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NUT fusion-associated cancers are heterogeneous and include NUT carcinoma and an emerging group with non-BRD4/BRD3/NSD3 fusion partners. In this study, we characterized 11 tumors harboring MAD::NUT fusions (10/11 in female patients; median age: 48 years; range: 1-67 years), all histologically different from NUT carcinoma. Eight cases were identified via sequencing database review and 3 were diagnosed prospectively. Eight (73%) patients presented with multifocal disease, including 6 with disseminated peritoneal tumors; 3 (27%) presented with solitary colonic, pulmonary, or orbital masses. Nine (82%) tumors harbored NUTM1 fusions, with MXI1 (5/9; 56%), MXD4 (2/9; 22%), and MGA (2/9; 22%). One tumor each harbored MXD4::NUTM2G and MXI1::NUTM2A fusions. The 9 MXD4/MXI1-rearranged sarcomas were high-grade, with epithelioid-to-spindle cell cytomorphology, amphophilic cytoplasm, vesicular nuclei, and prominent nucleoli. Histologic features included infiltrative growth (7/7 assessable tumors), rhabdoid morphology (7/9; 78%), prominent collagen (3/9; 33%), multinucleated tumor cells (2/9; 22%), and myxoid stroma (1/9; 11%). MXD4/MXI1-rearranged sarcomas expressed desmin (3/7; 43%) and keratin(s) (3/7; 43%), and not p63 (6 tumors), CD34 (5 tumors), or S-100 (5 tumors). The adult MGA::NUTM1 fusion sarcoma exhibited some cytologic overlap with MXD4/MXI1-rearranged sarcomas but showed lower grade myxoid spindle cell regions, microcystic spaces, and S-100 expression. The pediatric MGA::NUTM1 fusion sarcoma was low-grade with CD34/S-100 coexpression. Immunohistochemistry demonstrated NUTM1 expression in NUTM1-rearranged sarcomas (5/5), and weak and no expression in NUTM2A- and NUTM2G-rearranged sarcomas, respectively. Gene expression profiling demonstrated sarcomas with MXD4/MXI1::NUTM1/NUTM2A/NUTM2G fusions clustered separately from NUT carcinoma. Follow-up was available for 9 patients (82%; median length: 1.8 years; range: 2 months to 8.2 years). Four of 7 patients with MXD4/MXI1-rearranged sarcomas died of disease (median survival: 1.3 years; range: 5 months to 4.8 years), 1 entered hospice at 2 months, 1 was alive with pericardial masses at 2.8 years, and 1 was alive with no evidence of disease at 8.2 years. The adult with the MGA::NUTM1 fusion sarcoma died of other causes at 4.5 years; the child was alive without disease at 11 months. We conclude that MAD::NUT fusions define a sarcoma class distinct from NUT carcinoma. Among this group, MGA::NUTM1 fusion sarcomas might represent a distinctive subset. NUTM1 immunohistochemistry does not reliably detect NUTM2A/NUTM2G-rearranged sarcomas., (Copyright © 2025 United States & Canadian Academy of Pathology. Published by Elsevier Inc. All rights reserved.)

Background: Based on preclinical data showing addition of CDK4/6 inhibitors to gemcitabine was synergistic, ribociclib was evaluated in combination with gemcitabine to determine the maximum tolerated dose (MTD) and dose limiting toxicities (DLT)., Methods: In this single arm multicohort phase I trial, we evaluated the safety and efficacy of ribociclib plus gemcitabine in patients with advanced solid tumors. Patients received gemcitabine intravenously on days 1 and 8 followed by ribociclib days 8-14, with treatment repeated every 3 weeks., Results: The study enrolled 43 patients between October 2017 and September 2019. The escalation phase (19 patients) determined the MTD and recommended phase II dose (RP2D) to be ribociclib 800 mg daily and gemcitabine 1000 mg/m2 for the expansion phase (24 patients). One patient experienced Grade 4 thrombocytopenia. Eleven patients experienced Grade 3 adverse events (AE), the most common being neutropenia, thrombocytopenia, and anemia. No partial or complete responses were observed. 15/22 (68%) of efficacy evaluable patients who received the MTD achieved best response of stable disease., Conclusions: The addition of ribociclib to gemcitabine was tolerated well and yielded stability of tumors in both cohorts. Biomarkers such as Rb status and activity of CDK2 and CDK4/6 complexes may help to select patients who may respond better to the combination of gemcitabine and ribociclib., Clinical Trial Registration: NCT03237390., Competing Interests: Competing interests: The authors declare no competing interests. Ethics approval and consent to participate: All participants granted written informed consent according to federal and institutional guidelines. The trial was conducted with approval of Mayo Institutional Review Board. The study was performed in accordance with the Declaration of Helsinki. Consent for publication: No individual person’s data is included in this manuscript., (© 2025. The Author(s).)

Melanoma is the deadliest form of skin cancer. The median age at diagnosis is 66. While most patients are treated with immunotherapy, the use of targeted therapy is a valid alternative for patients whose tumors harbor a BRAF or c-KIT driver mutation. These agents, while effective, come with a variety of side effects which limit their use, especially in older patients. We sought to assess the efficacy and toxicity of these agents in older melanoma patients. Melanoma patients over 65 treated with BRAF/MEK or c-KIT inhibitors were retrospectively identified, and their data were analyzed for treatment efficacy and toxicity. All data were compared using the Chi-square test for categorical comparisons and the Kruskal-Wallis method for median comparisons. One hundred and sixteen patients were identified. One hundred and six patients were treated with BRAF/MEK inhibitors. The assessed response rate (RR) was 83% and was comparable across different subgroups, including advanced line patients and those with a more aggressive disease. The median progression free survival (PFS) was 7.9 months, and the median overall survival (OS) was 15.7 months. Twenty-seven percent experienced grade 3-4 toxicity leading to a 24% treatment discontinuation rate. Another 10 patients were treated with the c-KIT inhibitor imatinib, for whom the assessed RR was 55%. The median PFS was 4.3 months, and the median OS was 22.6 months. Forty percent needed dose reductions, yet none had to stop treatment due to adverse effects. The use of targeted therapy in older patients is effective yet challenging due to toxicity. Deploying mitigation strategies can help maximizing their usefulness., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: This was a single-arm, phase 2 clinical trial of Bavarian Nordic (BN)-Brachyury vaccine plus radiotherapy (RT) designed to determine the objective response rate (ORR), progression-free survival (PFS), and safety of the combination in chordoma., Methods: A total of 29 adult patients with advanced chordoma were treated with two subcutaneous priming vaccine doses of modified vaccinia Ankara-Bavarian Nordic (MVA-BN)-Brachyury and one vaccine dose of fowlpox virus (FPV)-Brachyury before RT. After RT, booster vaccinations were given with FPV-Brachyury every 4 weeks for 4 doses, then every 12 weeks (week 110). A minimum RT dose of >8 Gy in one fraction for each target was required. Response was evaluated by modified Response Evaluation Criteria in Solid Tumors 1.1 (mRECIST), where only radiated lesions were considered targets, and by standard RECIST 1.1 in a subset of patients., Results: Two of 26 evaluable patients experienced durable partial response (PR) (ORR of 7.7%; 90% confidence interval [CI], 2.6-20.8]) by mRECIST 1.1. A total of 21 patients (80.8%; 90% CI, 65.4-90.3) had stable disease, and three patients (11.5%; 90% CI, 4.7-25.6) had progressive disease as best response per mRECIST 1.1. Median PFS was not reached during the study., Conclusions: This trial confirms the safety of BN-Brachyury and RT. Although the study did not meet the predefined study goal of four responses in 29 patients, we did observe two PRs and a PFS of greater than 2 years. For a vaccine-based study in chordoma, an ultra-rare disease where response rates are low, a randomized study or novel trial designs may be required to confirm activity., (© 2024 American Cancer Society.)

Cardiac tumors are rare and encompass a variety of presentations. Clinica symptoms are usually nonspecific, but they can present as obstructive, embolic, or constitutional symptoms. Treatment options and prognosis vary highly depending on the subtype, tumor size, and location. Surgical resection is usually the first-line therapy, except for cardiac lymphomas, and provides favorable long-term prognosis in most benign tumors. Cardiac sarcomas, however, are usually diagnosed in advanced stages, and the treatment relies on a multimodal approach with chemotherapy and radiotherapy. Metastatic cardiac tumors are usually related to advanced disease and carry an overall poor prognosis.

Background: Undifferentiated small round-cell sarcomas (uSRCSs) are a subgroup of sarcomas that are difficult to diagnose. Some uSRCSs have specific gene re-arrangements, but others do not. Currently, there is no specific treatments for advanced uSRCSs, and its treatment is largely based on general experience with sarcomas, which includes chemotherapy, targeted therapy, and immunotherapy. In this article, we report a patient with uSRCS who responded to treatment with anti-VEGF inhibitor surufatinib and anti-PD-1 inhibitor camrelizumab after progression on first-line chemotherapy, second-line anlotinib combined with immunotherapy, and third-line chemotherapy., Case Description: In July 2020, a 37-year-old female patient was diagnosed with advanced uSRCS. Results for the Ewing sarcoma RNA binding protein 1 and Wilms tumor suppressor (EWSR1/WT1) fusion gene were negative. The patient was also negative with BCOR (BCL6 co-repressor) and CIC (capicua transcriptional repressor) fusion gene. The next-generation sequencing results revealed point mutations on Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Beta (PIK3CB), Transcription Factor Binding To IGHM Enhancer 3 (TFE3), Mucin 16 (MUC16), and AXL (Axl, also called UFO, ARK, and Tyro7, is part of a family of receptor tyrosine kinases). The patient received 4 cycles of the Ifosfamide and epirubicin hydrochloride regimen, and her best objective response was stable disease. On November 3, 2020, a computed tomography (CT) scan revealed progressive disease (PD). Two cycles of camrelizumab (a programmed death-1 inhibitor) plus anlotinib (an anti- vascular endothelial growth factor drug) were administered, but PD was again observed. Thus, a regimen of gemcitabine plus docetaxel was adopted. Unfortunately, the disease progressed once again after two cycles of the treatment. On February 4, 2021, the patient began to receive targeted therapy with surufatinib combined with camrelizumab. A CT scan showed that the tumor achieved a partial response. As of April 2023, the patient had a progression-free survival time of 26 months., Conclusions: Surufatinib in combination with camrelizumab could be effective in the treatment of advanced uSRCSs., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Li, Huang, Chen, Ye, Du, Voutsadakis, Seetharam, Zhang and Lu.)

Background: Based on preclinical data showing addition of CDK4/6 inhibitors to gemcitabine is synergistic, ribociclib was evaluated in combination with gemcitabine to determine the maximum tolerated dose (MTD) and dose limiting toxicities (DLT)., Methods: In this single arm multicohort phase I trial, we evaluated the safety and efficacy of Ribociclib plus Gemcitabine in patients with advanced solid tumors. Patients received Gemcitabine intravenously on days 1 and 8 followed by Ribociclib days 8-14, with treatment repeated every 3 weeks., Results: The study enrolled 43 patients between October 2017 and September 2019. The escalation phase (19 patients) determined the MTD and recommended phase II dose (RP2D) to be ribociclib 800mg daily and gemcitabine 1000mg/m2 for the expansion phase (24 patients). One patient experienced Grade 4 thrombocytopenia. Eleven patients experienced Grade 3 adverse events (AE), the most common being neutropenia, thrombocytopenia, and anemia. No partial or complete responses were observed. 15/22 (68%) of efficacy evaluable patients who received the MTD achieved best response of stable disease., Conclusions: The addition of Ribociclib to Gemcitabine was tolerated well and yielded stability of tumors in both cohorts. Ribociclib and gemcitabine could have synergistic activity in certain tumor types, and our data provides support for the combination., Clinical Trial Registration: NCT03237390., Competing Interests: Competing interests: The authors declare no conflict of interest.

Navitoclax (ABT-263) is an oral BCL2 homology-3 mimetic that binds with high affinity to pro-survival BCL2 proteins, resulting in apoptosis. Sorafenib, an oral multi kinase inhibitor also promotes apoptosis and inhibits tumor angiogenesis. The efficacy of either agent alone is limited; however, preclinical studies demonstrate synergy with the combination of navitoclax and sorafenib. In this phase 1 study, we evaluated the combination of navitoclax and sorafenib in a dose escalation cohort of patients with refractory solid tumors, with an expansion cohort in hepatocellular carcinoma (HCC). Maximum tolerated dose (MTD) was determined using the continual reassessment method. Navitoclax and sorafenib were administered continuously on days 1 through 21 of 21-day cycles. Ten patients were enrolled in the dose escalation cohort and 15 HCC patients were enrolled in the expansion cohort. Two dose levels were tested, and the MTD was navitoclax 150 mg daily plus sorafenib 400 mg twice daily. Among all patients, the most common grade 3 toxicity was thrombocytopenia (5 patients, 20%): there were no grade 4 or 5 toxicities. Patients received a median of 2 cycles (range 1-36 cycles) and all patients were off study treatment at data cut off. Six patients in the expansion cohort had stable disease, and there were no partial or complete responses. Drug-drug interaction between navitoclax and sorafenib was not observed. The combination of navitoclax and sorafenib did not increase induction of apoptosis compared with navitoclax alone. Navitoclax plus sorafenib is tolerable but showed limited efficacy in the HCC expansion cohort. These findings do not support further development of this combination for the treatment of advanced HCC. This phase I trial was conducted under ClinicalTrials.gov registry number NCT01364051., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose: Uterine leiomyosarcoma (uLMS) is an aggressive subtype of soft-tissue sarcoma with frequent metastatic relapse after curative surgery. Chemotherapy provides limited benefit for advanced disease. Multiomics profiling studies have identified homologous recombination deficiency in uLMS. In preclinical studies where olaparib and temozolomide provided modest activity, the combination was highly effective for inhibiting uLMS tumor growth., Patients and Methods: NCI Protocol 10250 is a single-arm, open-label, multicenter, phase II study evaluating olaparib and temozolomide in advanced uLMS. Patients with progression on ≥1 prior line received temozolomide 75 mg/m 2 orally once daily with olaparib 200 mg orally twice a day both on days 1-7 in 21-day cycles. The primary end point was the best objective response rate (ORR) within 6 months. A one-stage binomial design was used. If ≥5 of 22 responded, the treatment would be considered promising (93% power; α = .06). All patients underwent paired biopsies that were evaluated with whole-exome sequencing (WES)/RNAseq and a RAD51 foci formation assay., Results: Twenty-two patients were evaluable. The median age was 55 years, and 59% had received three or more prior lines. Best ORR within 6 months was 23% (5 of 22). The overall ORR was 27% (6 of 22). The median progression-free survival (mPFS) was 6.9 months (95% CI, 5.4 months to not estimable). Hematologic toxicity was common (grade 3/4 neutropenia: 75%; thrombocytopenia: 32%) but manageable with dose modification. Five of 16 (31%) of tumors contained a deleterious homologous recombination gene alteration by WES, and 9 of 18 (50%) were homologous recombination-deficient by the RAD51 assay. In an exploratory analysis, mPFS was prolonged for patients with homologous recombination-deficient versus homologous recombination-proficient tumors (11.2 v 5.4 months, P = .05) by RAD51., Conclusion: Olaparib and temozolomide met the prespecified primary end point and provided meaningful clinical benefit in patients with advanced, pretreated uLMS.

The treatment of sarcoma necessitates a collaborative approach, given its rarity and complex management. At a single institution, multidisciplinary teams of specialists determine and execute treatment plans involving surgical, radiation, and medical management. Treatment guidelines for systemic therapies in advanced or nonresectable soft tissue sarcoma have advanced in recent years as new immunotherapies and targeted therapies become available. Collaboration between institutions is necessary to facilitate accrual to clinical trials. Here, we describe the success of the Midwest Sarcoma Trials Partnership (MWSTP) in creating a network encompassing large academic centers and local community sites. We propose a new model utilizing online platforms to expand the reach of clinical expertise for the treatment of advanced soft tissue sarcoma.

Vesiculoviruses are attractive oncolytic virus platforms due to their rapid replication, appreciable transgene capacity, broad tropism, limited preexisting immunity, and tumor selectivity through type I interferon response defects in malignant cells. We developed a synthetic chimeric virus (VMG) expressing the glycoprotein (G) from Morreton virus (MorV) and utilizing the remaining structural genes from vesicular stomatitis virus (VSV). VMG exhibited in vitro efficacy by inducing oncolysis in a broad range of sarcoma subtypes across multiple species. Notably, all cell lines tested showed the ability of VMG to yield productive infection with rapid replication kinetics and induction of apoptosis. Furthermore, pilot safety evaluations of VMG in immunocompetent, non-tumor-bearing mice showed an absence of toxicity with intranasal doses as high as 1e10 50% tissue culture infectious dose (TCID 50 )/kg. Locoregional administration of VMG in vivo resulted in tumor reduction in an immunodeficient Ewing sarcoma xenograft at doses as low as 2e5 TCID 50 . In a murine syngeneic fibrosarcoma model, while no tumor inhibition was achieved with VMG, there was a robust induction of CD8+ T cells within the tumor. The studies described herein establish the promising potential for VMG to be used as a novel oncolytic virotherapy platform with anticancer effects in sarcoma., Competing Interests: M.J.B. has received grants to their institution from Senhwa Pharmaceuticals, Adaptimmune, Agios Pharmaceuticals, Halozyme Pharmaceuticals, Five Prime Pharmaceuticals, Celgene Pharmaceuticals, EMD Merck Serono, Toray, Dicerna, Taiho Pharmaceuticals, Sun Biopharma, Isis Pharmaceuticals, Redhill Pharmaceuticals, Boston Biomed, Basilea, Incyte Pharmaceuticals, Mirna Pharmaceuticals, Medimmune, Bioline, Sillajen, ARIAD Pharmaceuticals, PUMA Pharmaceuticals, Novartis Pharmaceuticals, QED Pharmaceuticals, and Pieris Pharmaceuticals; consultancy fees from ADC Therapeutics, Exelixis Pharmaceuticals, Inspyr Therapeutics, G1 Therapeutics, Immunovative Therapies, OncBioMune Pharmaceuticals, Western Oncolytics, and Lynx Group; and travel support from Astra Zeneca. These funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH. M.J.B. and B.M.N. declare that they filed a patent application for the vectors and their derivatives included in this manuscript., (© 2023 The Author(s).)

Abstract: A 39-year-old man presented with progressive dyspnea and lower extremity edema. Doppler ultrasound demonstrated bilateral leg partially occluded venous thromboses. A V/Q scan revealed a mismatched perfusion defect involving the entire right middle and lower lobes. Subsequent CT pulmonary angiogram revealed a mass lesion occluding the right interlobar pulmonary artery. Endobronchial ultrasound-guided fine-needle aspiration of the mass was concerning for neoplasm. 18 F-FDG PET/CT demonstrated marked hypermetabolism of the mass lesion. Patient underwent transmediastinal right pneumonectomy with histopathologic diagnosis of pulmonary artery angiomatoid fibrous histiocytoma, a rare etiology mimicking large pulmonary artery embolism., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: In patients with extremity soft tissue sarcoma (eSTS), we describe outcomes of preoperative external beam radiation therapy (EBRT), limb-sparing surgery (LSS), and intraoperative electron radiation therapy (IOERT)., Methods: One hundred and eighteen patients with eSTS treated between October 17, 2002 and July 28, 2021 were identified. EBRT was delivered preoperatively followed by LSS and IOERT., Results: The median follow-up was 24.9 months. The presentation was primary in 102 (94%) patients and recurrent in 6 (6%) patients. Tumor location was lower extremity in 82 (76%) patients and upper extremity in 26 (24%) patients. Stage distribution was as follows: 3 (3%) IA, 24 (22%) IB, 31 (29%) II, 24 (22%) IIIA, and 25 (23%) IIIB. Final surgical margins were negative in 96 (89%) patients. The 5-year local control, failure-free survival, and overall survival were 94%, 75%, and 64%, respectively. Univariate analysis identified age >50, lower extremity, and higher grade as significant negative prognostic factors for overall survival. Grade 3 fracture or osteoradionecrosis requiring surgical fixation, neuropathy, and lymphedema occurred in 7 (6%), 1 (1%), and 0 patients, respectively., Conclusions: This study represents one of the largest series using preoperative EBRT, LSS, and IOERT for eSTS, with high local control and a low rate of late severe toxicity., (© 2022 Wiley Periodicals LLC.)

Oncogenic RET fusions occur in diverse cancers. Pralsetinib is a potent, selective inhibitor of RET receptor tyrosine kinase. ARROW ( NCT03037385 , ongoing) was designed to evaluate pralsetinib efficacy and safety in patients with advanced RET-altered solid tumors. Twenty-nine patients with 12 different RET fusion-positive solid tumor types, excluding non-small-cell lung cancer and thyroid cancer, who had previously received or were not candidates for standard therapies, were enrolled. The most common RET fusion partners in 23 efficacy-evaluable patients were CCDC6 (26%), KIF5B (26%) and NCOA4 (13%). Overall response rate, the primary endpoint, was 57% (95% confidence interval, 35-77) among these patients. Responses were observed regardless of tumor type or RET fusion partner. Median duration of response, progression-free survival and overall survival were 12 months, 7 months and 14 months, respectively. The most common grade ≥3 treatment-related adverse events were neutropenia (31%) and anemia (14%). These data validate RET as a tissue-agnostic target with sensitivity to RET inhibition, indicating pralsetinib's potential as a well-tolerated treatment option with rapid, robust and durable anti-tumor activity in patients with diverse RET fusion-positive solid tumors., (© 2022. The Author(s).)

Purpose: Proton beam therapy (PBT) may provide an advantage when planning well-selected patients with extremity soft tissue sarcoma (eSTS), specifically for large, anatomically challenging cases. We analyzed our early experience with PBT on toxicity and outcomes., Materials and Methods: A retrospective study was performed for eSTS treated between June 2016 and October 2020 with pencil beam scanning PBT at 2 institutions. Diagnostic, treatment, and toxicity characteristics were gathered from baseline to last follow-up or death. Wound complications were defined as secondary operations for wound repair (debridement, drainage, skin graft, and muscle flap) or nonoperative management requiring hospitalization. Statistical analysis was performed with R software., Results: Twenty consecutive patients with a median age 51.5 years (range, 19-78 years) were included. Median follow-up was 13.7 months (range, 1.7-48.1 months). Tumor presentation was primary (n = 17) or recurrent after prior combined modality therapy (n = 3). Tumor location was either lower extremity (n = 16) or upper extremity (n = 4). Radiation was delivered preoperatively in most patients (n = 18). Median pretreatment tumor size was 7.9 cm (range, 1.3 -30.0 cm). The 1-year locoregional control was 100%. Four patients (20%) had developed metastatic disease by end of follow-up. Maximum toxicity for acute dermatitis was grade 2 in 8 patients (40%) and grade 3 in 3 patients (15%). After preoperative radiation and surgical resection, acute wound complications occurred in 6 patients (35%). Tumor size was larger in patients with acute wound complications compared with those without (medians 16 cm, range [12-30.0 cm] vs 6.3 cm, [1.3-14.4 cm], P = .003)., Conclusion: PBT for well selected eSTS cases demonstrated excellent local control and similar acute wound complication rate comparable to historic controls. Long-term follow-up and further dosimetric analyses will provide further insight into potential advantages of PBT in this patient population., Competing Interests: Conflicts of Interest: The authors have no relevant conflicts of interest to disclose., (©Copyright 2022 The Author(s).)

Background: Availability of checkpoint inhibitors has created a paradigm shift in the management of patients with solid tumors. Despite this, most patients do not respond to immunotherapy, and there is considerable interest in developing combination therapies to improve response rates and outcomes. B7-H3 (CD276) is a member of the B7 family of cell surface molecules and provides an alternative immune checkpoint molecule to therapeutically target alone or in combination with programmed cell death-1 (PD-1)-targeted therapies. Enoblituzumab, an investigational anti-B7-H3 humanized monoclonal antibody, incorporates an immunoglobulin G1 fragment crystallizable (Fc) domain that enhances Fcγ receptor-mediated antibody-dependent cellular cytotoxicity. Coordinated engagement of innate and adaptive immunity by targeting distinct members of the B7 family (B7-H3 and PD-1) is hypothesized to provide greater antitumor activity than either agent alone., Methods: In this phase I/II study, patients received intravenous enoblituzumab (3-15 mg/kg) weekly plus intravenous pembrolizumab (2 mg/kg) every 3 weeks during dose-escalation and cohort expansion. Expansion cohorts included non-small cell lung cancer (NSCLC; checkpoint inhibitor [CPI]-naïve and post-CPI, programmed death-ligand 1 [PD-L1] <1%), head and neck squamous cell carcinoma (HNSCC; CPI-naïve), urothelial cancer (post-CPI), and melanoma (post-CPI). Disease was assessed using Response Evaluation Criteria in Solid Tumors version 1.1 after 6 weeks and every 9 weeks thereafter. Safety and pharmacokinetic data were provided for all enrolled patients; efficacy data focused on HNSCC and NSCLC cohorts., Results: Overall, 133 patients were enrolled and received ≥1 dose of study treatment. The maximum tolerated dose of enoblituzumab with pembrolizumab at 2 mg/kg was not reached. Intravenous enoblituzumab (15 mg/kg) every 3 weeks plus pembrolizumab (2 mg/kg) every 3 weeks was recommended for phase II evaluation. Treatment-related adverse events occurred in 116 patients (87.2%) and were grade ≥3 in 28.6%. One treatment-related death occurred (pneumonitis). Objective responses occurred in 6 of 18 (33.3% [95% CI 13.3 to 59.0]) patients with CPI-naïve HNSCC and in 5 of 14 (35.7% [95% CI 12.8 to 64.9]) patients with CPI-naïve NSCLC., Conclusions: Checkpoint targeting with enoblituzumab and pembrolizumab demonstrated acceptable safety and antitumor activity in patients with CPI-naïve HNSCC and NSCLC., Trial Registration Number: NCT02475213., Competing Interests: Competing interests: CA reports personal fees from AstraZeneca, BluPrint Oncology, Celgene, Eli Lilly, Merck, Daiichi Sankyo for advisory boards, and research funding to the institution from Merck, MacroGenics, Novartis, and AstraZeneca; SA reports consulting fees from Bristol-Myers Squibb, Merck, CBMG, AstraZeneca, Memgen, RAPT, Venn, Achilles Therapeutics, Celsius, Samyang Biopharma, GlaxoSmithKline, Amgen, travel expenses from Bristol-Myers Squibb, Merck, Rapt, Achilles Therapeutics, Celsius, GlaxoSmithKline, Amgen, and grants from Novartis; VA reports personal fees and non-financial support from Bristol-Myers Squibb, and personal fees from Merck, MSD, Novartis, QBiotics, Nektar, Roche, Pierre Fabre; RC reports grants paid to the institution from MacroGenics, Merck, personal fees from AstraZeneca, grants to the institution and personal fees from Innate Pharma, Genocea Biosciences, Heat Biologics, advisory boards for Innate Pharma, Genocea Biosciences, AstraZeneca, Heat Biologics, Cantargia, research funding from Celldex, Kyn Therapeutics, Merck, Genocea Biosciences, Xencor, Innate Pharma, Heat Biologics, and travel expenses from Heat Biologics, Innate Pharma, Genocea Biosciences; RLF reports consulting fees from Aduro Biotech, Novasenta, Sanofi, Zymeworks, honoraria from Bristol-Myers Squibb, EMD Serono, MacroGenics, Merck, Numab Therapeutics, Pfizer for advisory boards, research funds to institution from AstraZeneca/MedImmune, Bristol-Myers Squibb, Novasenta, Tesaro, clinical trial support from AstraZeneca/MedImmune, Bristol-Myers Squibb, Merck, and stocks in Novasenta; VG reports honoraria from AstraZeneca, Roche/Genentech; ARK reports holding stocks in ECOM Medical, receiving consulting fees from Exelixis, AstraZeneca, Bayer, Pfizer, Novartis, Genentech, Bristol-Myers Squibb, EMD Serono, serving on Speakers’ Bureau at Janssen, Astellas Medivation, Pfizer, Novartis, Sanofi, Genentech/Roche, Eisai, AstraZeneca, Bristol-Myers Squibb, Amgen, Exelixis, EMD Serono, Merck, Seattle Genetics/Astellas, receiving research funding to the institution from Genentech, Exelixis, Janssen, AstraZeneca, Bayer, Bristol-Myers Squibb, Eisai, MacroGenics, Astellas Pharma, beyond spring, BioClin Therapeutics, Clovis Oncology, Bavarian Nordic, Seattle Genetics, Immunomedics, Epizyme, and receiving travel expenses from Genentech, Prometheus Laboratories, Astellas Medivation, Janssen, Eisai, Bayer, Pfizer, Novartis, Exelixis, AstraZeneca; SK reports consulting fees from MacroGenics and is a stock holder of Abbott, Aqua, Bank of America, Baxter, Betterment, Bristol-Myers Squibb, Etrade, ExxonMobil, Invesco, Johnson & Johnson, Lockheed Martin Corp, Marathon Oil, Marathon Petroleum, Pfizer, Takeda Pharm Co, Verizon, Welltower, Vanguard; NL reports research funding from ALX Therapeutics, Ascentage, Asana, BeiGene, Constellation Pharma, Alexion, Cerulean, Forty Seven, Alpine, Merck, Pfizer, Regeneron, TaiRx, Apexian, Formation Biologics (Forbius), Symphogen, CytomX, InhibRx, Incyte, Jounce, Livzon, Northern Biologics, Innovent Biologics, Ikena, Odonate, Loxo, Alpine Biosciences, Ikena, Mersana, and serves on advisory boards for Innovent Biologics; YL reports research funding from Merck, MacroGenics, Tolero Pharmaceuticals, AstraZeneca, Vaccinex, Blueprint Medicines, Harpoon Therapeutics, Sun Pharma Advanced Research, Kyowa Pharmaceuticals, Tesaro, Bayer HealthCare, honorarium from Clarion Healthcare, served on the advisory board for AstraZeneca, Novocure, and consultant for AstraZeneca; OR reports research support from Merck, Speakers’ Bureau activities supported by educational grants from Bristol-Myers Squibb and Merck, and honoraria for consulting activities for Merck, Celgene, Five Prime, GlaxoSmithKline, Bayer, Roche/Genentech, Puretech, Imvax, Sobi. In addition, OR has a patent pending for 'Methods of using pembrolizumab and trebananib'; MS received honoraria from Deciphera Pharmaceuticals and Daiichi Sankyo for serving on advisory boards; AT reports consulting fees from AbbVie, Adagene, Agenus, Aro Biotherapeutics, Ascentage, Aximmune, Bayer, BioInvent, Birdie, Cello Health, Ellipses, EMD Serono, Five Prime, Forbius, Gilde Healthcare Partners, HBM Partners, Immunomet, Karma Oncology, Mekanistic, Menarini, Mersana, Nanobiotix, Nuvalent, OSI, Partner Therapeutics, Pfizer, Pieris, Pierre Fabre, Ridgeway, RYVU Therapeutics, Scitemex, Seattle Genetics, Symphogen, Syneos, TFS Trial Form Support, and Trillium Therapeutics, and honoraria from Abgenomics, Adagene, ADC Therapeutics, Aro Biotherapeutics, BioInvent, Elucida, Immunome, Jazz, NBE Therapeutics, Pelican, Innate Pharma, TFS Trial Form Support International, and Zymeworks for serving on advisory boards. In addition, AT serves on the Independent Data Monitoring Committees for Mirati and Genentech; NV reports non-financial support for conducting trials with Amgen, Aravive, Arrowhead, Arvinas, AstraZeneca, Bayer, Bristol-Myers Squibb, Calithera, Clovis, Corvus, Dendreon, eFFECTOR, Eisai, Endocyte, Epizyme, ESSA, Exelixis, Genentech, Immunomedics, Kangpu, Kinter Suzhou, MacroGenics, Merck, Mirati, Nektar, Novartis, Seattle Genetics, Tolero, advisory boards for Amgen, Astellas, AstraZeneca, Aveo, Caris, Clovis, Corvus, Eisai, Exelixis, GeneCentric, Genentech, Janssen, Merck, Myovant, OnQuality Pharma, Pfizer, Sanofi-Genzyme, Tolero, serves on the Speakers’ Bureau at Bayer, Caris, Clovis, Sanofi-Genzyme, Seattle Genetics, consulting services to Cancer Expert Now, vice-chair responsibilities at SWOG, section editor at Up-To-Date, and legal defense advisor to Novartis, Sanofi-Genzyme; AW reports grants from Merck, grants and personal fees from Bristol-Myers Squibb, personal fees from Ipsen, Pfizer; DPZ received institutional research support from Merck, Bristol-Myers Squibb, GlaxoSmithKline, AstraZeneca, Aduro Biotech, Lilly, Astellas, MacroGenics for his role as a PI of clinical trials sponsored by these companies and received honoraria from Blueprint Medicines for serving on an advisory board; SMG is a former employee of MacroGenics serving as medical monitor; XZ, RC, and LP are employees of MacroGenics; JB was an employee of MacroGenics; PAM is an employee of MacroGenics, holds stock in MacroGenics, and holds a patent with all rights assigned to MacroGenics for 'Antibodies reactive with B7-H3, immunologically active fragments thereof' US Patent 9,150,656; EB is an employee of MacroGenics, holds stock in MacroGenics, and has a patent US20190389952 pending to MacroGenics; FA was an employee of MacroGenics and is now an employee of AstraZeneca; AP, AAA, AB, RH, and AMJ have nothing to disclose., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY. Published by BMJ.)