ALBERT

Description: Background: Based on promising results seen in patients treated with CD19-directed CAR-T cells in relapsed or refractory (R/R) pediatric B-cell acute lymphoblastic leukemia (Gardner, ASCO 2016) and adult B-cell non-Hodgkin lymphoma (Turtle, ASCO 2016), we are conducting a multicenter phase 1 trial of JCAR017 in R/R diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) (ClinicalTrials.gov Identifier: NCT02631044). JCAR017 is a second-generation, CD19-directed CAR-T cell product of defined cellular composition consisting of a 1:1 ratio of CD8+:CD4+ CAR+ T cells. Methods: Patients with R/R DLBCL (de novo or transformed from indolent lymphoma), follicular lymphoma grade 3B, or MCL and adequate organ function are eligible. There was no minimum absolute lymphocyte count (ALC) requirement for apheresis and no test expansion required. Treatment includes lymphodepletion (fludarabine 30 mg/m2 and cyclophosphamide 300 mg/m2 daily for 3 days) and JCAR017 given 2-7 days post-lymphodepletion at a starting dose of 5 x 107 CAR+ T cells (DL1). Single-dose and two-dose schedules are being evaluated. Primary objectives include safety and pharmacokinetics (PK) of JCAR017 measured by flow cytometry and quantitative PCR. Secondary objectives include complete and overall response (CR, OR) rates and duration of response (DOR). Response is assessed using the Lugano (2014) criteria. Results: As of August 1, 2016, 39 patients have been enrolled and 28 patients apheresed. Fourteen patients have been treated, all at DL1. Eight were male and 6 female. Thirteen patients had DLBCL and 1 had MCL. Median age was 61 years (range 37-79) and median number of prior therapies was 5 (range 2-9). Ten patients had undergone prior transplant (7 autologous; 3 allogeneic). Of the 14 patients, there were no cases of severe cytokine release syndrome (sCRS); 3 patients had low grade CRS (21%) (2 grade 1; 1 grade 2) and none required treatment with tocilizumab. Two of the 14 treated patients (14%) had neurotoxicity: 1 grade 4 encephalopathy and 1 grade 4 seizure. Both were in patients with DLBCL and were dose-limiting toxicities. Two deaths were seen in the DLBCL group and were due to disease progression. Twelve patients had at least 1 post-treatment response assessment; 11 patients with DLBCL and 1 with MCL. The patient with MCL had progressive disease at day 29 (D29). In the DLBCL group, response rates were: 82% (9/11) OR, 73% (8/11) CR, 9% (1/11) PR and 18% (2/11) PD at the time of post-treatment assessment on D29. All but one patient who achieved a CR were in remission at the time of this data cut. One DLBCL patient in CR had a parenchymal brain lesion in the right temporal lobe that also completely resolved. Of note, this patient had no CRS or neurotoxicity associated with JCAR017 treatment. The PK profile of JCAR017 in the peripheral blood and bone marrow show cellular expansion in all patients with persistence out to at least 3 months in patients with adequate follow up. Exploratory biomarker analyses will be presented at the meeting along with updated clinical data. Conclusions: Treatment with the defined cellular composition product JCAR017 following lymphodepletion with fludarabine and cyclophosphamide results in high CR rates in patients with heavily pretreated DLBCL, including the first report of a CR in a patient with secondary CNS lymphoma. Observed toxicities are manageable and compare favorably to other reported CAR T-cell products. Disclosures Abramson: Gilead: Consultancy; Kite Pharma: Consultancy; Abbvie: Consultancy; Seattle Genetics: Consultancy. Gordon:Northwestern University: Patents & Royalties: Patent for gold nanoparticles pending. Lunning:Celgene: Consultancy; Bristol-Myer-Squibb: Consultancy; Pharmacyclics: Consultancy; Genentech: Consultancy; Juno: Consultancy; AbbVie: Consultancy; Gilead: Consultancy; TG Therapeutics: Consultancy; Spectrum: Consultancy. Arnason:Gilead: Consultancy. Forero-Torres:Genentech/Roche: Research Funding; Seattle Genetics: Research Funding; Juno: Research Funding; Incyte: Research Funding; Abbvie: Research Funding; Novartis: Research Funding; Pfizer: Research Funding. Albertson:Juno Therapeutics: Employment, Equity Ownership. Sutherland:Juno therapeutics: Employment. Xie:Juno Therapeutics: Employment, Equity Ownership. Snodgrass:Juno therapeutics: Employment. Siddiqi:Pharmacyclics, LLC, an AbbVie Company: Speakers Bureau; Janssen: Speakers Bureau; Seattle Genetics: Speakers Bureau; Kite pharma: Other: Funded travel, 1 day registration, and 1 night hotel stay for EHA2016 so I could present trial data there.

Description: Background CD19, a member of the immunoglobulin superfamily, is a B-cell specific marker that is found on B cells as early as the pro-B cell stage. CD19 is maintained upon malignant transformation and is expressed in the majority of patients with B-lineage leukemia and non-Hodgkin lymphoma (NHL). SGN-CD19A is a novel antibody-drug conjugate composed of a humanized anti-CD19 monoclonal antibody conjugated to the microtubule-disrupting agent monomethyl auristatin F (MMAF) via a maleimidocaproyl (mc) linker. Upon binding to CD19, SGN-CD19A internalizes and releases cys-mcMMAF, which binds to tubulin and induces G2/M arrest and apoptosis in the targeted cells. Methods A first-in-human, phase 1, open-label, dose-escalation study has been initiated to investigate the safety, tolerability, pharmacokinetics (PK), and antitumor activity of SGN-CD19A in adult and pediatric patients with relapsed or refractory (R/R) B-cell leukemia or highly aggressive B-cell lymphoma (CT.gov NCT01786096). Eligible patients must have a pathologically confirmed diagnosis of B-cell acute leukemia (B-ALL), Burkitt leukemia or lymphoma, or B-cell lymphoblastic lymphoma (B-LBL), and be R/R to at least 1 (adults) or 2 (pediatric) prior systemic regimens. A modified continual reassessment method is being used for dose allocation and maximum tolerated dose (MTD) estimation. SGN-CD19A is administered IV on Days 1 and 8 of 21-day cycles at up to 7 cohort-specific doses (0.3–2.3 mg/kg). Results Thirteen patients (11 adults, 2 pediatric) with R/R leukemia (9 B-ALL) or lymphoma (3 B-LBL, 1 Burkitt lymphoma) have been treated in this ongoing study. Adults (73% female) have a median age of 60 years (range, 26–74) and have received a median of 2 prior systemic therapies (range, 1–6). Four of the 11 adults (36%) have also received an allogeneic stem cell transplant (SCT). The pediatric patients, 2 females 13-and 14-years-old, have each received 3 prior systemic therapies; one of the pediatric patients has also received 2 allogeneic SCTs. To date, patients have been treated at 0.3 mg/kg (2 patients), 0.6 mg/kg (3 patients), 1.0 mg/kg (3 patients), and 1.3 mg/kg (5 patients). The maximum number of cycles received by a patient is 7. Four patients remain on treatment and 9 patients have discontinued treatment (7 due to progressive disease, 1 because of investigator decision, and 1 due to death). One patient with B-ALL treated at 1.0 mg/kg developed cardiac arrest in the setting of pre-existing electrolyte abnormalities and died 7 days after the first dose of SGN-CD19A; although this event was considered unrelated to study drug by the investigator, a possible relationship could not be excluded due to temporal association. Treatment-emergent adverse events reported for ≥10% of adult patients were nausea (64%); fatigue and pyrexia (55% each); chills (36%); headache (27%); and dyspnea, hypertension, oral pain, thrombocytopenia, tumor lysis syndrome, and vomiting (18% each). Drug-related AEs in adult patients were pyrexia (55%); nausea (45%); chills (36%); fatigue (27%); and headache, oral pain, and blurred vision (9% each). Drug-related AEs reported for the pediatric patients were abdominal pain, cough, diarrhea, dyspepsia, hyperuricemia, nausea, peripheral neuropathy, pruritus, pyrexia, tachycardia, and urticaria (all Grade 1 or 2, each in one patient). Preliminary data demonstrate rapid clearance of antibody-drug conjugate at low doses in patients with leukemia, suggesting target-mediated drug disposition. To date, best responses for patients with lymphoma are stable disease (2 patients) and progressive disease (2 patients). Best responses for the 8 leukemia patients with available response assessments are complete remission (1 adult at 1.3 mg/kg); resistant disease with clinical benefit, i.e., improvement in leukemia-related symptoms (4 patients); and progressive disease (3 patients). Conclusions MTDs have not yet been identified for adult or pediatric patients and dose-escalation continues in both populations. Antitumor activity has been observed, including 1 complete remission in a heavily pretreated B-ALL patient. Nonlinear clearance of the antibody-drug conjugate in leukemia patients suggests target-mediated disposition. Updated safety, PK, and response data will be presented at the meeting. A second trial is evaluating SGN-CD19A every 3 weeks in aggressive B-cell NHL (CT.gov NCT01786135). Disclosures: Borate: Seattle Genetics, Inc.: Research Funding; Genoptix: Consultancy. Fathi:Millennium: Research Funding; Seattle Genetics, Inc.: Advisory/Scientific board membership Other, Research Funding; Agios: Membership on an entity’s Board of Directors or advisory committees; Teva: Membership on an entity’s Board of Directors or advisory committees. Shah:Seattle Genetics, Inc.: Research Funding; NCCN: Membership on an entity’s Board of Directors or advisory committees; SWOG: Membership on an entity’s Board of Directors or advisory committees; Celgene: Speakers Bureau; Janssen/Pharmacyclics: Speakers Bureau. DeAngelo:Seattle Genetics, inc.: Research Funding. Silverman:Seattle Genetics, Inc.: Advisory/scientific board membership Other. Cooper:Seattle Genetics, Inc.: Research Funding. Albertson:Seattle Genetics, Inc.: Employment, Equity Ownership. O'Meara:Seattle Genetics, Inc.: Employment, Equity Ownership. Sandalic:Seattle Genetics, Inc.: Employment, Equity Ownership. Stevison:Seattle Genetics, Inc.: Employment, Equity Ownership. Chen:Seattle Genetics, Inc.: Consultancy, Research Funding, Speakers Bureau, Travel expenses Other.

Description: Background CD19, a B cell-specific marker, is expressed in the majority of patients with B-lineage leukemia and non-Hodgkin lymphoma. SGN-CD19A is a novel antibody-drug conjugate (ADC) composed of a humanized anti-CD19 monoclonal antibody conjugated to the microtubule-disrupting agent monomethyl auristatin F (MMAF) via a maleimidocaproyl linker. Methods This first-in-human, phase 1, open-label, dose-escalation study is investigating the safety, tolerability, pharmacokinetics, and antitumor activity of SGN-CD19A in adult and pediatric patients with relapsed or refractory B-cell leukemia or highly aggressive lymphoma (NCT 01786096). Eligible patients must have B-cell acute lymphoblastic leukemia (B-ALL) or lymphoma (B-LBL), Burkitt leukemia or lymphoma, and be relapsed or refractory to at least 1 prior systemic regimen. A modified continual reassessment method is used for dose allocation and maximum tolerated dose (MTD) estimation for both pediatric and adult patients. The study is evaluating 2 schedules of IV SGN-CD19A administration: weekly (Days 1 and 8 of 21-day cycles; 0.3-4.5 mg/kg) or every 3weeks (q3week; 0.5-6 mg/kg). Results To date, 49 patients with relapsed or refractory leukemia (n=40) or lymphoma (n=9) have been treated. Median age of adult (n=38) and pediatric patients (n=11) was 37 and 11 years (range, 18-74 and 1-16), respectively. Patients received a median of 2 prior therapies (range 1-9); 14 patients (29%) previously received an allogeneic stem cell transplant. On the weekly schedule, 39 patients (28 adult, 11 pediatric) have been treated, and the median number of cycles is 2.5 (adults; range, 1-12) or 1 (pediatric; range, 1-4). On the q3week schedule, 10 adult patients have been treated, and the median number of cycles is 2.5 (range, 1-4) to date. Six patients remain on study treatment (3 on each schedule), and enrollment is ongoing. The toxicity profiles were similar across both dosing schedules (0.3-2.3 mg/kg weekly and 4-5 mg/kg q3week) and across adult and pediatric patients. The most frequently reported drug-related AEs included pyrexia, nausea, chills, vomiting, blurred vision, and dry eye. Frequent infusion-related reactions were observed early in the study, and recommendation for premedication was instituted. Ocular events were also observed and treated with ophthalmic steroids; steroid eye drop prophylaxis was instituted with each dose. Corneal findings consistent with superficial microcystic keratopathy were observed in 13 adult patients (34%) and in 1 pediatric patient (9%). Grade 3/4 corneal AEs have been observed in 4 adult patients; the majority of these events have resolved or improved to Grade 1 or 2. Steroid eye drop prophylaxis has reduced the incidence of Grade 3/4 events at this interim analysis. Three DLTs were observed: acidosis in a pediatric patient at 1 mg/kg weekly, cytokine release syndrome in an adult patient at 2 mg/kg weekly, and asymptomatic Grade 4 AST elevation in an adult patient at 5 mg/kg q3week. MTD has not yet been determined. SGN-CD19A ADC pharmacokinetic profiles indicate target-mediated drug disposition in patients with leukemia. Plasma ADC exposures generally increased with doses and were lower than those in patients with lymphoma. To date, no objective responses were observed in 9 efficacy-evaluable pediatric patients or in 3 adult patients with Burkitt lymphoma/leukemia. However, in efficacy-evaluable adult patients with B-ALL/B-LBL, objective responses were observed in 6 of 25 patients treated on the weekly schedule (3 CR, 2 CRp, 1 PR), and in 4 of 8 patients treated on the q3week schedule (2 CR, 2 CRp). Of 8 B-ALL patients with CR/CRp, 6 were MRD negative. Conclusions MTDs have not yet been identified, and dose escalation continues on weekly and q3week schedules. SGN-CD19A has been generally well tolerated. At this interim analysis, objective responses were observed in 30% (10 of 33) of heavily pretreated adult B-ALL/B-LBL patients dosed weekly or q3week. Evidence of activity in relapsed/refractory patients and lack of overlapping toxicities suggest opportunities for combination with conventional anti-leukemic therapies in lymphoblastic malignancies. Disclosures Fathi: Ariad: Consultancy; Exelixis: Research Funding; Takeda pharmaceuticals International Co.: Research Funding; Seattle Genetics, Inc.: Consultancy, Research Funding. Off Label Use: SGN-CD19A is an investigational agent being studied in patients with B-cell malignancies. SGN-CD19A is not approved for use. . Chen:Seattle Genetics, Inc.: Consultancy, Research Funding, Speakers Bureau, Travel expenses Other. Trippett:OSI Pharmaceuticals: Research Funding; Seattle Genetics, Inc.: Research Funding. O'Brien:Seattle Genetics, Inc.: Research Funding. DeAngelo:Seattle Genetics, Inc.: Research Funding. Shah:Pharmacyclics: Consultancy; SWOG: Consultancy; Celgene: Consultancy, Speakers Bureau; NCCN: Consultancy; Seattle Genetics, Inc.: Research Funding; Janssen: Consultancy. Cooper:Seattle Genetics, Inc.: Research Funding. Foran:Seattle Genetics, Inc.: Research Funding. Hale:Seattle Genetics, Inc.: Research Funding. Pressey:Seattle Genetics, Inc.: Research Funding. Silverman:Seattle Genetics, Inc.: Research Funding. Tibes:Seattle Genetics, Inc.: Research Funding. Kim:Bayer: Consultancy; Eli Lily: Consultancy; Seattle Genetics, Inc.: Consultancy, Research Funding. Albertson:Seattle Genetics, Inc.: Employment, Equity Ownership. Sandalic:Seattle Genetics, Inc.: Employment, Equity Ownership. Zhao:Seattle Genetics, Inc.: Employment, Equity Ownership. Borate:Genoptix: Consultancy; Seattle Genetics, Inc.: Research Funding.