Abstract: 4510 Background: The HCRN GU16-260 trial reported on the efficacy and toxicity of nivo monotherapy in treatment naïve clear cell RCC (Cohort A) and the efficacy of nivo/ipi salvage therapy in pts with tumors resistant to initial nivo monotherapy (Atkins JCO 2020.38.15_suppl.5006). Limited information is available on the effects of such an approach in pts with advanced nccRCC. Methods: Eligible pts with treatment-naïve nccRCC received nivo 240mg IV q2 wk x 6 doses followed by 360mg IV q3 wk x 4 doses followed by 480 mg q4 wk until progressive disease (PD), toxicity, or completion of 96 wks of treatment (Part A). Pts with PD prior to or stable disease (SD) at 48 wks (pSD) were potentially eligible to receive salvage nivo (3mg/kg) /ipi (1 mg/kg) q3 wk x 4 doses followed by q4 wk nivo maintenance for up to 48 wks (Part B). All pts were required to submit tissue from a metastatic lesion obtained within 12 months (mo) prior to study entry and prior to enrolling on Part B for correlative studies. Results: 35 pts with nccRCC were enrolled between 5/2017 and 12/2019 at 12 participating HCRN sites. Median age 63 (range 35-84 years); 89% male. IMDC favorable 8 (23%), intermediate 18 (51%) and poor risk 9 (26%). Of the 35 pts 19 (54%) had papillary, 6 (17%) chromophobe and 10 (29%) unclassified histology. RECIST defined ORR was 5 of 35 (14.3%) [CR 2 (5.7%), PR 3 (8.6%)], SD 16 (45.7%), PD 14 (40.0%). Immune-related ORR was 8 of 35 (22.9%). RECIST ORR by histology was: papillary - 1/19 (5%); chromophobe - 1/6 (17%); unclassified - 3/10 (30%). 9 pts (26%) had tumors with sarcomatoid features with 3 (33%) (2 unclassified, 1 papillary) responding. Median PFS was 4.0 (2.7, 4.3) mo. 21 pts remain alive. None of the responders have progressed or died. 28 pts (25 PD, 3 pSD) were potentially eligible for salvage nivo/ipi (Part B), but 12 did not enroll due to symptomatic PD (2), grade 3-4 toxicity on nivo (3), or other including no biopsy tissue (7). In the 16 Part B pts, best response to nivo/ipi was: PR (1, 6%) – (unclassified/non-sarcomatoid); SD (7, 44%); PD (8, 50%). Grade 3 Treatment-related adverse events (TrAEs) were seen in 7/35 (20%) on nivo. Grade 3-5 TrAEs were seen in 7/16 (44%) on nivo/ipi with 1 pt experiencing sudden death. Correlative studies including PD-L1 status, WES and RNAseq are pending. Conclusions: Nivo monotherapy has limited activity in treatment naïve nccRCC with most responses (4 of 5) seen in pts with sarcomatoid and/or unclassified tumors. Toxicity is consistent with prior nivo studies. Salvage treatment with nivo/ipi was provided in 16 of 28 (57%) pts with PD/pSD on nivo monotherapy, with 1 response observed. Clinical trial information: NCT03117309.

Abstract: 12003 Background: AIMSS are common and frequently lead to early discontinuation of adjuvant AI therapy. Single nucleotide polymorphisms (SNPs) in candidate genes have been associated with AIMSS and AI discontinuation. The primary objective of E1Z11 was to validate previously identified associations between 10 specific SNPs in candidate genes and AI discontinuation due to AIMSS in a community-based, racially diverse cohort. Methods: Postmenopausal women with hormone receptor-positive stage I-III breast cancer enrolled onto a prospective multi-site cohort study, the majority through the NCI Community Oncology Research Program (NCORP). Participants received anastrozole 1 mg oral daily, and completed patient-reported outcomes (PROs) at baseline, 3, 6, 9, and 12 months. AIMSS was defined as 〉 20% increase in Stanford Health Assessment Questionnaire (HAQ) score over baseline occurring within 1 year of AI therapy. We projected 40% would develop AIMSS and 25% would discontinue AI treatment within 1 year, informing a planned enrollment of 1000 women with a fixed number per strata (600 Caucasian, 200 African-American [AA] & 200 Asian) to provide 80% power to detect an effect size of 1.5-4. SNPs include ESR1 (rs2234693, rs2347868, rs9340835), CYP19A1 (rs1062033, rs4646), TCL1A (rs11849538, rs2369049, rs7158782, rs7159713), and HTR2A (rs2296972). Hardy-Weinberg equilibrium (HWE) was evaluated within each racial subset. SNP genotypes were coded as additive effects on the log odds ratio by coding as 0, 1 or 2 for the count of the minor allele. A Cochran-Armitage trend test was used with a 1-sided alpha of 0.0025 (Bonferroni correction for 10 tests). Results: We enrolled 999 evaluable women (616 Caucasian, 184 AA, 199 Asian). Genotyping was successful in 974 (98%). AIMSS developed in 43%, and AI therapy was discontinued in 12% within 1 year. While more AA and Asians developed AIMSS compared to Caucasians (48% vs 38%, p=0.017; 50% vs 38%, p=0.004), AI discontinuation rates were similar across racial groups. HWE was satisfied for all SNPs at the 5% alpha level, except for TCL1A/rs11849538 (p=0.002) in the AA cohort. None of the 10 SNPs were significantly associated with AI discontinuation or development of AIMSS in the overall population, or in any of the 3 cohorts. Conclusions: Although AIMSS were more common in AA and Asians, AI discontinuation rates were similar in the 3 cohorts. We were unable to prospectively validate 10 SNPs in 4 genes previously associated with AI discontinuation due to AIMSS. Future analyses will include other predictors of AIMSS, PROs, and additional genetic markers for the entire cohort and by race. Support: NCI UG1CA189828, UG1CA233196, UG1CA233277, UG1CA233320, UG1CA233178, UG1CA233160, UG1CA232760, UG1CA233341, UG1CA233329, U10CA180821, UG1CA189821, UG1CA189830, U10CA180888, UG1CA189859, UG1CA189863, UG1CA189971. Clinical trial information: NCT01824836.

Abstract: 619 Background: Development of predictive biomarkers would help select patients more likely to respond to nivolumab (nivo) in mccRCC. Here we evaluated biomarkers for nivo using endpoints based on either RECIST 1.1 (ORR and PFS) or irRECIST (irORR and irPFS), which were proposed to more accurately predict benefit of immunotherapy. Methods: We retrospectively analyzed tumor tissues from the Checkmate 010 trial (PMID: 25452452). PD-L1 expression on tumor cells (TC) was studied by IHC. Percentages of CD8 + tumor infiltrating cells (TIC) expressing the immune checkpoints PD1, TIM3 and LAG3 (either alone or in various combination) were determined by immunofluorescence (IF) and their predictive value assessed by the presence of a dose response relationship (DRR) with PFS or irPFS. The candidate biomarkers were then correlated with clinical outcomes using optimized cutoffs. Results: As previously shown, TC PD-L1 expression was not associated with PFS or ORR. In contrast, pts with TC PD-L1 ≥1% had longer median irPFS and higher irORR (Table). None of the TIC phenotypes determined by IF displayed a DRR with PFS. Conversely, we found that % of CD8 + TIC that are PD1 + TIM3 - LAG3 - (% CD8 + PD1 + TIM3 - LAG3 - TIC) was correlated with irPFS (HR = 0.58, p = 0.007). At the optimized cutoff (36%), pts with high % CD8 + PD1 + TIM3 - LAG3 - TIC had longer median irPFS and higher irORR (Table). Notably, combination of TC PD-L1 expression with % CD8 + PD1 + TIM3 - LAG3 - TIC identified 3 groups of pts for which irPFS and irORR were significantly different (Table). Conclusions: Our results suggest that, in mccRCC, tumor-immune biomarkers for nivo response show improved association with clinical endpoints defined by irRECIST relative to RECIST. The increased predictive value of TC PD-L1 combined with immune checkpoints expression on CD8 + TIC seen in this cohort requires independent validation. [Table: see text]

Abstract: 5006 Background: Nivolumab (nivo) is FDA approved for pts with VEGFR TKI-resistant RCC and the nivo + ipilimumab (nivo/ipi) combination is FDA approved for treatment naïve pts with IMDC intermediate and poor risk RCC. Little information is available on the efficacy and toxicity of nivo monotherapy in treatment naïve RCC or the efficacy of nivo/ipi salvage therapy in pts with tumors resistant to initial nivo monotherapy. Methods: Eligible pts with treatment naïve RCC received nivo 240mg IV q2 wk x 6 doses followed by 360mg IV q3 wk x 4 doses followed by 480 mg q4 wk until progressive disease (PD), toxicity, or completion of 96 wks of treatment (Part A). Pts with PD prior to or stable disease (SD) at 48 wks (pSD) were potentially eligible to receive salvage nivo (3mg/kg) /ipi (1 mg/kg) q3 wk x 4 doses followed by q4 wk nivo maintenance for up to 48 wks (Part B). All pts were required to submit tissue from a metastatic lesion obtained within 12 months (mo) prior to study entry and prior to Part B. Pathology specimens will be analyzed by immunohistochemistry, quantitative immunofluorescence, WES and RNAseq with results linked to clinical outcome. Results: 123 pts with clear cell(cc) RCC were enrolled between 5/2017 and 12/2019 at 12 participating HCRN sites. Median age 65 (range 32-86 years); 72% male. IMDC favorable 30 (25%), intermediate 79 (65%) and poor risk 12 (10%). 22 (18%) had a component of sarcomatoid histology (SARC). 117 pts are currently evaluable for response. RECIST defined ORR was: 34 (29.3%)[CR 5 (4.3%), PR 29 (24.8%)], SD 47 (40.2%), PD 36 (30.7%). ORR by irRECIST was 35%. ORR by IMDC was: favorable 12/29 (41.4%), intermediate/poor 22/87 (25.3%) and for SARC 6/22 (27.3%). Median DOR is 13.8 (10.9, NA) mo. Median PFS is 7.4 (5.5, 10.9) mo. 110 pts remain alive. 60 pts (54 PD, 6 pSD) to date were potentially eligible for salvage nivo/ipi (Part B), but 28 did not enroll due to symptomatic PD (17), grade 3-4 toxicity on nivo (8), other (3). 27 of 32 Part B pts are currently evaluable for efficacy and 30 for toxicity. Best response to nivo/ipi was PR (11%), SD (30%), PD (59%). ORR by irRECIST was 19%. Grade 3-5 Treatment-related AEs (TrAE) were seen in 35/123 (28)% on nivo with 1 death due to respiratory failure. Grade 3-4 TrAE were seen in 10/30 (33%) on nivo/ipi with 0 deaths. Correlative studies are pending. Conclusions: Nivo monotherapy is active in treatment naïve ccRCC across all IMDC groups. Toxicity is consistent with prior nivo studies. Salvage treatment with nivo/ipi after nivo monotherapy was feasible in 53% of pts with PD/pSD, with 11% responding. Clinical trial information: NCT03117309 .

Abstract: 4524 Background: Nivo monotherapy demonstrated anti-tumor activity in treatment-naïve RCC in Part A of HCRN GU16-260 across all IMDC groups and in multiple histologies. Patient tumor samples were collected to characterize the tumor-immune microenvironmental determinants of effective anti-tumor immunity with nivo. Methods: Whole exome sequencing (WES) was performed on formalin-fixed, paraffin-embedded tissue collected within one year prior to nivo. For single-cell RNA-sequencing (scRNA-seq), eligible patients (pts) with any RCC histology underwent tumor biopsy prior to and/or at resistance to nivo monotherapy. Gene expression signatures discovered through scRNA-seq were used to interrogate previously published bulk transcriptomic data of nivo in the treatment-refractory setting. Results: WES analysis (n = 96 tumors) identified recurrent focal amplifications within chromosome 11q13 (amp11q13), which was observed in 6 of 18 (33.3%) of tumors from pts with progressive disease (PD) compared to 0 of 20 (0%) of tumors from pts with complete or partial response (CR/PR; p = 0.005). amp11q13 was associated with worse progression free survival (PFS; p = 0.008) and overall survival (OS; p = 0.010). ScRNA-seq was performed on tumors from 17 pts (8 with baseline only, 7 with progression only, and 2 with paired baseline and progression samples) across 7 trial sites. Trajectory inference analysis of tumor-infiltrating T cells revealed a bifurcating structure, starting with naïve T cells and ending either in terminally exhausted CD8+ T cells or SLAMF7+ CD8+ T cells. Surprisingly, the SLAMF7+ T cell population expressed high levels of cytotoxic genes (including GZMA, GZMB, GNLY) and markers of tissue residency ( ZNF683/HOBIT and ITGAE/CD103). Of the 14 pts with at least 100 sequenced tumor-infiltrating T cells, the presence of a higher percentage of SLAMF7+ CD8+ T cells (relative to total T cells) was associated with primary resistance to nivo (mean percentage in PD [n = 4] pts 32.7%; stable disease [n = 4] pts, 9.1%; CR/PR [n = 6] pts, 2.2%; p = 0.019 for CR/PR vs PD). Of 172 pre-treatment tumors from the nivo arms of the CheckMate-009/010/025 trials that we analyzed by bulk RNA-seq, a signature score derived using genes expressed in the SLAMF7+ CD8+ T cell trajectory branch was enriched in pts with PD compared to CR/PR as best response (p = 0.032). Conclusions: Bulk genomic and single-cell transcriptomic analyses uncovered somatic alterations (amp11q13) and infiltrating T cell populations ( SLAMF7+ CD8+) associated with resistance to frontline nivo monotherapy in a phase II study in RCC. Additional independent and functional validation studies are in progress.

Abstract: Initial therapy for MCL is effective, but most patients eventually relapse. Validated intermediate biomarkers for MCL are important to provide early assessment of treatment efficacy, prognostic information and potentially guide consolidation. The US-Canadian Intergroup trial E1411 randomly assigned patients (pts) to receive induction with BR ± bortezomib (V), followed by consolidation with R ± L. As a planned correlative, MRD was assessed after cycle 3 (I3), end of induction (EOI) and after 4 cycles of consolidation (C4) by two methods: a research version of clonoSEQ® a next generation sequencing (NGS) MRD assay, (Adaptive Biotechnologies, Seattle, WA) that leverages multiplex PCR followed by NGS to identify and track rearrangements of IgH, V-J, D-J and IgK/L loci as well as translocations in Bcl1/2-IgH, and flow cytometry (FC) (I3 and EOI only) at a central laboratory (Mayo Clinic). While outcomes by treatment arm remain blinded, we report here the results of the MRD assessments by each method and the associated progression free survival (PFS). In E1411, 373 pts, accrued between May 2012 - Sept. 2016, were randomly assigned (stratified by MIPI and age ( & lt;/≥60)) to receive BR induction x 6 followed by R for 2 years, BVR followed by R, BR followed by LR or BVR followed by LR. Eligible pts were ≥ age 18 and had untreated MCL, ECOG PS 0-2, and adequate hematologic and organ function. Of the 373 pts, 296 (79%) consented to correlatives. Of these, 255 (86%) had baseline NGS samples, and 214 were analyzable. Excluded were 6 patients that were protocol ineligible, 20 without clinical follow-up; only 7 (2.7%) patients were ineligible due to inability to identify a dominant clone necessary to follow MRD by the NGS method. At baseline pre-treatment, NGS detected a dominant clone in bone marrow (BM) or peripheral blood (PB) in 92%, with only 17 (8%) requiring study of biopsy tissue. Of the 296, 240 had baseline FC data, 9 were protocol exclusions, leaving 231 analyzable. FC detected a non-MCL monoclonal B cell lymphocytosis clone in a small number of cases. While NGS may have higher sensitivity, as FC sensitivity is 10-4, for this analysis we used that cutoff for both NGS and FC. Cohen's Kappa statistic compares concordance between MRD pairs, and p-value is from exact McNemar's test. BR-based initial MCL therapy achieved early MRD negativity ( & lt; 10-4) in a high proportion of patients. Analyzing PB at mid-induction (I3): by NGS 89% MRD-, 9% MRD+ and 2% indeterminate, whereas by FC 87% MRD-, 12% MRD+ and 1% indeterminate. Concordance was high with 127 MRD- by both methods, 13 MRD+ by both, and 6 NGS-/FC+ (Kappa Statistic = 0.79, p-value = 0.031). By NGS, of 12 pts MRD+ at I3, 7 became MRD- at EOI, and 4 remained MRD+ (1 indeterminate). Analyzing at EOI: MRD- rates were 91% by NGS analysis of PB (147/161) and 90% in BM (96/107), vs 95% (174/183) by FC in PB. As some were indeterminate, only 7% were MRD+ by NGS in BM, 3% by NGS in PB and 5% by FC. In 88 informative samples with EOI NGS in both BM and PB, concordance was high, with 81 negative in both, 1 positive in both and 6 BM+/PB- (Kappa Statistic = 0.23, p-value = 0.031). Of 101 pts with data at all 3 timepoints, I3, EOI, and C4: 7 were MRD+ at I3, 5 of these were MRD- at EOI, but 2 of these 5 were again MRD+ at C4. Of 2 MRD+ EOI, 1 became MRD- at C4. By FC, of 17 patients MRD+ at I3, 11 (65%) became MRD- at EOI. MRD status correlated with progression-free survival (PFS). Due to the low MRD+ rate at EOI and C4, we focus here on MRD status at I3 (10-4 cutoff for both NGS and FC), using a landmark analysis of 4 months on study. Median PFS (Figure) for pts MRD- at I3 mid-induction was 58.9 months by either NGS or FC, while for those MRD+ by NGS it was 26.9 months, vs 29.9 months MRD+ by FC. Conclusions: Both NGS and FC were feasible to assess MRD status in this multi-center trial. Results of NGS and FC are concordant at the 10-4 cutoff. NGS can be more sensitive when adequate material is available, and analysis of this subgroup is ongoing. The high MRD- rate (≥ 90%) at EOI in this BR-based trial and MRD correlation with PFS supports its use as a platform for MCL trials, although consolidation may confound PFS. Early interim MRD testing at cycle 3 identifies a high-risk population who may benefit from alternative treatment strategies. Analysis by treatment arm with longer follow-up, as well as comparison with centrally reviewed PET/CTs included in this study, will help define the most informative method(s), cutoff values, and timing for assessing degree of response in MCL. Figure. Disclosures Smith: Astra-Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; EUSA: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Parekh:Foundation Medicine Inc.: Consultancy; Celgene Corporation: Research Funding; Karyopharm Inc.: Research Funding. Martin:Sandoz: Consultancy; Karyopharm: Consultancy; Teneobio: Consultancy; Celgene: Consultancy; Janssen: Consultancy; I-MAB: Consultancy. Till:Mustang Bio: Patents & Royalties, Research Funding. Leonard:Gilead: Consultancy; Akcea Therapeutics: Consultancy; Bayer Corporation: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; BeiGene: Consultancy; Celgene: Consultancy; Akcea Therapeutics: Consultancy; Nordic Nanovector: Consultancy; ADC Therapeutics: Consultancy; Sandoz: Consultancy; MorphoSys: Consultancy; Sutro Biopharma: Consultancy; Karyopharm Therapeutics: Consultancy; Karyopharm Therapeutics: Consultancy; Merck: Consultancy; Genentech, Inc./F. Hoffmann-La Roche Ltd: Consultancy; Epizyme, Inc: Consultancy; Gilead: Consultancy; AstraZeneca: Consultancy; Epizyme, Inc: Consultancy; Bayer Corporation: Consultancy; Miltenyi: Consultancy; Celgene: Consultancy; ADC Therapeutics: Consultancy; MorphoSys: Consultancy; Sandoz: Consultancy; Miltenyi: Consultancy; AstraZeneca: Consultancy; Nordic Nanovector: Consultancy; Merck: Consultancy; BeiGene: Consultancy; Sutro Biopharma: Consultancy. Friedberg:Bayer: Honoraria, Other: Data & Safety Monitoring Committee; Acerta: Other: Data & Safety Monitoring Committee. Kahl:TG Therapeutics: Consultancy; ADC Therapeutics: Consultancy, Research Funding; Seattle Genetics: Consultancy; BeiGene: Consultancy.