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Anderson, S. Keith

https://orcid.org/0000-0003-1542-9726

Mayo Clinic

Mayo Clinic

Citations 52

Final report on North Central Cancer Treatment Group N0877 (alliance): A phase II randomized, placebo-controlled trial of chemoradiotherapy with or without dasatinib for glioblastoma
Breen, William G. , Anderson, S. Keith , Brown, Paul D. , Yan, Elizabeth , Kizilbash, Sani H. , Anderson, Daniel M. , Tran, David , Mazurczak, Miroslaw, Geoffroy, Francois J., Leinweber, Clinton, Dixon, Jesse G. , Anderson, S Keith , Yan, Elizabeth S, Kizilbash, Sani, Galanis, Eva, Kizilbash, Sani H , Sarkaria, Jann N. , Galanis, Evanthia , Tran, David D. , Johnson, Derek R. , Laack, Nadia N.

Neuro-Oncology | June 27, 2025 | Volume: 27 | Issue: 10 | Pages: 2661-2670

10.1093/neuonc/noaf156 Get It

Abstract Background Dasatinib is an oral inhibitor of the Src kinase family, with preclinical data indicating impact on gliomagenesis, tumor invasion, and radiosensitivity. Methods North Central Cancer Treatment Group N0877 is a phase 1 dose escalation and phase II randomized study evaluating the maximum tolerated dose (MTD), safety, and efficacy of dasatinib with radiation and temozolomide (TMZ) for glioblastoma. Following identification of the MTD, adult patients with a histologic diagnosis of glioblastoma were randomized 2:1 between dasatinib given with standard concurrent and adjuvant TMZ, versus placebo with standard concurrent and adjuvant TMZ. Radiation dose was 60 Gy in 30 fractions. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), toxicity, and quality of life. Results Thirteen patients were enrolled in the phase I component and established the MTD and phase II dose of 150 mg given daily. A total of 204 patients were enrolled in the phase II component. OS was not different between arms (median OS 15.6 months for dasatinib compared to 19.3 months for placebo, hazard ratio:1.21 favoring placebo, 95% CI: 0.88–1.65, log-rank P-value: .238). Similarly, PFS was not significantly different between the dasatinib and placebo arms. There was a significant increase in anemia, nausea, and creatinine elevation with dasatinib, but significantly more grade 3 lymphopenia with placebo. Conclusions The addition of dasatinib to standard chemoradiation did not improve outcomes for patients with glioblastoma. Clinical Trial Identifier NCT00869401.
Efficacy of Adding Veliparib to Temozolomide for Patients With MGMT -Methylated Glioblastoma
Kizilbash, Sani H. , Friday, Bret B., Butowski, Nicholas , Mohile, Nimish, Battiste, James , Campian, Jian , Mashru, Sandeep H., Jaeckle, Kurt A. , O’Brien, Barbara , Kabat, Brian, Laack, Nadia L., Hu, Leland , Kumthekar, Priya , Anderson, S. Keith , Dixon, Jesse G. , Kabat, Brian F, Kaufmann, Timothy, Kizilbash, Sani H , Sarkaria, Jann N. , Ballman, Karla V. , Sulman, Erik P. , Giannini, Caterina , Piccioni, David Eric , Drappatz, Jan , Kaufmann, Timothy J. , Ellingson, Benjamin M. , Galanis, Evanthia

JAMA Oncology | October 31, 2024 | Volume: 10 | Issue: 12 | Pages: 1637

10.1001/jamaoncol.2024.4361 Get It

Importance The prognosis for patients with glioblastoma is poor following standard therapy with surgical resection, radiation, temozolomide, and tumor-treating fields. Objectives To evaluate the combination of veliparib and temozolomide in glioblastoma based on preclinical data demonstrating significant chemosensitizing effects of the polyadenosine diphosphate-ribose polymerase 1/2 inhibitor veliparib when combined with temozolomide. Design, Setting, and Participants Patients with newly diagnosed glioblastoma with MGMT promoter hypermethylation who had completed concomitant radiation and temozolomide were enrolled between December 15, 2014, and December 15, 2018, in this Alliance for Clinical Trials in Oncology trial. The data for this analysis were locked on April 21, 2023. Interventions Patients were randomized and treated with standard adjuvant temozolomide (150-200 mg/m 2 orally, days 1-5) combined with either placebo or veliparib (40 mg orally, twice daily, days 1-7) for 6 cycles. Main Outcomes and Measures The primary end point for the phase 3 portion of the trial was overall survival (OS). Results There were 322 patients randomized during the phase 2 accrual period and an additional 125 patients randomized to complete the phase 3 accrual, for a total of 447 patients in the final phase 3 analysis. The median (range) age for patients was 60 (20-85) years and 190 patients (42.5%) were female. The median OS was 24.8 months (90% CI, 22.6-27.7) for the placebo arm and 28.1 months (90% CI, 24.3-33.3) for the veliparib arm ( P = .17). The difference in survival did not meet the prespecified efficacy end point. However, there was a separation of the survival curves that favored the veliparib arm over 24 to 48 months of follow-up. The experimental combination was well tolerated with an acceptable elevation in grade 3 or 4 hematologic toxic effects. Conclusions and Relevance This trial found that adding veliparib to adjuvant temozolomide did not significantly extend OS in patients with newly diagnosed, MGMT -hypermethylated glioblastoma. Trial Registration ClinicalTrials.gov Identifier: NCT02152982
CODEL (Alliance-N0577; EORTC-26081/22086; NRG-1071; NCIC-CEC-2): Phase III Randomized Study of RT vs. RT+TMZ vs. TMZ for Newly Diagnosed 1p/19q-Codeleted Anaplastic Oligodendroglial Tumors. Analysis of Patients Treated on the Original Protocol Design (PL02
Jaeckle, Kurt A. , Vogelbaum, Michael A. , Anderson, S. Keith , Aldape, Kenneth , Cerhan, Jane H. , Nordstrom, Donald G., Jenkins, Robert B. , Raizer, Jeffrey J. , Flynn, Patrick , Dhermain, F., Cairncross, J. G., Brown, Paul D. , Ballman, Karla V. , Giannini, Caterina , Wefel, Jeffrey S. , Klein, Martin , Bent, Martin J. van den , Wick, Wolfgang , Flynn, Patrick, Galanis, Evanthia

Neurology | December 7, 2023 | Volume: 86 | Issue: 16_supplement | Pages: No page available

10.1212/wnl.86.16_supplement.pl02.005 Get It

Association of circulating markers with cognitive decline after radiation therapy for brain metastasis
Huntoon, Kristin , Anderson, S. Keith , Twohy, Erin , Dooley, Katharine , Jiang, Wen , An, Yi , Qie, Yaqing, Ross, Owen A. , Cerhan, Jane H. , Whitton, Anthony , Greenspoon, Jeffrey , Ashman, Jonathan B. , Bahary, Jean-Paul , Urbanic, James J., Farace, Elana, Khuntia, Deepak , Laack, Nadia N., Brown, Paul D. , Jiang, Wen , Ross, Owen A , Dooley, Katharine , Ballman, Karla V. , Li, Jing , Roemeling, Christina A. Von , Parney, Ian F. , Hadjipanayis, Costas G. , Roberge, David , Kim, Betty Y.S.

Neuro-Oncology | December 6, 2022 | Volume: 25 | Issue: 6 | Pages: 1123-1131

10.1093/neuonc/noac262 Get It

AbstractBackgroundA recent phase III trial (NCT01372774) comparing use of stereotactic radiosurgery [SRS] versus whole-brain radiation therapy [WBRT] after surgical resection of a single brain metastasis revealed that declines in cognitive function were more common with WBRT than with SRS. A secondary endpoint in that trial, and the primary objective in this secondary analysis, was to identify baseline biomarkers associated with cognitive impairment after either form of radiotherapy for brain metastasis. Here we report our findings on APOE genotype and serum levels of associated proteins and their association with radiation-induced neurocognitive decline.MethodsIn this retrospective analysis of prospectively collected samples from a completed randomized clinical trial, patients provided blood samples every 3 months that were tested by genotyping and enzyme-linked immunosorbent assay, and results were analyzed in association with cognitive impairment.ResultsThe APOE genotype was not associated with neurocognitive impairment at 3 months. However, low serum levels of ApoJ, ApoE, or ApoA protein (all P < .01) and higher amyloid beta (Aβ 1–42) levels (P = .048) at baseline indicated a greater likelihood of neurocognitive decline at 3 months after SRS, whereas lower ApoJ levels were associated with decline after WBRT (P = .014).ConclusionsPatients with these pretreatment serum markers should be counseled about radiation-related neurocognitive decline.
Association of Long-term Outcomes With Stereotactic Radiosurgery vs Whole-Brain Radiotherapy for Resected Brain Metastasis
Klamer, Brett , Brown, Paul D. , Cerhan, Jane H. , Anderson, S. Keith , Carrero, Xiomara W., Whitton, Anthony , Greenspoon, Jeffrey , Ashman, Jonathan B. , Bahary, Jean-Paul , Urbanic, James J., Barker, Fred G., Farace, Elana, Khuntia, Deepak , Buckner, Jan C. , Laack, Nadia N I, Palmer, Joshua D. , Ballman, Karla V. , Parney, Ian F. , Laack, Nadia N. , Hadjipanayis, Costas G. , Giannini, Caterina , Galanis, Evanthia , Roberge, David

JAMA Oncology | October 20, 2022 | Volume: 8 | Issue: 12 | Pages: 1809

10.1001/jamaoncol.2022.5049 Get It

Importance Long-term outcomes of radiotherapy are important in understanding the risks and benefits of therapies for patients with brain metastases. Objective To determine how the use of postoperative whole-brain radiotherapy (WBRT) or stereotactic radiosurgery (SRS) is associated with quality of life (QOL), cognitive function, and intracranial tumor control in long-term survivors with 1 to 4 brain metastases. Design, Setting, and Participants This secondary analysis of a randomized phase 3 clinical trial included 48 institutions in the US and Canada. Adult patients with 1 resected brain metastases but limited to those with 1 to 4 brain metastasis were eligible. Unresected metastases were treated with SRS. Long-term survivors were defined as evaluable patients who lived longer than 1 year from randomization. Patients were recruited between July 2011 and December 2015, and data were first analyzed in February 2017. For the present study, intracranial tumor control, cognitive deterioration, QOL, and cognitive outcomes were measured in evaluable patients who were alive at 12 months from randomization and reanalyzed in June 2017. Interventions Stereotactic radiosurgery or WBRT. Main Outcomes and Measures Intracranial tumor control, toxic effects, cognitive deterioration, and QOL. Results Fifty-four patients (27 SRS arm, 27 WBRT arm; female to male ratio, 65% vs 35%) were included for analysis with a median follow-up of 23.8 months. Cognitive deterioration was less frequent with SRS (37%-60%) compared with WBRT (75%-91%) at all time points. More patients declined by 2 or more standard deviations (SDs) in 1 or more cognitive tests for WBRT compared with SRS at 3, 6, and 9 months (70% vs 22%, 46% vs 19%, and 50% vs 20%, respectively). A 2 SD decline in at least 2 cognitive tests was associated with worse 12-month QOL in emotional well-being, functional well-being, general, additional concerns, and total scores. Overall QOL and functional independence favored SRS alone for categorical change at all time points. Total intracranial control for SRS alone vs WBRT at 12 months was 40.7% vs 81.5% (difference, −40.7; 95% CI, −68.1% to −13.4%), respectively. Data were first analyzed in February 2017. Conclusions and Relevance The use of SRS alone compared with WBRT resulted in less cognitive deterioration among long-term survivors. The association of late cognitive deterioration with WBRT was clinically meaningful. A significant decline in cognition (2 SD) was associated with overall QOL. However, intracranial tumor control was improved with WBRT. This study provides detailed insight into cognitive function over time in this patient population. Trial Registration ClinicalTrials.gov Identifier: NCT01372774 ; ALLIANCE/CCTG: N107C/CEC.3 (Alliance for Clinical Trials in Oncology/Canadian Cancer Trials Group)
Phase I trial of adjuvant mature autologous dendritic cell/allogeneic tumor lysate vaccines in combination with temozolomide in newly diagnosed glioblastoma
Parney, Ian F. , Anderson, S. Keith , Gustafson, Michael P. , Steinmetz, Susan, Peterson, Timothy E., Kroneman, Trynda, Buckner, Jan C. , Solseth, Mary L., Dietz, Allan B. , Kroneman, Trynda N, Raghunathan, Aditya , Buckner, Jan C , Solseth, Mary, Parney, Ian F , Dietz, Allan B , Anderson, S Keith , Steinmetz, Susan, Raghunathan, Aditya , O’Neill, Brian Patrick

Neuro-Oncology Advances | June 24, 2022 | Volume: 4 | Issue: 1 | Pages: No page available

10.1093/noajnl/vdac089 Get It

Abstract Background Glioblastoma (GBM) has poor prognosis despite aggressive treatment. Dendritic cell (DC) vaccines are promising, but widespread clinical use has not been achieved, possibly reflecting manufacturing issues of antigen choice and DC potency. We previously optimized vaccine manufacture utilizing allogeneic human GBM tumor cell lysate and potent, mature autologous DCs. Here, we report a phase I study using this optimized DC vaccine in combination with standard therapy. Methods Following surgical resection and radiation with concurrent temozolomide (TMZ), newly diagnosed adult GBM patients received intradermal DC vaccines plus TMZ. Primary endpoints were safety and feasibility. Immune and treatment responses were recorded. Results Twenty-one patients were enrolled in this study. One progressed between leukapheresis and vaccine manufacture. Twenty patients received treatment per protocol. Vaccine doses (≥15) were generated following a single leukapheresis for each patient. No dose-limiting vaccine toxicities were encountered. One patient had symptomatic, histologically proven pseudoprogression. Median progression-free survival was 9.7 months. Median overall survival was 19 months. Overall survival was 25% at 2 years and 10% at 4 years. One patient remains progression-free 5 years after enrollment. Specific CD8 T-cell responses for the tumor-associated antigen gp100 were seen post-vaccination. Patients entered the trial with a leukocyte deficit compared to healthy donors which partly normalized over the course of therapy. Conclusions This vaccine platform is safe and highly feasible in combination with standard therapy for newly diagnosed patients. Imaging, histological, survival, and immunological data suggest a positive biological response to therapy that warrants further investigation.
Randomized phase II/III trial of veliparib or placebo in combination with adjuvant temozolomide in newly diagnosed glioblastoma (GBM) patients with MGMT promoter hypermethylation (Alliance A071102).
Mashru, Sandeep H., Friday, Bret Edward Buckley, Kabat, Brian, Hu, Leland , Kumthekar, Priya , Anderson, S. Keith , Sarkaria, Jann N. , Ballman, Karla V. , Kizilbash, Sani H. , Sulman, Erik P. , Giannini, Caterina , Piccioni, David Eric , Dixon, Jesse G. , Laack, Nadia N. , Ellingson, Benjamin M. , Galanis, Evanthia

Journal of Clinical Oncology | June 6, 2022 | Volume: 40 | Issue: 16_suppl | Pages: 2001-2001

10.1200/jco.2022.40.16_suppl.2001 Get It

2001 Background: PolyADP-ribose polymerase (PARP) is an important modulator of DNA repair following temozolomide (TMZ) therapy. Pre-clinical testing demonstrated significant survival benefit for the combination of TMZ and PARP inhibitor veliparib in a subset of GBM pt-derived xenografts with MGMT promoter hypermethylation. Methods: After central pathology review and MGMT testing, patients (pts) with newly diagnosed, MGMT promoter hypermethylated GBM who had completed concurrent radiation and TMZ were randomized to adjuvant therapy with TMZ (Days 1-5 q28 days) combined with either placebo or veliparib (Days 1-7 q28 days). Veliparib/placebo+TMZ treatment was continued for up to 6 cycles. Pts accrued on the phase II and III portions of the trial were included in the primary endpoint analysis of overall survival (OS), with 90% power to detect a hazard ratio of 0.71 using a one-sided log-rank test with type I error rate of 0.05. The planned phase III sample size was 400 pts with data maturity after 302 deaths. Results: The phase II and III portions of the trial were open to accrual from 12/15/2014 to 2/6/2017 and 11/8/2017 to 10/15/2018, respectively; 447 pts were accrued to the trial and used in this intention to treat analysis. The two treatment groups were well balanced for prognostic factors, 421 pts initiated treatment, median follow-up was 57.8 months (mos), 380 pts had disease progression and 335 pts have died. There was no difference in OS (p = 0.15; HR 0.89 (0.71-1.11), median OS 28.1 vs. 24.8 mo. for TMZ+veliparib vs. TMZ+placebo, respectively) and no difference in secondary endpoint progression free survival (PFS, p = 0.31; HR 1.05 (0.86-1.30), median 13.2 vs. 12.1 mo, respectively). There was a notable trend for extended OS with TMZ+veliparib treatment at intermediate time-points between 24 and 42 mos (3-year OS 36.6% vs. 28.9% with TMZ+placebo, p = 0.09). In an unplanned exploratory analysis, treatment with TMZ at the time of first recurrence was associated with extended post-recurrence OS (p = 0.03) for pts treated on the experimental arm; median post-recurrence OS with TMZ salvage was 17.0 mo in the TMZ+veliparib arm and 12.6 mo in the TMZ+placebo arm, as compared to 9.6 mo in either arm if TMZ salvage was not used. These data are consistent with a possible effect of veliparib limiting the emergence of TMZ resistance in a subset of GBM pts. Conclusions: Veliparib combined with adjuvant TMZ therapy was not associated with significant extension in OS or PFS in newly diagnosed, MGMT hypermethylated GBM pts. However, a subset of pts treated with TMZ+veliparib may have an extended survival following re-treatment with TMZ at first recurrence. Clinical trial information: NCT02152982.
Phase I/randomized phase II trial of TRC105 plus bevacizumab versus bevacizumab in recurrent glioblastoma: North Central Cancer Treatment Group N1174 (Alliance)
Galanis, Evanthia , Anderson, S. Keith , Twohy, Erin , Butowski, Nicholas , Hormigo, Adı́lia , Schiff, David , Jaeckle, Kurt A. , Kumar, Shaji , Kaufmann, Timothy J. , Geyer, Susan M. , Kumthekar, Priya , Campian, Jian , Buckner, Jan C. , Wen, Patrick Y , Kaufmann, Timothy J , Giannini, Caterina , Buckner, Jan C , Galanis, Evanthia , Anderson, S Keith , Omuro, Antonio , Giannini, Caterina

Neuro-Oncology Advances | April 4, 2022 | Volume: 4 | Issue: 1 | Pages: No page available

10.1093/noajnl/vdac041 Get It

Abstract Background Patients with glioblastoma (GBM) have a poor prognosis and limited effective treatment options. Bevacizumab has been approved for treatment of recurrent GBM, but there is questionable survival benefit. Based on preclinical and early clinical data indicating that CD105 upregulation may represent a mechanism of resistance to bevacizumab, we hypothesized that combining bevacizumab with the anti-CD105 antibody TRC105 may improve efficacy in recurrent GBM. Methods Phase I dose-escalation/comparative randomized phase II trial in patients with GBM. During phase I, the maximum tolerated dose (MTD) of TRC105 in combination with bevacizumab was determined. In phase II, patients were randomized 1:1 to TRC105 and bevacizumab or bevacizumab monotherapy. Patients received TRC105 (10 mg/kg) weekly and bevacizumab (10 mg/kg) every 2 weeks. Efficacy, as assessed by progression-free survival (PFS), was the primary endpoint; safety, quality of life, and correlative outcomes were also evaluated. Results In total, 15 patients were enrolled in phase I and 101 in phase II; 52 patients were randomized to TRC105 with bevacizumab and 49 to bevacizumab monotherapy. The MTD was determined to be 10 mg/kg TRC105 weekly plus bevacizumab 10 mg/kg every 2 weeks. An increased occurrence of grade ≥3 adverse events was seen in the combination arm, including higher incidences of anemia. Median PFS was similar in both treatment arms: 2.9 months for combination versus 3.2 months for bevacizumab monotherapy (HR = 1.16, 95% CI = 0.75–1.78, P = .51). Quality of life scores were similar for both treatment arms. Conclusions TRC105 in combination with bevacizumab was well tolerated in patients with recurrent GBM, but no difference in efficacy was observed compared to bevacizumab monotherapy.
CTNI-28. VOLUMETRIC AND DOSIMETRIC PATTERNS OF FAILURE ANALYSIS OF A PHASE II CLINICAL TRIAL OF 18F-DOPA-PET DIRECTED DOSE ESCALATED RADIOTHERAPY FOR GLIOBLASTOMA
Breen, William G. , Anderson, S. Keith , Pafundi, Deanna, Lowe, Val J. , Vogen, Diane, Yan, Elizabeth , Brown, Paul D. , Uhm, Joon H. , Ruff, Michael W. , Zakhary, Mark J. , Zhang, Yan , Seaberg, Maasa , Rehim, Abdou Abdel , Tseung, Hok Seum Wan Chan, Kabat, Brian, Kemp, Bradley J. , Brinkmann, Debra H. , Kaufmann, Timothy J. , Hunt, Christopher H. , Sarkaria, Jann N. , Kizilbash, Sani H. , Qian, Jing, Laack, Nadia N.

Neuro-Oncology | November 18, 2021 | Volume: 23 | Issue: Supplement_6 | Pages: vi65-vi65

10.1093/neuonc/noab196.253 Get It

Abstract While dose escalation of radiotherapy (DERT) has failed to improve overall survival (OS) or progression-free survival (PFS) for glioblastoma in previous studies, a recent phase II clinical trial utilizing 18F-DOPA-PET-directed DERT demonstrated improved PFS in MGMT-unmethylated patients and OS in MGMT-methylated patients compared to historical controls. This planned secondary analysis sought to determine 1) how 18F-DOPA-PET changes RT volumes beyond standard MRI-planning, 2) which patients benefit most and least from this protocol, 3) which are mostly likely to experience clinically significant radionecrosis after DERT, and 4) patterns of failure after DERT. For 69 evaluable patients, median MRI-defined, PET-defined, and combined low-dose gross tumor volumes (GTV51) were 54 cc (range 9-248), 23 cc (0.4-179), and 62 cc (10-260), respectively. Median MRI-defined, PET-defined, and combined high-dose GTVs (GTV76) were 32 cc (range 4-136), 6 cc (0.1-138), and 34 cc (4-162), respectively. 18F-DOPA-PET resulted in a median volumetric expansion of 13% (0-243%) and 5% (0-217%) from MRI-defined low-dose and high-dose GTV’s, respectively. Central failures ( >95% of recurrence tumor volume) occurred within the 76 Gy, 60 Gy, and 51 Gy isodose lines in 32 (46%), 60 (87%), and 64 (93%) patients, respectively. Recursive partitioning analysis stratified patients by OS and PFS. Patients with 18F-DOPA-PET-defined GTV76 > 7.8cc, MRI-defined GTV76 > 42.7cc, and MGMT promotor-unmethylated tumors had the shortest OS, while patients with smaller PET and MRI-defined tumors had the longest OS (median 10.4 vs. 64.6 months, p< 0.001). Similarly, PFS was worst in patients with 18F-DOPA-PET-defined GTV76 > 2.17 cc who had biopsy only (median PFS 3.2 months, p< 0.001). Patients with 18F-DOPA-PET-defined GTV51 > 50 cc had the highest risk of grade 3+ radionecrosis (p< 0.001). In conclusion, larger 18F-DOPA-PET and MRI-defined tumor volumes were associated with worse outcomes, and 18F-DOPA-PET-directed DERT appears to reduce risk of central recurrence in high-dose volumes.
CTNI-29. CODEL: PHASE III TRIAL OF RT ALONE, RT PLUS TMZ, OR TMZ ALONE FOR NEWLY-DIAGNOSED, 1p/19q CODELETED ANAPLASTIC OLIGODENDROGLIOMA. ANALYSIS FROM THE INITIAL STUDY DESIGN. (NCCTG N0577, ALLIANCE)
Jaeckle, Kurt A. , Brown, Paul D. , Jenkins, Robert B. , Cairncross, Gregory, Aldape, Kenneth, Anderson, S. Keith , Schiff, David , Raizer, Jeffrey J. , Dhermain, F., Nordstrom, Donald G., Flynn, Patrick J. , Vogelbaum, Michael A. , Ballman, Karla V. , Bent, Martin J. van den , Giannini, Caterina , Galanis, Evanthia , Wick, Wolfgang , Weller, Michael , Dixon, Jesse G. , Cerhan, James R. , Wefel, Jeffrey S. , Klein, Martin , Grossman, Stuart A.

Neuro-Oncology | December 4, 2020 | Volume: 22 | Issue: Supplement_2 | Pages: ii48-ii49

10.1093/neuonc/noaa215.196 Get It

Abstract BACKGROUND The original 3-arm CODEL design included a radiotherapy (RT)-alone control arm, an RT plus temozolomide (TMZ) arm, and an exploratory TMZ-alone arm. We report the analysis involving patients treated per the initial design. METHODS Adults (18+ years) with newly-diagnosed 1p/19q codeleted WHO grade III oligodendroglioma were randomized to RT (5940 cGy) alone (Arm A); RT with concomitant and adjuvant TMZ (Arm B); or TMZ alone (Arm C). Primary endpoint was OS, Arm A vs. B. Secondary comparisons were performed for OS and PFS, comparing pooled RT arms with the TMZ-alone arm. RESULTS 36 patients were randomized equally to the three arms. At median follow-up of 7.5 years, 83.3% (10/12) TMZ-alone patients had progressed, versus 37.5% (9/24) patients on the RT arms. PFS was shorter in TMZ-alone patients compared to RT-treated patients (HR=3.12; 95% CI: 1.26, 7.69; p=0.014). Death from disease progression occurred in 3/12 (25%) of TMZ-alone patients and 4/24 (16.7%) of RT-treated patients. OS did not statistically differ between arms, although this comparison was underpowered. After adjustment for IDH status (mutated vs. wildtype) in a Cox regression model, with IDH status and RT treatment status as co-variables (Arm C vs pooled A and B), PFS remained shorter for patients not receiving RT (HR= 3.33; 95% CI: 1.31, 8.45; p=0.011), and OS differences remained non-significant ((HR = 2.78; 95% CI 0.58, 13.22, p=0.20). Grade 3+ adverse events occurred in 25%, 42% and 33% patients (Arms A, B and C, respectively). Neurocognitive assessments, comparing baseline and 3 month timepoints, showed no significant differences between arms. CONCLUSIONS TMZ-alone treated patients experienced significantly shorter PFS than patients treated on the pooled RT arms, which remained significant when adjusting for IDH status. CODEL has been redesigned to compare the efficacy and toxicity of RT+PCV versus RT+TMZ. Clinicaltrials.gov Identifier: NCT00887146. Support: U10CA180821, U10CA180882, https://acknowledgments.alliancefound.org.