Phase II Single-arm Study of Durvalumab and Tremelimumab with Concurrent Radiotherapy in Patients with Mismatch Repair–proficient Metastatic Colorectal Cancer

While immunotherapy with immune checkpoint inhibition (ICI), using mAbs targeting programmed cell death 1 (PD-1), PD-1 ligand (PDL-1), and CTL antigen 4 (CTLA-4), may lead to durable benefit in patients with several tumor types, patients with mismatch repair–proficient (MMR-P) metastatic colorectal cancer have limited benefit (1–3). Novel strategies to augment immunity are thus needed in this population.

Radiotherapy is a commonly used treatment modality for all stages of colorectal cancer and may augment antitumor activity when combined with immunotherapy by synergistically priming and sustaining the immune response. Initial preclinical and clinical studies suggested increased tumor antigen release; immunogenic tumor cell death with release of endogenous danger signals, such as HMGB1 and ATP; upregulation of proinflammatory cytokines, such as TNFα, and IL1α; recruitment and activation of dendritic cells; improved antigen presentation; and increased T lymphocyte infiltration (4–12, 13).

Combining radiotherapy with ICI is therefore compelling, with reported observations of regression in distant nonirradiated tumors, in several types of malignancies, including melanoma, lung cancer, and pancreatic ductal adenocarcinoma (14–16). We have previously described a case of tumor regression of nonirradiated distant tumors in a patient with metastatic MMR-P colorectal cancer following radiotherapy plus pembrolizumab (17).

In this study, we aimed to determine whether the combination of tremelimumab, a selective human IgG2 mAb inhibitor of CTLA-4 (18), and durvalumab, a selective, high-affinity, engineered human IgG1 mAb that blocks PD-L1 binding to PD-1 (19), can lead to enhanced immunity with shrinkage of nonirradiated tumors (an abscopal effect) in patients with metastatic MMR-P colorectal cancer.

Patients ages 18 years or older with a histologic or cytologic diagnosis of metastatic colorectal cancer, Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, and who had received at least two prior therapies were eligible for the study. Patients had at least one lesion for which palliative radiotherapy was considered appropriate therapy, and at least one other index lesion that is outside of the radiotherapy field and measurable based on the RECIST, version 1.1 (RECIST v1.1; ref. 20). All patients had adequate organ and bone marrow function. Standard key exclusion criteria were applied. The study was approved by the Institutional Review Board of Memorial Sloan Kettering Cancer Center (MSKCC, New York, NY) and was conducted in accordance with the Declaration of Helsinki and the International Conference on Harmonization Good Clinical Practice guidelines. All patients provided written informed consent before study enrollment. ClinicalTrials.gov number, NCT03122509.

This was an investigator-initiated, single-center, nonrandomized phase II study. Patients received durvalumab 1,500 mg and tremelimumab 75 mg intravenously every 4 weeks during the first four cycles followed by durvalumab 1,500 mg alone, beginning within 1 week prior to starting radiotherapy (Supplementary Fig. S1).The radiotherapy dose and schedule was not prespecified, and was determined per standard care. Treatment was continued until progression of disease, initiation of alternative cancer therapy, or unacceptable toxicity. Patients who had a prior response, and who did not discontinue tremelimumab due to toxicity, could resume combination therapy with tremelimumab plus durvalumab for four doses upon disease progression, followed by durvalumab alone. No dose reductions were permitted, but dose interruption and repeat palliative radiotherapy were allowed. Patients could continue to receive treatment beyond radiographic progression in the absence of clinical deterioration.

Biopsies for research purposes were performed pretreatment, 1 week after completing radiotherapy (of the irradiated lesion) and 4 weeks after starting ICI (of a nonirradiated lesion). Peripheral blood samples were obtained at baseline, then at week 2, week 4, and week 8 after starting ICI.

Safety was assessed for all patients by physical exam, vital signs, and routine blood tests every 2 to 4 weeks. Adverse events (AE) were monitored throughout treatment and for 28 days thereafter. Serious AEs were collected for 90 days after the end of treatment and were graded in severity according to the Common Terminology Criteria for Adverse Events version 4.03. Treatment-related AEs (TRAE) were defined as any AE possibly, probably, or definitely related to study drug.

The primary endpoint was objective response rate (ORR) in a nonirradiated lesion according to RECIST v1.1. ORR was defined as the percentage of patients achieving either a partial response (PR) or a complete response (CR) to treatment. Tumor response was assessed by means of CT and/or MRI performed at baseline and every 8 weeks thereafter. The secondary endpoints were safety and tolerability, overall survival (OS), and progression-free survival (PFS). All patients were followed up to 2 years for survival or until death, consent withdrawal, or study closure.

A two-stage Simon optimal design was employed to test the null hypothesis that the ORR was ≤5% versus the alternative hypothesis that the ORR was at least 25% with type I and II error rates of 10% each. In the first stage, 9 patients were enrolled, with the study expanded to the second stage to enroll an additional 15 patients if at least 1 of 9 patients achieved a PR or CR. It was predefined that further investigation of the treatment would be considered worthwhile if ≥ 3 of 24 objective responses were observed by RECIST v1.1. Accrual time was estimated to be 2 years.

IHC staining for MMR protein expression was performed using standard procedures (21). Microsatellite instability (MSI) was assessed from Memorial Sloan Kettering–Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) via MSIsensor. MSI-high (MSI-H) status was defined as an MSIsensor score ≥ 10 or an MSIsensor score ≥ 3 with tumor mutation burden (TMB) > 10 mutations/megabase (mut/Mb; ref. 22). MSK-IMPACT is approved by the NYS Department of Health for clinical use and authorized by the FDA for clinical reporting of somatic mutations, indels, rearrangements, and MSI calculated from the microsatellite regions covered by the assay (23, 24).

Peripheral blood mononuclear cells (PBMC) were isolated and cryopreserved from patient whole blood samples. Flow cytometry was then performed as described previously (25), on batch thawed PBMC samples in the Immune Monitoring Facility at MSKCC (New York, NY) to examine T-cell phenotypic markers. Samples were stained with a fixable viability dye (FVS510, BD Biosciences) and a cocktail of antibodies to the following surface markers: CD45RA-BUV395 (BD, HI100), CD4-BUV496 (BD, SK3), ICOS-BUV563 (BD, DX29), CD25-BUV615 (BD, 2A3), TIM-3-BUV661 (BD, 7D3), CD27-BUV737 (BD, L128), CD8-BUV805 (BD, SK1), CD57-BV421 (BD, NK-1), CXCR5-BV480 (BD, RF8B2), CD14-BV570 (BioLegend, M5E2), CD19-BV570 (BioLegend, HIB19), CCR4-BV605 (BioLegend, L291H4), CCR7-SB645 (eBioscience, 3D12) HLA-DR-BV711 (BD, G46-6), CD3-BV750 (BD, SK7), CD28-BV786 (BD, CD28.2), PD-1-BB515 (BD, MIH4), CD127-BB700 (BD, HIL-7R-M21), CD38-BB790 (BD, HIT2), TIGIT-PE (eBioscience, MBSA43), and GITR-PE-Cy7 (eBioscience, eBioAITR), in the presence of Brilliant Stain Buffer Plus (BD). Cells were next fixed and permeabilized with the FoxP3/Ki-67 Fixation/Permeabilization Concentrate and Diluent (eBioscience), and subsequently stained intracellularly with antibodies to LAG-3-BB660 (BD, T47-530), Ki-67-AlexaFluor700 (BD, B56), FoxP3-PE-Cy5.5 (eBioscience, PCH101), CTLA-4-PE-Cy5 (BD, BNI3), Eomes-PE-eFluor610 (eBioscience, WD1928), T-bet-APC (eBioscience, ebio4B10), and Granzyme B-APC-Fire750 (BioLegend, QA16A02), in the presence of Brilliant Stain Buffer Plus (BD). Stained cells were acquired on a BD Biosciences FACSymphony and analyzed using FlowJo software (FlowJo, LLC).

Patient demographic and disease characteristics were summarized using frequency for categorical and median (range) for continuous characteristics. ORR and 95% confidence interval (CI) were estimated using a binomial distribution. Kaplan–Meier methods were used to evaluate PFS and OS. PFS was measured from the start of treatment with ICI until the documentation of disease progression, or death due to any cause, whichever occurs first. Patients who came off study due to clinical progression were included as progression of disease at the off-study date. OS was determined as the time from the start of treatment with ICI until death. For patients who are alive at the end of study or lost to follow-up, OS was censored on the last date when patients were known to be alive. The data-lock date was September 3, 2019. The data-lock for survival endpoints was May 22, 2020.

Immunobiomarkers at baseline, week 2 and week 8 after treatment were summarized using median and range. Wilcoxon Sign-rank test was used to evaluate the difference in median of biomarkers from baseline to week 2, as well as from baseline to week 8. FDR approach was applied to control the type I errors (26). Two-sided P values less than 0.05 were considered statistically significant. All analyses were performed using R version 3.4.1 (R Foundation for Statistical Computing) or SAS 9.3 (The SAS Institute).

A total of 24 patients were enrolled between May 2017 and February 2019, and received at least one dose of durvalumab plus tremelimumab (durva/treme). Median radiotherapy dose delivered was 4,500 cGy (range: 2,000–7,000 cGY) over five fractions (Fx; range: 3–30 Fx). Most patients received radiotherapy to tumor located within liver (29%), colorectum (17%), lung (13%), or bone (13%). The demographic and patient characteristics of the patients at baseline are shown in Table 1. Radiation details are provided in Supplementary Table S1. MMR status was confirmed proficient on IHC or determined to be microsatellite stable (MSS) on MSK-IMPACT in 23 patients (96%), with results unavailable for 1 patient (a nonresponder). Patients had received a median of two prior treatments (range: 1–6). All patients were included in the analyses of the primary and secondary endpoints.

TRAEs occurring in >10 patients, or any grade 3–4 TRAE are summarized in Table 2 (complete list of TRAE in Supplementary Table S2). TRAEs of any grade occurred in 21 of 24 patients (88%). Grade 3/4 TRAEs occurred in 6 of 24 patients (25%); one grade 4 TRAE of hyperglycemia. The most common immune-mediated AEs were pruritis (33%), skin rash (25%), diarrhea (21%), colitis (13%), and arthralgia (13%).

The most common grade 3–4 immune-mediated AEs were diarrhea (13%), colitis (8%), and hyperglycemia (8%). Four (16%) patients developed grade 3 gastrointestinal toxicity (colitis, enteritis, or gastroenteritis), having received radiotherapy to pelvis/colorectum (n = 2), mesentery (n = 1), or liver (n = 1), respectively. Two patients (8%) developed diabetes mellitus, having received radiotherapy to liver, one in the setting of pancreatic metastases. Among patients who experienced TRAEs, 7 (29%) received systemic corticosteroids, and 7 (29%) experienced treatment interruption. No patient fully discontinued treatment on study due to toxicity. Three (13%) patients discontinued tremelimumab due to toxicity.

Two patients of the 24 treated had an objective response in nonirradiated tumors, with an ORR of 8.3% (95% CI, 1.0–27%). One patient progressed 3.4 months after achieving PR, the other patient remains progression free at 12 months following PR. Three patients (12%) experienced stable disease as best response, no SD of 4 months or more was observed. The characteristics of response to durva/treme are shown in Table 3 and Fig. 1. The median follow-up at the time of data-lock was 21.8 (range: 15.9–26.3) months among survivors. Twenty-one deaths were observed at analysis. No deaths were attributed to treatment. Median PFS was 1.8 (95% CI, 1.7–1.9) months. The median OS was 11.4 (95% CI, 10.1–17.4) months.

Two patients demonstrated a PR in terms of overall nonirradiated tumor burden (outside of the radiotherapy field). Patient 1 received radiotherapy (5,000 cGy over 5 Fx) to a liver metastasis 7 days after starting durva/treme. The tumor was MMR-P on IHC and MSS on MSK-IMPACT (MSISensor score 0.77), TMB was 10.8 mt/Mb and 11 gene mutations were identified (Supplementary Table S3). For comparison, median TMB available for 18 nonresponders was 5.9 mt/Mb (range: 3.0–8.8 mt/Mb). The primary tumor was located in the distal transverse colon. The second follow up scan (week 15) showed PR in lung metastases (−46% according to RECIST v1.1) that was subsequently confirmed (Fig. 2). Duration of response was 3.4 months. The patient experienced grade 2 colitis, with improvement on high-dose steroids. Prior therapies included FOLFOX, floxuridine, and mitomycin via hepatic arterial infusion pump, FOLFIRI, and panitumumab.

Patient 2 underwent radiotherapy (2,000 cGy over 5 Fx) to a left retroperitoneal mass 3 days after starting durva/treme. The tumor was MMR-P on IHC and MSS on MSK-IMPACT (MSISensor score 1.1), TMB was 5.3 mt/Mb and six-gene mutations were identified (Supplementary Table S3). The primary tumor was located in the left-sided colon. The first follow-up scan (week 8) showed a mixed response in liver metastases, with areas of pseudoprogression. Imaging at week 16 showed PR overall in nonirradiated tumor burden (−52% according to RECIST v1.1) that was subsequently confirmed. Tumor biopsies revealed necrosis and an immune infiltrate (Fig. 3). The patient continues on treatment. At data-lock, duration of response was 12 months. Prior systemic therapies included CAPEOX/bevacizumab, IFL/bevacizumab, regorafenib, followed by TAS-102.

Flow cytometry was performed on PBMCs obtained prior to treatment (n = 21 patients), and then at 2, 4, and 8 weeks after starting durva/treme. Because radiotherapy started after durva/treme, the on-treatment time points corresponded to a median of approximately 11 days, 3.5 weeks, and 7.6 weeks after starting radiotherapy.

Exploratory flow analysis of the patient aggregate data showed a slight decrease in the frequency of CD3⁺ T lymphocytes as a percentage of all live cells at week 2 [0.8-fold of baseline (P_adj 0.013), median of 56% CD3⁺ vs. 44% CD3⁺)], although the proportion of CD8⁺ and CD4⁺ T lymphocytes was unchanged. At 2–4 weeks after initial treatment, both CD4⁺ and CD8⁺ T-cell populations showed increased markers of T-cell activation and exhaustion, such as Ki-67, CD38, HLA-DR, ICOS, TIM-3, LAG-3, and PD-1. The population of Ki-67⁺ proliferating CD8⁺ and CD4⁺ T lymphocytes peaked at week 2 [2.5-fold increase over baseline for CD8 (P_adj < 0.001), 3.5-fold increase over baseline for CD4 (P_adj < 0.001)], and then declined by week 8. Regulatory T cells (FoxP3⁺CD4⁺ Treg) increased in frequency by week 2 [1.5-fold of baseline (P_adj 0.001; Supplementary Table S4]).

Among the two responders, flow cytometry data revealed a relatively higher percentage of CD25⁺CD4⁺ T lymphocytes compared with nonresponders at baseline and on-treatment, indicative of increased frequencies of activated CD4⁺ T lymphocytes in these patients. Among the responders' CD8⁺ T lymphocytes, there were more sustained increases in HLA-DR, Ki-67, and PD-1, along with increases in effector memory CD8⁺ T lymphocytes, indicating more pronounced CD8⁺ T lymphocyte activation, differentiation, and proliferation compared with nonresponders. Moreover, there was increased coexpression of Ki-67, ICOS, and PD-1 in responders that may indicate reinvigoration of exhausted cells, compared with nonresponders. There appeared to be a more sustained increase in effector memory CD8⁺ T lymphocytes (CCR7⁻CD45RA⁻) that were actively proliferating as indicated by expression of Ki-67 on effector memory T cells, compared with nonresponders (Fig. 4 and representative flow dot plots for Ki-67 and PD-1 in Supplementary Fig. S2).

We report the safety and efficacy of radiotherapy plus durvalumab and tremelimumab in metastatic colorectal cancer. The study did not meet the predefined endpoint for further study (defined as ≥3 of 24 objective responses by RECIST v1.1), yet the results did demonstrate that radiotherapy in combination with durvalumab and tremelimumab can lead to shrinkage of distant, nonirradiated tumors in MMR-P metastatic colorectal cancer, with manageable safety. To our knowledge, this is the first prospective report of safety and efficacy of combination ICI plus radiotherapy in colorectal cancer.

Our observations are supported by two recent studies. We previously described that radiotherapy plus pembrolizumab, an anti-PD-1 mAb, led to shrinkage of nonirradiated distant tumors in a patient with metastatic MMR-P colorectal cancer, with an ORR of 4.8% (1/24; ref. 17). Parikh and colleagues described that radiotherapy plus ipilimumab, an anti-CTLA-4 mAb, and nivolumab, an anti-PD-1 mAb, led to shrinkage of nonirradiated distant tumors in patients with metastatic MMR-P colorectal cancer with an ORR of 15% (4/27; ref. 27). Combined, these studies suggest abscopal immunity in 7 of 75 patients with metastatic MMR-P colorectal cancer following radiotherapy plus ICI.

This finding is significant because neither radiotherapy or ICI alone is expected to result in clinically meaningful distant tumor regression in patients with MMR-P colorectal cancer (1–3). As previously reported, MMR-P colorectal cancer has been exceedingly challenging to treat with ICI, and responses are rare and anecdotal, including with the combination of durvalumab plus tremelimumab that resulted in one response out of 118 patients (<1% ORR; ref. 28).

Our observations in colorectal cancer provide further support for synergy between ICI and radiotherapy with shrinkage in nonradiated lesions, as reported in other tumor types, including melanoma, Hodgkin lymphoma, lung cancer, and pancreatic ductal adenocarcinoma (14–16, 29, 30).

We observed two confirmed objective responses (8.3%) outside of the radiation field, and an overall median survival of 11.4 months. Both patients were confirmed MMR-P on IHC and MSS on MSK-IMPACT. TMB in the two responders was 10.8 mt/Mb and 5.3 mt/Mb, respectively. For comparison, the median TMB among 18 nonresponders was 5.9 mt/Mb (range: 3.0–8.8 mt/Mb). These data do not support a hypothesis that an abscopal effect is more likely in tumors with higher TMB. Of note, the proportion of MSS colorectal cancer estimated to be TMB high (≥11.7 mut/Mb) is approximately 2.9% (31), and the recent study of durva/treme in patients with colorectal cancer identified a possible correlation between TMB (measured in cell-free DNA) and improved outcome, but not between TMB and response rate (28).

The combination of durva/treme and radiation overall appeared tolerable with manageable safety. The rate of grade 3–4 TRAE (25%) was consistent with prior reports of the combination of CTLA-4 and PD-1/PDL-1 blockade (28, 32–34), and no new safety signals were identified. Four (16%) patients experienced grade 3 gastrointestinal TRAE, following radiotherapy to the liver, mesentery, or pelvis, that improved with standard immunosuppressive treatment. The most common toxicities observed, regardless of grade, were pruritus, fatigue, rash, diarrhea, chills, dry mouth, and nausea.

To identify additional biomarkers of immune activation and response to combination ICI plus radiotherapy, we performed an exploratory analysis using PBMC samples obtained from patients prior to starting treatment and on treatment. We observed increased proliferation and activation of CD4⁺ and CD8⁺ T lymphocytes after the combination ICI and radiotherapy. In general, changes were seen early, by the first analysis at week 2, and were variable by week 8, with slowing of CD8⁺ and CD4⁺ T lymphocyte proliferation. Although we had only two responders, we observed an association between clinical benefit and increased CD8⁺ T lymphocyte activation and proliferation, along with increased effector memory phenotype CD8⁺ T lymphocytes and reinvigoration of exhausted cells as indicated by increased Ki-67⁺-proliferating CD8⁺ T lymphocytes that were PD-1⁺. These phenotypic changes suggest enhanced CD8⁺ adaptive immunity in the 2 patients who derived clinical benefit. Studies of archival tumor samples collected before and during treatment are ongoing.

This study is limited by the small number of patients evaluated. It also leaves several questions unanswered in general, and in colorectal cancer in particular, about the optimal use of radiation plus ICI to prime immunity and lead to an abscopal response. These include, the optimal immune checkpoint combination, sequencing the treatments, understanding the optimal radiotherapy dose and schedule, and understanding differences in host organ metastatic site for radiation. The current trial was not designed or powered to answer these questions.

In summary, although infrequent antitumor activity in nonirradiated lesions was observed, the results did not meet the study's prespecified endpoint criteria to be considered worthwhile. However, we observed that radiotherapy can lead to immunomodulation in metastatic MMR-P colorectal cancer, and together with combination ICI, lead to systemic immunity. Further studies to identify predictive biomarkers to allow for a priori identification of appropriate subgroups more likely to achieve abscopal immunity are needed. In addition, further studies of radiotherapy plus novel immunotherapy combinations are warranted.

N.H. Segal reported grants from AstraZeneca and MSK Cancer Center Support Grant/Core Grant (P30 CA008748) during the conduct of the study; grants from Pfizer, Merck and Incyte outside the submitted work; grants and personal fees from Roche/Genentech, Immunocore, and BMS outside the submitted work; personal fees from AstraZeneca, Boehringer Ingelheim, ABL Bio, Revitope, PsiOxus, PureTech Ventures, Amgen, GSK, CStone Pharmaceuticals, Synlogic, Pieris, Gritstone Oncology, TRM oncology, Kyn Therapeutics, and Aduro outside the submitted work. A. Cercek reported personal fees from Bayer and Array Biopharma; grants from RGenix, GSK/Tesaro, and Seattle Genetics during the conduct of the study. G. Ku reported grants from AstraZeneca; grants and personal fees from BMS and Merck during the conduct of the study; grants from Arog, Daiichi Sankyo, Zymeworks, and Oncolys; grants and personal fees from Pieris outside the submitted work. A.J. Wu reported grants from CivaTech Oncology, Inc.; personal fees from AstraZeneca and MORE Health, nonfinancial support from AlphaTau Medical, and other from Simphotek, Inc. outside the submitted work. A. Rimner reported grants and personal fees from AstraZeneca, Boehringer Ingelheim, and Merck; grants from Varian Medical Systems and Pfizer; personal fees from ResearchToPractice, Cybrexa, and MoreHealth; and nonfinancial support from Philips/Elekta outside the submitted work. D.N. Khalil reported personal fees from AbbVie outside the submitted work; in addition, D.N. Khalil had a patent for US20200079860A1 pending and a patent for US20200055947A1 pending. D. Reidy-Lagunes reported grants from Merck, Novartis, and Ipsen outside the submitted work. P.B. Romesser reported grants from EMD Serono, personal fees from EMD Serono, and nonfinancial support from Elekta outside the submitted work. Z.K. Stadler reported other from Genentech/Roche, Novartis, RegenexBio, Neurogene, Optos Plc, Regeneron, Allergan, Gyroscope Tx, and Adverum outside the submitted work. A.M. Varghese participates in clinical trials and is the institutional PI of several industry-sponsored studies, including the following industry sponsors: Silenseed, Lilly, Bristol-Myers Squibb, and GSK. R. Yaeger reported grants and personal fees from Array BioPharma/Pfizer, grants from Boehringer Ingelheim, and personal fees from Natera outside the submitted work. G.K. Abou-Alfa reported grants from ActaBiologica, Agios, AstraZeneca, Bayer, Beigene, Berry Genomics, BMS, Casi, Celgene, Exelixis, Genentech/Roche, Halozyme, Incyte, Mabvax, Puma, QED, Sillajen, and Yiviva during the conduct of the study; personal fees from Agios, AstraZeneca, Autem, Bayer, Beigene, Berry Genomics, Celgene, CytomX, Debio, Eisai, Eli Lilly, Exelixis, Flatiron, Genentech/Roche, Gilead, Helio, Incyte, Ipsen, Loxo, Merck, MINA, Polaris, QED, Redhill, Silenseed, Sillajen, Sobi, Therabionics, Twoxar, Vector, and Yiviva outside the submitted work; in addition, G.K. Abou-Alfa had a patent for Articles and Methods for Preventing and Treating Dermatologic Adverse Events, identified by International Patent Application No. PCT/US2014/031545 filed on March 24, 2014, and priority application Serial No.: 61/804,907; Filed: March 25, 2013 issued. P. Wong reported personal fees from Leap Therapeutics and Sellas Life Sciences outside the submitted work. T. Merghoub is a cofounder and holds an equity in IMVAQ Therapeutics; is a consultant of Immunos Therapeutics, ImmunoGenesis and Pfizer; has research support from Bristol-Myers Squibb, Surface Oncology, Kyn Therapeutics, Infinity Pharmaceuticals Inc., Peregrine Pharmaceuticals Inc., Adaptive Biotechnologies, Leap Therapeutics Inc., and Aprea; and has patents on applications related to work on oncolytic viral therapy, alpha virus-based vaccine, neo antigen modeling, CD40, GITR, OX40, PD-1, and CTLA-4. T.J. Hollmann reported other from Parker Institute for Cancer Immunotherapy outside the submitted work. J. Erinjeri reported personal fees from AztraZeneca outside the submitted work. S. Solomon reported grants from GE Healthcare, Elesta, and AngioDynamics; grants and personal fees from Johnson & Johnson; personal fees from Varian Medical Systems outside the submitted work. Y. Yamada reported personal fees from varian medical systems, vision RT, and BrainLab; grants from chordoma foundation outside the submitted work. N. Kemeny reported grants from Amgen outside the submitted work. L.B. Saltz reported grants from Taino Pharmaceuticals outside the submitted work. No disclosures were reported by the other authors.

N.H. Segal: Conceptualization, resources, data curation, formal analysis, funding acquisition, investigation, visualization, methodology, writing–original draft, project administration, writing–review and editing. A. Cercek: Conceptualization, resources, investigation, methodology, writing–review and editing. G. Ku: Resources, investigation, writing–review and editing. A.J. Wu: Resources, investigation, writing–review and editing. A. Rimner: Resources, investigation, writing–review and editing. D.N. Khalil: Conceptualization, resources, investigation, methodology, writing–review and editing. D. Reidy-Lagunes: Resources, investigation, writing–review and editing. J. Cuaron: Resources, investigation, writing–review and editing. T.J. Yang: Resources, investigation, writing–review and editing. M.R. Weiser: Resources, investigation, writing–review and editing. P.B. Romesser: Resources, investigation, writing–review and editing. Z.K. Stadler: Resources, investigation, writing–review and editing. A.M. Varghese: Resources, investigation, writing–review and editing. K. Ganesh: Resources, investigation, writing–review and editing. R. Yaeger: Resources, investigation, writing–review and editing. L.C. Connell: Resources, investigation, writing–review and editing. D. Faleck: Resources, investigation, writing–review and editing. G.K. Abou-Alfa: Resources, investigation, writing–review and editing. K.C. McAuliffe: Resources, data curation, supervision, investigation, methodology, project administration, writing–review and editing. P. Vaiskauskas: Resources, investigation, writing–review and editing. M.L. Solter: Resources, data curation, investigation, methodology, project administration, writing–review and editing. M. Ogle: Resources, data curation, supervision, visualization, methodology, project administration, writing–review and editing. M.J. Adamow: Conceptualization, resources, data curation, formal analysis, investigation, visualization, methodology, writing–review and editing. A. Holland: Resources, investigation, writing–review and editing. P. Vedantam: Conceptualization, resources, data curation, formal analysis, investigation, visualization, methodology, writing–review and editing. P. Wong: Conceptualization, resources, data curation, formal analysis, supervision, investigation, methodology, writing–review and editing. T. Merghoub: Conceptualization, resources, supervision, investigation, visualization, methodology, writing–review and editing. E. Vakiani: Conceptualization, resources, investigation, writing–review and editing. T.J. Hollmann: Conceptualization, resources, supervision, investigation, writing–review and editing. K. Juluru: Resources, investigation, writing–review and editing. J.F. Chou: Conceptualization, resources, data curation, formal analysis, methodology, writing–review and editing. M. Capanu: Conceptualization, resources, data curation, formal analysis, methodology, writing–review and editing. J. Erinjeri: Resources, investigation, writing–review and editing. S. Solomon: Resources, investigation, writing–review and editing. Y. Yamada: Resources, investigation, writing–review and editing. N. Kemeny: Resources, investigation, writing–review and editing. C.H. Crane: Resources, investigation, writing–review and editing. L.B. Saltz: Conceptualization, resources, investigation, methodology, writing–review and editing.

We acknowledge the support of the Immune Monitoring Facility, Ludwig Center for Cancer Immunotherapy, MSKCC. This work was supported by AstraZeneca, and the MSK Cancer Center Support Grant/Core Grant (no. P30 CA008748).

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