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von Mehren, Margaret

0000-0001-6158-890X

Mayo Clinic

Fox Chase Cancer Center

Citations 9

Updated Overall Survival and Long-Term Safety With Ripretinib Versus Sunitinib in Patients With GI Stromal Tumor: Final Overall Survival Analysis From INTRIGUE
Heinrich, Michael C. , Blay, Jean‐Yves , Gelderblom, Hans , George, Suzanne , Schöffski, Patrick , Mehren, Margaret von , Jones, Robin L. , Kang, Yoon‐Koo , Razak, Albiruni R. Abdul , Attia, Steven , Cesne, Axel Le , Goldstein, David , Sánchez, César , Cox, P. H. , Davis, Erika, Sherman, Matthew L. , Ruiz‐Soto, Rodrigo , Bauer, Sebastian , von Mehren, Margaret , Jones, Robin L , Kang, Yoon-Koo , Razak, Albiruni Abdul , Trent, Jonathan , Attia, Steven , Le Cesne, Axel , Boye, Kjetil , Sánchez, César , Cox, Paulina , Ruiz-Soto, Rodrigo , Bauer, Sebastian , Blay, Jean-Yves , Gelderblom, Hans , Heinrich, Michael C , George, Suzanne , Zalcberg, John , Trent, Jonathan C. , Siontis, Brittany L.

Journal of Clinical Oncology | May 23, 2025 | Volume: 43 | Issue: 20 | Pages: 2239-2244

10.1200/jco-24-02818 Get It

In the INTRIGUE phase III trial (ClinicalTrials.gov identifier: NCT03673501 ), adult patients with advanced gastrointestinal stromal tumor previously treated with imatinib were randomly assigned 1:1 to ripretinib 150 mg once daily or sunitinib 50 mg once daily (4 weeks on/2 weeks off). In the primary analysis, overall survival (OS) was immature. In this study, we report the final planned analysis of OS (key secondary end point), progression-free survival (PFS) on third-line therapy (second PFS; prespecified exploratory end point), and long-term safety. Final OS analysis was prespecified to occur with approximately 200 and ≥145 events in the overall and KIT exon 11 intention-to-treat (ITT) populations, respectively. As of March 15, 2023, there were 211 and 151 OS events in the overall ITT and KIT exon 11 ITT populations, respectively. Median OS was similar between second-line ripretinib and sunitinib in both populations (overall, 35.5 v 31.5 months; KIT exon 11, 35.5 v 32.8 months). Median second PFS (on third-line therapy) for the overall ITT population was similar between the ripretinib and sunitinib arms (7.7 v 7.4 months). Safety was consistent with the primary analysis. OS from this analysis was similar between arms, and second PFS suggests that receiving ripretinib did not adversely affect the PFS of third-line therapy.
A Single-Arm Phase 2 Trial of Trametinib in Patients with Locally Advanced or Metastatic Epithelioid Hemangioendothelioma
Schuetze, Scott M. , Heise, Rachel S. , Ganjoo, Kristen N. , Davis, Elizabeth J. , George, Suzanne , Burgess, Melissa , Choy, Edwin , Shepard, Dale R. , Tinoco, Gabriel , Kelly, Ciara M. , Attia, Steven , Deshpande, Hari A. , Riedel, Richard F. , Kozlowski, Erin , Astbury, Caroline , Ballman, Karla V. , Schuetze, Scott M , Heise, Rachel , Ganjoo, Kristen N , Davis, Elizabeth J , George, Suzanne , Burgess, Melissa A , Choy, Edwin , Shepard, Dale R , Tinoco, Gabriel , Hirbe, Angela C , Kelly, Ciara M , Attia, Steven , Deshpande, Hari A , Schwartz, Gary K , Siontis, Brittany L , Riedel, Richard F , von Mehren, Margaret , Kozlowski, Erin , Chen, Helen X , Astbury, Caroline , Rubin, Brian P. , Ballman, Karla , Hirbe, Angela C. , Schwartz, Gary K. , Siontis, Brittany L. , Mehren, Margaret von

Clinical Cancer Research | March 6, 2024 | Volume: 30 | Issue: 20 | Pages: 4584-4592

10.1158/1078-0432.ccr-23-3817 Get It

Abstract Purpose: Epithelioid hemangioendothelioma (EHE) is a rare vascular cancer with pathogenic TAZ–CAMTA1 (calmodulinbinding transcription activator 1) operating as an oncogenic driver through activation of the MAPK pathway. Trametinib is an inhibitor of MEK, a critical kinase in the MAPK pathway. We sought to evaluate the effect of trametinib in patients with EHE. Patients and Methods: A phase 2 trial of trametinib was conducted in patients with locally advanced or metastatic EHE. Eligibility requirements included evidence of tumor progression or presence of EHE-related pain requiring opiates for management before enrollment. The primary endpoint was objective response rate (ORR) as per RECIST1.1 in cases with TAZ– CAMTA1 confirmed by fusion-FISH. Secondary objectives were to estimate ORR for all patients, median progression-free survival (PFS), 2-year overall survival (OS) rate, patient safety, and change in patient-reported global health and pain scores per PROMIS questionnaires. Results: 44 patients enrolled and 42 started trametinib. TAZ– CAMTA1 was detected in 27 tumor samples. TheORRwas 3.7%[95% confidence interval (CI), 0.094–19.0], median PFS was 10.4 months (95%CI, 7.1–NA), and 2-year OS rate was 33.3%(95%CI, 19.1–58.2) in the target population. Median pain intensity and interference scores improved significantly after 4 weeks of trametinib in patients using opiates. Common adverse events related to trametinib were rash, fatigue, nausea/vomiting, diarrhea/constipation, alopecia, and edema; one grade 5 ARDS/pneumonitis was related to trametinib. Conclusions: Trametinib was associated with reduction in EHE-related pain and median PFS of more than 6 months, providing palliative benefit in patients with advanced EHE, but the trial did not meet the ORR goal. See related commentary by Van Tine and Haarberg, p. 4552
Adolescent and Young Adult (AYA) Oncology, Version 2.2024, NCCN Clinical Practice Guidelines in Oncology
Pappo, Alberto S. , Acquazzino, Melissa , Barnett, Marie , Casey, Robert, Choo, Sun , Dinner, Shira, Fair, Douglas , Federman, Noah , Folbrecht, Jeanelle , Gandhi, Shipra , Germann, Julie N. , Goldsby, Robert E. , Hayashi, Robert J. , Huang, Mary , Jacobs, Linda A. , Lee‐Miller, Cathy , Link, Michael P., Lustberg, Maryam B. , Malogolowkin, Marcio H., Oeffinger, Kevin C. , Pratilas, Christine A. , Mehren, Margaret von , Yeager, Nicholas D. , Hang, Lisa, von Mehren, Margaret , Lustberg, Maryam , Bhatia, Smita , Allen‐Rhoades, Wendy , Borinstein, Scott C. , Chugh, Rashmi , Ermoian, Ralph P. , Huang, Alex Yee-Chen , Livingston, J. Andrew , Reed, Damon R. , Skiles, Jodi L. , Montgomery, Sarah E.

Journal of the National Comprehensive Cancer Network | August 7, 2023 | Volume: 21 | Issue: 8 | Pages: 851-880

10.6004/jnccn.2023.0040 Get It

This selection from the NCCN Guidelines for Adolescent and Young Adult (AYA) Oncology focuses on considerations for the comprehensive care of AYA patients with cancer. Compared with older adults with cancer, AYA patients have unique needs regarding treatment, fertility counseling, psychosocial and behavioral issues, and supportive care services. The complete version of the NCCN Guidelines for Adolescent and Young Adult (AYA) Oncology addresses additional aspects of caring for AYA patients, including risk factors, screening, diagnosis, and survivorship.
NCCN Guidelines® Insights: Gastrointestinal Stromal Tumors, Version 2.2022
Mehren, Margaret von , Riedel, Richard F. , Agulnik, Mark , Carr, Janai R. , Connelly, Mary, Ganjoo, Kristen N. , Holder, Ashley M. , Homsi, Jade , Keedy, Vicki L. , Kelly, Ciara M. , Kim, Edward , McCarter, Martin D. , McGarry, Sean V., Mesko, Nathan W. , Meyer, Christian F. , Pappo, Alberto S. , Petersen, Ivy A. , Poppe, Matthew M. , Schuetze, Scott M. , Shabason, Jacob E. , Zimel, Melissa N. , Bergman, Mary Anne, Sundar, Hema, Hang, Lisa E., Riedel, Richard F , von Mehren, Margaret , Kane, John M., Sicklick, Jason Keith , Pollack, Seth M. , Bui, Marilyn M. , Choy, Edwin , Connelly, Mary, Dry, Sarah , González, Ricardo , Liebner, David A. , Parkes, Amanda , Spraker, Matthew B.

Journal of the National Comprehensive Cancer Network | November 9, 2022 | Volume: 20 | Issue: 11 | Pages: 1204-1214

10.6004/jnccn.2022.0058 Get It

Gastrointestinal stromal tumors (GIST) are the most common type of soft tissue sarcoma that occur throughout the gastrointestinal tract. Most of these tumors are caused by oncogenic activating mutations in the KIT or PDGFRA genes. The NCCN Guidelines for GIST provide recommendations for the diagnosis, evaluation, treatment, and follow-up of patients with these tumors. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines, including revised systemic therapy options for unresectable, progressive, or metastatic GIST based on mutational status, and updated recommendations for the management of GIST that develop resistance to specific tyrosine kinase inhibitors.
Ripretinib Versus Sunitinib in Patients With Advanced Gastrointestinal Stromal Tumor After Treatment With Imatinib (INTRIGUE): A Randomized, Open-Label, Phase III Trial
Bauer, Sebastian , Jones, Robin L. , Blay, Jean‐Yves , Gelderblom, Hans , George, Suzanne , Schöffski, Patrick , Mehren, Margaret von , Kang, Yoon‐Koo , Razak, Albiruni Abdul , Attia, Steven , Cesne, Axel Le , Su, Ying , Meade, Julie, Wang, Tao , Sherman, Matthew L. , Ruiz‐Soto, Rodrigo , von Mehren, Margaret , Kang, Yoon-Koo , Trent, Jonathan , Attia, Steven , Le Cesne, Axel , Su, Ying , Ruiz-Soto, Rodrigo , Heinrich, Michael C , Blay, Jean-Yves , Jones, Robin L , Gelderblom, Hans , George, Suzanne , Bauer, Sebastian , Zalcberg, John , Trent, Jonathan C. , Heinrich, Michael C.

Journal of Clinical Oncology | August 10, 2022 | Volume: 40 | Issue: 34 | Pages: 3918-3928

10.1200/jco.22.00294 Get It

PURPOSE Sunitinib, a multitargeted tyrosine kinase inhibitor (TKI), is approved for advanced gastrointestinal stromal tumor (GIST) after imatinib failure. Ripretinib is a switch-control TKI approved for advanced GIST after prior treatment with three or more TKIs, including imatinib. We compared efficacy and safety of ripretinib versus sunitinib in patients with advanced GIST who were previously treated with imatinib (INTRIGUE, ClinicalTrials.gov identifier: NCT03673501 ). PATIENTS AND METHODS Random assignment was 1:1 to once-daily ripretinib 150 mg or once-daily sunitinib 50 mg (4 weeks on/2 weeks off) and stratified by KIT/ platelet-derived growth factor α mutation and imatinib intolerance. The primary end point was progression-free survival (PFS) by independent radiologic review using modified Response Evaluation Criteria in Solid Tumors version 1.1. Secondary end points included objective response rate by independent radiologic review, safety, and patient-reported outcome measures. RESULTS Overall, 453 patients were randomly assigned to ripretinib (intention-to-treat [ITT], n = 226; KIT exon 11 ITT, n = 163) or sunitinib (ITT, n = 227; KIT exon 11 ITT, n = 164). Median PFS for ripretinib and sunitinib ( KIT exon 11 ITT) was 8.3 and 7.0 months, respectively (hazard ratio, 0.88; 95% CI, 0.66 to 1.16; P = .36); median PFS (ITT) was 8.0 and 8.3 months, respectively (hazard ratio, 1.05; 95% CI, 0.82 to 1.33; nominal P = .72). Neither was statistically significant. Objective response rate was higher for ripretinib versus sunitinib in the KIT exon 11 ITT population (23.9% v 14.6%, nominal P = .03). Ripretinib was associated with a more favorable safety profile, fewer grade 3/4 treatment-emergent adverse events (41.3% v 65.6%, nominal P < .0001), and better scores on patient-reported outcome measures of tolerability. CONCLUSION Ripretinib was not superior to sunitinib in terms of PFS. However, meaningful clinical activity, fewer grade 3/4 treatment-emergent adverse events, and improved tolerability were observed with ripretinib.
Soft Tissue Sarcoma, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology
Mehren, Margaret von , Kane, John M. , Agulnik, Mark , Carr, Janai R. , Connelly, Mary, Ganjoo, Kristen N. , Holder, Ashley M. , Homsi, Jade , Keedy, Vicki L. , Kelly, Ciara M. , Kim, Edward , McCarter, Martin D. , McGarry, Sean V., Mesko, Nathan W. , Meyer, Christian F. , Pappo, Alberto S. , Petersen, Ivy A. , Poppe, Matthew M. , Riedel, Richard F. , Schuetze, Scott M. , Shabason, Jacob E. , Zimel, Melissa N. , Hang, Lisa E., Sundar, Hema, Bergman, Mary Anne, Riedel, Richard F , von Mehren, Margaret , Bui, Marilyn M. , Choy, Edwin , Connelly, Mary, Dry, Sarah , González, Ricardo , Liebner, David A. , Parkes, Amanda , Pollack, Seth M. , Sicklick, Jason Keith , Spraker, Matthew B.

Journal of the National Comprehensive Cancer Network | July 13, 2022 | Volume: 20 | Issue: 7 | Pages: 815-833

10.6004/jnccn.2022.0035 Get It

Soft tissue sarcomas (STS) are rare malignancies of mesenchymal cell origin that display a heterogenous mix of clinical and pathologic characteristics. STS can develop from fat, muscle, nerves, blood vessels, and other connective tissues. The evaluation and treatment of patients with STS requires a multidisciplinary team with demonstrated expertise in the management of these tumors. The complete NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Soft Tissue Sarcoma provide recommendations for the diagnosis, evaluation, and treatment of extremity/superficial trunk/head and neck STS, as well as retroperitoneal/intra-abdominal STS, desmoid tumors, and rhabdomyosarcoma. This portion of the NCCN Guidelines discusses general principles for the diagnosis and treatment of retroperitoneal/intra-abdominal STS, outlines treatment recommendations, and reviews the evidence to support the guidelines recommendations.
Selinexor in Advanced, Metastatic Dedifferentiated Liposarcoma: A Multinational, Randomized, Double-Blind, Placebo-Controlled Trial
Gounder, Mrinal M. , Razak, Albiruni Abdul , Somaiah, Neeta , Chawla, Sant P. , Martín‐Broto, Javier , Schuetze, Scott M. , Vincenzi, Bruno , Wagner, Andrew J. , Chmielowski, Bartosz , Jones, Robin L. , Riedel, Richard F. , Stacchiotti, Silvia , Ganjoo, Kristen N. , Cesne, Axel Le , Italiano, Antoîne , Ryan, Christopher W. , Mulcahy, Mary F. , Forscher, Charles, Okuno, Scott H. , Hartner, Lee , Philip, Tony , Alcindor, Thierry , Reichardt, Peter , Chevreau, Christine , Morales, Claudia Maria Valverde, Chen, James L. , Deshpande, Hari A. , Nicholas, Garth , Gröschel, Stefan , Hatcher, Helen, Duffaud, Florence , Beveridge, Roberto Díaz, Meyer, Christian F. , Götze, Katharina S. , Mazzeo, F , Yakobson, Alexander, Zick, Aviad , Lee, Alexander T.J. , Estival, Anna , Napolitano, Andrea , Dickson, Mark A. , Michel, Dayana , Meng, Changting , Ben‐Shahar, Osnat , Chang, Hua, Landesman, Yosef , Shah, Jatin J., Shacham, Sharon, Kauffman, Michael , Attia, Steven , Schuetze, Scott M , Vincenzi, Bruno , Wagner, Andrew J , Chmielowski, Bartosz , Jones, Robin L , Riedel, Richard F , Loggers, Elizabeth T , Le Cesne, Axel , Italiano, Antoine , Garcia Del Muro, Xavier , Mulcahy, Mary F , Penel, Nicolas , Okuno, Scott , Elias, Anthony D , Hartner, Lee , Philip, Tony , Alcindor, Thierry , Lapeire, Lore , Blay, Jean-Yves , Chen, James L , Davis, Elizabeth J , Hatcher, Helen , Meyer, Christian , von Mehren, Margaret , Van Tine, Brian A , Götze, Katharina , Mazzeo, Filomena , Zick, Aviad , Lee, Alexander , Gonzalez, Anna Estival , Napolitano, Andrea , Michel, Dayana , Meng, Changting , Ben-Shahar, Osnat , Van Domelen, Dane R , Grignani, Giovanni , Burgess, Melissa , Piperno‐Neumann, Sophie , Elias, Anthony , Kasper, Bernd , Blay, Jean‐Yves , Schwartz, Gary K. , Davis, Elizabeth J. , Casado, Antonio , Badalamenti, Giuseppe , Eriksson, Mikael , Mehren, Margaret von , Tine, Brian A. Van , Li, Lingling , Liu, Jianjun , Walker, Christopher James

Journal of Clinical Oncology | April 8, 2022 | Volume: 40 | Issue: 22 | Pages: 2479-2490

10.1200/jco.21.01829 Get It

PURPOSE Antitumor activity in preclinical models and a phase I study of patients with dedifferentiated liposarcoma (DD-LPS) was observed with selinexor. We evaluated the clinical benefit of selinexor in patients with previously treated DD-LPS whose sarcoma progressed on approved agents. METHODS SEAL was a phase II-III, multicenter, randomized, double-blind, placebo-controlled study. Patients age 12 years or older with advanced DD-LPS who had received two-five lines of therapy were randomly assigned (2:1) to selinexor (60 mg) or placebo twice weekly in 6-week cycles (crossover permitted). The primary end point was progression-free survival (PFS). Patients who received at least one dose of study treatment were included for safety analysis (ClinicalTrials.gov identifier: NCT02606461 ). RESULTS Two hundred eighty-five patients were enrolled (selinexor, n = 188; placebo, n = 97). PFS was significantly longer with selinexor versus placebo: hazard ratio (HR) 0.70 (95% CI, 0.52 to 0.95; one-sided P = .011; medians 2.8 v 2.1 months), as was time to next treatment: HR 0.50 (95% CI, 0.37 to 0.66; one-sided P < .0001; medians 5.8 v 3.2 months). With crossover, no difference was observed in overall survival. The most common treatment-emergent adverse events of any grade versus grade 3 or 4 with selinexor were nausea (151 [80.7%] v 11 [5.9]), decreased appetite (113 [60.4%] v 14 [7.5%]), and fatigue (96 [51.3%] v 12 [6.4%]). Four (2.1%) and three (3.1%) patients died in the selinexor and placebo arms, respectively. Exploratory RNA sequencing analysis identified that the absence of CALB1 expression was associated with longer PFS with selinexor compared with placebo (median 6.9 v 2.2 months; HR, 0.19; P = .001). CONCLUSION Patients with advanced, refractory DD-LPS showed improved PFS and time to next treatment with selinexor compared with placebo. Supportive care and dose reductions mitigated side effects of selinexor. Prospective validation of CALB1 expression as a predictive biomarker for selinexor in DD-LPS is warranted.
Clinical Activity of Ripretinib in Patients with Advanced Gastrointestinal Stromal Tumor Harboring Heterogeneous KIT/PDGFRA Mutations in the Phase III INVICTUS Study
Bauer, Sebastian , Heinrich, Michael C. , Zalcberg, John , Serrano, César , Gelderblom, Hans , Jones, Robin L. , Attia, Steven , D’Amato, Gina Z. , Reichardt, Peter , Meade, Julie, Su, Ying , Ruiz‐Soto, Rodrigo , Schöffski, Patrick , Zalcberg, John , Serrano, César , Gelderblom, Hans , Jones, Robin L , Su, Ying , Blay, Jean-Yves , von Mehren, Margaret , Schöffski, Patrick , Heinrich, Michael C , Bauer, Sebastian , George, Suzanne , Chi, Ping , Blay, Jean‐Yves , Mehren, Margaret von

Clinical Cancer Research | September 9, 2021 | Volume: 27 | Issue: 23 | Pages: 6333-6342

10.1158/1078-0432.ccr-21-1864 Get It

Abstract Purpose: Most patients with gastrointestinal stromal tumor (GIST) have activating mutations in KIT/PDGFRA and are initially responsive to tyrosine kinase inhibitors (TKI). The acquisition of secondary mutations leads to refractory/relapsed disease. This study reports the results of an analysis from the phase III INVICTUS study (NCT03353753) characterizing the genomic heterogeneity of tumors from patients with advanced GIST and evaluating ripretinib efficacy across KIT/PDGFRA mutation subgroups. Patients and Methods: Tumor tissue and liquid biopsy samples that captured circulating tumor DNA were collected prior to study enrollment and sequenced using next-generation sequencing. Subgroups were determined by KIT/PDGFRA mutations and correlation of clinical outcomes and KIT/PDGFRA mutational status was assessed. Results: Overall, 129 patients enrolled (ripretinib 150 mg once daily, n = 85; placebo, n = 44). The most common primary mutation subgroup detected by combined tissue and liquid biopsies were in KIT exon 11 (ripretinib, 61.2%; placebo, 77.3%) and KIT exon 9 (ripretinib, 18.8%; placebo, 15.9%). Patients receiving ripretinib demonstrated progression-free survival (PFS) benefit versus placebo regardless of mutation status (HR 0.16) and in all assessed subgroups in Kaplan–Meier PFS analysis (exon 11, P &lt; 0.0001; exon 9, P = 0.0023; exon 13, P &lt; 0.0001; exon 17, P &lt; 0.0001). Among patients with wild-type KIT/PDGFRA by tumor tissue, PFS ranged from 2 to 23 months for ripretinib versus 0.9 to 10.1 months for placebo. Conclusions: Ripretinib provided clinically meaningful activity across mutation subgroups in patients with advanced GIST, demonstrating that ripretinib inhibits a broad range of KIT/PDGFRA mutations in patients with advanced GIST who were previously treated with three or more TKIs.
Phase II Randomized Study of CMB305 and Atezolizumab Compared With Atezolizumab Alone in Soft-Tissue Sarcomas Expressing NY-ESO-1
Chawla, Sant P., Tine, Brian A. Van , Pollack, Seth M., Ganjoo, Kristen N., Elias, Anthony , Riedel, Richard F. , Attia, Steven, Choy, Edwin , Okuno, Scott H., Agulnik, Mark , Livingston, Michael B., Keedy, Vicki L. , Philip, Tony , Bohac, G. Chet, Yurasov, Sergey , Yakovich, Adam, Lu, Hailing , Chen, Michael, Maki, Robert G. , Van Tine, Brian A , Elias, Anthony D , von Mehren, Margaret , Keedy, Vicki L , Verschraegen, Claire F , Philip, Tony , Yurasov, Sergey , Lu, Hailing , Maki, Robert G , Choy, Edwin , Riedel, Richard F , Chawla, Sant P., Pollack, Seth M., Ganjoo, Kristen N., Attia, Steven, Okuno, Scott H., Agulnik, Mark , Livingston, Michael B., Bohac, G. Chet, Yakovich, Adam, Chen, Michael

Journal of Clinical Oncology | July 14, 2021 | Volume: 40 | Issue: 12 | Pages: 1291-1300

10.1200/jco.20.03452 Get It

PURPOSE CMB305 is a heterologous prime-boost vaccination regimen created to prime NY-ESO-1–specific CD8 T-cell populations and then activate the immune response with a potent TLR-4 agonist. This open-label randomized phase II trial was designed to investigate the efficacy and safety of adding the CMB305 regimen to atezolizumab (anti–programmed death ligand-1 therapy) in comparison with atezolizumab alone in patients with synovial sarcoma or myxoid liposarcoma. PATIENTS AND METHODS Patients with locally advanced, relapsed, or metastatic synovial sarcoma or myxoid liposarcoma (any grade) were randomly assigned to receive CMB305 with atezolizumab (experimental arm) or atezolizumab alone (control arm). The primary end points were progression-free survival (PFS) and overall survival (OS) analyzed using the Kaplan-Meier method. Safety and immune responses were assessed. RESULTS A total of 89 patients were enrolled; 55.1% had received ≥ 2 prior lines of chemotherapy. Median PFS was 2.6 months and 1.6 months in the combination and control arms, respectively (hazard ratio, 0.9; 95% CI, 0.6 to 1.3). Median OS was 18 months in both treatment arms. Patients treated with combination therapy had a significantly higher rate of treatment-induced NY-ESO-1–specific T cells ( P = .01) and NY-ESO-1–specific antibody responses ( P < .0001). In a post hoc analysis of all dosed patients, OS was longer (36 months) in the subset who developed anti-NY-ESO-1 T-cell immune response (hazard ratio, 0.3; P = .02). CONCLUSION Although the combination of CMB305 and atezolizumab did not result in significant increases in PFS or OS compared with atezolizumab alone, some patients demonstrated evidence of an anti-NY-ESO-1 immune response and appeared to fare better by imaging than those without such an immune response. Combining prime-boost vaccines such as CMB305 with anti–programmed death ligand-1 therapies merits further evaluation in other clinical contexts.