Khan, Ahsan Masood

4594 Background: Cisplatin based neoadjuvant chemotherapy (NAC) followed by definitive therapy improves survival in patients with muscle invasive bladder cancer (MIBC). However, the clinical benefit of NAC might vary with the choice of definitive therapy. Therefore, we assessed the absolute benefit of NAC followed by radical cystectomy or radical radiotherapy separately using the totality of evidence. Methods: MEDLINE and EMBASE were systematically searched to identify randomized trials assessing cisplatin based neoadjuvant chemotherapy followed by either radical cystectomy or definitive radiotherapy in patients with MIBC. Outcomes of interest included overall survival (OS) and disease-free survival (DFS). Treatment effects were expressed as hazard ratios (HR) with 95% confidence interval (CI). Incidence rate ratios were calculated to estimate time to event outcomes for trials not reporting HR. A random-effects DerSimonian-Laird meta-analysis was conducted. Absolute effects were then obtained using baseline risks from the control arm of RCTs. Results: Of 4887 studies identified, 13 trials with 2529 patients were included in this meta-analysis. Most trials included patients with T2-4 and N0 patients and only 3 trials included patients with node positive disease. Total of 180 (47%) DFS events were observed with NAC+RC compared to 213 (56%) events in RC alone (HR: 0.72; 95% CI: 0.59-0.89) and 346 (58%) OS events were observed with NAC+ RC compared to 385 (52%) events in RC alone (HR: 0.80; 95% CI: 0.69-0.92). Total of 186 (70%) DFS events were observed with NAC + radiotherapy compared to 205 (71%) events in radiotherapy alone (HR: 0.91; 95% CI: 0.74-1.12) and 263 (58%) OS events were observed with NAC+ radiotherapy compared to 294 (61%) events in radiotherapy alone (HR:0.93; 95% CI: 0.79-1.08). Conclusions: The choice of definitive therapy after cisplatin-based NAC impacts survival in patients with MIBC. RC after NAC improved DFS (114 fewer events per 1000 events) and OS (76 fewer per 1000 events) whereas radiotherapy after NAC showed no survival benefit. [Table: see text]

518 Background: Cisplatin (C) based neoadjuvant chemotherapy (NAC) has been the mainstay treatment for muscle invasive bladder cancer (MIBC). However, the optimal choice of NAC is not well-established. We therefore conducted a network-meta-analysis (NMA) to assess comparative efficacy of different treatment options. Methods: Several electronic databases (MEDLINE, and EMBASE) and conference proceedings were systematically used to identify randomized trials evaluating first-line treatments in neoadjuvant MIBC. Outcomes of interest included overall survival (OS), progression-free survival (PFS), objective response rate (ORR) and pathologic complete response (pCR). DerSimonian-Laird random-effects meta-analysis was used to compute direct comparisons between NAC and local therapy (LT) only. Fixed effect NMA was conducted within the frequentist framework for mixed treatment comparisons. P-scores were used to assess relative treatment rankings. All statistical analyses were conducted in R (v 4.1.1). Results: This systematic review included 23 trials (25 references) with a total of 5313 patients with 10 unique treatments. Direct comparisons showed significant benefit in PFS (HR: 0.82; 95% CI: 0.71-0.94), and in OS (HR: 0.85; 95% CI: 0.78-0.92) with NAC when compared to LT only. However, the likelihood of achieving an objective response (RR: 1.18; 95% CI: 0.72-1.95: I2: 85%) or CR (RR: 1.51; 95% CI: 0.87-2.61; I2: 79%) was not different between the two arms. Data available in 15 trials contributed to the network for PFS outcome while only eight trials contributed to OS outcome. Mixed treatment comparisons showed significantly improved PFS with nintedanib-gemcitabine-cisplatin (NinGC; HR: 0.42; 95% CI: 0.20-0.87) and dose-dense-methotrexate-vinblastine-doxorubicin-cisplatin (ddMVAC; HR: 0.61; 95% CI: 0.43-0.88) compared to LT only. Consistent benefit was observed when NinGC (HR: 0.48; 95% CI: 0.24-0.97) and ddMVAC (HR: 0.70; 95% CI: 0.51-0.96) were compared to GC only. However, no significant differences were observed between NinGC (rank 1) and ddMVAC (rank 2) or among other mixed treatment comparisons. Similarly, OS was significantly improved with NinGC (rank 1) relative to MVAC (HR: 0.41; 95% CI: 0.17-0.97), MVC (HR: 0.37; 95% CI: 0.16-0.88), MC (HR: 0.38; 95% CI: 0.16-0.92), AC (HR: 0.36; 95% CI: 0.15-0.91), and GC (HR: 0.39; 95% CI: 0.17-0.90). While similar results were observed with ddMVAC (rank 2) when compared to MVC (HR: 0.63; 95% CI: 0.42-0.94), MC (HR: 0.64; 95% CI: 0.42-0.98), and GC (HR: 0.66; 95% CI: 0.47-0.92), no significant differences were observed with ddMVAC when compared to MVAC (HR: 0.62; 95% CI: 0.38-1.01) and NinGC (HR: 1.70; 95% CI: 0.69-4.19). Conclusions: Current evidence shows improved PFS and OS with the use of neoadjuvant ddMVAC and Nin-GC in patients with MIBC relative to other treatment options.

6549 Background: Representation and outcomes of women, older adults, and racial minorities in ICI trials has not been previously described. Methods: MEDLINE and Embase were searched to identify ICI RCTs. Data for trial characteristics, proportion of trials reporting race, age and sex as well as the proportion of patients by race, age and sex enrolled in ICI trials was collected. Descriptive statistics were reported for trials reporting minority representation and proportion of included patients by race, age and sex. Disparities in representation were calculated using enrollment incidence disparity (EID) and enrollment incidence ratios (EIR) by comparing trial enrollment against U.S. population-based estimates acquired from the SEER 18 incidence database. The relationship of EID to key trial characteristics were compared using standard parametric and non-parametric statistical tests. Trends in EIR were analyzed using the Joinpoint Regression Analysis software. Results: 108 ICI trials from 2009 to 2020 with 48,360 patients were included in this analysis. All RCTs reported sex (101/101). 78 trials reported race (72%), of which only 41 trials (38%) reported data on all 5 U.S. racial categories (Black, White, Asian, Pacific Islander and Native American). Participation of Black patients was reported in 66 trials (61%), White participants in 78 trials (72%), Asians in 69 trials (64%), Native Americans and Pacific Islanders in 41 trials (38%), and Hispanics in 24 trials (22%). Age categories were inconsistently defined, and 80 trials (74%) reported the proportion of patient by age categories. Subgroup analyses of clinical outcomes by race, age and sex were reported in 17 (22%), 62 (79%) and 57 (73%) trials respectively. Women (trial proportion [TP]: 32%; EIR: 0.77), patients aged ≥ 65 years (TP: 42%; EIR: 0.74), Black participants (TP: 1.8%; EIR: 0.17) and Hispanic participants (TP: 5.9%; EIR: 0.67) were largely underrepresented, and Asians were overrepresented (TP: 15.9%; EIR: 2.64). Black patients were underrepresented across all cancer types. Similarly, women, older adults ( > 65 years of age) and Hispanic patients were consistently underrepresented across cancer types with few exceptions. Representation of older adults increased significantly from 2010-2020 (APC: 2.72), while representation of Black patients decreased significantly from 2009-2020 (APC: -23.37). Black patients were found to be significantly underrepresented in phase III trials (p = 0.0005), trials with OS as the primary endpoint (p = 0.004), and PD1 inhibitor trials (p = 0.002). Hispanics were significantly underrepresented in PD1 inhibitor trials (p = 0.003). Conclusions: There is both suboptimal reporting about participation and underrepresentation of women, racial minorities (particularly Black patients) and older adults in ICI trials as compared to their cancer incidence.

e12057 Background: Several RCTs have evaluated a shorter duration of T ( < 12 months) with hopes of similar efficacy, reduced cardiotoxicity, cost and burden of treatment. Of the 5 major studies, PERSPHONE showed that 6 months was non-inferior compared to 12 months. However, four additional studies of shorter duration failed to demonstrate non-inferiority. Therefore, we performed an updated systematic review and a meta-analysis to assess the optimal duration of adjuvant T. Methods: MEDLINE, EMBASE, Cochrane, Scopus and conference proceedings were searched to identify RCTs comparing one year of adjuvant T with a shorter duration in early-stage HER2+ breast cancer. The DerSimonian-Laird random-effects Meta-Analysis was performed using CMAv3 software to derive pooled Hazard Ratio (HR) estimates for overall survival (OS, Disease-Free Survival (DFS) and Odds Ratio(OR) estimates of cardiac toxicity. Q-test was used to assess between-study heterogeneity; I2 statistic was computed to express the percentage of the total observed variability due to study heterogeneity. The risk for bias was assessed using the Cochrane Collaboration’s tool. Results: We screened 1772 citations and identified 5 studies(n = 11,377) for analysis. 5691 patients were randomized to 12 months of adjuvant T while 5686 were randomized to a shorter duration (3 studies evaluated 6 vs 12 months, 2 studies evaluated 9 weeks vs 12 months). OS (HR, 1.16, 95% CI 1.03-1.31, P= 0.015,I2 0.00, p= 0.837) and DFS (HR, 1.14, 95% CI 1.02-1.26 , P = 0.016,I2 14.90, p= 0.319) were significantly worse in patients receiving shorter duration T as compared to 12 months. Cardiotoxicity was significantly higher in the 12 month group vs shorter duration (OR, 2.10, 95% CI 1.58-2.80, p = 0.000 ,I2 51.182, p= 0.085). Grade 3/4 cardiac events and cardiac events leading to discontinuation of therapy were significantly higher in patients receiving 12 months (HR 2.06, 95% CI 1.60-2.63, P = 0.000, I2 3.967, p= 0.384). There was no significant heterogeneity among studies. Risk of bias was low. Conclusions: Twelve months of adjuvant T is associated with significantly better DFS and OS compared to a shorter duration. As such, 12 months should remain the standard of care for most patients. There is an unmet need to identify lower risk groups which might do well with from shorter duration of HER2-directed therapy.