Giri, Sharmila

ABSTRACT First‐line therapy for mantle cell lymphoma (MCL) represents a critical opportunity for clinical benefit via sustained complete response. We conducted a phase 2 multicenter trial in the academic and community cancer research united (ACCRU) network, testing a multitargeted 1st line regimen. CARiBOU (ACCRU‐LY‐1804) employs alternating VR‐CAP and R‐cytarabine with continuous acalabrutinib, in six 21‐day cycles, for previously untreated MCL. The primary endpoint was complete metabolic response (CMR) rate. Secondary endpoints included safety, feasibility of stem cell collection, proportion proceeding to ASCT, and progression‐free (PFS) and overall survival (OS). Peripheral blood measurable residual disease (MRD) was tested using the ClonoSEQ assay (Adaptive Biotechnologies). Of 41 patients enrolled, 39 (95%) responded to therapy, including 37 patients achieving CMR (90%). Two nonresponders discontinued therapy for toxicity early, prior to study‐defined restaging, and received alternate therapy. Undetectable MRD at a 10 6 threshold was achieved in 26/33 tested patients (79%), and 94% at 10 5 . 18‐month estimated PFS is 79% (95% CI 64%–97%), and OS is 96% (95% CI 88%–100%). Toxicities were primarily hematologic (grade 3 hematologic AE in 32 patients, [78%]). Twelve required platelet transfusions, and one grade 3 bleeding event occurred. Febrile neutropenia occurred in 4 patients, and 6 (14%) experienced SAEs. There were no treatment‐related deaths. CARiBOU is an efficient, highly effective outpatient 1st line MCL regimen, employing intermediate‐dose cytarabine and continuous acalabrutinib for 6 cycles. This multitargeted regimen addresses the biologic heterogeneity of MCL and permits flexible MRD‐guided decisions on consolidation and maintenance. Trial Registration: ClinicalTrials.gov identifier: NCT04626791

8057 Background: The NCI Adjuvant Lung Cancer Enrichment Marker Identification and Sequencing Trials (ALCHEMIST) study tested resected stage II-IIIB(N2) NSCLC for targetable EGFR and ALK alterations and PD-L1 expression to screen patients for biomarker-driven adjuvant therapy trials (NCT02194738). Local lab results were requested when available for comparison to central lab results. Methods: We identified patients with both central and local PD-L1 results in the ALCHEMIST adjuvant immunotherapy study screening population. Discrepancies in tumor proportion score (TPS) between central and local PD-L1 were defined using prespecified cut-points (granular: <1%, 1-<5%, 5-<10%, 10-<20%, 20-<30%, 30-<40%, 40-<50%, 50-60%, 60-<70%, 70-<80%, 80-<90%, 90-<100%; clinical: <1%, 1-<50%, 50-100%). Large discrepancies were defined as ≥ 50 percentage point differences; for these cases, local PD-L1 and hematoxylin & eosin-stained slides were requested. These and all central slides were digitally scanned at 40X. Three expert pathologists reviewed the scanned slides in a blinded fashion. Differences between patient or tumor characteristics were assessed by Chi-square and Wilcoxon rank sum tests. Percent agreement was computed within and between the reviewers. Results: Central and local PD-L1 results were available for 497 patients. 177 cases (36%) had discrepancies that placed patients in different clinical TPS categories (<1%, 1-<50%, 50-100%). Among these, 43 cases had large TPS discrepancies; 14 had available local testing slides. 46 of the 320 cases without discrepancy were randomly selected as controls. No patient or tumor characteristics were associated with discrepancy, including tumor location, histology, grade or cancer stage (p > 0.05). Pairwise comparisons of TPS according to three pathologists re-reading the same scanned PD-L1 slides showed similar levels of disagreement in clinical TPS category whether there was initial discrepancy between central and local results (24%, 34%, and 23%; mean 27%) or not (33%, 30%, and 20%; mean 28%). Among the 14 cases with large initial discrepancies and local slides available, there was agreement in clinical TPS category when the anonymized central and local scanned slides were re-read by the pathologists in 54%, 38%, and 43% of cases, despite 100% non-agreement in initial reads. There were higher rates of agreement when the tested slides both originated from the same (100%) versus different (35%) blocks, when the same (48%) versus different (40%) PD-L1 antibodies were used, and when the cases were of non-squamous (52%) versus squamous (14%) cell carcinoma. Conclusions: There are substantial differences in PD-L1 TPS read by pathologists that can result in placement of patients in different categories commonly used for clinical management. These differences have clear implications in clinical trials and routine patient care.

8001 Background: The ALCHEMIST clinical trial platform, launched by the National Clinical Trials Network (NCTN) in 2014, screened patients with resected non-small cell lung cancer (NSCLC) for molecular markers and tailored post-operative adjuvant therapy trials. A081105 evaluated whether adjuvant erlotinib improved overall survival (OS) following complete resection in patients with early stage EGFR mutated lung adenocarcinoma. Methods: A081105 was a randomized phase III trial enrolling patients with completely resected stage IB (≥4 cm), II, or IIIA non-squamous NSCLC (per the 7 th TNM staging classification) harboring EGFR exon 19 deletion or L858R mutations. Patients were randomized 1:1 to erlotinib 150 mg daily for up to 2 years or placebo/observation, stratified by stage, prior chemotherapy, EGFR mutation subtype, and ECOG performance status. The primary endpoint was OS in the per-protocol (PP) population with centrally confirmed EGFR mutations, designed to detect a hazard ratio (HR) of 0.67 in favor of erlotinib with a power of 86% and one sided type I error rate of 5%. Secondary endpoints included OS and disease free survival (DFS) in a modified intent-to-treat (mITT) population with local or centrally confirmed EGFR mutations, and safety. A prespecified backstop analysis was conducted after a minimum of 5 years of follow-up on all patients. Results: Trial enrollment was discontinued when 390 of the intended 450 patients had been enrolled due to the proven benefit of adjuvant osimertinib. Among 390 enrolled patients, the arms were balanced for age (median: 67.0 years), sex (70% female), race (70% white), stage (II: 51%, IIIA: 37%), prior chemotherapy (82%), ECOG PS 0 (60%), and exon 19 deletion (57%). Adjuvant erlotinib did not significantly improve OS compared with placebo/observation in the overall PP population (364 patients, 108 events, HR 0.89; 95% CI, 0.59–1.34; 1-sided P = 0.29) or within exon 19 deletion (HR: 0.94) or L858R mutation (HR: 0.82) subgroups. Five-year OS rates were 78.6% versus 77.9%, respectively. Results were consistent in the mITT analysis (379 patients, 113 events, HR 0.86; 95% CI, 0.58–1.28). Erlotinib improved DFS (mITT: 181 events, median: 68 vs 50 months, HR 0.74; 95% CI, 0.55–1.01). Across both arms, 11% of patients started non-protocol treatment (Osimertinib: 9%) prior to disease progression, and 9% withdrew consent for all follow-up prior to recurrence. In the erlotinib arm, 3 deaths on study were reported; grade 3 or higher adverse events were reported on 39% of patients. Median duration of treatment on Erlotinib arm was 16 months; only 37% of patients completed the planned treatment. Conclusions: In resected EGFR -mutant NSCLC, adjuvant erlotinib did not improve overall survival but improved DFS. Additional studies are exploring efficacy in selected subsets of patients using genomics and proteomic analyses. Clinical trial information: NCT02193282 .

Abstract Introduction: First-line therapy for mantle cell lymphoma (MCL) represents a critical opportunity for clinical benefit via sustained complete response. Multitargeted combinations, including optimized chemotherapy with novel agents targeted to MCL, may best address the biologic heterogeneity of this disease. Building on prior experience using modified VR-CAP and R-cytarabine, we enhanced this regimen by adding acalabrutinib while reducing cytarabine, aiming for improved efficacy and safety without impeding stem cell collection. To evaluate this regimen, we conducted a phase 2 multicenter trial at four centers in the Academic and Community Cancer Research United (ACCRU) network. Methods: CARiBOU (ACCRU-LY-1804) employs alternating VR-CAP and R-cytarabine with continuous acalabrutinib, in six 21-day cycles, for previously untreated MCL. Eligible patients (pts) were at least 18 years old with adequate organ function, measurable disease, no CNS involvement; and were ASCT-eligible per investigator. VR-CAP (cycles 1, 3, and 5) employed bortezomib 1.3 mg/m² subcutaneously days 1,8, and 15; rituximab 375 mg/m² day 1; cyclophosphamide 750 mg/m² day 1; doxorubicin 50 mg/m2 day 1; and prednisone 100 mg PO days 1-5. Cycles 2,4, and 6 used outpatient rituximab with cytarabine at 3 g/m² x 2 daily doses in the first 5 pts, after which the dose was reduced to 2 gm/m2 x 2 daily doses due to thrombocytopenia. Acalabrutinib 100 mg p.o. twice daily was given continuously but held for grade 4 thrombocytopenia or clinically significant toxicity. Growth factors and prophylactic antimicrobials were required. Responses were assessed after six cycles using FDG PET/CT, bone marrow aspirate/biopsy (BM Bx), and endoscopy when indicated (Lugano 2014). The primary endpoint was complete metabolic response (CMR) rate at end of treatment (EOT). Secondary endpoints included safety, feasibility of stem cell collection, proportion proceeding to ASCT, and progression-free (PFS) and overall survival (OS). Peripheral blood measurable residual disease (MRD) was evaluated using the ClonoSEQ assay (Adaptive Biotechnologies). A Simon two-stage design was used, targeting a CMR rate ≥ 70% versus a null rate of 50%, with a total sample size of 39 evaluable pts. Results: 41 pts were accrued from October 2021 through May 2025, 37 of whom completed all 6 cycles and are evaluable for response; two are still on therapy, and two discontinued therapy early for toxicity. Median age was 63 years (range 41-73), 22% were female, and 85% were White. MIPI risk groups were low (44%), intermediate (39%), and high (17%), and Ki-67 was ≥ 30% in 54% of pts. Three pts (7%) had known TP53 mutations by sequencing. At EOT, the CMR rate was 85.3% among all pts (35/41; 95% CI 67.9%-92.9%), or 94.5% among evaluable pts (35/37). BM Bx was performed in 31 pts at EOT, 30 of which (96.8%) were negative for MCL. Undetectable peripheral blood MRD using a 10^6 threshold (uMRD6) was achieved at EOT in 78.1% (25/32) of tested pts, and 93.8% (30/32) achieved uMRD5. Nine of 41 pts underwent ASCT; no patient failed stem cell collection. Maintenance therapy was not protocol-defined but included rituximab in 91.9% of pts and a BTK inhibitor in 21.6% of pts. With a median follow-up of 16.7 months, PFS and OS rates at 18 months were 76.7% (95% CI: 60.7%-96.9%) and 95.5% (95% CI: 87.1%-100%). Toxicities were primarily hematologic. Grade 3+ toxicities included thrombocytopenia (66.6%), neutropenia (28.2%), and anemia (25.6%). Grade 3+ febrile neutropenia was observed in 10.2% of pts. Peripheral neuropathy was seen in 20.5% of pts and all grade 1-2. Bleeding events included purpura in 2 pts (5.2%) and epistaxis in 1 patient (2.6%). One case of atrial fibrillation was observed. Eighteen pts required temporary dose hold of acalabrutinib for toxicity (mainly thrombocytopenia), and 2 had acalabrutinib dose reductions. Serious adverse events occurred in 6 pts, and no treatment-related deaths occurred. Conclusions: CARiBOU is an efficient, highly effective outpatient regimen for 1st line MCL, employing intermediate dose cytarabine with continuous acalabrutinib. With supportive care and platelet monitoring, this approach safely yielded high rates of CMR and uMRD6, supporting multitargeted induction therapy for appropriate pts with untreated MCL.

7012 Background: DLBCL with expression of MYC and BCL2 (double expressor lymphoma, DEL), has an adverse prognosis. Venetoclax, an inhibitor of BCL2, was previously studied in combination with R-CHOP. A051701 is a phase II/III randomized trial of chemoimmunotherapy +/- venetoclax in DEL and double hit lymphoma cohorts. Here we report initial phase II results from the DEL cohort. Methods: Patients (pts) age ≥ 18 years (y) with untreated DEL were randomized 1:1 to R-CHOP (Arm 1) or R-CHOP-venetoclax (Arm 2). DEL was defined as MYC expression ≥40% and BCL2 expression ≥50%, without double hit cytogenetics. Enrollment was based on local pathology results that were centrally confirmed. Venetoclax 800 mg was given orally days 4-8 of cycle 1 and days 1-5 of subsequent cycles for up to 6 cycles. All cycles were supported by GCSF or peg-GCSF. The primary endpoint was progression-free survival (PFS) with 84% power to detect a HR of 0.518 corresponding to 2y PFS rate of 65% in Arm 1 and 80% in Arm 2 (1-sided α=0.20). Results: 119 DEL pts were enrolled: 60 Arm 1; 59 Arm 2. Analyses were performed for the modified intent-to-treat population, defined as eligible pts with confirmed DEL histology (n=113; 56 Arm 1, 57 Arm 2). Median age was 64 y (range 22-85); baseline demographic factors were well balanced except for advanced stage (more common in Arm 1; (77% vs 60%, p=0.051). Most pts were non-germinal center B cell-like by immunohistochemistry (Arm 1 72%, Arm 2 58%), high-intermediate/high risk IPI (Arm 1 54%, Arm 2 51%) and ECOG performance status 0-1 (Arm 1 95%, Arm 2 86%). BCL2 rearrangements were detected in 25% and 33% of pts on Arm 1 and Arm 2, respectively. Most pts completed therapy per protocol (84% Arm 1, 75% Arm 2). Median follow up is 27 months (m). No difference in PFS was observed with 12-m PFS estimates of 77% in Arm 1, 76% in Arm 2 [HR = 0.98 (95% CI: 0.48 – 2.01), p=0.95]. The end of treatment (EOT) overall and complete response rates among patients with an EOT assessment were 87.5% and 70% in Arm 1, and 90% and 82% in Arm 2. Overall survival (OS) was not statistically significantly different with 12-mo OS estimates of 94% in Arm 1 and 79% in Arm 2 [HR = 1.27 (95% CI: 0.57 – 2.79), p=0.56]. Grade ≥3 adverse events (AEs) occurred more frequently in Arm 2 (42% vs 76%). The most commonly increased grade ≥3 AEs included neutropenia (20% vs 47%), anemia (4% vs 25.5%), thrombocytopenia (5.5% vs 24%), febrile neutropenia (7% vs 16%) and fatigue (0% vs 11%). No grade 5 AEs on treatment were reported on Arm 1, and 3 were reported on Arm 2 (lung infection and sudden death NOS, both possibly related; respiratory failure, unlikely related). Conclusions: Adding venetoclax to R-CHOP in DEL pts did not improve PFS and resulted in increased toxicity. The study did not meet its primary endpoint in phase II, and so did not proceed to phase III. Clinical trial information: NCT03984448 .

Abstract Although it is evident that standard-dose whole-brain radiotherapy as consolidation is associated with significant neurotoxicity, the optimal consolidative strategy for primary central nervous system lymphoma (PCNSL) is not defined. We performed a randomized phase 2 clinical trial via the US Alliance cancer cooperative group to compare myeloablative consolidation supported by autologous stem cell transplantation with nonmyeloablative consolidation after induction therapy for PCNSL. To our knowledge, this is the first randomized trial to be initiated that eliminates whole-brain radiotherapy as a consolidative approach in newly diagnosed PCNSL. Patients aged 18 to 75 years were randomly assigned in a 1:1 manner to induction therapy (methotrexate, temozolomide, rituximab, and cytarabine) followed by consolidation with either thiotepa plus carmustine and autologous stem cell rescue vs induction followed by nonmyeloablative, infusional etoposide plus cytarabine. The primary end point was progression-free survival (PFS). A total of 113 patients were randomized, and 108 (54 in each arm) were evaluable. More patients in the nonmyeloablative arm experienced progressive disease or death during induction (28% vs 11%; P = .05). Thirty-six patients received autologous stem cell transplant, and 34 received nonmyeloablative consolidation. The estimated 2-year PFS was higher in the myeloablative vs nonmyeloablative arm (73% vs 51%; P = .02). However, a planned secondary analysis, landmarked at start of the consolidation, revealed that the estimated 2-year PFS in those who completed consolidation therapy was not significantly different between the arms (86% vs 71%; P = .21). Both consolidative strategies yielded encouraging efficacy and similar toxicity profiles. This trial was registered at www.clininicals.gov as #NCT01511562.

Abstract Background: High grade B-cell Lymphoma with rearrangements of MYC and BCL2 and/or BCL6, also known as double hit lymphoma (DHL), and double expressing lymphomas (DEL; DLBCL with IHC expression of MYC and BCL2, but without double hit cytogenetics) are highly aggressive B cell non-Hodgkin lymphomas and patients (pts) often develop relapsed/refractory disease following standard first-line chemoimmunotherapy. DA-EPOCH-R is widely used in patients with DHL, and a phase 1 trial of venetoclax + DA-EPOCH-R established the dose of 600 mg for 5 days with each cycle as the recommended phase 2 dose (Rutherford, et al. Proc ASCO 2020). A051701 is a phase II/III randomized trial evaluating chemoimmunotherapy +/- the BCL2 inhibitor venetoclax in a DHL cohort (pts with DHL with BCL2 rearrangement and/or expression), and a DEL cohort. Here we report the initial results from the DHL cohort of A051701. Methods: Pts age ≥ 18 years with newly diagnosed DHL were stratified on International Prognostic Index (IPI) score and receipt of a single cycle of chemotherapy prior to registration, which was permitted, and randomized 1:1 to receive DA-EPOCH-R (Arm 1) or DA-EPOCH-R with venetoclax (Arm 2). Enrollment was based on local pathology results which were centrally confirmed. DA-EPOCH-R was administered as previously published. Venetoclax was dosed at 600 mg po daily on days 4-8 of cycle 1 and on days 1-5 of subsequent cycles for up to 6 total cycles. All cycles were supported by GCSF or peg-GCSF. For the interim analysis at the end of phase II, 53 events ensured 90% power to detect an improvement in 24-month progression-free survival (PFS) from 40% in Arm 1 to 60% in Arm 2 (HR=0.557) using a one-sided stratified log-rank test with type I error rate of 20%. The Alliance Data and Safety Monitoring Board approved the data release after accrual was stopped early due to excess toxicity in Arm 2. These data were frozen July 8, 2021. Results: 73 pts were registered (36 in Arm 1 and 37 in Arm 2) between 8/7/19 and 9/18/20. Analyses were performed for the modified intent-to-treat (mITT) population, defined as eligible pts with DHL histology confirmed (n=66; 30 Arm 1, 36 Arm 2). Median age was 65 years in both arms (range 37-80) and baseline demographic factors were well balanced. An allowed pre-protocol chemoimmunotherapy cycle was administered in 60% and 56% of Arm 1 and Arm 2 pts, respectively. The majority of pts had advanced stage disease (Arm 1 87%, Arm 2 86%), GCB immunophenotype (Arm 1 100%, Arm 2 88%), ECOG PS 0-1 (Arm 1 90%, Arm 2 86%), and high-intermediate/high risk IPI score (Arm 1 63%, Arm 2 64%). Therapy was completed per protocol in 70% and 47% of pts, respectively, for Arm 1 and 2, and disease progression on therapy occurred in 10% and 3%. Treatment was discontinued due to adverse events in 7% of pts in Arm 1 and 11% of pts in Arm 2. Consent was withdrawn after beginning treatment in 3% and 11% in Arm 1 and 2, respectively. Death on treatment occurred in 1 patient (3%; PJP pneumonia) in Arm 1 and 6 pts (17%; sepsis (n=4), cardiac arrest (n=2)) in Arm 2. The observation of excess deaths on Arm 2 prompted suspension of accrual to the DHL cohort. Treatment was discontinued for other reasons in 3 (10%) and 4 (11%) pts in Arms 1 and 2, respectively. Venetoclax was dose-reduced and/or omitted in 15 (42%) pts. Grade 4 neutropenia was not significantly different between arms (Arm 1 67%, Arm 2 71%), nor was grade ≥3 neutropenic fever (Arm 1 36%, Arm 2 40%). Sepsis occurred more frequently in Arm 2 (14% vs. 23%). The end of treatment overall and complete response rates in the mITT population were 73% and 67% in Arm 1, and 58% and 50% in Arm 2. The end of treatment overall and complete response rates among only pts evaluated for response (n=52) were 79% and 71% in Arm 1, and 88% and 75% in Arm 2. With a median follow-up of 7.4 months, the median PFS was not reached (NR) in Arm 1 (95% CI 6.1-NR) and was 6.7 months in Arm 2 (95% CI 4.5-NR) (two-sided p=0.13). The median OS was NR in Arm 1 and was 8.5 months in Arm 2 (95% CI 5.2-NR) (two-sided p=0.004). Conclusions: DA-EPOCH-R plus venetoclax in DHL pts resulted in excess treatment-related mortality compared to DA-EPOCH-R alone, prompting early discontinuation of accrual and venetoclax treatment for the study cohort. Based on these data, we recommend against combining venetoclax with DA-EPOCH-R in DHL. Robust accrual to this study shows that prospective trials are feasible in DHL, and the favorable outcome thus far in the DA-EPOCH-R arm may serve as a benchmark for future trials Figure 1 Figure 1. Disclosures Abramson: Astra-Zeneca: Consultancy; Allogene Therapeutics: Consultancy; Incyte Corporation: Consultancy; BeiGene: Consultancy; Kymera: Consultancy; Bluebird Bio: Consultancy; Genmab: Consultancy; EMD Serono: Consultancy; Bristol-Myers Squibb Company: Consultancy, Research Funding; C4 Therapeutics: Consultancy; Morphosys: Consultancy; Kite Pharma: Consultancy; Novartis: Consultancy; Seagen Inc.: Research Funding; AbbVie: Consultancy; Karyopharm: Consultancy; Genentech: Consultancy. Ruppert: Telios Pharma: Consultancy. Hsi: Seattle Genetics: Honoraria; Cytomx: Honoraria; Eli Lilly: Research Funding; AbbVie: Research Funding. Landsburg: Triphase: Research Funding; Takeda: Research Funding; Curis: Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Other: DSMB member; ADCT: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; Morphosys: Membership on an entity's Board of Directors or advisory committees. Kahl: AbbVie, Adaptive, ADCT, AstraZeneca, Bayer, BeiGene, Bristol-Myers Squibb, Celgene, Genentech, Incyte, Janssen, Karyopharm, Kite, MEI, Pharmacyclics, Roche, TG Therapeutics, and Teva: Consultancy; AbbVie, Acerta, ADCT, AstraZeneca, BeiGene, Genentech: Research Funding. Friedberg: Acerta: Other: DSMC ; Novartis: Other: DSMC ; Bayer: Other: DSMC . Bartlett: Millennium: Research Funding; Janssen: Research Funding; Kite, a Gilead Company: Research Funding; Merck: Research Funding; Genentech: Research Funding; Celgene: Research Funding; Forty Seven: Research Funding; Bristol Myers Squibb: Research Funding; Roche/Genentech: Consultancy; Autolus: Research Funding; Seagen: Consultancy, Research Funding; Pharmacyclics: Research Funding; ADC Therapeutics: Consultancy, Research Funding. Leonard: ADC Therapeutics, AstraZeneca, Bayer, BMS/Celgene, Epizyme, Inc., Genmab, Gilead/Kite, Karyopharm, BMS/Celgene, Regeneron, MEI Pharma, Miltenyi, Roche/Genentech, Sutro: Consultancy; Roche/Genentech: Consultancy. OffLabel Disclosure: venetoclax in double hit lymphoma

7506 Background: Optimal consolidative therapy for primary central nervous system lymphoma (PCNSL) is not defined. Avoidance of whole brain radiation may reduce risk of neurotoxicity. Non-radiation consolidative options include myeloablative chemotherapy with autologous stem cell transplantation (HDT/ASCT) or non-myeloablative chemotherapy. Methods: This is a randomized phase 2, National Clinical Trials Network study of induction methotrexate (MTX) (8 g/m2 days 1, 15), temozolomide (TMZ) (150-200 mg/m2 D7-11), and rituximab (RTX) (C1 D3, 10, 17, 24 and C2 D3, 10 ) in four 28-day cycles followed by one cycle of cytarabine (ARA-C) (2 g/m2 BID, D1, 2) (MTRA). After induction, patients (pts) received consolidation with thiotepa (5 mg/kg BID, D -5, -4) plus carmustine (400 mg/m2, day -6) and ASCT (Arm A) or one cycle of ARA-C (2 g/m2 BID, D1-4) plus infusional etoposide (40 mg/kg over 96h) (Arm B). Pts were stratified on age and performance status and randomized 1:1 before induction. The primary endpoint was progression-free survival (PFS) from randomization. With 110 pts, there was 84% power to detect an improvement in PFS using a log-rank test (1-sided α= 10%), assuming a median PFS of 3 months for pts who progress during induction, and a median PFS of 2 years (yrs) for Arm B and 4.5 yrs for Arm A consolidation. This report includes the results for the primary endpoint analysis. Results: 113 pts (median age 61 yrs, range 33-75) were randomized (Arm A: 57, Arm B: 56) across 27 centers. 108 eligible pts who received induction therapy were included in the primary endpoint analysis (Arm A: 54, Arm B: 54). 72/108 pts started consolidation and 70/72 completed consolidation per protocol (Arm A: 36, Arm B: 34). With a median follow-up of 3.8 years, median PFS from randomization was 6 yrs (95% CI 3.9-not reached) in Arm A vs 2.4 yrs (95% CI 0.6-not reached) in Arm B (p = 0.02). However, more pts randomized to Arm B went off treatment before consolidation due to progression or death (28% vs 11%, p = 0.05). PFS landmarked at start of consolidation demonstrated a trend for improved PFS favoring Arm A (HR 0.58, 95% CI 0.25-1.36; p = 0.21). Median OS was not reached in either arm, and 3-yr estimates were 83% (95% CI 69-91; Arm A) vs 72% (95% CI 57-82; Arm B). Toxicities were similar between arms with no treatment-related mortality during consolidation. Conclusions: MTRA induction followed by myeloablative consolidation (Arm A) had improved PFS vs MTRA induction followed by non-myeloablative consolidation (Arm B), though more progressions or deaths leading to treatment discontinuation prior to consolidation in Arm B were noted. Both consolidation regimens were well-tolerated with encouraging PFS and OS in newly-diagnosed PCNSL. Support: U10CA180821, U10CA180882; https://acknowledgments.alliancefound.org . Clinical trial information: NCT01511562.

Follicular lymphoma (FL) is an indolent B-cell neoplasm of germinal center origin. Standard treatment regimens consist of anti-CD20 therapy with or without chemotherapy. While high response rates to initial therapy are common, patients ultimately relapse or have progressive disease. Clinical risk factors such as the Follicular Lymphoma International Prognostic Index (FLIPI) have been identified, but there is a need for prognostic and predictive biomarkers. We studied markers of lymphoma cells and tumor microenvironment by immunohistochemistry in tissue samples from patients enrolled in 1 of 4 phase 2 trials of anti–CD20-based biological therapy for previously untreated grades 1 to 2 or 3A FL. Results were correlated with progression-free survival (PFS) and PFS status at 24 months. The 4 trials included 238 patients (51.1% male, median age: 55 y) with stage III, IV, or bulky stage II disease. By FLIPI, 24.6% had low-risk, 56.8% had intermediate-risk, and 18.6% had high-risk disease. The outcome differed significantly for patients treated with lenalidomide and rituximab (CALGB 50803) compared with the other 3 trials (median: PFS not reached vs. 3.0 y, hazard ratio=3.47, 95% confidence interval: 2.11-5.72); therefore, data were stratified by clinical trial (CALGB 50803 vs. all others) and adjusted for FLIPI risk group. Among 154 patients with available tissue, interfollicular BCL6 positivity, interfollicular CD10 positivity, and elevated Ki67 proliferation index ≥30% within neoplastic follicles were each associated with inferior PFS and a high risk of the early event by PFS status at 24 months. We identify promising biomarkers for FL risk stratification that warrant further validation in phase 3 trials.