Phase I Trial of Targeted Alpha-Particle Therapy Using Actinium-225 (225Ac)-Lintuzumab (Anti-CD33) in Combination with Low-Dose Cytarabine (LDAC) for Older Patients with Untreated Acute Myeloid Leukemia (AML)

Abstract Background: Lintuzumab, a humanized anti-CD33 monoclonal antibody, targets myeloid leukemia cells but has only modest activity in AML. To increase the antibody’s potency yet avoid nonspecific cytotoxicity of β-emitting isotopes, 225Ac (t½=10 d), a radiometal that yields 4 α-particles, was conjugated to lintuzumab. A phase I trial showed that 225Ac-lintuzumab is safe at doses ≤ 3 µCi/kg and has anti-leukemic activity across all dose levels studied (Jurcic et al. ASH, 2011). We are conducting a multicenter, phase I dose-escalation trial to determine the maximum tolerated dose (MTD), toxicity, and biological activity of fractionated-dose 225Ac-lintuzumab in combination with LDAC. Patients and Methods: Patients ≥ 60 yrs who had untreated AML with poor prognostic factors, e.g., an antecedent hematologic disorder, unfavorable cytogenetic or molecular abnormalities, and significant comorbidities, were eligible. Patients received LDAC 20 mg twice daily for 10 d every 4-6 wks for up to 12 cycles. During Cycle 1, beginning 4-7 days after completion of LDAC, two doses of 225Ac-lintuzumab were given approximately one week apart. To prevent radiation-induced nephrotoxicity, patients were given furosemide while receiving 225Ac-lintuzumab and spironolactone for one year afterward. Results: Nine patients (median age, 76 yrs; range, 73-81 yrs) were treated. Seven patients (78%) had a history of myelodysplastic syndromes (MDS), for which five (56%) received prior therapy with hypomethylating agents (n=4) or allogeneic hematopoietic cell transplantation (n=1). One patient (11%) had chronic myeloid leukemia in a molecularly undetectable state at the time of AML diagnosis. Six patients (67%) had intermediate-risk cytogenetics, and three (33%) had unfavorable cytogenetics. The median CD33 expression was 76% (range, 45-100%). Patients received 225Ac-lintuzumab at doses of 0.5 (n=3) or 1 (n=6) μCi/kg/fraction. Total administered activity ranged from 68-199 μCi. The median number of cycles administered was 2 (range, 1-4). Dose-limiting toxicity was seen in one patient receiving 1 µCi/kg/fraction who had grade 4 thrombocytopenia with bone marrow aplasia persisting > 6 wks after receiving 225Ac-lintuzumab. Hematologic toxicities included grade 4 neutropenia (n=1) and thrombocytopenia (n=3). Grade 3/4 non-hematologic toxicities included febrile neutropenia (n=6), pneumonia (n=2), bacteremia (n=1), cellulitis (n=1), transient increase in creatinine (n=1), hypokalemia (n=1), and generalized weakness (n=1). Bone marrow blast reductions were seen in 5 of 7 patients (71%) evaluated after Cycle 1. Mean blast reduction was 61% (range, 34-100%). Three of the 7 patients (43%) had marrow blast reductions of ≥ 50%; however, no remissions were observed. Median progression-free survival (PFS) was 2.5 mos (range, 1.7-15.7+ mos). Median overall survival (OS) from study entry was 5.4 mos (range, 2.2-24 mos). For the 7 patients with prior MDS, median OS was 9.1 mos (range 2.3-24 mos). Conclusions: Fractionated-dose 225Ac-linutuzmab in combination with LDAC is feasible, safe, and has anti-leukemic activity. Dose escalation continues to define the MTD, with planned doses up to 2 µCi/kg/fraction. Additional patients will be treated at the MTD in the phase II portion of this trial to determine response rate, PFS, and OS. Disclosures Ravandi: Actinium Pharmaceuticals, Inc.: Research Funding. Pagel:Actinium Pharmaceuticals, Inc.: Equity Ownership, Research Funding. Park:Actinium Pharmaceuticals, Inc.: Research Funding. Wahl:Actinium Pharmaceuticals, Inc.: Research Funding. Earle:Actinium Pharmaceuticals, Inc.: Employment, Equity Ownership. Cicic:Actinium Pharmaceuticals, Inc.: Employment, Equity Ownership. Scheinberg:Actinium Pharmaceuticals, Inc.: Equity Ownership, Research Funding.

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Phase I Trial Of The Targeted Alpha-Particle Nano-Generator Actinium-225 (225Ac)-Lintuzumab (Anti-CD33) In Combination With Low-Dose Cytarabine (LDAC) For Older Patients With Untreated Acute Myeloid Leukemia (AML)

Blood ◽

10.1182/blood.v122.21.1460.1460 ◽

2013 ◽

Vol 122 (21) ◽

pp. 1460-1460 ◽

Cited By ~ 16

Author(s):

Joseph G. Jurcic ◽

Farhad Ravandi ◽

John M. Pagel ◽

Jae H Park ◽

Dan Douer ◽

...

Keyword(s):

Bone Marrow ◽

Phase I ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Phase I Trial ◽

Advisory Committees ◽

Molecular Abnormalities ◽

Equity Ownership ◽

Dose Levels

Abstract Background Lintuzumab, a humanized anti-CD33 antibody, targets myeloid leukemia cells and has modest activity against AML. To increase the antibody’s potency yet avoid nonspecific cytotoxicity seen with β-emitting isotopes, the isotope generator 225Ac (t½=10 days), which yields 4 α-particles, was conjugated to lintuzumab. A phase I trial demonstrated that 225Ac-lintuzumab is safe at doses ≤ 3 μCi/kg and has anti-leukemic activity across all dose levels studied (Jurcic et al. ASH, 2011). We are conducting a multicenter, phase I dose escalation trial to determine the maximum tolerated dose (MTD), toxicity, and biological activity of fractionated-dose 225Ac-lintuzumab in combination with LDAC. Patients and Methods Patients ≥ 60 yrs who had untreated AML with poor-prognostic factors, such as an antecedent hematologic disorder (AHD), unfavorable cytogenetic or molecular abnormalities, and significant comorbidities, were eligible. Patients received LDAC 20 mg bid for 10 days every 4-6 weeks. During cycle 1, beginning 4-7 days after LDAC, two doses of 225Ac-lintuzumab were given approximately one week apart. Results Seven patients (median age, 76 yrs; range, 72-80 yrs) were treated, all of whom had AHDs. Five (71%) had intermediate-risk cytogenetics, and two (29%) had unfavorable cytogenetics. The median CD33 expression was 76% (range, 69-95%). Prior therapy for myelodysplastic syndrome included hypomethylating agents (n=4) and allogeneic hematopoietic cell transplantation (n=1). Patients received 225Ac-lintuzumab at doses of 0.5 (n=3) or 1 (n=4) μCi/kg/fraction, two fractions per patient (total administered activity, 68-199 μCi). Dose-limiting toxicity was seen in one patient receiving 1 μCi/kg/fraction who had grade 4 thrombocytopenia in the setting of an aplastic bone marrow that persisted > 6 wks after completing the second fraction of 225Ac-lintuzumab. Other toxicities included grade 3 febrile neutropenia (n=5), bacteremia (n=1), pneumonia (n=1), cellulitis (n=1), transient increase in creatinine (n=1), and generalized weakness (n=1). Bone marrow blast reductions were seen in 4 of 6 evaluable patients (67%) after cycle 1 (mean blast reduction, 58%; range, 34-100%). No CRs, however, were observed. The median number of cycles administered was 2 (range, 1-4), and the median time to progression was 2.5 months (range, 2-7+ months). Conclusions Fractionated-dose 225Ac-linutuzmab in combination with LDAC is feasible, safe, and has anti-leukemic activity. Accrual continues to define the MTD, with planned dose levels up to 2 μCi/kg/fraction. Additional patients will be treated at the MTD in the phase II portion of this trial to determine response rate, progression-free survival, and overall survival. Disclosures: Jurcic: Actinium Pharmaceuticals, Inc.: Membership on an entity’s Board of Directors or advisory committees. Ravandi:Actinium Pharmaceuticals, Inc.: Research Funding. Pagel:Actinium Pharmaceuticals, Inc.: Equity Ownership, Membership on an entity’s Board of Directors or advisory committees, Research Funding. Park:Actinium Pharmaceuticals, Inc.: Research Funding. Douer:Actinium Pharmaceuticals, Inc.: Research Funding. Estey:Actinium Pharmaceuticals, Inc.: Membership on an entity’s Board of Directors or advisory committees. Cicic:Actinium Pharmaceuticals, Inc.: Employment, Equity Ownership. Scheinberg:Actinium Pharmaceuticals, Inc.: Ac-225-Lintuzumab, Ac-225-Lintuzumab Patents & Royalties, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees.

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Phase I Trial of Targeted Alpha-Particle Therapy with Actinium-225 (225Ac)-Lintuzumab and Low-Dose Cytarabine (LDAC) in Patients Age 60 or Older with Untreated Acute Myeloid Leukemia (AML)

Blood ◽

10.1182/blood.v128.22.4050.4050 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4050-4050 ◽

Cited By ~ 23

Author(s):

Joseph G. Jurcic ◽

Moshe Yair Levy ◽

Jae H. Park ◽

Farhad Ravandi ◽

Alexander E. Perl ◽

...

Keyword(s):

Phase I ◽

Phase Ii ◽

Dose Escalation ◽

Initial Phase ◽

Myeloid Leukemia ◽

Research Funding ◽

Phase I Trial ◽

Poor Risk ◽

Genetics Research ◽

Equity Ownership

Abstract Background: 225Ac-lintuzumab is a radioimmunoconjugate composed of 225Ac (t½=10 days), which emits 4 α-particles, linked to a humanized anti-CD33 monoclonal antibody. Short-ranged (50-80 µm), high-energy (~100 keV/µm) α particle-emitting isotopes such as 225Ac may result in more specific tumor cell kill and less damage to normal tissues than β-emitters. An initial phase I trial in 20 patients with relapsed/refractory AML showed that a single infusion of 225Ac-lintuzumab is safe at doses ≤ 3 µCi/kg and has anti-leukemic activity (Jurcic et al. ASH, 2011). We conducted a multicenter, phase I dose-escalation trial to determine the maximum tolerated dose (MTD), toxicity, and biological activity of fractionated-dose 225Ac-lintuzumab in combination with LDAC. Patients and Methods: Patients ≥ 60 years with untreated AML not candidates for standard induction therapy (e.g., antecedent hematologic disorder, poor-risk cytogenetic or molecular features, and significant comorbidities) were eligible. Patients received LDAC 20 mg twice a day for 10 days every 4-6 weeks for up to 12 cycles. During Cycle 1, 2 fractions of 225Ac-lintuzumab were given 1 week apart, beginning 4-7 days following completion of LDAC. To prevent radiation-induced nephrotoxicity, patients were given furosemide while receiving 225Ac-lintuzumab then spironolactone for 1 year afterward. Four dose levels of 225Ac-lintuzumab were studied using a 3+3 design. Dose escalation proceeded if < 33% of patients in a cohort experienced dose-limiting toxicity (DLT). Results: Eighteen patients (median age, 77 years; range, 68-87 years) completed therapy. Twelve (67%) had prior myelodysplastic syndrome (MDS), for which 10 (83%) received therapy with hypomethylating agents (n=9) or allogeneic hematopoietic cell transplantation (n=1). One patient (6%) had chronic myeloid leukemia in molecular remission prior to developing AML. Eleven patients (61%) had intermediate-risk and 7 (39%) had poor-risk disease by NCCN criteria. Median CD33 expression was 81% (range, 30-100%). 225Ac-lintuzumab was given at 0.5 (n=3), 1 (n=6), 1.5 (n=3), or 2 (n=6) μCi/kg/fraction. Up to 4 cycles of LDAC were administered. Two patients experienced DLT (grade 4 thrombocytopenia with marrow aplasia for > 6 weeks following therapy), one each in the 1 and 2 µCi/kg/fraction cohorts. Although the MTD was not reached, 2 µCi/kg/fraction was chosen as the phase II dose to limit prolonged myelosuppression. Hematologic toxicities included grade 4 neutropenia (n=5) and thrombocytopenia (n=9). Grade 3/4 non-hematologic toxicities included febrile neutropenia (n=6), pneumonia (n=5), other infections (n=3), atrial fibrillation/syncope (n=1), transient creatinine increase (n=1), generalized fatigue (n=1), hypokalemia (n=1), mucositis (n=1), and rectal hemorrhage (n=1). Thirty- and 60-day mortality rates were 0% and 17%, respectively. Eleven of 14 patients (79%) evaluated after Cycle 1 had bone marrow blast reductions (mean reduction, 66%; range, 19-100%). Objective responses (2 CR, 1 CRp, 2 CRi) were seen in 5 of the 18 patients (28%), but only at doses ≥ 1 µCi/kg/fraction (Table 1). One of the responders received 15 cycles of azacitidine for prior MDS. All responses occurred after 1 cycle of therapy, in contrast to historical data with LDAC alone, where the median time to response was 3 cycles. Median progression-free survival (PFS) for all patients was 2.7 months (range, 1.0-31.8+ months). Median overall survival (OS) was 5.6 months (range, 1.6-32+ months). Median response duration was 5.6 months (range, 4.9-32+ months). Peripheral blood blast counts were a strong predictor of response. Among 38 patients treated in the current and initial phase I trials, responses were seen in 8 of 19 patients (42%) with blast counts < 200/µL, compared with 0 of 17 patients with blast counts ≥ 200/µL (P=0.002). This difference is likely due to decreased marrow targeting in patients with higher circulating blast counts when the subsaturating antibody doses used in this trial are given. Conclusions: Fractionated-dose 225Ac-linutuzmab can be safely combined with LDAC and induce remission in older patients with untreated AML. A phase II trial of 225Ac-lintuzumab monotherapy at 2 µCi/kg/fraction using hydroxyurea, if needed, to lower peripheral blast counts prior toadministration will be undertaken to determine response rate, PFS, and OS in this patient population. Disclosures Jurcic: Forma Therapeutics: Research Funding; Seattle Genetics: Research Funding; Kura Oncology: Research Funding; Celgene: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy; Alexion Pharmaceuticals: Consultancy; Merck & Co.: Consultancy; Astellas: Research Funding; Actinium Pharmaceuticals, Inc.: Research Funding; Daiichi-Sankyo: Research Funding. Levy:Janssen: Speakers Bureau; Actinium Pharmaceuticals, Inc.: Research Funding; Seattle Genetics: Research Funding; Amgen: Speakers Bureau; Takeda Pharmaceuticals International Co.: Speakers Bureau. Park:Amgen: Consultancy; Genentech/Roche: Research Funding; Juno Therapeutics: Consultancy, Research Funding. Ravandi:Actinium Pharmaceuticals, Inc.: Research Funding. Perl:Actinium Pharmaceuticals, Inc.: Research Funding; Seattle Genetics: Consultancy. Smith:Actinium Pharmaceuticals, Inc.: Research Funding. Cicic:Actinium Pharmaceuticals, Inc.: Employment, Equity Ownership. Scheinberg:Actinium Pharmaceuticals, Inc.: Equity Ownership, Patents & Royalties: Ac-225-Lintuzumab.

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Phase I Trial of Targeted Alpha-Particle Immunotherapy with Actinium-225 (225Ac)-Lintuzumab (Anti-CD33) and Low-Dose Cytarabine (LDAC) in Older Patients with Untreated Acute Myeloid Leukemia (AML)

Blood ◽

10.1182/blood.v126.23.3794.3794 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3794-3794 ◽

Cited By ~ 7

Author(s):

Joseph G. Jurcic ◽

Farhad Ravandi ◽

John M. Pagel ◽

Jae H. Park ◽

B. Douglas Smith ◽

...

Keyword(s):

Phase I ◽

Board Of Directors ◽

Dose Escalation ◽

Older Patients ◽

Myeloid Leukemia ◽

Research Funding ◽

Phase I Trial ◽

Advisory Committees ◽

Equity Ownership ◽

Dose Levels

Abstract Background: The use of short-ranged (50-80 µm), high-energy (~100 keV/µm) α particle-emitting isotopes for radioimmunotherapy may result in more specific tumor cell kill and less damage to normal tissues than β-emitters. 225Ac-lintuzumab consists of a radiometal that emits four α-particles linked to an anti-CD33 antibody. A phase I trial showed that 225Ac-lintuzumab is safe at doses ≤ 3 µCi/kg and has anti-tumor activity against relapsed/refractory AML across all dose levels studied (Jurcic et al. ASH, 2011). We are conducting a multicenter, phase I dose-escalation trial to determine the maximum tolerated dose (MTD), toxicity, and biological activity of fractionated-dose 225Ac-lintuzumab in combination with LDAC. Patients and Methods: Patients ≥ 60 years with untreated AML not suitable for standard induction chemotherapy (e.g., antecedent hematologic disorder, unfavorable cytogenetic or molecular abnormalities, and significant comorbidities) were eligible. Patients received LDAC 20 mg twice daily for 10 days every 4-6 weeks for up to 12 cycles. During Cycle 1, two fractions of 225Ac-lintuzumab were given one week apart, beginning 4-7 days following completion of LDAC. To prevent radiation-induced nephrotoxicity, patients were given furosemide while receiving 225Ac-lintuzumab and spironolactone for one year afterward. 225Ac doses were escalated using a 3+3 design. Four dose levels were studied with a total accrual of up to 24 patients. In planned analyses, dose escalation proceeded if < 33% of patients in a cohort experienced dose-limiting toxicity (DLT). Results: Fourteen patients (median age, 77 years; range, 68-87 years) completed therapy. An additional patient received only one of two planned fractions of 225Ac-lintuzumab due to technical issues and is excluded from analysis. Nine (64%) had prior myelodysplastic syndrome, for which seven received prior therapy with hypomethylating agents (n=6) or allogeneic hematopoietic cell transplantation (n=1). One patient (7%) had chronic myeloid leukemia in molecular remission prior to development of AML. Nine patients (64%) had intermediate-risk and five (36%) had unfavorable cytogenetics. Median CD33 expression was 81% (range, 45-100%). 225Ac-lintuzumab was given at 0.5 (n=3), 1 (n=6), 1.5 (n=3), or 2 (n=2) μCi/kg/fraction. Up to 4 cycles of LDAC were administered. DLT was seen in one patient at 1 µCi/kg/fraction who had grade 4 thrombocytopenia with marrow aplasia for more than 6 weeks following therapy. Hematologic toxicities included grade 4 neutropenia (n=4) and thrombocytopenia (n=6). Grade 3/4 non-hematologic toxicities included febrile neutropenia (n=7), pneumonia (n=4), bacteremia (n=1), cellulitis (n=1), transient creatinine increase (n=1), hypokalemia (n=1), rectal hemorrhage (n=1), and generalized weakness (n=2). Eight of 11 patients (73%) evaluated after Cycle 1 had bone marrow blast reductions (mean reduction, 72%; range, 34-100%). Seven (64%) had blast reductions of at least 50%. Objective responses (1 CR, 1 CRp, 2 CRi) were seen in four of the 14 patients (29%) after one cycle of therapy (Table 1). Responses were seen only at doses ≥ 1 µCi/kg/fraction (4 of 11 patients, 36%). Median progression-free survival (PFS) was 2.7 months (range, 1.7-16.9 months). Median overall survival (OS) was 5.5 months (range, 2.2-24 months). Conclusions: Fractionated-dose 225Ac-linutuzmab can be safely combined with LDAC and produce remission in older patients with untreated AML. Dose escalation continues to define the MTD. Additional patients will be treated at the MTD in the phase II portion of this trial to determine response rate, PFS, and OS. Table 1. Objective Responses Response Dose Level (μCi/kg/fraction) Total (n=14) 0.5 (n=3) 1 (n=6) 1.5 (n=3) 2 (n=2) CR 0 0 1 (33%) 0 1 (7%) CRp 0 0 0 1 (50%) 1 (7%) CRi 0 1 (17%) 1 (33%) 0 2 (14%) Overall Response 0 1 (17%) 2 (67%) 1 (50%) 4 (29%) Abbreviations: CR, complete remission; CRp, CR with incomplete platelet recovery; CRi, CR with incomplete count recovery. Disclosures Jurcic: Ambit Biosciences: Research Funding; Astellas Pharma US, Invc.: Research Funding; Tetralogic Pharmaceuticals: Research Funding; Sunesis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy; Bayer Pharmaceuticals: Consultancy; Merck and Co.: Consultancy; Celgene Corp.: Research Funding; Actrinium Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding. Off Label Use: Ac-225-lintuzumab is an investigational agent being developed for the treatment of acute myeloid leukemia.. Pagel:Actinium Pharmacetuicals, Inc.: Equity Ownership. Park:Actinium Pharmaceuticals, Inc.: Research Funding; Juno Therapeutics: Consultancy. Levy:Takeda: Consultancy. Perl:Actinium Pharmaceuticals, Inc.: Research Funding. Earle:Actinium Pharmaceuticals, Inc.: Employment. Cicic:Actinium Pharmaceuticals, Inc.: Employment, Equity Ownership. Scheinberg:Actinium Pharmaceuticals, Inc.: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.

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EZH2 Mutations and Impact on Clinical Outcome Analyzed in 1604 Patients with Acute Myeloid Leukemia

Blood ◽

10.1182/blood-2018-99-114421 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1528-1528

Author(s):

Sebastian Stasik ◽

Jan Moritz Middeke ◽

Michael Kramer ◽

Christoph Rollig ◽

Alwin Krämer ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Employment Equity ◽

Advisory Committees ◽

Mutational Status ◽

Equity Ownership ◽

Acute Myeloid

Abstract Purpose: The enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase and key epigenetic regulator involved in transcriptional repression and embryonic development. Loss of EZH2 activity by inactivating mutations is associated with poor prognosis in myeloid malignancies such as MDS. More recently, EZH2 inactivation was shown to induce chemoresistance in acute myeloid leukemia (AML) (Göllner et al., 2017). Data on the frequency and prognostic role of EZH2-mutations in AML are rare and mostly confined to smaller cohorts. To investigate the prevalence and prognostic impact of this alteration in more detail, we analyzed a large cohort of AML patients (n = 1604) for EZH2 mutations. Patients and Methods: All patients analyzed had newly diagnosed AML, were registered in clinical protocols of the Study Alliance Leukemia (SAL) (AML96, AML2003 or AML60+, SORAML) and had available material at diagnosis. Screening for EZH2 mutations and associated alterations was done using Next-Generation Sequencing (NGS) (TruSight Myeloid Sequencing Panel, Illumina) on an Illumina MiSeq-system using bone marrow or peripheral blood. Detection was conducted with a defined cut-off of 5% variant allele frequency (VAF). All samples below the predefined threshold were classified as EZH2 wild type (wt). Patient clinical characteristics and co-mutations were analyzed according to the mutational status. Furthermore, multivariate analysis was used to identify the impact of EZH2 mutations on outcome. Results: EZH2-mutations were found in 63 of 1604 (4%) patients, with a median VAF of 44% (range 6-97%; median coverage 3077x). Mutations were detected within several exons (2-6; 8-12; 14-20) with highest frequencies in exons 17 and 18 (29%). The majority of detected mutations (71% missense and 29% nonsense/frameshift) were single nucleotide variants (SNVs) (87%), followed by small indel mutations. Descriptive statistics of clinical parameters and associated co-mutations revealed significant differences between EZH2-mut and -wt patients. At diagnosis, patients with EZH2 mutations were significantly older (median age 59 yrs) than EZH2-wt patients (median 56 yrs; p=0.044). In addition, significantly fewer EZH2-mut patients (71%) were diagnosed with de novo AML compared to EZH2-wt patients (84%; p=0.036). Accordingly, EZH2-mut patients had a higher rate of secondary acute myeloid leukemia (sAML) (21%), evolving from prior MDS or after prior chemotherapy (tAML) (8%; p=0.036). Also, bone marrow (and blood) blast counts differed between the two groups (EZH2-mut patients had significantly lower BM and PB blast counts; p=0.013). In contrast, no differences were observed for WBC counts, karyotype, ECOG performance status and ELN-2017 risk category compared to EZH2-wt patients. Based on cytogenetics according to the 2017 ELN criteria, 35% of EZH2-mut patients were categorized with favorable risk, 28% had intermediate and 37% adverse risk. No association was seen with -7/7q-. In the group of EZH2-mut AML patients, significantly higher rates of co-mutations were detected in RUNX1 (25%), ASXL1 (22%) and NRAS (25%) compared to EZH2-wt patients (with 10%; 8% and 15%, respectively). Vice versa, concomitant mutations in NPM1 were (non-significantly) more common in EZH2-wt patients (33%) vs EZH2-mut patients (21%). For other frequently mutated genes in AML there was no major difference between EZH2-mut and -wt patients, e.g. FLT3ITD (13%), FLT3TKD (10%) and CEBPA (24%), as well as genes encoding epigenetic modifiers, namely, DNMT3A (21%), IDH1/2 (11/14%), and TET2 (21%). The correlation of EZH2 mutational status with clinical outcomes showed no effect of EZH2 mutations on the rate of complete remission (CR), relapse free survival (RFS) and overall survival (OS) (with a median OS of 18.4 and 17.1 months for EZH2-mut and -wt patients, respectively) in the univariate analyses. Likewise, the multivariate analysis with clinical variable such as age, cytogenetics and WBC using Cox proportional hazard regression, revealed that EZH2 mutations were not an independent risk factor for OS or RFS. Conclusion EZH mutations are recurrent alterations in patients with AML. The association with certain clinical factors and typical mutations such as RUNX1 and ASXL1 points to the fact that these mutations are associated with secondary AML. Our data do not indicate that EZH2 mutations represent an independent prognostic factor. Disclosures Middeke: Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Rollig:Bayer: Research Funding; Janssen: Research Funding. Scholl:Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Abbivie: Other: Travel support; Alexion: Other: Travel support; MDS: Other: Travel support; Novartis: Other: Travel support; Deutsche Krebshilfe: Research Funding; Carreras Foundation: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees. Hochhaus:Pfizer: Research Funding; Incyte: Research Funding; Novartis: Research Funding; Bristol-Myers Squibb: Research Funding; Takeda: Research Funding. Brümmendorf:Janssen: Consultancy; Takeda: Consultancy; Novartis: Consultancy, Research Funding; Merck: Consultancy; Pfizer: Consultancy, Research Funding. Burchert:AOP Orphan: Honoraria, Research Funding; Bayer: Research Funding; Pfizer: Honoraria; Bristol Myers Squibb: Honoraria, Research Funding; Novartis: Research Funding. Krause:Novartis: Research Funding. Hänel:Amgen: Honoraria; Roche: Honoraria; Takeda: Honoraria; Novartis: Honoraria. Platzbecker:Celgene: Research Funding. Mayer:Eisai: Research Funding; Novartis: Research Funding; Roche: Research Funding; Johnson & Johnson: Research Funding; Affimed: Research Funding. Serve:Bayer: Research Funding. Ehninger:Cellex Gesellschaft fuer Zellgewinnung mbH: Employment, Equity Ownership; Bayer: Research Funding; GEMoaB Monoclonals GmbH: Employment, Equity Ownership. Thiede:AgenDix: Other: Ownership; Novartis: Honoraria, Research Funding.

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Nascent Transcript and Single Cell Rnaseq Analysis Defines the Mechanism of Action of the LSD1 Inhibitor INCB059872 in Myeloid Leukemia

Blood ◽

10.1182/blood-2019-130458 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2509-2509

Author(s):

Gretchen Johnston ◽

Haley E. Ramsey ◽

Kristy Stengel ◽

Shilpa Sampathi ◽

Pankaj Acharya ◽

...

Keyword(s):

Bone Marrow ◽

Drug Treatment ◽

Board Of Directors ◽

Myeloid Leukemia ◽

Research Funding ◽

Myeloid Differentiation ◽

Employment Equity ◽

Advisory Committees ◽

Equity Ownership ◽

Upregulated Genes

Drugs targeting chromatin-modifying enzymes have entered clinical trials for myeloid malignancies, including INCB059872, a selective irreversible inhibitor of Lysine-Specific Demethylase 1 (LSD1). LSD1 is a component of the CoREST complex, in which it associates with histone deacetylases 1 and 2, the transcriptional co-repressor, mSin3A or mSin3B, and the REST corepressor (RCOR1), so a role in gene expression was expected. While initial studies of LSD1 inhibitors have suggested these compounds may be used to induce differentiation of acute myeloid leukemia, the mechanisms underlying this effect and dose-limiting toxicities are not well understood. Here, we have used precision nuclear run-on sequencing (PROseq) and single-cell RNA-sequencing (scRNAseq) to show that INCB059872 de-represses GFI1/GFI1B-regulated genes to promote a myeloid differentiation gene signature in AML cells while stalling maturation of megakaryocyte progenitor cells. Within 3 days of treatment with INCB059872, the majority of THP-1, which contain an the MLL-translocation, undergo myeloid differentiation. RNAseq analysis indicated that 24h drug treatment upregulated genes involved in hematopoietic cell lineage, which is consistent with the differentiation. In addition, PROseq was used to measure the effects of INCB059872 on nascent transcription at genes and enhancers, as this is one of the best methods to define enhancer activity. In THP-1 cells after 24h treatment, there were 203 genes with at least a 1.5-fold increase in transcription, while there are nearly 1300 enhancers meeting this threshold. Upregulated genes include those associated with myeloid cell differentiation, such as CSF1R and CD86. Given that LSD1 catalyzes the removal of mono- and di-methyl marks from histone H3, we expected that INCB059872 would cause a buildup of histone methylation. Surprisingly, ChIPseq for H3K4me2 and H3K4me1 showed only subtle changes in these marks after 48h drug treatment in THP-1. Only a handful of LSD1i-induced enhancers overlapped with detectable changes in H3K4 methylation. However, our PROseq data is consistent with the increases in H3K27 acetylation seen with OG86 (a compound that disrupts the LSD1:GFI1 interaction) at GFI1 binding sites (PMID: 29590629). Indeed, motif analysis of INCB059872-upregulated enhancers identified the GFI1 recognition sequence as the most highly enriched. Moreover, siRNA inhibition of key components of LSD1-containing chromatin remodeling complexes pinpointed the CoREST complex as mediating the THP-1 myeloid differentiation effects of INCB059872. To investigate on-target thrombocytopenia seen with LSD1 inhibitors in preclinical studies, we analyzed the bone marrow of wild-type mice treated daily with INCB059872 for 0, 4, or 6 days before harvesting and sorting lin-bone marrow cells for scRNA-seq. Notably, one of the most highly upregulated genes in treated cells was Gfi1b. Unsupervised clustering identified 22 clusters, corresponding to unique subpopulations (Fig. 1A). While the distribution of cells into different progenitor populations was mostly unaffected by drug treatment, these data revealed a striking increase in the proportion of cells from treated mice assigned to a megakaryocyte stem/progenitor cluster. Cells within this expanded cluster expressed stem cell markers such as MYCN and PBX1, but also expressed VWF (Fig. 1B). Thus, LSD1 inhibition caused accumulation of megakaryopoiesis-biased stem cells that failed to mature into efficient platelet producers. Finally, we used scRNAseq to analyze bone marrow from an AML patient who responded to treatment with INCB059872 plus azacytidine (AZA). A pre-treatment bone marrow sample was divided into separate cultures to study the effects of INCB059872, AZA, or the combination. Remarkably, unsupervised clustering of patient cells assigned the majority of INCB059872 and combination-treated cells to clusters that were not found in control- or AZA-treated samples. Cells exposed to INCB059872 had upregulated GFI1 and GFI1B, as well as differentiation-related genes that were also observed in AML cell lines. Overall, these data indicate that INCB059872 affects gene expression with kinetics consistent with a loss of CoREST activity to stimulate differentiation of AML blasts, but the inactivation of GFI1/GFI1B impairs megakaryocyte maturation likely explaining thrombocytopenia seen in preclinical models. Disclosures Stubbs: Incyte Corporation: Employment, Equity Ownership. Burn:Incyte: Employment, Equity Ownership. Hiebert:Incyte Corporation: Research Funding. Savona:Karyopharm Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Incyte Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Selvita: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sunesis: Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer Ingelheim: Patents & Royalties; AbbVie: Membership on an entity's Board of Directors or advisory committees.

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Changing the Natural History of Fanconi Anemia Complementation Group-A with Gene Therapy: Early Results of U.S. Phase I Study of Lentiviral-Mediated Ex-VivoFANCA Gene Insertion in Human Stem and Progenitor Cells

Blood ◽

10.1182/blood-2019-127352 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3350-3350

Author(s):

Agnieszka Czechowicz ◽

Maria Grazia Roncarolo ◽

Brian C Beard ◽

Ken Law ◽

Eileen Nicoletti ◽

...

Keyword(s):

Bone Marrow ◽

Phase I ◽

Peripheral Blood ◽

Research Funding ◽

Phase I Study ◽

Employment Equity ◽

Hematopoietic Stem ◽

Early Evidence ◽

Stem And Progenitor Cells ◽

Equity Ownership

Background: Fanconi anemia (FA) is a rare genetic disorder characterized by defective cellular deoxyribonucleic acid (DNA) repair, associated with developmental abnormalities, progressive bone marrow failure (BMF), and a predisposition to hematologic malignancies and solid tumors. 80% of FA patients develop BMF. Although allogeneic hematopoietic stem cell transplant (allo-HSCT) is a curative treatment for BMF, its utilization and efficacy is limited by availability of suitable human leukocyte antigen (HLA)-matched donors, risk of graft-versus-host disease (GVHD) and transplant-related toxicities. Ex-vivo insertion of a functional FANCA gene into autologous FA-A CD34+ enriched hematopoietic stem and progenitor cells (HSPCs) has been shown in preclinical studies to provide a survival advantage to the gene-modified stem cells, leading to correction of BMF. Feasibility of this approach was established in the FANCOLEN-1 clinical trial (Spain), although cell doses and transduction levels varied considerably. Modifications to the collection and manufacturing processes were made in the clinical studies to enhance the dose of transduced HSPCs, with the goal of preventing progression of BMF to obviate the need of an allo-HSCT. Design and Methods: RP-L102-0418 (clinicaltrials.gov # NCT03814408) is a U.S. Phase I clinical trial evaluating the feasibility and safety of autologous CD34+ cells transduced with a lentiviral vector (LV) carrying the FANCA gene (PGK-FANCA-WPRE) in two pediatric patients with FA-A. Patients <12 years of age, with early evidence of cytopenias, but with bone marrow (BM) CD34+ count >30/µL were eligible for treatment. Peripheral blood mononuclear cells were collected via leucocytapheresis on two consecutive days after mobilization with granulocyte-colony stimulating factor (G-CSF) and Plerixafor (Mozobil). CD34+ HSPCs were enriched, placed in culture with cytokines, and transduced with PGK-FANCA-WPRE LV. The investigational drug product (DP) (RP-L102) was infused fresh into patients within 4 hours of release, without any prior conditioning regimen. Patients are being followed for 3 years post-infusion for safety assessments (replication competent lentivirus (RCL), insertion site analysis (ISA)) and to ascertain early evidence of efficacy (increasing peripheral blood vector copy number (VCN) and BM mitomycin-C (MMC) resistance), along with stabilization/correction of cytopenias. Results: Two FA-A patients (aged 5 and 6 years) were consented and enrolled on the study at Stanford University. Mobilization and apheresis procedures were performed successfully without any serious adverse events. DP was successfully manufactured using "Process B" optimization including transduction enhancers, commercial-grade vector, and modified cell processing. Because of higher transduced CD34+ and colony forming cell (CFC) doses, we anticipate early development of BM MMC resistance in the current study patients. Safety and efficacy data 4 to 6 months post-treatment, including peripheral blood VCN, blood counts and bone marrow MMC resistance, will be available at the time of presentation. Conclusions: DP has been successfully manufactured in the Phase I study (N=2) to meet the required specifications.Patients are being monitored for early efficacy assessments; 6+ months of follow-up may be required to observe the proliferative advantage of transduced HSPCs.Plans for Phase II portion of the study are in progress. Disclosures Czechowicz: Rocket Pharmaceuticals, Inc.: Research Funding. Beard:Rocket Pharmaceuticals: Employment, Equity Ownership. Law:Rocket Pharmaceuticals: Employment, Equity Ownership. Nicoletti:Rocket Pharmaceuticals, Inc.: Employment, Equity Ownership. Río:Rocket Pharmaceuticals: Equity Ownership, Patents & Royalties, Research Funding. Bueren:Rocket Pharmaceuticals, Inc.: Consultancy, Equity Ownership, Patents & Royalties: Inventor on patents on lentiviral vectors filled by CIEMAT, CIBERER and F.J.D and may be entitled to receive financial benefits from the licensing of such patents, Research Funding. Schwartz:Rocket Pharmaceuticals: Employment, Equity Ownership.

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Safety, Clinical Activity, Pharmacokinetics, and Pharmacodynamics from a Phase I Study of PF-06863135, a B-Cell Maturation Antigen (BCMA)-CD3 Bispecific Antibody, in Patients with Relapsed/Refractory Multiple Myeloma (RRMM)

Blood ◽

10.1182/blood-2019-121805 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1869-1869 ◽

Cited By ~ 13

Author(s):

Noopur S. Raje ◽

Andrzej Jakubowiak ◽

Cristina Gasparetto ◽

Robert F. Cornell ◽

Heike I. Krupka ◽

...

Keyword(s):

Phase I ◽

Board Of Directors ◽

Dose Escalation ◽

Research Funding ◽

Phase I Study ◽

Employment Equity ◽

Advisory Committees ◽

Best Response ◽

Equity Ownership ◽

Dose Levels

Introduction: PF-06863135 (PF-3135) is a bispecific, humanized, monoclonal antibody (mAb) consisting of BCMA- and CD3-targeting arms paired on an IgG2a backbone by hinge-mutation technology. PF-3135 binds BCMA+ myeloma cells and CD3+ T cells with affinities of 20 pM and ~40 nM, respectively (Panowski et al. Blood 2016). We report here findings from the dose-escalation portion of an ongoing, multi-center, open-label, phase I study (NCT03269136) of PF-3135 in patients with RRMM. Methods: Adult patients (≥18 years of age) with RRMM, previously treated with a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 mAb, received escalating, intravenous (IV) doses of PF-3135, once weekly. Prior BCMA-targeted bispecific T-cell engager or chimeric antigen receptor T-cell (CART) treatment was allowed by protocol. Patients had measurable disease per the International Myeloma Working Group (IMWG) updated criteria 2014. A modified toxicity probability interval method (mTPI), targeting a dose-limiting toxicity (DLT) rate of 25% (equivalence interval ± 5%) was used for dose escalation. The primary study objectives are to assess PF-3135 safety and tolerability, to determine the maximum tolerated dose (MTD) and select the recommended phase II dose (RP2D). Secondary objectives include evaluation of anti-myeloma activity, pharmacokinetics (PK), and immunogenicity of PF-3135. Results: As of April 9, 2019, 17 patients had received once weekly, non-continuous, IV infusion of PF-3135 in 6 dose-escalation groups. The majority were men (71%). The median age was 61 yrs (range, 47-82 yrs) and median disease duration since onset was 7 yrs (range, 1.1-13.3 yrs). Ten (59%) patients had ≥1 chromosomal abnormality and 5 (29%) had a normal karyotype (status not known for 2 [12%] patients). The median number of prior anti-myeloma therapies was 11; 5 (29%) patients had received prior BCMA-targeted therapy. Eight (47%) patients had relapsed MM and 8 (47%) had refractory disease (recurrence type not known for 1 [6%] patient). Ten (59%) patients experienced treatment-related (TR) AEs of any grade. Most TRAEs were grade 1-2, including cytokine release syndrome (CRS, 24%), thrombocytopenia (24%), anemia (18%), and pyrexia (18%). Three (18%) patients had grade 3 TRAEs (increased alanine aminotransferase/aspartate aminotransferase, leukocytopenia, neutropenia, and lymphopenia). One patient treated at the highest dose level, who had received prior BCMA CART therapy, developed treatment-related febrile neutropenia, a DLT, which may have been related to CRS and borderline/low neutrophil count at baseline. None of the patients had grade 4-5 TRAEs or discontinued treatment due to a TRAE. The median duration of treatment was 4 (range, 2-12) actual dosing days. Sixteen of the 17 patients were evaluable for response. At the time of data cut-off, one (6%) patient had a minimal response and 6 (35%) patients had stable disease (SD) across dose levels, as best response by investigator IMWG assessment; 9 (53%) patients experienced disease progression. The clinical benefit rate (defined as best response ≥SD) was 41% (95% CI: 18.4%, 67.1%). Conclusions: Treatment with IV PF-3135 was well tolerated at the dose levels evaluated. The observed CRS events were moderate and dose-dependent. Additional dose cohorts are accruing. The latest clinical, biomarker, and PK data will be presented for this ongoing study. Disclosures Raje: Medscape: Honoraria; Research to Practice: Honoraria; Takeda: Consultancy, Honoraria; Merck: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AstraZeneca: Research Funding. Jakubowiak:Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy, Honoraria; Juno: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; SkyLineDx: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; KaryoPharm Therapeutics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Millennium: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Gasparetto:Janssen: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed ; BMS: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed ; Celgene: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed . Cornell:KaryoPharm: Consultancy; Takeda: Consultancy. Krupka:Pfizer: Employment, Equity Ownership. Navarro:Pfizer: Employment, Equity Ownership. Forgie:Pfizer: Employment, Equity Ownership. Udata:Pfizer: Employment, Equity Ownership. Basu:Pfizer: Employment, Equity Ownership. Chou:Pfizer: Employment, Equity Ownership. Leung:Pfizer: Employment, Equity Ownership. Lesokhin:BMS: Consultancy, Honoraria, Research Funding; Serametrix Inc.: Patents & Royalties; Takeda: Consultancy, Honoraria; Genentech: Research Funding; Juno: Consultancy, Honoraria; GenMab: Consultancy, Honoraria; Janssen: Research Funding. OffLabel Disclosure: PF-06863135, investigational agent

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Final Results of the Phase I Study of Lenalidomide In Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia (CLL-001 Study)

Blood ◽

10.1182/blood.v116.21.1376.1376 ◽

2010 ◽

Vol 116 (21) ◽

pp. 1376-1376 ◽

Cited By ~ 1

Author(s):

Clemens Wendtner ◽

Peter Hillmen ◽

Daruka Mahadevan ◽

Stephan Stilgenbauer ◽

Lutz Uharek ◽

...

Keyword(s):

Phase I ◽

Dose Escalation ◽

Research Funding ◽

Off Label Use ◽

Duration Of Treatment ◽

Employment Equity ◽

Advisory Committees ◽

High Risk Disease ◽

Starting Dose ◽

Equity Ownership

Abstract Abstract 1376 Introduction: Patients who relapse after fludarabine-based treatments have poor prognosis. These patients have deteriorating immune functions with high infection rates resulting from progressing disease complicated further by ineffective and often immunosuppressive therapies. Two phase II studies in patients with relapsed or refractory (rel/ref) CLL at starting doses of 10 mg or 25 mg daily of lenalidomide (Len) demonstrated promising responses. A phase II/III study was initiated to assess Len 10 mg/d vs 25 mg/d given continuously for 21 days of a 28-day cycle. Four cases of serious tumor lysis syndrome (TLS) prompted an independent data monitoring committee to amend the protocol into a phase I trial (de Parseval et al., JCO 2007) Here we present results from this amended study. Methods: Eligible patients had rel/ref CLL, received prior treatment with an alkylating agent and fludarabine, and progressed during or ≤ 12 months after completing fludarabine-based treatment. Primary objective was to determine whether Len 2.5 mg was a safe starting dose and the maximum tolerated dose escalation level (MTDEL). Prophylaxis with allopurinol and hydration were employed as part of an aggressive monitoring plan for TLS prevention. All patients initiated Len at 2.5 mg/d with subsequent dose escalation to 5 mg/d after 28 days with further dose escalations in 5 mg increments performed every 28 days until MTDEL was defined, or the maximum targeted 20 mg/d dose level attained. The first 6 patients at 10, 15 and 20 mg/d dose levels were considered a cohort and could not escalate beyond that dose level for the duration of treatment. Treatment continued until disease progression or unacceptable toxicity. Results: The redesigned phase I study enrolled 52 patients with a median age of 65 years (range, 37–80) and bulky disease (> 5 cm) in 70%. Cytogenetic data was available for 46 patients, of whom 22 (48%) had high-risk disease: 8 (17%) had del(17p), 12 (26%) had del(11q), 2 had both. Patients were heavily pretreated with a median of 4 prior therapies (range, 1–14); 54% were fludarabine refractory (no-response/relapse ≤ 6 mo), 42% had prior FCR or PCR and 21% had prior alemtuzumab. The TLS prevention strategy resulted in only 2 (3.8%) cases of TLS, both observed at 2.5 mg/d (1 patient with Gr.2 and another with lab TLS). Gr.3/4 tumor flare occurred in 5 (9.6%) patients and was managed with NSAIDs or low-dose steroids. The most common Gr.3/4 adverse events (AEs) included neutropenia (65%) and thrombocytopenia (33%). Febrile neutropenia occurred in 4 (8%) patients. Gr.3/4 infections were observed in 21 (40%) patients; 10 (19%) patients developed pneumonia and 3 developed sepsis; 2 cases of sepsis-related death at day 37 and 94 of therapy were also noted but deemed unrelated to study drug by the investigators. Reasons for study discontinuation included disease progression (37%), AEs (29%), consent withdrawal (15%), death (4%), and other reasons (10%). For 16 (31%) patients, 2.5 mg/d was the maximum dose reached and 22 (42%) patients were unable to escalate beyond 5 mg/d. Gr.4 neutropenia was the primary reason for delay in dose escalation. By intent-to-treat (ITT) analysis, 6 patients (12%) had a partial response (NCI-WG 1996), 30 patients (58%) had stable disease and 13 patients (25%) progressed; 3 patients were non-evaluable. Median duration of treatment was 3.1 months (range, 0.07–18.4) and the median time to response was 4.3 months (range, 2.8–7.4). Responses were observed at 10 mg/d (n=3), at 15 mg/d (n=1), and at 20 mg/d (n=2); Median PFS (ITT) was 5.5 months and median PFS for responders was 12 months. Three patients still remain on therapy. Conclusion: We conclude that a Len starting dose of 2.5 mg/d appears safe, feasible and can be safely titrated to 20 mg/d (maximum intended dose). The MTDEL was not reached at 20 mg/d. Based on the response rate reported in this study, a higher starting dose, such as previously reported by Chanan-Khan et al (JCO 2006) and Ferrajoli et al (Blood 2008), may be needed to achieve clinical efficacy, particularly for patients with high-risk disease. Adequate TLS prophylaxis and monitoring allows for higher starting doses to be investigated. To identify a safe and clinically active starting dose, the CLL-009 study is evaluating Len at starting doses of 5 mg/d, 10 mg/d, and 15 mg/d in the setting of rel/ref CLL. Disclosures: Wendtner: Celgene, BayerSchering, Roche, Mundipharma: Consultancy, Honoraria. Off Label Use: off-label use of lenalidomide. Hillmen:Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Alexion Pharmaceuticals: Consultancy; Bayer Schering: Consultancy. Mahadevan:Pfizer, millenium, Amgen: Honoraria. Stilgenbauer:Roche, Bayer, Celgene, GSK, Amgen, Mundipharma: Consultancy, Honoraria, Research Funding. Frankfurt:Bayer, Celgene: Research Funding, Speakers Bureau. Kimby:Roche, Bayer-Schering, Mundipharma: Membership on an entity's Board of Directors or advisory committees, lecturer. Gobbi:Novartis, Jansen Cilag, Roche, Celgene, Amgen: Consultancy, Research Funding, Speakers Bureau. Hurd:Celgene: Research Funding. Sekeres:Celgene: Research Funding, Speakers Bureau. Ferrajoli:Celgene: Honoraria, Research Funding. Shah:Celgene: Employment, Equity Ownership. Zhang:Celgene: Employment. Moutouh de Parseval:Celgene: Employment, Equity Ownership.

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Phase 1 Study of CB-839, a First-in-Class, Orally Administered Small Molecule Inhibitor of Glutaminase in Patients with Relapsed/Refractory Leukemia

Blood ◽

10.1182/blood.v126.23.2566.2566 ◽

2015 ◽

Vol 126 (23) ◽

pp. 2566-2566 ◽

Cited By ~ 12

Author(s):

Eunice S. Wang ◽

Olga Frankfurt ◽

Keith William Orford ◽

Mark Bennett ◽

Ian W. Flinn ◽

...

Keyword(s):

Bone Marrow ◽

Dose Escalation ◽

Research Funding ◽

Phase 1 ◽

Safety Data ◽

Tca Cycle ◽

Glutamine Metabolism ◽

Allogeneic Bone ◽

Employment Equity ◽

Equity Ownership

Abstract Background: Malignant cells alter metabolism in order to enable their highly anabolic state. In addition to a massive increase in glycolysis, neoplastic cells frequently depend on glutamine to feed the TCA cycle and provide key building blocks for cell growth and proliferation. CB-839 is a first-in-class potent and selective inhibitor of the glutaminase (GLS), the first step in glutamine metabolism, and has broad in vitro and in vivo anti-tumor activity in solid and heme malignancies. Acute myeloid leukemia (AML) cells are particularly dependent on glutamine, and treatment of AML cell lines and primary AML cells with CB-839 results in growth arrest and/or cell death (Padre et al., ASH, 2014 and Jacque et al., Blood, 2015). CB-839 causes a decrease in glutamate and glutamate-derived metabolites, such as TCA cycle intermediates and glutathione, crippling the proliferative capacity of these cells and in some cases inducing apoptosis. Methods: CX-839-003 is an ongoing Phase 1 (Ph1) trial of CB-839 in patients with relapsed/refractory hematologic malignancies. This study includes a dose escalation cohort to identify a recommended Phase 2 dose (RP2D), followed by expansion cohorts of patients (pts) with relapsed/refractory AML (IDH wt and mutant), acute lymphocytic leukemia, and IDH-mutant myelodysplastic syndrome (MDS). Pharmacokinetics (PK) is being monitored on Days 1 and 15. Results: Safety data are available for a total of 20 patients (18 AML, 1 ALL, and 1 mixed-lineage leukemia) that have enrolled across the dose escalation and expansion cohorts. These patients have received a median of 3 prior lines of systemic induction therapy, with 5 pts (25%) having received prior allogeneic bone marrow transplantation. Patients' median age was 75 (range 35 to 84). Dose levels from 100-1000 mg TID were explored during the dose escalation. CB-839 has been well tolerated to date, with no DLTs occurring on study. One patient discontinued due to an adverse event (AE) of elevated transaminases, and 5 pts (25%) had G3/4 AEs considered possibly related to study drug. Across three Ph1 studies for CB-839 in solid tumors and heme malignancies, reversible asymptomatic elevations in transaminases have been the primary G3 AE. Although initially CB-839 was given three times daily (TID) without food, the drug is now being given twice daily (BID) with meals based on PK and safety data generated across these 3 studies. Liver abnormalities occurred primarily on the TID schedule in 6/59 (10.2%) pts, but in only one of 60 pts (1.7%) receiving the BID regimen. Pts are currently being enrolled in expansion cohorts at the RP2D, 600 mg BID. Inhibition of GLS activity was evaluated across all 3 Ph1 studies and established clear exposure-dependent inhibition of the target in peripheral blood 4 hr after the first dose of CB-839, with >90% inhibition being maintained for most patients at the RP2D. Preliminary evidence of clinical activity has been noted, including reductions in blast counts in the bone marrow and/or periphery in 2 pts, one of whom achieved a CRi and remains on study for more than one year. 5 (31%) of 16 evaluable pts have remained on study for at least 4 cycles (range 4-17). Additional data from >8 additional patients have recently started on the "BID with meals" regimen will be presented. Correlative studies on clinical samples will also be presented. Conclusions: CB-839 has been well tolerated at and above doses that produced robust inhibition of GLS in blood platelets and in tumors. Dosing BID with food has mitigated the frequency and severity of LFT elevations, which has been the primary safety signal to date. Reductions in marrow and peripheral blast counts in a heavily pretreated acute leukemia population, with a significant number of patients tolerating therapy and remaining on study for a prolonged period, provide the rationale for continued evaluation of CB-839 as a single agent, and in combination with azacitidine, in AML patients. Disclosures Wang: Immunogen: Research Funding. Orford:Calithera Biosciences: Employment, Equity Ownership. Bennett:Calithera Biosciences: Employment, Equity Ownership. Flinn:Cephalon, Inc; Teva Pharmaceutical Industries Ltd; Genentech, inc; Gilead: Research Funding. Konopleva:Novartis: Research Funding; AbbVie: Research Funding; Stemline: Research Funding; Calithera: Research Funding; Threshold: Research Funding.

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Data from the First CD20-Targeted Immunotoxin, MT-3724, in a Phase I/Ib Study in Relapsed/Refractory (R/R) Non-Hodgkin's B-Cell Lymphoma (NHL)

Blood ◽

10.1182/blood.v128.22.4200.4200 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4200-4200 ◽

Cited By ~ 1

Author(s):

Paul A Hamlin ◽

Michelle A. Fanale ◽

Steven I. Park ◽

David J. Valacer ◽

Jack Higgins ◽

...

Keyword(s):

Phase I ◽

B Cell ◽

Board Of Directors ◽

Dose Escalation ◽

Research Funding ◽

B Cell Lymphoma ◽

Employment Equity ◽

Advisory Committees ◽

Equity Ownership ◽

Cd20 Antibodies

Abstract Background Novel mechanisms of action (MOA) are needed for the treatment of NHL. Because of the ubiquity and persistence of CD20 expression in B-cell malignancies, there is strong rationale to develop novel MOAs targeting CD20. However, CD20's non-internalizing nature has impeded the development of novel MOAs against this target.. MT-3724 is a recombinant fusion protein consisting of a CD20 binding variable fragment (scFv) fused to the ribosomal inhibitory protein Shiga-like toxin-I A1 subunit (SLT-I A1). Upon scFv binding to surface CD20, SLT-I A1 forces MT-3724 internalization and irreversibly inactivates cell ribosomes triggering cell death. MT-3724 has been shown to specifically bind and kill CD20+ malignant human B-cells in vitro and in in vivo animal models. Data from the first eighteen subjects evaluable for efficacy in the on-going Phase I/Ib monotherapy dose-escalation study of MT-3724 are presented. Methods MT-3724 is being tested in a first-in-human, open label, ascending dose study (3 + 3 design) in cohorts of 5, 10, 20, 50, 100, and 75 mcg/kg/dose. Eligible subjects who previously responded to a CD20 MAb containing therapy followed by relapse/recurrence of NHL receive 6 infusions over 2 hours in the first 12 days of a 28 day cycle (first cycle). With continued safety, tolerability and lack of tumor progression, subjects may receive 4 additional 6-dose cycles (21 days) with tumor assessments after cycles 2, 4 and 5. Dose escalation is based on < 33% dose limiting toxicities (DLTs) observed during the first 28 day cycle. Results To date, 18 R/R NHL subjects (mean number of prior therapies >4) have enrolled and completed at least one cycle in either the 5, 10, 20, 50, 100, or 75 mcg/kg/dose cohort. Two DLTs were identified in the 100 mcg/kg cohort considered possibly consistent with early signs/symptoms of capillary leak syndrome, a known side effect of immunotoxins. These adverse events (AEs) were non-life threatening and reversible upon drug withdrawal. The most common non-DLT AEs have been reversible hypoproteinemia (≤ Grade 2) with or without transient peripheral edema (≤ Grade 2). A summary of AEs and pharmacodynamic results will be presented. Anti-drug antibodies (ADA) have been observed with MT-3724 but the advent of ADA in subjects has not precluded deepening tumor responses. These data are consistent with the clinical experience of denileukin diftitox, the only approved toxin-based oncology therapeutic. Consistent signs of efficacy including responses were seen in subjects without recent exposure to CD20 antibodies (see table). Conversely, progression by cycle 2 was seen in all subjects who had recent CD20 antibody exposure. CD20 antibodies compete with MT-3724 for target binding and high tissue levels of CD20 antibodies likely inhibit MT-3724 activity. Conclusions Targeting CD20 with antibodies has substantially improved survival in NHL, but unmet need remains and there is strong rationale for agents with new MOAs. MT-3724 is the first CD20 targeted immunotoxin to enter clinic trials. Encouraging clinical activity has been seen; safety, efficacy, PK, and ADA data will be presented. Ribosome inhibition represents a novel mechanism of action for the treatment of R/R NHL and continued development of MT-3724 is warranted. *both Drs. Hamlin and Fanale contributed equally to this work Table Table. Disclosures Hamlin: Molecular Templates: Research Funding; Novartis: Research Funding; Xencor: Membership on an entity's Board of Directors or advisory committees; Portola: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Research Funding. Fanale:molecular templates: Research Funding. Valacer:Molecular Templates: Employment, Equity Ownership. Higgins:Molecular Templates: Employment, Equity Ownership. Younes:Molecular Templates: Membership on an entity's Board of Directors or advisory committees, Research Funding.

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