Jain, Rajul K.

Abstract ZUMA-3 is a phase 1/2 study evaluating KTE-X19, an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, in adult relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). We report the phase 1 results. After fludarabine-cyclophosphamide lymphodepletion, patients received a single infusion of KTE-X19 at 2 × 106, 1 × 106, or 0.5 × 106 cells per kg. The rate of dose-limiting toxicities (DLTs) within 28 days after KTE-X19 infusion was the primary end point. KTE-X19 was manufactured for 54 enrolled patients and administered to 45 (median age, 46 years; range, 18-77 years). No DLTs occurred in the DLT-evaluable cohort. Grade ≥3 cytokine release syndrome (CRS) and neurologic events (NEs) occurred in 31% and 38% of patients, respectively. To optimize the risk-benefit ratio, revised adverse event (AE) management for CRS and NEs (earlier steroid use for NEs and tocilizumab only for CRS) was evaluated at 1 × 106 cells per kg KTE-X19. In the 9 patients treated under revised AE management, 33% had grade 3 CRS and 11% had grade 3 NEs, with no grade 4 or 5 NEs. The overall complete remission rate correlated with CAR T-cell expansion and was 83% in patients treated with 1 × 106 cells per kg and 69% in all patients. Minimal residual disease was undetectable in all responding patients. At a median follow-up of 22.1 months (range, 7.1-36.1 months), the median duration of remission was 17.6 months (95% confidence interval [CI], 5.8-17.6 months) in patients treated with 1 × 106 cells per kg and 14.5 months (95% CI, 5.8-18.1 months) in all patients. KTE-X19 treatment provided a high response rate and tolerable safety in adults with R/R B-ALL. Phase 2 is ongoing at 1 × 106 cells per kg with revised AE management. This trial is registered at www.clinicaltrials.gov as #NCT02614066.

7006 Background: KTE-X19 is an autologous anti-CD19 CAR T cell therapy under investigation for adult R/R ALL. In an interim analysis of Phase 1 of ZUMA-3, we reported manageable safety and encouraging efficacy of KTE-X19; 72% of pts achieved a complete remission (CR) or CR with incomplete bone marrow (BM) recovery (CRi; Wierda et al, ASH 2018. #897). Here, we present end of Phase 1 results. Methods: Adults with R/R B cell ALL, > 5% BM blasts, and ECOG 0-1 received 2, 1, or 0.5 × 106 KTE-X19 cells/kg after conditioning chemotherapy. Revised adverse event management (rAE mgmt) was implemented for additional pts in a 1 × 106 dose cohort: corticosteroids were given earlier at onset of Grade ≥ 2 neurologic events (NEs) and tocilizumab was used only for active toxicity. The primary endpoint was the dose-limiting toxicity (DLT) rate. Key additional endpoints were KTE-X19 levels, incidence of AEs, minimal residual disease (MRD), and CR/CRi rate. Results: As of 9/27/18, 45 pts had received KTE-X19 (median follow-up [f/u], 16 mo). The median age was 46 y (range, 18–77); 30 pts (66%) had ≥ 3 prior therapies and the median pre-conditioning BM blasts was 70% (range, 0–97). Six, 23, and 16 pts received 2, 1, and 0.5 × 106 cells/kg, respectively. There were no DLTs in the DLT-evaluable pts. The most common Grade ≥ 3 AEs were hypotension (38%), pyrexia (38%) and thrombocytopenia (31%). There were 2 previously reported KTE-X19–related Grade 5 AEs of cerebral infarction and multiorgan failure, both in the context of CRS. Grade ≥ 3 CRS and NEs occurred in 13 (29%) and 17 (38%) pts, respectively. Of 41 pts with ≥ 2 mo of f/u, 68% had CR/CRi, and 73% had undetectable MRD. Of 19 pts with ≥ 2 mo of f/u treated with 1 × 106 cells/kg, 16 (84%) had a CR/CRi and the median event-free survival was 15 mo. In 9 pts treated with 1 × 106 cells/kg and rAE mgmt, 2 (22%) had Grade 3 CRS and 1 (11%) had Grade 3 NE with no Grade 4/5 events. Conclusions: KTE-X19 dosing and safety mgmt have been successfully refined by testing 3 cell doses and evaluating a new AE mgmt guideline with altered corticosteroids/tocilizumab use for NE/CRS. Pivotal Phase 2 is ongoing at the 1 × 106 dose with rAE mgmt. Clinical trial information: NCT02614066.

Abstract Background: Although approximately half of adult patients with acute lymphoblastic leukemia (ALL) achieve long-term survival, those who relapse have poor long-term outcomes (El Fakih et al. Hematol Oncol Stem Cell Ther. 2017; Oriol et al. Haematologica. 2010). The initial report of Phase 1 of ZUMA-3, the Phase 1/2 trial of KTE-C19 for treatment of relapsed/refractory (R/R) ALL (NCT02614066), has thus far demonstrated promising efficacy among patients infused with KTE-C19, with a 71% complete remission (CR) rate (CR or CR with incomplete hematologic recovery [CRi]), 88% undetectable minimal residual disease (MRD), and manageable toxicity across all doses (Shah et al. ASH 2017. #888). Here, we present updated safety and efficacy data from Phase 1 of ZUMA-3. Methods: Adult patients (≥ 18 y) with R/R ALL (Ph+ allowed), > 5% bone marrow blasts, and ECOG 0-1 received 2, 1, or 0.5 × 106 CAR T cells/kg after low-dose conditioning chemotherapy with fludarabine 25 mg/m2/day for 3 days and a single dose of cyclophosphamide 900 mg/m2 on the third day of conditioning. The primary endpoint for Phase 1 was incidence of dose-limiting toxicities (DLTs). Key secondary endpoints included incidence and time to onset and resolution of adverse events (AEs), rate of undetectable MRD remission in the bone marrow using flow cytometry, and duration of remission. KTE-C19 expansion and persistence were also assessed. Safety analyses included all patients who received KTE-C19, and patients with ≥ 2 months of follow-up were evaluated for efficacy. Results: As of April 12, 2018, 35 patients have received KTE-C19 with a median follow-up of 11 months (range, 2 - 25 months). The median age was 40 years (range, 18 - 69 years), 51% of patients were male, 66% had ECOG 1, 13 patients (37%) had prior blinatumomab, and 60% had received ≥ 3 prior lines of treatment. The median bone marrow blast burden at screening was 70% (range, 5 - 100). Six patients received the 2 × 106 cells/kg dose, 14 received 1 × 106 cells/kg, and 15 received 0.5 × 106 cells/kg. No DLTs were observed in the DLT period. The most common Grade ≥ 3 AEs were hypotension (40%), pyrexia (34%), decreased platelet counts (34%), and anemia (31%). Grade ≥ 3 CRS occurred in 9 patients (26%), with a median time to onset of 5 days (range, 1 - 15 days). There were 2 KTE-C19-related Grade 5 events: 1 cerebral infarction at the 0.5 × 106 cells/kg dose and 1 previously reported multiorgan failure secondary to cytokine release syndrome (CRS) at the 2 × 106 cells/kg dose. Grade ≥ 3 CRS resolved in all patients (not including 2 patients with a Grade 5 event), and the median time to resolution was 11 days (range, 7 - 42 days). Grade ≥ 3 treatment-emergent neurologic events occurred in 16 patients (46%), and the median time to onset was 7 days (range, 4 - 24 days). With the exception of 2 patients with unresolved neurologic events due to death, Grade ≥ 3 neurologic events resolved in all patients (14/14), with a median time to resolution of 17 days (range, 6 - 53 days). Among the 32 patients evaluable for response, the overall rate of undetectable MRD was 78% (95% CI, 60% - 91%). CR or CRi was achieved by 23 patients (72%), and 1 patient (3%) had blast-free BM. KTE-C19 levels were examined in 23 patients as of July 31, 2017. Robust KTE-C19 expansion was observed across all dose levels assessed. Conclusion: High rates of remission were achieved by adult patients with R/R ALL, with approximately three-quarters of patients achieving CR or CRi with undetectable MRD after a single dose of KTE-C19 in ZUMA-3. The safety profile was generally manageable, and most cases of high-grade CRS and neurologic events resolved. These results demonstrate that KTE-C19 offers clinical benefit for patients with otherwise limited treatment options. Disclosures Wierda: AbbVie, Inc: Research Funding; Genentech: Research Funding. Bishop:United Healthcare: Employment; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Speakers Bureau; Juneau Therapeutics: Speakers Bureau; Novartis Pharmaceuticals Corporation: Speakers Bureau. Logan:Adaptive Biotech: Consultancy; Napajen: Consultancy; Shire: Consultancy; Pfizer: Consultancy; Novartis: Consultancy, Research Funding; Incyte: Consultancy; Jazz Pharmaceuticals: Consultancy, Research Funding; Amgen: Consultancy; Astellas: Research Funding; Pharmacyclics: Research Funding; Kite: Research Funding. Schiller:Astellas Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; bluebird bio: Research Funding. Holmes:Unum: Research Funding; Seattle Genetics: Research Funding, Speakers Bureau; Novartis: Research Funding; Genentech: Research Funding; Celgene: Research Funding; Rigel: Consultancy; Gilead: Consultancy, Research Funding, Speakers Bureau; Bayer: Consultancy. Abedi:Seattle Genetics: Speakers Bureau; Celgene: Speakers Bureau; Amgen: Research Funding; CIRM: Research Funding; BMS: Speakers Bureau; Takeda: Speakers Bureau; Gilead: Speakers Bureau; Celgene: Research Funding. Arellano:Cephalon: Research Funding. Pagel:Pharmacyclics, an AbbVie Company: Consultancy; Gilead: Consultancy. Mardiros:Kite, a Gilead Company: Employment; Kite, a Gilead Company: Equity Ownership; Mustang Bio: Patents & Royalties; Kite, a Gilead Company: Other: TRAVEL, ACCOMMODATIONS, EXPENSES. Shen:Zhejiang DTRM Biopharma LLC: Other: Clinical Operations Director. Vezan:Kite Pharma: Employment; Kite, Gilead, Abbv, MRK: Equity Ownership. Jain:Kite Pharma, Amgen: Equity Ownership; Kite Pharma: Employment; Kite Pharma: Patents & Royalties.