BACKGROUND In a single-group, phase 1b trial, avelumab plus axitinib resulted in objective responses in patients with advanced renal-cell carcinoma. This phase 3 trial involving previously untreated patients with advanced renal-cell carcinoma compared avelumab plus axitinib with the standard-of-care sunitinib. METHODS We randomly assigned patients in a 1:1 ratio to receive avelumab (10 mg per kilogram of body weight) intravenously every 2 weeks plus axitinib (5 mg) orally twice daily or sunitinib (50 mg) orally once daily for 4 weeks (6-week cycle). The two independent primary end points were progression-free survival and overall survival among patients with programmed death ligand 1 (PD-L1)–positive tumors. A key secondary end point was progression-free survival in the overall population; other end points included objective response and safety. RESULTS A total of 886 patients were assigned to receive avelumab plus axitinib (442 patients) or sunitinib (444 patients). Among the 560 patients with PD-L1–positive tumors (63.2%), the median progression-free survival was 13.8 months with avelumab plus axitinib, as compared with 7.2 months with sunitinib (hazard ratio for disease progression or death, 0.61; 95% confidence interval [CI], 0.47 to 0.79; P<0.001); in the overall population, the median progression-free survival was 13.8 months, as compared with 8.4 months (hazard ratio, 0.69; 95% CI, 0.56 to 0.84; P<0.001). Among the patients with PD-L1–positive tumors, the objective response rate was 55.2% with avelumab plus axitinib and 25.5% with sunitinib; at a median follow-up for overall survival of 11.6 months and 10.7 months in the two groups, 37 patients and 44 patients had died, respectively. Adverse events during treatment occurred in 99.5% of patients in the avelumab-plus-axitinib group and in 99.3% of patients in the sunitinib group; these events were grade 3 or higher in 71.2% and 71.5% of the patients in the respective groups. CONCLUSIONS Progression-free survival was significantly longer with avelumab plus axitinib than with sunitinib among patients who received these agents as first-line treatment for advanced renal-cell carcinoma. (Funded by Pfizer and Merck [Darmstadt, Germany]; JAVELIN Renal 101 ClinicalTrials.gov number, .)

We report on molecular analyses of baseline tumor samples from the phase 3 JAVELIN Renal 101 trial (N=886; NCT02684006), which demonstrated significantly prolonged progression-free survival (PFS) with first-line avelumab + axitinib vs sunitinib in advanced renal cell carcinoma (aRCC). We found that neither expression of the commonly assessed biomarker PD-L1 nor tumor mutational burden differentiated PFS in either study arm. Similarly, the presence of FcɣR SNPs was unimpactful. We identified important biological features associated with differential PFS between the treatment arms, including novel immunomodulatory and angiogenesis gene expression signatures (GES), previously undescribed mutational profiles and their corresponding GES, and several HLA types. These findings provide insight into the determinants of response to combined PD-1/PD-L1 and angiogenic pathway inhibition and may aid in the development of strategies for improved patient care in aRCC.

101 Background: The phase 3 JAVELIN Renal 101 trial in previously untreated patients (pts) with aRCC demonstrated a progression-free survival (PFS) benefit and higher objective response rate with A+Ax vs S (Motzer, ESMO 2018; LBA6_PR). Here, we report outcomes from biomarker analyses of baseline tumor samples. Methods: We correlated efficacy with the results of molecular analyses of tissue samples from all 886 pts enrolled in JAVELIN Renal 101. Nephrectomy or tumor samples were characterized by immunohistochemistry (CD8 and PD-L1), whole-exome sequencing (WES), and RNAseq. WES and RNAseq were used to examine somatic mutations and analyze relevant gene expression signatures (GES) in relation to clinical outcomes. GES analyses included published and de novo signatures: effector T cell (Teff), angiogenesis (angio),T cell-inflamed (Tinf), and a novel immune-related signature incorporating pathway indicators for T- and NK-cell activation and IFNγ signaling, among others. Results: PD-L1 expression (≥1% immune cells) was associated with the longest PFS in the A+Ax arm and the shortest in the S arm (HR, 0.63; 95% CI, 0.49, 0.81). Significant treatment arm–specific differences in PFS were observed relative to wildtype when mutations in genes such as CD1631L, PTEN, or DNMT1 were present. Tumor mutational burden did not distinguish pts with respect to PFS. High-angio GES was associated with significantly improved PFS in the S arm but did not differentiate PFS in the A+Ax arm. In the low-angio subset, A+Ax improved PFS vs S. Pts with high Teff and Tinf in the A+Ax arm had longer PFS vs the S arm. In the A+Ax arm, PFS was enhanced in patients with immune GES–positive tumors vs those in the negative group (HR, 0.63; 95% CI, 0.46, 0.86; 2-sided p = 0.004), as well as in an independent dataset (JAVELIN Renal 100; Choueiri, Lancet Oncol, 2018) (HR, 0.46; 95% CI, 0.20, 1.05; 2-sided p = 0.064). Updated efficacy, including overall survival, will be presented. Conclusions: These findings define molecular features that differentiate therapy-specific outcomes in first-line aRCC and may inform personalized therapy strategies for pts with aRCC. Funding: Pfizer and Merck KGaA. Clinical trial information: NCT02684006.

Introduction: DLL3, an atypical Notch ligand, is expressed in SCLC tumors but is not detectable in normal adult tissues. Rovalpituzumab tesirine (Rova-T) is an antibody-drug conjugate containing a DLL3targeting antibody tethered to a cytotoxic agent pyrrolobenzodiazepine by means of a protease-cleavable linker. The efficacy and safety of Rova-T compared with topotecan as second-line therapy in patients with SCLC expressing high levels of DLL3 (DLL3-high) was evaluated.Methods: The TAHOE study was an open-label, two-to-one randomized, phase 3 study comparing Rova-T with topotecan as second-line therapy in DLL3-high advanced or metastatic SCLC. Rova-T (0.3 mg/kg) was administered intravenously on day 1 of a 42-day cycle for two cycles, with two additional cycles available to patients who met protocol-defined criteria for continued dosing. Topotecan (1.5 mg/m 2 ) was administered intravenously on days 1 to 5 of a 21-day cycle. The primary end point was overall survival (OS).Results: Patients randomized to Rova-T (n ¼ 296) and topotecan (n ¼ 148) were included in the efficacy analyses. The median age was 64 years, and 77% had the extensive disease at initial diagnosis. The median OS (95% confidence interval) was 6.3 months (5.6-7.3) in the Rova-T arm and 8.6 months (7.7-10.1) in the topotecan arm (hazard ratio, 1.46 [95% confidence interval: 1.17-1.82]). An independent data monitoring committee recommended that enrollment be discontinued because of the shorter OS observed with Rova-T compared with topotecan. Safety profiles for both drugs were consistent with previous reports.Conclusions: Compared with topotecan, which is the current standard second-line chemotherapy, Rova-T exhibited an inferior OS and higher rates of serosal effusions, photosensitivity reaction, and peripheral edema in patients with SCLC. A considerable unmet therapeutic need remains in this population.

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Purpose: This study investigated the efficacy and safety of oral PARP inhibitor veliparib, plus carboplatin and etoposide in patients with treatment-naïve, extensive-stage small cell lung cancer (ED-SCLC).Patients and Methods: Patients were randomized 1:1:1 to veliparib [240 mg twice daily (BID) for 14 days] plus chemotherapy followed by veliparib maintenance (400 mg BID; veliparib throughout), veliparib plus chemotherapy followed by placebo (veliparib combination only), or placebo plus chemotherapy followed by placebo (control). Patients received 4-6 cycles of combination therapy, then maintenance until unacceptable toxicity/progression. The primary endpoint was progression-free survival (PFS) with veliparib throughout versus control.Results: Overall (N ¼ 181), PFS was improved with veliparib throughout versus control [hazard ratio (HR), 0.67; 80% confidence interval (CI), 0.50-0.88; P ¼ 0.059]; median PFS was 5.8 and 5.6 months, respectively. There was a trend toward improved PFS with veliparib throughout versus control in SLFN11-positive patients (HR, 0.6; 80% CI, 0.36-0.97). Median overall survival (OS) was 10.1 versus 12.4 months in the veliparib throughout and control arms, respectively (HR, 1.43; 80% CI, 1.09-1.88). Grade 3/4 adverse events were experienced by 82%, 88%, and 68% of patients in the veliparib throughout, veliparib combination-only and control arms, most commonly hematologic.Conclusions: Veliparib plus platinum chemotherapy followed by veliparib maintenance demonstrated improved PFS as firstline treatment for ED-SCLC with an acceptable safety profile, but there was no corresponding benefit in OS. Further investigation is warranted to define the role of biomarkers in this setting.

4574 Background: In the phase 3 JAVELIN Renal 101 trial (NCT02684006), treatment-naive patients with aRCC receiving A + Ax showed improved progression-free survival (PFS) and objective response rate (ORR) across International Metastatic RCC Database Consortium (IMDC) risk groups (favorable [F], intermediate [I], and poor [P]) compared with patients receiving S. Here we report updated efficacy results for A + Ax vs S by IMDC risk groups from the third interim analysis. Methods: Patients were randomized 1:1 to receive either A (10 mg/kg intravenously every 2 weeks) plus Ax (5 mg orally twice daily) or S (50 mg orally once daily) for 4 weeks (6-week cycle). Patients were categorized per IMDC risk group into F, I, and P subgroups, and outcomes were assessed for F, I, P, and I + P. Overall survival (OS) and PFS, ORR, complete response (CR), and duration of response (DoR) per investigator assessment (RECIST v1.1) were assessed. Results: The study enrolled 886 patients with aRCC. At data cutoff (Apr 2020), median (95% CI) follow-up for OS in the A + Ax was NR (42.2-NE) vs 37.8 (31.4-NE) months with S. The Table shows OS, PFS, ORR, CR, and DOR by IMDC risk group. A + Ax generally showed improved efficacy compared with S across IMDC groups. Conclusions: Consistent with previously reported results from prior interim analyses, extended follow-up confirms the efficacy benefits of A + Ax vs S across IMDC risk groups in patients with aRCC. Patients continue to be followed up for the final OS analysis. Clinical trial information: NCT02684006. [Table: see text]

TPS763 Background: Bempegaldesleukin (BEMPEG; NKTR-214) is a first-in-class interleukin-2 (IL-2) receptor pathway agonist that activates and expands effector T cells and natural killer cells in the tumor microenvironment and increases tumor PD-L1 expression, making BEMPEG a promising agent for combination with immune checkpoint inhibitors. In a phase 1/2 study, BEMPEG plus nivolumab (NIVO) demonstrated an encouraging objective response rate (ORR) in first-line advanced RCC (46%) and a manageable safety profile. BEMPEG plus NIVO offers a potential novel immunooncology treatment option for patients with advanced RCC. Methods: A global, multicenter, randomized, open-label phase 3 study is evaluating the efficacy and safety of BEMPEG plus NIVO vs investigator’s choice of tyrosine kinase inhibitor (TKI; sunitinib [SUNI] or cabozantinib [CABO]) in patients with previously untreated advanced or metastatic RCC with a clear-cell component. Patients must not have had prior systemic therapy (including neoadjuvant, adjuvant or vaccine therapy) for RCC. Key exclusion criteria include active brain metastasis and autoimmune disease requiring systemic immunosuppressive agents. Approximately 600 patients will be randomized 1:1 to receive 0.006 mg/kg BEMPEG plus 360 mg NIVO intravenously every 3 weeks or TKI (50 mg SUNI [4 weeks on, 2 weeks off schedule] or 60 mg CABO; orally each day). Patients will be stratified by International Metastatic RCC Database Consortium (IMDC) prognostic score (0 [favorable risk] vs 1-2 [intermediate risk] vs 3-6 [poor risk]) and TKI choice (SUNI vs CABO). Primary objectives are ORR by blinded independent central review (BICR) and overall survival in the IMDC intermediate/poor risk population and the intention-to-treat (ITT) population. Secondary objectives are progression-free survival by BICR in the IMDC intermediate/poor risk population and the ITT population, safety, PD-L1 expression as a predictive biomarker, and quality of life. Enrollment is ongoing. Clinical trial information: NCT03729245.