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Gilbert, Mark R.

https://orcid.org/0000-0003-2556-9722

Mayo Clinic

National Institutes of Health

Citations 44

Treatment Effect Reanalysis of the Randomized Individual Screening Trial of Innovative Glioblastoma Therapy in Newly Diagnosed Glioblastoma With External Control Data
Gupta, Tulika Rudra, Polley, Mei‐Yin C. , Redd, Robert , Lee, Eudocia Q., Arrillaga‐Romany, Isabel , Tan, Yujue, Welch, Mary R., Galanis, E, Ahluwalia, Manmeet S., Colman, Howard , Nabors, L. Burt, Hepel, Jaroslaw, Elinzano, Heinrich, Chukwueke, Ugonma N., Beroukhim, Rameen, Nayak, L., McFaline-Figueroa, J. Ricardo, Batchelor, Tracy T. , Lu‐Emerson, Christine , Bi, W. L., Arnaout, Omar, Peruzzi, Pier Paolo, Haas-Kogan, Daphne, Aizer, Ayal , Doherty, Lisa, Chiocca, E Antonio, Reardon, David A. , Wen, Patrick Y. , Trippa, Lorenzo , Rahman, Rifaquat, Gilbert, Mark R. , Redd, Robert , Lee, Eudocia Q , Gilbert, Mark R , Touat, Mehdi , Welch, Mary R , Ahluwalia, Manmeet S , Colman, Howard , Nabors, Louis Burt , Schiff, David , Nayak, Lakshmi , Batchelor, Tracy T , Kaley, Thomas , Lu-Emerson, Christine , Mellinghoff, Ingo K , Peruzzi, Pier Paolo , Haas-Kogan, Daphne , Tanguturi, Shyam K , Aizer, Ayal , Chiocca, E Antonio , Reardon, David A , Ligon, Keith L , Weller, Michael , Mehta, Minesh P , Wen, Patrick Yung , Rahman, Rifaquat , Lee, Eudocia Q. , Arrillaga‐Romany, Isabel , Drappatz, Jan , Galanis, Evanthia , Ahluwalia, Manmeet S. , Nabors, Burt , Hepel, Jaroslaw T., Elinzano, Heinrich, Chukwueke, Ugonma , Nayak, Lakshmi , McFaline-Figueroa, J Ricardo , Mellinghoff, Ingo K. , Arnaout, Omar M. , Haas‐Kogan, Daphne A. , Doherty, Lisa, Santagata, Sandro , Meredith, David M. , Mehta, Minesh P. , Rahman, Rifaquat

Journal of Clinical Oncology | May 22, 2026 | Volume: 44 | Issue: 21 | Pages: 2048-2058

10.1200/jco-25-01586 Get It

PURPOSE Integrating external control data into clinical trial designs and analyses has the potential to accelerate drug development processes. We reanalyzed the three experimental arms of the Individual Screening Trial of Innovative Glioblastoma Therapy (INSIGhT), a randomized phase II platform trial in newly diagnosed O 6 -methylguanine-DNA methyltransferase-unmethylated glioblastoma (ClinicalTrials.gov identifier: NCT02977780 ). To evaluate the validity of using external data sets, we compared treatment effect estimates based on internal INSIGhT control data and matched external control data. METHODS The three experimental arms of INSIGhT (abemaciclib [n = 72], neratinib [n = 80], and CC-115 [n = 12]) did not improve survival compared with internal controls (standard chemoradiation [n = 70]). We derived external control patient-level data from multiple real-world and clinical trial data sets. We applied propensity score matching and Cox proportional hazards models to estimate treatment effects with external controls. Additionally, using this glioblastoma (GBM) data collection, we specified simulation scenarios to evaluate trial designs that integrate external controls. RESULTS After matching to external controls, no survival benefit was observed for patients receiving abemaciclib (hazard ratio [HR], 1.00 [95% CI, 0.75 to 1.34]), neratinib (HR, 0.93 [95% CI, 0.70 to 1.24]), or CC-115 (HR, 0.88 [95% CI, 0.41 to 1.88]). Simulations, together with the INSIGhT data and a collection of GBM data sets, allowed us to examine efficiencies and risks of clinical trial designs that leverage external control data. CONCLUSION The use of carefully matched external controls, to replace or augment the internal controls of INSIGhT, produced treatment effect estimates that were similar to previously published analyses. Single-arm trial designs and hybrid randomized designs incorporating propensity score–matched external control data evaluated treatment effects in the early-phase testing of experimental therapies in newly diagnosed GBM. The validity of this approach and risks of bias depended on the availability of comprehensive and accurate data on all potential confounders, in the absence of unmeasured confounding.
Glioblastoma in adults: A Society for Neuro-Oncology (SNO) and European Society of Neuro-Oncology (EANO) consensus review on current management and future directions
Wen, Patrick Y. , Lee, Eudocia Q. , Khasraw, Mustafa , Rahman, Rifaquat , Platten, Michael , Lim, Michael , Verhaak, Roel G.W. , Albert, Nathalie L. , Schiff, David , Ostrom, Quinn T. , Aldape, Kenneth , Batchelor, Tracy T. , Chiocca, E. Antonio, DeGroot, John, French, Pim J. , Hegi, Monika E. , Lassman, Andrew B. , Mellinghoff, Ingo K. , Minniti, Giuseppe, Taphoorn, Martin , Weiss, von Deimling, Tobias, Zadeh, Gelareh , Reardon, David A. , Chang, Susan M. , Short, Susan , Weller, Michael , Touat, Mehdi , Khasraw, Mustafa , Platten, Michael , Winkler, Frank , Verhaak, Roel Gw , Albert, Nathalie L , Tonn, Joerg-Christian , Barnholtz-Sloan, Jill S , Cloughesy, Timothy F , French, Pim J , Galanis, Evanthia , Galldiks, Norbert , Mellinghoff, Ingo K , Roth, Patrick , Sanson, Marc , Wick, Wolfgang , Reardon, David A , Short, Susan C , Ostrom, Quinn T , Wen, Patrick Yung , Horbinski, Craig , Huang, Raymond Y. , Ahluwalia, Manmeet S. , Barnholtz‐Sloan, Jill S. , Bindra, Ranjit S. , Cloughesy, Timothy F. , Galanis, Evanthia , Gilbert, Mark R. , Rhun, Émilie Le , Mehta, Minesh P. , Roth, Patrick , Sanson, Marc , Weiss, von Deimling, Tobias, Wick, Wolfgang , Bent, Martin J. van den , Preusser, Matthias

Neuro-Oncology | July 22, 2025 | Volume: 27 | Issue: 11 | Pages: 2751-2788

10.1093/neuonc/noaf177 Get It

Abstract Glioblastoma is the most common type of malignant primary brain tumor and a major cause of morbidity and mortality. In 2021, the World Health Organization updated the classification of Central Nervous System (CNS) tumors to restrict glioblastomas to isocitrate dehydrogenase-wildtype (IDHwt) tumors, improving understanding of the prognosis and optimal therapy for these tumors. This revision also enables more homogeneous populations of patients to be enrolled in clinical trials, facilitating the evaluation of novel therapies. In this updated consensus review from the Society for Neuro-Oncology (SNO) and the European Association of Neuro-Oncology (EANO), the current management of patients with glioblastoma is discussed. In addition, novel therapies such as immunotherapies, viral therapies, targeted molecular therapies, theranostics, and antibody–drug conjugates will be reviewed, as well as the current challenges and future directions for research.
Establishing the content validity of patient-reported outcome measures used in neuro-oncology based on the WHO ICF framework: Part of the RANO-PRO initiative
Asogwa, Ogechukwu A , Walbert, Tobias , Arons, David, Blakeley, Jaishri O. , Coomans, Marijke B , Brown, Paul D. , Bulbeck, Helen , Chang, Susan M. , Coens, Corneel , Grant, Robin, Jalali, Rakesh , Koekkoek, Johan A F , Panda, Pankaj Kumar , Leach, Danielle, Mendoza, Tito R. , Nayak, Lakshmi , Oliver, Kathy , Reijneveld, Jaap C. , Taylor, Jennie , Wen, Patrick Y. , Taphoorn, Martin , Walbert, Tobias , Blakeley, Jaishri O , Bulbeck, Helen , Gilbert, Mark R , Grant, Robin , Jalali, Rakesh , Nayak, Lakshmi , Le Rhun, Emilie , Taylor, Jennie W , Weller, Michael , Mendoza, Tito , Koekkoek, Johan A F , Dirven, Linda , Armstrong, Terri S. , Bent, Martin J. van den , Chang, Susan Marina , Gilbert, Mark R. , Leeper, Heather , Rhun, Émilie Le , Rubinstein, Larry , Wen, Patrick Yung

Neuro-Oncology | April 28, 2025 | Volume: 27 | Issue: 9 | Pages: 2399-2414

10.1093/neuonc/noaf108 Get It

Abstract Background Instruments to assess patient-reported outcomes (PRO) should generate high-quality evidence. Reliable PRO evidence is essential to policymakers, in conjunction with outcomes such as survival and radiological response, to understand the net clinical benefit of antitumor treatments. This study aimed to establish the content validity of 215 identified PRO measures used in patients with brain tumors. Methods A survey (n = 148 items) was developed reflecting aspects of the WHO International Classification of Functioning, Disability, and Health (ICF) framework. Patients with brain tumors, their proxies, and healthcare professionals (HCPs) were asked to rate each survey item on relevance. An item was considered a relevant issue if ≥25% of the patients or proxies or ≥50% of the HCPs considered that item to be an issue. Next, all items in the identified PRO measures were linked to ICF and relevant items in the survey, and the percentage of content coverage was calculated. Results In total, 114 patients, 71 proxies, and 65 HCPs from different countries completed the survey. Fifty-six of 148 (37.8%) items in the survey were considered relevant. The most important aspects mentioned by both patients and proxies were difficulty concentrating, difficulty remembering, multitasking, and handling stress. Depending on the definition, between 35% and 49% of PRO measures were considered to have sufficient content validity (≥80% coverage). Conclusion The content validity was insufficient in more than half of the identified PRO measures, particularly multidimensional measures. Future research should investigate whether different approaches to PRO assessment better meet the needs of all stakeholders.
cIMPACT-NOW update 8: Clarifications on molecular risk parameters and recommendations for WHO grading of meningiomas
Sahm, Felix , Aldape, Kenneth , Brastianos, Priscilla K. , Dahiya, Sonika , Giannini, Caterina , Louis, David N. , Raleigh, David R. , Reifenberger, Guido, Sarkar, Chitra, Zadeh, Gelareh , Dahiya, Sonika , von Deimling, Andreas , Giannini, Caterina , Zadeh, Gelareh , Sahm, Felix , Brat, Daniel J. , Deimling, Andreas von , Gilbert, Mark R. , Santagata, Sandro , Wesseling, Pieter , Perry, Arie

Neuro-Oncology | August 30, 2024 | Volume: 27 | Issue: 2 | Pages: 319-330

10.1093/neuonc/noae170 Get It

Abstract Meningiomas are the most frequent primary intracranial tumors. Hence, they constitute a major share of diagnostic specimens in neuropathology practice. The 2021 WHO Classification of Central Nervous System Tumors (“CNS5”) has introduced the first molecular grading parameters for meningioma with oncogenic variants in the TERT promoter and homozygous deletion of CDKN2A/B as markers for CNS WHO grade 3. However, after the publication of the new classification volume, clarifications were requested, not only on novel but also on long-standing questions in meningioma grading that were beyond the scope of the WHO “blue book.” In addition, more recent research into possible new molecular grading parameters could not yet be implemented in the 2021 classification but constitutes a compelling body of literature. Hence, the consortium to inform molecular and practical approaches to CNS tumor taxonomy-not official WHO (cIMPACT-NOW) Steering Committee convened a working group to provide such clarification and assess the evidence of possible novel molecular criteria. As a result, this cIMPACT-NOW update provides guidance for more standardized morphological evaluation and interpretation, most prominently pertaining to brain invasion, identifies scenarios in which advanced molecular testing is recommended, proposes to assign CNS WHO grade 2 for cases with CNS WHO grade 1 morphology but chromosomal arm 1p deletion in combination with 22q deletion and/or NF2 oncogenic variants, and discusses areas in which the current evidence is not yet sufficient to result in new recommendations.
RANO 2.0: Update to the Response Assessment in Neuro-Oncology Criteria for High- and Low-Grade Gliomas in Adults
Wen, Patrick Y. , Bent, Martin J. van den , Youssef, Gilbert , Cloughesy, Timothy F. , Ellingson, Benjamin M. , Barboriak, Daniel P. , Groot, John de , Huang, Raymond Y. , Lassman, Andrew B. , Molinaro, Annette M. , Rahman, Rifaquat , Shankar, Lalitha , Macdonald, David R., Reardon, David A. , Vogelbaum, Michael A. , Chang, Susan M. , van den Bent, Martin J , Weller, Michael , Barboriak, Daniel P , de Groot, John , Huang, Raymond , Lassman, Andrew B , Mehta, Minesh P , Molinaro, Annette M. , Preusser, Matthias , Rahman, Rifaquat , Stupp, Roger , Villanueva-Meyer, Javier E. , Wick, Wolfgang , Reardon, David A , Vogelbaum, Michael A , Ellingson, Benjamin M , Cloughesy, Timothy F , Wen, Patrick Yung , Galanis, Evanthia , Gilbert, Mark R. , Mehta, Minesh P. , Preusser, Matthias , Stupp, Roger , Wick, Wolfgang

Journal of Clinical Oncology | September 29, 2023 | Volume: 41 | Issue: 33 | Pages: 5187-5199

10.1200/jco.23.01059 Get It

PURPOSE The Response Assessment in Neuro-Oncology (RANO) criteria for high-grade gliomas (RANO-HGG) and low-grade gliomas (RANO-LGG) were developed to improve reliability of response assessment in glioma trials. Over time, some limitations of these criteria were identified, and challenges emerged regarding integrating features of the modified RANO (mRANO) or the immunotherapy RANO (iRANO) criteria. METHODS Informed by data from studies evaluating the different criteria, updates to the RANO criteria are proposed (RANO 2.0). RESULTS We recommend a standard set of criteria for both high- and low-grade gliomas, to be used for all trials regardless of the treatment modalities being evaluated. In the newly diagnosed setting, the postradiotherapy magnetic resonance imaging (MRI), rather than the postsurgical MRI, will be used as the baseline for comparison with subsequent scans. Since the incidence of pseudoprogression is high in the 12 weeks after radiotherapy, continuation of treatment and confirmation of progression during this period with a repeat MRI, or histopathologic evidence of unequivocal recurrent tumor, are required to define tumor progression. However, confirmation scans are not mandatory after this period nor for the evaluation of treatment for recurrent tumors. For treatments with a high likelihood of pseudoprogression, mandatory confirmation of progression with a repeat MRI is highly recommended. The primary measurement remains the maximum cross-sectional area of tumor (two-dimensional) but volumetric measurements are an option. For IDH wild-type glioblastoma, the nonenhancing disease will no longer be evaluated except when assessing response to antiangiogenic agents. In IDH-mutated tumors with a significant nonenhancing component, clinical trials may require evaluating both the enhancing and nonenhancing tumor components for response assessment. CONCLUSION The revised RANO 2.0 criteria refine response assessment in gliomas.
OS09.4.A RANO 2.0: UPDATE TO THE RESPONSE ASSESSMENT IN NEURO-ONCOLOGY (RANO) CRITERIA FOR HIGH- AND LOW-GRADE GLIOMAS IN ADULTS
Wen, Patrick Y. , Youssef, George , Barboriak, Daniel P. , DeGroot, John, Lassman, Andrew B. , Molinaro, Annette M. , Rahman, Rifaquat , Shankar, Lalitha , Sul, Joohee, Villanueva‐Meyer, Javier , Macdonald, David , Reardon, David A. , Vogelbaum, Michael A. , Chang, Susan M. , Barboriak, Daniel P , Wen, Patrick Yung , Bent, Martin J. van den , Youssef, G, Cloughesy, Timothy F. , Ellingson, Benjamin M. , Weller, Michael , Galanis, Evanthia , Gilbert, Mark R. , Huang, Raymond Y. , Mehta, Minesh P. , Molinaro, Annette M. , Preusser, Matthias , Stupp, Roger , Villanueva-Meyer, Javier E. , Wick, Wolfgang

Neuro-Oncology | September 8, 2023 | Volume: 25 | Issue: Supplement_2 | Pages: ii21-ii21

10.1093/neuonc/noad137.061 Get It

Abstract BACKGROUND The Response Assessment in Neuro-Oncology (RANO) criteria for high-grade gliomas (RANO-HGG) and low-grade gliomas (RANO-LGG) were developed to improve reliability of response assessment in glioma trials. Over time some limitations of these criteria were identified, and uncertainty emerged regarding integrating features of the modified RANO (mRANO) or the immunotherapy RANO (iRANO) criteria. MATERIAL AND METHODS Informed by data from a cohort of glioblastoma patients and other evaluations of RANO criteria that allowed evaluation of features of the different criteria, the RANO working group developed updates to the RANO criteria (RANO 2.0). RESULTS Based on the 2021 WHO classification of gliomas, we recommend a standard set of criteria for both high and low-grade gliomas, to be used for all trials regardless of the treatment modalities being evaluated. In the newly diagnosed setting, the post-radiotherapy MRI, rather than the post-surgical MRI, will be used as the baseline for future comparison. Since the incidence of pseudoprogression is high in the 12 weeks following radiotherapy, continuation of treatment and confirmation of progression during this period with a repeat MRI, or histopathologic evidence of unequivocal recurrent tumor, is required to define tumor progression. However, confirmation scans are not mandatory after this period nor for recurrent tumors. For treatments with a high likelihood of pseudoprogression, mandatory confirmation of progression with a repeat MRI is highly recommended. The primary measurement remains the maximum cross-sectional area of tumor (2-dimensional) but volumetric measurements are an option. For IDH-wildtype glioblastoma, the non-enhancing disease will no longer be evaluated. In IDH-mutated tumors with a significant non-enhancing component, clinical trials may require evaluating both the enhancing and non-enhancing tumor components for response assessment. CONCLUSION These criteria represent a work in progress that will hopefully improve the assessment of response in glioma trials. Future updates will incorporate novel developments, advanced imaging techniques, and endpoints as they become validated.
CLRM-07 RANO 2.0: PROPOSAL FOR AN UPDATE TO THE RESPONSE ASSESSMENT IN NEURO-ONCOLOGY (RANO) CRITERIA FOR HIGH- AND LOW-GRADE GLIOMAS IN ADULTS
Wen, Patrick Y. , Barboriak, Danial, DeGroot, John, Lassman, Andrew B. , Molinaro, Annette M. , Preusser, Mattias, Rahman, Rifaquat , Shankar, Lalitha , Sul, Joohee, Villanueva‐Meyer, Javier , Macdonald, David , Reardon, David A. , Vogelbaum, Michael A. , Chang, Susan M. , Wen, Patrick Yung , Bent, Martin J. van den , Youssef, Gilbert , Cloughesy, Timothy F. , Ellingson, Benjamin M. , Weller, Michael , Galanis, Evanthia , Gilbert, Mark R. , Huang, Raymond Y. , Mehta, Minesh P. , Molinaro, Annette M. , Stupp, Roger , Villanueva-Meyer, Javier E. , Wick, Wolfgang

Neuro-Oncology Advances | August 4, 2023 | Volume: 5 | Issue: Supplement_3 | Pages: iii8-iii8

10.1093/noajnl/vdad070.029 Get It

Abstract The Response Assessment in Neuro-Oncology (RANO) criteria for high-grade gliomas (RANO-HGG) and low-grade gliomas (RANO-LGG) were developed to improve the reliability of response assessment in glioma trials. Over time some limitations of these criteria were identified, and uncertainty emerged regarding integrating features of the modified RANO (mRANO) or the immunotherapy RANO (iRANO) criteria. Informed by data from a cohort of glioblastoma patients and other evaluations of RANO criteria that allowed evaluation of features of the different criteria, we propose updates to the RANO criteria (RANO 2.0). Based on the 2021 WHO classification of gliomas, we recommend a standard set of criteria for both high and low-grade gliomas, to be used for all trials regardless of the treatment modalities being evaluated. In the newly diagnosed setting, the post-radiotherapy MRI, rather than the post-surgical MRI, will be used as the baseline for future comparison. Since the incidence of pseudoprogression is high in the 12 weeks following radiotherapy, continuation of treatment and confirmation of progression during this period with a repeat MRI, or histopathologic evidence of unequivocal recurrent tumor, is required to define tumor progression. However, confirmation scans are not mandatory after this period nor for recurrent tumors. For treatments with a high likelihood of pseudoprogression, mandatory confirmation of progression with a repeat MRI is an option. The primary measurement remains the maximum cross-sectional area of tumor (2-dimensional) but volumetric measurements are an option. For IDH-wildtype glioblastoma, the non-enhancing disease will no longer be evaluated. In IDH-mutated tumors with a significant non-enhancing component, clinical trials may require evaluating both the enhancing and non-enhancing tumor components for response assessment.
RANO 2.0: Proposal for an update to the Response Assessment in Neuro-Oncology (RANO) criteria for high- and low-grade gliomas in adults.
Wen, Patrick Y. , Groot, John Frederick De, Lassman, Andrew B. , Molinaro, Annette M. , Shankar, Lalitha , Reardon, David A. , Vogelbaum, Michael A. , Chang, Susan M. , Wen, Patrick Yung , Bent, Martin J. van den , Youssef, Gilbert , Cloughesy, Timothy F. , Ellingson, Benjamin M. , Weller, Michael , Galanis, Evanthia , Barboriak, Daniel P. , Gilbert, Mark R. , Huang, Raymond Y. , Mehta, Minesh P. , Molinaro, Annette M. , Preusser, Matthias , Wick, Wolfgang

Journal of Clinical Oncology | June 4, 2023 | Volume: 41 | Issue: 16_suppl | Pages: 2017-2017

10.1200/jco.2023.41.16_suppl.2017 Get It

2017 Background: Response Assessment in Neuro-Oncology (RANO) criteria for high-grade and low-grade glioma (HGG and LGG) were developed to improve reliability of response assessment in glioma trials. Several limitations of the original RANO criteria have been reported. Methods: To address limitations of the original RANO criteria, a large cohort of patients with newly diagnosed and recurrent glioblastoma were evaluated comparing RANO-HGG with modified RANO (mRANO) and immunotherapy RANO (iRANO) criteria to inform the following proposed updates (RANO 2.0). Results: Based on the 2021 WHO classification of glioma, we recommend a single common set of criteria for all gliomas regardless of WHO grade and IDH mutational status. These criteria will be used for all trials regardless of the treatment modalities being evaluated. In newly diagnosed glioblastoma, the post-radiotherapy MRI, usually obtained approximately 4 weeks after completion of radiotherapy, rather than the post-surgical MRI as proposed in original RANO criteria, will be used as the baseline for comparison of subsequent scans. Since the incidence of pseudoprogression is high in the first 3 months following radiotherapy, confirmation of progression during this period with a repeat MRI (in 4-8 weeks) will be required for determining radiographic progression of disease (PD) if the patient is clinically stable. However, confirmation scans are not mandatory after this period nor for recurrent tumors since these scans do not appear to improve reliability in determining progression. For agents with a high likelihood of producing pseudoprogression such as viral therapies and some other immunotherapies, mandatory confirmation of progression with a repeat MRI is an option. The primary measurement will remain the 2-dimensional maximum cross-sectional area of tumor as the simplest method, but where resources are available, volumetric measurements are an option. For IDH wild-type tumors with contrast enhancement, non-enhancing tumor will no longer be evaluated with the possible exception of patients receiving antiangiogenic therapies. However, in tumors with a significant non-enhancing component, both the contrast enhancing and non-enhancing components will be evaluated as target lesions. Conclusions: We hope that these and other proposed changes by the RANO working group will improve response assessment in glioma clinical trials and help the development of more effective therapy for patients.
Objective response rate targets for recurrent glioblastoma clinical trials based on the historic association between objective response rate and median overall survival
Ellingson, Benjamin M. , Wen, Patrick Y. , Chang, Susan M. , Bent, Martin J. van den , Vogelbaum, Michael A. , Li, Shanpeng , Wick, Wolfgang , Lassman, Andrew B. , Galanis, Evanthia , Wick, Wolfgang , Lassman, Andrew B , Weller, Michael , Galanis, Evanthia , van den Bent, Martin J , Ellingson, Benjamin M , Wen, Patrick Yung , Li, Gang , Kim, Jiyoon , Youssef, Gilbert , Gilbert, Mark R. , Groot, John de , Cloughesy, Timothy F.

Neuro-Oncology | January 5, 2023 | Volume: 25 | Issue: 6 | Pages: 1017-1028

10.1093/neuonc/noad002 Get It

Abstract Durable objective response rate (ORR) remains a meaningful endpoint in recurrent cancer; however, the target ORR for single-arm recurrent glioblastoma trials has not been based on historic information or tied to patient outcomes. The current study reviewed 68 treatment arms comprising 4793 patients in past trials in recurrent glioblastoma in order to judiciously define target ORRs for use in recurrent glioblastoma trials. ORR was estimated at 6.1% [95% CI 4.23; 8.76%] for cytotoxic chemothera + pies (ORR = 7.59% for lomustine, 7.57% for temozolomide, 0.64% for irinotecan, and 5.32% for other agents), 3.37% for biologic agents, 7.97% for (select) immunotherapies, and 26.8% for anti-angiogenic agents. ORRs were significantly correlated with median overall survival (mOS) across chemotherapy (R2= 0.4078, P < .0001), biologics (R2= 0.4003, P = .0003), and immunotherapy trials (R2= 0.8994, P < .0001), but not anti-angiogenic agents (R2= 0, P = .8937). Pooling data from chemotherapy, biologics, and immunotherapy trials, a meta-analysis indicated a strong correlation between ORR and mOS (R2= 0.3900, P < .0001; mOS [weeks] = 1.4xORR + 24.8). Assuming an ineffective cytotoxic (control) therapy has ORR = 7.6%, the average ORR for lomustine and temozolomide trials, a sample size of ≥40 patients with target ORR>25% is needed to demonstrate statistical significance compared to control with a high level of confidence (P < .01) and adequate power (>80%). Given this historic data and potential biases in patient selection, we recommend that well-controlled, single-arm phase II studies in recurrent glioblastoma should have a target ORR >25% (which translates to a median OS of approximately 15 months) and a sample size of ≥40 patients, in order to convincingly demonstrate antitumor activity. Crucially, this response needs to have sufficient durability, which was not addressed in the current study.