Melear, Jason M.

RET fusions appear in 1%-2% of non–small cell lung cancers (NSCLCs). The results from the ARROW study (ClinicalTrials.gov identifier: NCT03037385 ) supported US Food and Drug Administration approval of pralsetinib, an oral selective RET inhibitor, for metastatic RET -altered NSCLC and RET fusion–positive thyroid cancers. ARROW was a phase I/II open-label study of pralsetinib 400 mg once daily in RET fusion–positive NSCLCs. Coprimary end points were overall response rate (ORR) and safety. Key secondary end points included duration of response, progression-free survival, and overall survival (OS). At data lock (May 20, 2024), 281 patients initiated pralsetinib (median treatment duration, 15.0 months). ORR (measurable disease patients; n = 259) was 78% (95% CI, 69 to 86) for treatment-naïve patients and 63% (95% CI, 54 to 71) for prior platinum-based chemotherapy patients. Median OS was 44.3 months (95% CI, 30.9 to 53.1), 50.1 months (95% CI, 28.3 to not reached) in treatment-naïve patients, and 39.7 months (95% CI, 27.8 to 53.2) in prior platinum patients. Common grade ≥3 treatment-related adverse events were anemia (21%), hypertension (15%), and decreased neutrophils (13%). Three treatment-related deaths occurred (pneumonia, n = 2; interstitial lung disease and rhabdomyolysis, n = 1 each). Safety was consistent with previous ARROW reports; no hypersensitivity was reported in patients receiving prior immunotherapies. Pralsetinib produced robust, durable responses with manageable safety in treatment-naïve and previously treated patients with RET fusion–positive NSCLCs, confirming previous findings with longer follow-up.

8644 Background: RET fusions are targetable oncogenic drivers in 1-2% of non-small cell lung cancers (NSCLC). ARROW (NCT03037385) study results (final data lock May 20, 2024) supported the US FDA approval of pralsetinib, a highly potent, oral, selective RET inhibitor for metastatic RET -altered NSCLC. Here, we present final study results. Methods: ARROW was a phase 1/2 open-label study conducted at 84 sites in 13 countries. Phase 2 included patients with RET -fusion-positive NSCLC who received 400 mg pralsetinib once daily (QD). Initially, treatment-naïve patients were not candidates for platinum-based therapy and presented with several unfavorable prognostic factors; this requirement was removed by protocol amendment in July 2019. Primary objectives were overall response rate (ORR, per RECIST v1.1) and safety. Progression-free survival (PFS) and overall survival (OS) are reported in the full efficacy population; the measurable disease population (MDP) was the primary analysis population for ORR and duration of response (DOR). Results: 281 patients with RET -fusion-positive NSCLC received pralsetinib 400 mg QD, with a median duration of treatment of 14.95 months (mos). Median age was 60 years; 46% were male. In the MDP (n=259), ORR was 70.3% (95% confidence intervals [CI]: 64.3, 75.8) and median DOR was 19.1 mos (95% CI: 14.5, 27.9; Table). In the efficacy population (N=281), median OS was 44.3 mos (95% CI: 30.9, 53.1) with median follow up of 47.6 mos (95% CI: 44.8, 49.2), and median PFS was 13.1 mos (95% CI: 11.4, 16.8). ORR (Table) and median PFS were markedly higher in the US (25.9 mos, n=64) vs. Asia (12.6 mos, n=122) or Europe (12.9 mos, n=95). In the safety population, 95% of patients experienced treatment-related adverse events (TRAEs); 66% experienced ≥grade 3. Common TRAEs included increased AST (n=128 [46%]), anemia (n=121 [43%]), increased ALT (n=98 [35%]), and hypertension (n=77 [27%]). 3 patients died due to TRAEs (pneumonia, n=2; interstitial lung disease and rhabdomyolysis, n=1 each). No new safety signals were identified with this update. Conclusions: Pralsetinib produced clinically meaningful and durable responses in patients with RET -fusion-positive NSCLC (regardless of prior therapies) with a manageable safety profile, confirming with this longer follow up previously published results. Clinical trial information: NCT03037385 . All MDP(n=259) Prior Platinum (n=130) Treatment-naive(n=106) ORR, % (95% CI) Overall 70.3(64.3, 75.8) 63.1(54.2, 71.4) 78.3(69.2, 85.7) US (n=58)77.6(64.7, 87.5) (n=31)64.5(45.4, 80.8) (n=19)100(82.4, 100) Europe (n=89)65.2(54.3, 75) (n=36)63.9(46.2, 79.2) (n=43)65.1(49.1, 79) Asia (n=112)70.5(61.2, 78.8) (n=63)61.9(48.8, 73.9) (n=44)81.8(67.3, 91.8) Median DOR, mos (95% CI) a (n=182)19.1(14.5, 27.9) (n=82)31.8(15.1, 40.4) (n=83)13.4(9.4, 21.7) Median DOR follow up, mos (95% CI) 46.8(42.3, 50.2) 50.3(46.9, 56.8) 42.3(37.4, 44.2) a Per FDA censoring rule.

INTRODUCTION: Luxeptinib (CG-806; LUX) is an orally active noncovalent kinase inhibitor of Bruton's tyrosine kinase (BTK), wild type and mutant forms of Fms-like tyrosine kinase 3 (FLT3) (including the internal tandem duplicates (ITD), tyrosine kinase domain (TKD), and F691L mutant forms), and growth receptors like KIT, CSF1R, PDGFRα, and TRKs. In prior studies, LUX has been shown to suppress aberrant proliferative signaling in B cell malignancies and acute myeloid leukemia (AML) via regulation of BTK, LYN, SYK, AKT, ERK, and MAPK. LUX is cytotoxic to primary AML cells insensitive to other FLT3 inhibitors and to malignant B-cells insensitive to ibrutinib, at pM and nM concentrations, respectively. AIMS: The primary objectives of these studies are to assess the safety, tolerability, and pharmacokinetics (PK) of LUX and determine recommended phase 2 doses for relapsed or refractory (R/R) AML and B cell malignancy patients. METHODS: In two studies (NCT04477291; NCT03893682), LUX (original formulation, G1) was administered continuously as oral capsules BID in 28-day cycles of ascending cohorts (relapsed or refractory de novo, secondary, or therapy-related AML or higher risk myelodysplastic syndrome (MDS), and relapsed and refractory for B cell lymphoma and chronic lymphocytic/small lymphocytic leukemia). A novel generation 3 (G3) formulation of LUX designed to increase bioavailability was tested at a single-dose (sub-study) for relative bioavailability (RBA), followed by continuous dosing in subsequent R/R AML patients. RESULTS: In the B-cell study (as of 15 th May 2023), LUX has been administered to 36 patients at dose levels from 150 mg to 900 mg BID in patients with a median of 3 lines of prior treatment, with 47.2% having received a BTK-inhibitor. Only one (2.8%) patient had a DLT of hypertension and 14 (38.9%) experienced at least one drug related ≥Grade3 treatment emergent adverse event (TEAE). Two patients (900 mg) are currently on study with no DLT and no ≥Grade 3 related TEAEs. A Follicular lymphoma patient is at cycle 28, and achieved a best response as partial response (PR) with a decrease in lesion size of 76.2%; an SLL patient is at cycle 13, and achieved stable disease (SD) showing a decrease in lesion size of 43.1% (Figure A). The overall best response achieved among the 17 patients who have been on treatment for more than 12 weeks are stable disease (SD) (n=11), partial response (PR) (n=3), minor response (n=2) and complete response (CR) (n=1). As of 5 th June 2023, in the AML trial, a total of 40 patients (16 (40%) FLT3-ITD, 21 (52.5%) FLT3-WT, 2 (5.0%) FLT3-TKD, and 1 (2.5%) unknown mutations) with a median of 3 prior treatments (range, 1 - 10) have been treated with LUX G1 formulation at dose levels from 450 mg - 900 mg BID (n=34) or with 50 mg BID of G3 formulation (n=6). Four (10%) experienced drug related SAE and 7 (17.5%) had a drug related grade ≥3 TEAEs. The most common related TEAEs were lymphocyte count decrease, platelet count decrease, and anemia (n=2; 5% patients each). One (2.5%) patient at 450 mg dose, reported complete remission without minimum residual disease (CRmrd) and remained on study for 56 weeks. In the RBA sub-study, G3 (50 mg) produced comparable exposures to G1 (450-900 mg range) (Figure B) and was, therefore, selected as the starting dose for use in the R/R AML study. Six patients were treated with a continuous dosing of 50 mg BID G3; with plasma levels of 274 ng/mL and 195 ng/mL LUX observed by the end of C1D15 and C1D22 respectively. No drug related Grade ≥3 TEAEs or DLTs were observed in 50 mg BID G3 LUX treated patients; with no new safety signals observed for the G3 formulation. Based on these findings and expected exposures for higher dose levels, the cohort safety review committee has approved escalation of G3 dosing to 200 mg BID at which dosing is ongoing. CONCLUSIONS: LUX has a favorable safety profile in patients at all tested dose levels, for multiple cycles, for both studies. Antitumor activity was observed in a heavily pretreated relapsed AML patient and in multiple B-NHL subtypes and CLL/SLL patients including several with prior ibrutinib exposure. Continuous dosing of patients with R/R AML and Higher-Risk MDS with the G3 formulation is ongoing; with updated clinical data (200 mg dose level) to be presented at the meeting.

Abstract Background: Patients with relapsed indolent NHL (iNHL) have limited standard treatment options. Lenalidomide combined with rituximab (R 2) has shown complimentary clinical activity and is a tolerable regimen in both untreated and relapsed or refractory (R/R) patients with iNHL (RELEVANCE : N Engl J Med 2018;379:934 and AUGMENT: J Clin Oncol. 2019;37:1188). Methods: MAGNIFY is a multicenter, phase 3b trial in patients with R/R follicular lymphoma (FL) grades 1-3b, transformed FL (tFL), marginal zone lymphoma (MZL), or mantle cell lymphoma (MCL; NCT01996865) exploring optimal lenalidomide duration. In the induction phase, lenalidomide 20 mg PO on days 1-21 of a 28-day cycle + rituximab IV at 375 mg/m 2/week cycle 1 and then every 8 weeks starting with cycle 3 (R 2) are administered for 12 cycles. Patients with stable disease, partial response, or complete response/complete response unconfirmed (CR/CRu) were randomized 1:1 to R 2 vs rituximab maintenance for 18 months. Data presented here are the complete analysis from the induction phase in efficacy-evaluable patients with FL grades 1-3a or MZL (FL grade 3b, tFL, and MCL not included). The focus of this interim analysis was overall response rate (ORR) by 1999 IWG criteria in the induction intention-to-treat population. Results: As of March 5, 2021, 394 patients (318 [81%] FL gr1-3a; 76 [19%] MZL) were enrolled. The median follow-up was 40.6 mo (range, 0.6-79.6). Median age was 66 y (range, 35-91), 328 (83%) had stage III/IV disease, with a median of 2 prior therapies (94% prior rituximab-containing). ORR was 71% (n = 279) with 42% (n = 164) CR/CRu (Table). All patients have completed R 2 induction (n = 232, 59%) or discontinued study treatment (n = 162, 41%). 141 patients (36%) prematurely discontinued both lenalidomide and rituximab, primarily due to adverse events (AEs) (n = 54, 14%) or progressive disease (n = 42, 11%). The majority of patients who have completed induction have been randomized and entered maintenance (n = 217). Median duration of response in the induction period was not reached (95% CI, 43.9 mo-NR), and median progression-free survival in the induction safety population (n = 393) was 50.5 mo (95% CI, 39.5-NR). Efficacy results are reported in the table by histology subgroups (FL vs MZL), and rituximab-refractory, double-refractory, and early relapse statuses. Most common all-grade AEs were 47% fatigue, 43% neutropenia, 37% diarrhea, 30% nausea, and 30% constipation. Grade 3/4 AEs occurring in ≥ 5% of patients included 37% neutropenia (10 patients [3%] had febrile neutropenia), 8% leukopenia, 6% thrombocytopenia, 5% anemia, and 5% fatigue. Conclusions: These data represent complete analysis of all patients in the induction phase of MAGNIFY which continue to support that R 2 is active with a tolerable safety profile in patients with R/R FL grade 1-3a and MZL, including rituximab-refractory, double-refractory, and early relapse patients. Figure 1 Figure 1. Disclosures Lansigan: Celgene/BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees. Andorsky: Abbvie: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding; Epizyme: Research Funding. Coleman: immunomedics: Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Abbvie: Research Funding; Bristol Myers: Research Funding; Celgene: Research Funding; Genentech: Research Funding; Gilead: Research Funding; BeiGene: Research Funding; Innocare: Research Funding; Merck: Research Funding; Pfizer: Research Funding; Roche: Research Funding. Yacoub: Dynavex: Current equity holder in publicly-traded company; Cara: Current equity holder in publicly-traded company; Ardelyx: Current equity holder in publicly-traded company; Agios: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; ACCELERON PHARMA: Membership on an entity's Board of Directors or advisory committees; CTI Biopharma: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Honoraria, Speakers Bureau; Seattle Genetics: Honoraria, Speakers Bureau; Hylapharm: Current equity holder in publicly-traded company. Melear: TG Therapeutics: Speakers Bureau; Astrazeneca: Speakers Bureau; Janssen: Speakers Bureau. Fanning: Sanofi: Speakers Bureau; Genmab: Membership on an entity's Board of Directors or advisory committees; TG Pharma: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech: Membership on an entity's Board of Directors or advisory committees; Takeda: Speakers Bureau; ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees; BMS: Speakers Bureau. Kolibaba: TG Therapeutics: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Atara Biotechm: Consultancy; McKesson Specialty Health: Consultancy; Sunitomo Dainippon Pharma: Consultancy; Tolero Pharma: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Nowakowski: Incyte: Consultancy; Kymera Therapeutics: Consultancy; TG Therapeutics: Consultancy; Blueprint Medicines: Consultancy; Nanostrings: Research Funding; Curis: Consultancy; Selvita: Consultancy; Zai Labolatory: Consultancy; Daiichi Sankyo: Consultancy; Bantham Pharmaceutical: Consultancy; Karyopharm Therapeutics: Consultancy; Ryvu Therapeutics: Consultancy; Genentech: Consultancy, Research Funding; Kyte Pharma: Consultancy; Roche: Consultancy, Research Funding; Celgene/Bristol Myers Squibb: Consultancy, Research Funding; MorphoSys: Consultancy. Gharibo: BMS: Current Employment, Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Ahn: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company; ADC therapeutics: Current equity holder in publicly-traded company. Li: BMS: Current Employment, Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding. Sharman: BeiGene: Consultancy; TG Therapeutics: Consultancy; Lilly: Consultancy; Centessa: Current holder of stock options in a privately-held company, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics LLC, an AbbVie Company: Consultancy; AstraZeneca: Consultancy; BMS: Consultancy; AbbVie: Consultancy.

Abstract INTRODUCTION: Luxeptinib (CG-806) is a potent, non-covalent oral inhibitor of BTK and FLT3. It suppresses BCR signaling pathways (LYN, SYK, BTK, AKT, ERK) and other oncogenic pathways in cell lines and primary CLL cells, kills malignant B-cells insensitive to ibrutinib or venetoclax at low nM concentrations, and shows enhanced activity in combination with venetoclax. Luxeptinib is currently being evaluated in a Phase 1a/b trial in patients with relapsed or refractory B-cell malignancies (NCT03893682). AIMS: Primary objectives are to assess the safety and tolerability of luxeptinib and determine the recommended expansion dose for future clinical trials in patients with R/R CLL/SLL or B-NHL. Key secondary objectives include elucidation of the pharmacokinetic (PK) and pharmacodynamic (PD) characteristics, and evidence of antitumor activity. METHODS: Luxeptinib is administered continuously as oral capsules BID in 28-day cycles, in ascending cohorts of 3 patients. Treatment emergent adverse events (TEAEs) and tumor responses are evaluated per disease specific guidelines. RESULTS: As of June 7, 2021, a total of 23 patients (median age 64.0 years, 11 CLL/SLL, 4 follicular lymphoma (FL), 1 Richter's transformation lymphoma, 2 Waldenstrom's macroglobulinemia (WM), 2 mantle cell lymphoma, 3 diffuse large B cell lymphoma (DLBCL)) with a median of 3 prior systemic regimens (range of 1 - 12) have been treated with luxeptinib at doses of 150 mg (n=1), 300 mg (n=1), 450 mg (n=9), 600 mg (n=4) and 750 mg (n=8). Drug related grade ≥ 3 TEAEs included neutropenia (n=5, 21.7%), leukocytosis (n=2, 8.7%), decreased white blood cell count, decreased platelet count, anemia, increased alanine aminotransferase, diarrhea, hypertension, and headache (n=1, 4.3 % each). One patient, who experienced progressive hypertension before receiving luxeptinib, developed grade 1 hypertension during screening evolving to grade 2 prior to dosing on C1D1, experienced grade 4 hypertension after luxeptinib treatment at 750 mg BID for 5 days. While this was considered a DLT per protocol, luxeptinib plasma levels in this patient were lower than those observed in patients at this and lower dose levels, and no drug-related hypertension has been observed in any other patient treated to date. The average steady-state (C min) plasma levels of luxeptinib in patients treated with 750 mg BID were > 1µM and were sustained over multiple cycles. PD analysis demonstrated that C min of luxeptinib in the plasma of patients treated with doses of 300 mg or higher significantly reduced levels of phosphorylated BTK, SYK, ERK and FLT3 in EOL-1 reporter cells in a plasma inhibitor activity assay, demonstrating multi-target engagement. Response evaluations were available for 12 patients who had at least one imaging study or IgM measurements (WM patients) after starting treatment. Eight out of these 12 patients had various reductions of lesion size or IgM measurements compared to baseline (3 SLL, 2 FL, 1 CLL, 1 WM and 1 DLBCL), demonstrating anti-tumor activity. FDG PET-CT scans in one FL patient, who had 2 prior regimens, revealed lesion growth during treatment with luxeptinib at 450 mg BID for 7 cycles. After dose-escalation to 600 mg BID in Cycle 8, lesion measurements demonstrated continuous reduction. By C15D1, target lesions decreased by 42.5% and 11.3% when compared with peak tumor size and baseline measurements, respectively. One WM patient in Cohort 5 (750 mg BID), who had 2 prior regimens including ibrutinib, has had a 24.9% reduction in IgM level by C3D1 compared with baseline as her best response so far. CONCLUSIONS: Luxeptinib has a favorable safety profile in patients treated with 150 mg to 600 mg BID over multiple cycles. A single apparent DLT (grade 4 hypertension in one patient with pre-existing hypertension) led to expansion of the 750 mg dose level to 6 patients. Pharmacodynamic studies documented inhibition of SYK, BTK and ERK in the BCR signaling pathway. Anti-tumor activity was observed in multiple B-NHL subtypes and CLL/SLL patients. Enrollment of patients with R/R CLL/SLL and B-NHL at dose level 5 (750 mg) is ongoing and updated clinical data will be presented at the meeting. Disclosures Samaniego: Arog: Research Funding; Imbrium: Membership on an entity's Board of Directors or advisory committees. Burke: AstraZeneca: Consultancy; Verastem: Consultancy; Bristol Myers Squibb: Consultancy; Epizyme: Consultancy; Kura: Consultancy; Kymera: Consultancy; SeaGen: Consultancy, Speakers Bureau; X4 Pharmaceuticals: Consultancy; Adaptive Biotechnologies: Consultancy; Beigene: Consultancy, Speakers Bureau; AbbVie: Consultancy; MorphoSys: Consultancy; Roche/Genentech: Consultancy. Mahadevan: caris: Speakers Bureau; Guardanthealt: Speakers Bureau; PFIZER: Other: Clinical trial Adverse events committee; TG Therapeuticals: Other: Clinical trial Adverse events committee. Cherry: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees. Sadiq: Dava Oncology: Honoraria. Reid: ADC Therapeutics: Other: Serves as Principle Investigator, Research Funding; Aptose Biosciences: Other: Serves as Principle Investigator, Research Funding; Millennium Pharmaceuticals: Other: Serves as Principle Investigator, Research Funding; Xencor: Other: Serves as Principle Investigator, Research Funding. Roeker: TG Therapeutics: Consultancy; Pfizer: Consultancy, Research Funding; AbbVie, AstraZeneca, Janssen, LOXO, Pharmacyclics, TG Therapeutics, Vaniam Group, Verastem: Consultancy; Loxo Oncology: Consultancy; Abbot Laboratories: Current equity holder in publicly-traded company; Pharmacyclics: Consultancy. Melear: Astrazeneca: Speakers Bureau; TG Therapeutics: Speakers Bureau; Janssen: Speakers Bureau. Zhang: Aptose Biosciences, Inc.: Current Employment. Rastgoo: Aptose Biosciences, Inc.: Current Employment. Benbatoul: Aptose Biosciences, Inc.: Current Employment. Haney: Aptose Biosciences, Inc.: Current Employment. Jin: Aptose Biosciences, Inc.: Current Employment. Marango: Aptose Biosciences, Inc.: Current Employment, Current equity holder in publicly-traded company. Howell: Aptose Biosciences, Inc.: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees, Research Funding. Rice: Oncolytics Biotech Inc.: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Aptose Biosciences, Inc.: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties. Bejar: Astex: Consultancy; Silence Therapeutics: Consultancy; Aptose Biosciences, Inc.: Current Employment, Current equity holder in publicly-traded company; Epizyme: Consultancy, Honoraria; Takeda: Research Funding; Gilead: Consultancy, Honoraria; BMS: Consultancy, Research Funding.

Background: Lenalidomide combined with rituximab (R2) has shown complimentary clinical activity and is a tolerable regimen in both untreated and relapsed or refractory (R/R) patients with indolent non-Hodgkin lymphoma. Patients with advanced age at diagnosis are considered to be high risk, supporting post-hoc subgroup analyses by age, with a focus on patients aged ≥ 70 years from the MAGNIFY study. Methods: MAGNIFY is a multicenter, phase IIIb trial in patients with R/R follicular lymphoma (FL) grades 1-3b, transformed FL (tFL), marginal zone lymphoma (MZL), or mantle cell lymphoma (MCL; NCT01996865) exploring optimal lenalidomide duration. Lenalidomide 20 mg on days 1-21 of a 28-day cycle + rituximab 375 mg/m2/week cycle 1 and then every 8 weeks starting with cycle 3 (R2) are administered for 12 cycles followed by 1:1 randomization in patients with stable disease, partial response, or complete response/complete response unconfirmed (CR/CRu) to R2 vs rituximab maintenance for 18 months. Data presented here focus on induction R2 in efficacy-evaluable FL grade 1-3a and MZL patients (FL grade 3b, tFL, and MCL not included) receiving ≥ 1 treatment with baseline/postbaseline assessments. The primary end point is progression-free survival (PFS) by 1999 International Working Group criteria. Post-hoc analyses were performed by analyzing data from patients aged ≥ 70 years at time of study entry. Results: As of November 30, 2019, 393 patients have enrolled and 152 (39%) were aged ≥ 70 years. Baseline characteristics including histology, disease status, and prior treatments of patients ≥ 70 and the overall population are shown in the table. Median PFS in the ≥ 70 subgroup was 36.0 months (95% CI, 28.3-NR). Overall response rate and CR/CRu were 75% and 38%, with a median duration of response that was not reached (95% CI, 27.1-NR). Efficacy results for the overall population are shown in the table. In patients ≥ 70 the most common (≥ 20%) any-grade treatment emergent adverse events (TEAEs) were fatigue (44%), neutropenia (41%), diarrhea (34%), constipation (34%), and nausea (27%). Neutropenia (35%) was the only grade 3/4 TEAE occurring in > 10% of patients (febrile neutropenia occurred in 3 patients [2%]). TEAEs led to lenalidomide dose reduction in 69 patients (46%) and discontinuation in 40 patients (26%). Seventy-eight patients ≥ 70 (51%) completed all 12 cycles of induction treatment, and 72 (47%) have entered the maintenance phase. Sixty-one patients ≥ 70 (40%), compared to 35% of patients in overall population, prematurely discontinued both lenalidomide and rituximab, due to TEAEs (n = 26; 17%), progressive disease (n = 15; 10%), patient withdrawal (n = 12; 8%), death (n = 5; 3%), and other reasons (n = 3; 2%). Neutropenia was the only TEAE leading to discontinuation of lenalidomide in more than 2 patients (n = 10; 7%). Conclusions: Similar to findings in the overall population, R2 treatment in advanced-age patients with R/R FL and MZL resulted in encouraging efficacy, and with close attention to dose reduction there is a tolerable safety profile. Table Disclosures Lansigan: BMS Steering Committee for MAGNIFY Program: Membership on an entity's Board of Directors or advisory committees; Spectrum Pharma: Consultancy, Research Funding; BMS: Consultancy; Seattle Genetics: Consultancy. Andorsky:AstraZeneca: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; CTI: Research Funding. Coleman:Novartis Pharmaceuticals: Research Funding; Merck Sharp & Dohme Corp.: Research Funding; Boston BIoMedical, Inc.: Research Funding; BeiGene: Research Funding; Acerta: Research Funding; Innocare: Research Funding; ARCUS Biosciences: Research Funding; AstraZeneca Pharmaceuticals, LP (Acerta Pharma BV Trials): Research Funding; AstraZeneca Pharmaceuticals, LP: Research Funding; BMS (Celgene Corporation): Research Funding; Eli Lilly and Company: Research Funding; EMD Serono Research and Development Institute Inc.: Research Funding; Genetech (F. Hoffman-LaRoche Ltd): Research Funding; Hutchinson MediPharma, LTD: Research Funding; Incyte Corporation: Research Funding; Ipsen Group: Research Funding; Karyopharma Therapeutics, Inc.: Research Funding; Klus Pharma, Inc.: Research Funding; MeiPharma, Inc.: Research Funding; Seattle Genetics: Research Funding. Yacoub:Novartis: Honoraria, Speakers Bureau; Agios: Speakers Bureau; Incyte: Speakers Bureau; Hylapharm: Current equity holder in private company; Cara therapeutics: Current equity holder in publicly-traded company; Ardelyx: Current equity holder in publicly-traded company; Dynavax: Current equity holder in publicly-traded company. Melear:AstraZeneca: Speakers Bureau; Janssen: Speakers Bureau. Fanning:Prisma Health: Current Employment; Abbvie: Consultancy; TG Therapeautics: Consultancy; Bristol Myers Squibb: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Sanofi Aventis: Speakers Bureau. Kolibaba:Compass Oncology: Ended employment in the past 24 months; Atara Biotech: Consultancy; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sumitomo Dainippon Pharma Oncology: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company; AbbVie: Research Funding; Acerta: Research Funding; Celgene: Research Funding; Genentech: Research Funding; Gilead: Research Funding; Pharmacyclics: Research Funding; Seattle Genetics: Research Funding; Verastem: Honoraria; Janssen: Research Funding; Novartix: Research Funding. Reynolds:IHA Hematology/Oncology Consultants: Current Employment. Nowakowski:Ryvu: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other; Nanostrings: Research Funding; Seattle Genetics: Consultancy; Curis: Consultancy; MorphoSys: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Kymera: Consultancy; Denovo: Consultancy; Kite: Consultancy; Celgene/BMS: Consultancy, Research Funding. Gharibo:Bayer: Ended employment in the past 24 months; Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Ahn:BMS: Current Employment, Current equity holder in publicly-traded company. Li:BMS: Current Employment, Current equity holder in publicly-traded company. Rummel:Celgene: Consultancy, Honoraria; Janssen: Honoraria; Amgen GmbH: Honoraria; Roche: Honoraria; Novartis Pharma GmbH: Honoraria. Sharman:Bristol Meyers Squibb: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Acerta: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; BeiGene: Research Funding; Genentech: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding.

Background: Relapse is expected when treating patients with follicular lymphoma (FL) and marginal zone lymphoma (MZL), with a shortened response associated with each relapse. Lenalidomide combined with rituximab (R2) has shown enhanced activity, with a recently reported median progression free-survival (PFS) of 39.4 months in patients with relapsed/refractory (R/R) indolent non-Hodgkin lymphoma, including those with FL and MZL (AUGMENT; J Clin Oncol. 2019;37:1188). Methods: MAGNIFY is a multicenter, phase IIIb trial in patients with R/R FL grades 1-3b, transformed FL (tFL), MZL, or mantle cell lymphoma (MCL; NCT01996865) in which optimal lenalidomide duration is being explored. Patients received 12 cycles of R2 (lenalidomide 20 mg/d, d1-21/28 + rituximab 375 mg/m2 weekly in cycle 1 and then on day 1 of cycles 3, 5, 7, 9, and 11) followed by 1:1 randomization in patients with stable disease, partial response, or complete response/complete response unconfirmed (CR/CRu) to R2 versus rituximab maintenance for 18 months. Data presented here focus on induction R2 in efficacy-evaluable MZL patients compared with the overall population of FL grades 1-3a+MZL (not including FL grade 3b, tFL, or MCL) receiving ≥ 1 treatment with baseline/post-baseline assessments. The primary end point is progression-free survival (PFS) by 1999 International Working Group criteria. Results: As of November 30, 2019, 393 patients with FL grades 1-3a and MZL enrolled; 76 (19%) had MZL. The median age of MZL patients was 68 years (range, 46-90), 68 (89%) had stage III/IV disease, and 72 (95%) had prior rituximab-containing therapy. Overall response rate was 68% with 39% CR/CRu, and median duration of response was 38.6 months (95% CI, 29.4-not reached [NR]). The median PFS was 41.2 months (95% CI, 38.4-NR). Efficacy results for MZL subtypes and the overall population (FL grades 1-3a + MZL) are shown in the table. Forty-two patients (55%) have completed 12 cycles of R2, and 41 (54%) have been randomized and entered maintenance. Twenty-eight patients (37%) prematurely discontinued both lenalidomide and rituximab, primarily due to adverse events (AEs; n = 11; 14%) and progressive disease (n = 6; 8%). The most common (≥ 20%) all-grade AEs were neutropenia (49%), diarrhea (37%), anemia (25%), thrombocytopenia (24%), and constipation (24%). Most common (≥ 10%) grade 3/4 AEs were neutropenia (41%; 1 patient [1%] had febrile neutropenia), thrombocytopenia (13%), and leukopenia (11%). Conclusions: R2 is active with a tolerable safety profile in patients with R/R MZL. The efficacy and safety profile of R2 in MZL patients were similar to results observed in the overall MAGNIFY population. Disclosures Coleman: Seattle Genetics: Research Funding; EMD Serono Research and Development Institute Inc.: Research Funding; Innocare: Research Funding; ARCUS Biosciences: Research Funding; AstraZeneca Pharmaceuticals, LP (Acerta Pharma BV Trials): Research Funding; AstraZeneca Pharmaceuticals, LP: Research Funding; BMS (Celgene Corporation): Research Funding; Eli Lilly and Company: Research Funding; Genetech (F. Hoffman-LaRoche Ltd): Research Funding; Hutchinson MediPharma, LTD: Research Funding; Ipsen Group: Research Funding; Karyopharma Therapeutics, Inc.: Research Funding; Klus Pharma, Inc.: Research Funding; MeiPharma, Inc.: Research Funding; Merck Sharp & Dohme Corp.: Research Funding; Novartis Pharmaceuticals: Research Funding; Incyte Corporation: Research Funding; Boston BIoMedical, Inc.: Research Funding; BeiGene: Research Funding; Acerta: Research Funding. Andorsky:CTI: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Research Funding. Yacoub:Roche: Other: Support of parent study and funding of editorial support; Dynavax: Current equity holder in publicly-traded company; Ardelyx: Current equity holder in publicly-traded company; Incyte: Speakers Bureau; Hylapharm: Current equity holder in private company; Cara Therapeutics: Current equity holder in publicly-traded company; Agios: Honoraria, Speakers Bureau; Novartis: Speakers Bureau. Melear:Janssen: Speakers Bureau; AstraZeneca: Speakers Bureau. Fanning:Takeda: Consultancy, Speakers Bureau; Bristol Myers Squibb: Consultancy, Speakers Bureau; TG Therapeautics: Consultancy; Abbvie: Consultancy; Prisma Health: Current Employment; Sanofi Aventis: Speakers Bureau. Kolibaba:Atara Biotech: Consultancy; Compass Oncology: Ended employment in the past 24 months; Verastem: Honoraria; Seattle Genetics: Research Funding; Pharmacyclics: Research Funding; Novartix: Research Funding; Janssen: Research Funding; Gilead: Research Funding; Genentech: Research Funding; Celgene: Research Funding; Acerta: Research Funding; AbbVie: Research Funding; Sumitomo Dainippon Pharma Oncology: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Lansigan:BMS: Consultancy; Seattle Genetics: Consultancy; BMS Steering Committee for MAGNIFY Program: Membership on an entity's Board of Directors or advisory committees; Spectrum Pharma: Consultancy, Research Funding. Reynolds:IHA Hematology/Oncology Consultants: Current Employment. Nowakowski:Kymera: Consultancy; Ryvu: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other; Curis: Consultancy; Kite: Consultancy; MorphoSys: Consultancy, Research Funding; Denovo: Consultancy; Seattle Genetics: Consultancy; Nanostrings: Research Funding; Celgene/BMS: Consultancy, Research Funding; Roche: Consultancy, Research Funding. Gharibo:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company; Bayer: Ended employment in the past 24 months. Ahn:BMS: Current Employment, Current equity holder in publicly-traded company. Li:BMS: Current Employment, Current equity holder in publicly-traded company. Rummel:Roche: Honoraria; Amgen GmbH: Honoraria; Celgene: Consultancy, Honoraria; Janssen: Honoraria; Novartis Pharma GmbH: Honoraria. Sharman:BeiGene: Research Funding; Bristol Meyers Squibb: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; Acerta: Consultancy, Research Funding; Roche: Consultancy, Research Funding; Celgene: Consultancy, Research Funding.