Zahoor, Haris

709 Background: Several immunotherapy (IMT) combinations either as an IMT doublet or IMT in combination with TKIs are now available for first-line therapy of metastatic renal cell carcinoma (mRCC). In the absence of head-to-head clinical trials, we performed an indirect comparison of frontline treatment options to provide clinical guidance. Methods: Medline, Embase and Cochrane Library were searched to identify relevant trials. Hazard ratios (HR) and confidence interval (CI) for primary outcome of progression-free survival (PFS) and secondary outcome of overall survival (OS) were abstracted. Network meta-analysis was performed using a multivariate, consistency model, random-effects meta-regression. Data on Grade 3 or higher AEs was abstracted and meta-analyzed. Pre-specified subgroup analyses were performed based on risk categories (high risk vs low and intermediate vs), history of prior nephrectomy, PD-L1 positivity, age and sex. Risk for bias(RoB) was assessed using the Cochrane Collaboration’s tool. Results: Nine studies were included for PFS analysis, and 6 studies for OS analysis. Avelumab-axitinib (AA) (HR 0.69, 0.48-0.96), and Pembrolizumab-Axitinib (PA) (HR 0.89, 0.50-0.96) significantly improved PFS, while there was no significant PFS benefit with atezolizumab-bevacizumab (AB) (HR 0.83, 0.62-1.13) and nivolumab-ipilimumab (NI) (HR 0.85, 0.63-1.15) as compared to Sunitinib. PA (HR 0.53, 0.38-0.75) and NI (HR 0.63, 0.44-0.90) significantly improved OS, while AB (HR 0.93, 0.75-1.12) showed no significant OS benefit as compared to Sunitinib. NI and AB had significantly fewer grade ≥3 AE than sunitinib. No significant interaction was found by risk group, age, sex or prior nephrectomy. Significant interaction was found by PD-L1 expression(p<0.001), with significant PFS improvement in PD-L1 positive (HR 0.62, 0.53-0.73) but not in PD-L1 negative patients (HR 0.92, 0.81-1.05). Overall, RoB was low amongst included studies. Conclusions: AA improved PFS, NI improved OS, whereas PA improve both PFS and OS as compared to sunitinib monotherapy. However, no IMT combination was superior to other combinations. Cost effectiveness analysis will be reported separately.

e13119 Background: Tyrosine kinase inhibitors (TKIs) are routinely used in the treatment of metastatic RCC and Sunitinib is approved for the use in adjuvant setting. Arterial thromboembolic events (ATEs) have been described with these agents, although the overall risk remains unclear. We did a systematic review and meta-analysis to determine the incidence associated with the use of FDA approved TKIs used in treatment of RCC. Methods: PubMed, EMBASE, Cochrane Central and Scopus databases were searched to identify phase 2 and 3 RCTs of TKI therapy in RCC. Trials were included if they reported ATEs defined as arterial thrombosis, cerebral ischemia or infarction, myocardial ischemia and myocardial infarction. The DerSimonian-Laird random effects meta-analysis was performed using CMAv3 software to derive pooled estimates of incidence rates of ATEs with its 95% confidence interval (CI). I2 statistic was computed to express the percentage of the total observed variability due to study heterogeneity. Risk for bias was assessed using the Cochrane Collaboration’s tool. Results: 1755 studies retrieved in the initial search, and 13 phase 2 and 3 clinical trials (n = 4983) were included in the quantitative analysis. The trials had open label design which can potentially result in bias. Risk of bias was low in all other domains. TKIs used for the treatment of RCC included sunitinib (n = 2632), sorafenib (n = 981), cabozantinib (n = 78), pazopanib (n = 844), axitinib (n = 189) and tivozanib (n = 259). The incidence of ATEs with the use of TKIs was 2.9% (95% CI: 2-3%). Cabozantinib was associated with the highest rate of ATEs (11.5%, 95% CI: 6-21%), followed by sunitinib (2.6%, 95% CI:2-3%) pazopanib (2.6%, 95% CI:2-4%) and axitinib (2.1%, 95% CI: 1-6%). The TKI with lowest event rate of ATE was tivozanib (0.8%, 95% CI:0.2-3%). Conclusions: The use of TKIs is associated with increased risk of developing ATEs. Clinicians should be aware of the possibility of increased ATEs and counsel the patients about this increased risk to enhance the process of informed decision making.