in cancer clinical trials appears to be less than their expected share based on their burden of cancer incidence. [Table: see text]