Minimal Residual Disease Negative CR Research Articles

A potential best-in-class BCMA-CD19 bispecific CART with advanced safety by self-inhibiting IFNG signaling during CRS.

2502 Background: CART cells have demonstrated remarkable clinical efficacy in treating hematological cancers. However, CRS remains as a major challenge in clinical application, with multiple cytokines significantly elevated. IL6 signaling blockade by Tocilizumab has become a standard treatment to relieve CRS in patients. Our previous studies suggested that CAR T secreting IL6 antagonist could effectively maintain IL6 at very low levels during CRS. Furthermore, we observed that a huge quantity of tumor cells in one patient was significantly reduced after CART infusion, but a low level of IFNG with only grade 2 CRS was present. Therefore, we hypothesized that high level of IFNG might not be necessary to CART clinical efficacy and direct blockade of IFNG signaling by CART secreting an IFNG antagonist (designated as SAFET) serves an interesting approach to effectively reduce CRS toxicity. Although IFNG is usually thought important in T cell cytotoxicity, our results indicated that IFNG KO or autonomous secretion of IFNG antagonist did not affect the killing activity of CART cells. Methods: This pilot phase 1 study of SAFET BCMA/CD19 BiCART self-inhibiting IFNG signaling is a single arm study conducted in China, enrolling refractory/relapsed multiple myeloma patients. The patients had received more than 3 lines of prior therapies including at least a proteasome inhibitor and an immunomodulatory agent and were refractory to the last line of treatment. Lymphodepletion was performed with fludarabine and cyclophosphamide prior to the CART infusion. Following 2-14 days of rest, patients received a single infusion of SAFET BCMA/CD19 BiCART, at the dose of 0.4-1.0 × 108 CAR+ T cells/patient. The primary objectives of this study were to evaluate the safety and efficacy of SAFET BCMA/CD19 BiCART. The pharmacokinetics of SAFET BCMA/CD19 BiCART was investigated by quantitative PCR based detection of CAR vector copies in peripheral blood. Minimal residual disease (MRD) negativity was assessed by standardized multicolor flow cytometry analysis of bone marrow aspirate. Results: 10/11 R/R MM patients achieved CR and 1 achieved VGPR. Among the 10 CR patients, 7 remained CR after treatment with a median PFS 858 days; 1 patient showed relapse at Days 215; 2 patients showed MRD positive relapse at Days 637 and 733, and then received KRd and/or Kd treatment to achieve SD and MRD negative CR. Interestingly, the remarkable short and long term remission suggested that CART self-inhibiting IFNG signaling did not impair the CART clinical efficacy. Notably, minimal CRS was observed, including 6 grade 0, 2 grade 1, 2 grade 2, and 1 grade 3 who displayed mild transient hypotension for only 1 day while there were 79.5% blast tumor cells in the bone marrow before CART therapy. Conclusions: These results suggest BCMA-CD19 bispecific CART self-inhibiting IFNG signaling is promising in translation to a best-in-class treatment for MM. Clinical trial information: ChiCTR2000032124.

Venetoclax Combined with CACAG Regimen in the Treatment of Patients with Refractory/Relapse Acute Myeloid Leukemia: A Prospective Clinical Study

To investigate the efficacy and safety of Venetoclax combined with CACAG regimen in treatment of patients with refractory/relapse acute myeloid leukemia(R/R AML). The study was a singlecenter prospective clinical trial. The enrolled patients met the criteria for R/R AML. Treatment included Azacidine(75 mg/m2，d 1-7), Ara-C (75-100 mg/m2, q12h, d 1-5), Aclacinomycin(20 mg d1,d3,d5), Chidamide(30 mg d1,d4), Venetoclax(100 mg d1, 200 mg d2, 400 mg d3-d14, in combination with Triazole Drug, reduced to 100 mg/d), and granulocyte colony-stimulating factor (300 μg /d until neutrophil recovery). The primary endpoint of observation was overall response rate after 1 course of treatment. A total of 19 patients were enrolled from January 2022 to April 2023. After 1 course of treatmen, the overall response rate was 81.3%(13/16), the CR rate was 68.8%(11/16), and the PR was 12.5%(2/16). Among the 11 patients who got CR/CRi, 8 cases achieved CRm (minimal residual disease negative CR) and 3 cases did not. As of March 27, 2023, the median follow-up time was 111(19-406) days. The six-month overall survival and progression-free survival rates were both 55.7%, the 1-year overall survival and progression-free survival rates were 46.4% and 47.7%, respectively. In addition, compared with the non-CRm group, CRm patients had a better PFS (377 days vs 111 days, P =0.046). Treatment-related adverse events were mainly 3-4 degrees of bone marrow suppression, complicated by various degrees of infection(n=12), hypokalemia(n=12) and hypocalcemia (n=10) and elevated liver enzymes (n=8), of which 3/4 degrees accounted for 47.4%(9/19). The Venetoclax combined with CACAG regimen is an effective salvage therapy for patients with R/R AML, with high remission rate and safety profile.

High Response Rates Following Point-of-Care Anti-CD19 CAR T-Cell Therapy in Adults with Relapsed/Refractory Acute B Lymphoblastic Leukemia

Background Tisagenlecleucel and brexucabtagene autoleucel have demonstrated remarkable efficacy and safety results in adult patients with relapsed/ refractory acute B lymphoblastic leukemia (R/R B-ALL). Long term follow-up of the ZUMA-3 trial recently reported a median duration of response (DOR) of 14.6 months and an overall response rate of 71% (Hadjivassileva, EBMT 2023). Methods and patients We report results of a phase 1b/2 single center clinical trial (NCT02772198) involving point-of-care (POC) anti-CD19/CD28 costimulatory domain chimeric antigen receptor (CAR) T-cell therapy in adults with R/R B-ALL. Inclusion criteria were age ≥18 years, failure of at least 2 prior therapies, and a preserved organ function. Patients underwent a single leukapheresis procedure. Fresh CAR T products were delivered for immediate infusion. Lymphodepletion included fludarabine and cyclophosphamide. Cell dose was 1x10 6 CAR T cells/kg. Primary endpoints were 1-month disease response and safety. Secondary endpoints were the minimal residual disease (MRD) negativity rate, overall survival, progression-free survival (PFS), and production feasibility. Last follow-up was July 2023. Results Between 03/2017-05/2023, 28 patients enrolled. CAR T-cells were successfully produced in 27 patients (96%) who were included in the analysis. The median age was 33 years (range 19-77), and 7 (25%) patients had Karnofsky Performance Status <90%. Six patients (22%) had positive Philadelphia chromosome, and 14 patients (52%) had an extramedullary disease at leukapheresis. Nineteen patients (70%) had ≥3 prior lines of therapy, 18 patients (67%) underwent prior allogeneic hematopoietic stem-cell transplantation (allo-HCT), and 20 patients (74%) had prior exposure to inotuzumab-ozogamicin or blinatumomab. At leukapheresis, 16 patients (60%) had an active disease, while 11 patients (40%) were in complete morphological response (CR; MRD positive, n=7 [26%], MRD negative or not evaluated, n=4 [15%]). The median time between leukapheresis and cell infusion was 11 days (IQR 10-11). Only 3 patients (11%) received bridging chemotherapy. Grade 3-4 cytokine release syndrome and immune effector cell-associated neurotoxicity syndromes were observed in 30% of the patients, each. Six (22%) and 16 (59%) patients were treated with tocilizumab or corticosteroids, respectively. Severe neutropenia (<0.5k/μl) and thrombocytopenia (≤50 K/μl) occurred in 81% and 70% of the patients, respectively, and anemia requiring blood transfusion occurred in 71%. Three patients (11%) had grade 3 cardiovascular events, and 1 patient (4%) had grade 3 pleural effusion. Bloodstream bacterial infection occurred in 3 (11%) patients. Cellular therapy-related mortality was observed in 2 (7%) patients (both due to septic shock). The 1-month overall response rate was 88% (81% CR; MRD negative CR, 63%). MRD was evaluated by RT-PCR in most of the patients. The median follow-up was 19.7 months (IQR 4.7-43.2). Two-year overall survival and PFS were 62% (95% CI: 42-91), and 56% (95% CI: 38-84), respectively. The median DOR was not reached (95% CI: 6.1 months-not reached). PFS was not affected by prior exposure to inotuzumab-ozogamicin or blinatumomab (hazard ratio (HR) 0.7, 95% CI: 0.17-2.68, p=0.6). All eligible patients who achieved a response were offered consolidation with allo-HCT. Eight patients (30%) underwent allo-HCT (2 nd allo-HCT in 3 of them). The DOR was not affected by consolidation of CR with allo-HCT (HR 0.9, 95% CI: 0.2-4.1, p>0.9). Nevertheless, 2 patients (7%) died due to allo-HCT related complications while in CR. Conclusion Treatment with POC CAR T-cells, produced in an academic center, achieved high response and survival rates in adults with R/R B-ALL. These results are also comparable to the FDA approved CAR T-cells. The use of POC CAR T abrogates the need for cryopreservation and shipment of the cells, thus allowing a short vein-to-vein time without the need of bridging therapy in most patients.

Venetoclax and Hypomethylating Agents Followed By Allogeneic Stem Cell Transplantation in Patients with Acute Myeloid Leukemia

Background So far, it was a treatment paradigm to induce remission in patients with either newly diagnosed (ND) or relapsed/refractory (R/R) acute myeloid leukemia (AML) prior to allogeneic stem cell transplantation (allo-SCT) using intensive therapies with anthracyclins in combination with low- or intermediate to high-dose cytarabine. For AML patients ineligible for intensive therapy, the combination of hypomethylating agents (HMA) and the BCL2 inhibitor Venetoclax (VEN) has become the new treatment standard due to high and rapidly achieved remission rates and a favorable toxicity profile. These properties make this combination also attractive for frontline induction of ND-AML or as salvage therapy in R/R-AML patients with borderline fitness to tolerate and/or limited chance to achieve remission by intensive therapy. Considering the limited evidence from the literature so far, we here report our single-center experience of allo-SCT after HMA/VEN-based therapy. Design/Methods: We retrospectively analyzed all consecutive ND and R/R AML patients, who had received HMA/VEN therapy followed by allo-SCT at our center from 2021 to 2022, regarding outcome after transplant. The study was approved by the ethics committee of the University Duisburg/Essen (approval number: 22-10708-BO) and all patients gave written informed consent for scientific use of their data. Results: Overall, 26 patients (median age 64 years, range 26 to 75) with ND (n=14, 54%) or R/R (n=12, 46%) AML were treated with a median of 2 cycles HMA/VEN (range, 1 to 5; Azacitidine n=10, Decitabine n=16). Overall response rate (CR/CRi, MLFS) in the entire cohort was 58% with no difference between patients with ND and R/R AML (57% vs. 58%, p>0.99). Minimal residual disease (MRD) determined by molecular genetics as part of the clinical routine was not detectable prior transplant in 43% of the responding patients. Allo-SCT using PBSC (n=25, 96%) or BM (n=1, 4%) from a matched sibling (n=4, 15%), unrelated (n=19, 73%) or haploidentical donor (n=3, 12%) was performed in median 98 days (range, 31 to 220) after start of HMA/VEN treatment. Neither the rate of MRD negativity nor time to allo-SCT differed between ND and R/R patients. A reduced-intensity conditioning (RIC) was used in all patients including 11 patients (42%) receiving melphalan- or FLAMSA-based sequential conditioning. Median follow-up from start of HMA/VEN therapy was 10 months (range, 4 to 19 months) and from allo-SCT 6 months (range, 1 to 15 months), respectively. Median overall survival (OS) calculated from start of HMA/VEN therapy and from allo-SCT is both not reached, while the estimated 1-year OS rates were 81% and 80% respectively. OS after transplant was numerically higher in patients with CR at transplant (90% vs. 69%), but did not differ between patients with ND and those with R/R AML (75% vs. 80%) nor between MRD negative and positive CR patients (75% vs. 100%). All patients achieved CR following allo-SCT, but 1 patient had a persistence of his cytogenetic marker and two patients had mixed chimerism. Incidence of acute GvHD was 31% (including 8% with acute GvHD grade III/IV) and of chronic GvHD 4%. A total of 6 patients relapsed after allo-SCT and a total of 4 patients have died due to relapse (n=3) or treatment-related toxicity (n=1). Median relapse-free survival (RFS) after allo-SCT was not reached and the estimated 1-year RFS rate was 67%. Again, RFS numerically differed between in patients in remission and with active disease at transplant (84% vs. 48%), but did not differ between patients with ND and those with R/R AML (70% vs. 64%) nor between MRD negative and positive CR patients (83% vs. 86%). Conclusion: Treatment with HMA/VEN either as induction or salvage therapy in ND or R/R AML leads to reasonable remission rates facilitating subsequent allo-SCT with promising survival rates. This warrants confirmatory analyses in larger patient cohorts with longer follow-up, ideally in a prospective clinical trial.

Mitoxantrone in Combination with Clofarabine (MITCL) in Children, Adolescents and Young Adults with Refractory/Relapsed Acute Leukemia

BACKGROUNDDespite excellent outcomes in pediatric ALL, patients who relapse or become refractory to frontline therapies do poorly (Gaynon et al, BJH 2005). In pediatric AML, five-year overall survival remains around 60% among children and adolescents overall with similarly poor prognosis for relapsed or refractory AML (Wells et al, JCO 2003). Novel combinations with improved complete response rates and long term outcomes are required for these high risk patients. Mitoxantrone and clofarabine as single agents, have proven effective in children with relapsed/refractory ALL and AML and offer possible synergistic activity in vivo with less drug resistance. (Wells et al, JCO 2003; Jeha et al, JCO 2009; Chow et al, Leukemia & Lymphoma 2000). We have previously reported our Phase I results using this combination and have shown excellent early results. The MTD of this combination was demonstrated to be Clofarabine 35mg/m2 x 5 days and Mitoxantrone 12mg/m2 x 4 days. Here, we present data on the first 14 patients to be treated at this recommended Phase 2 dose level (RP2D). OBJECTIVESTo determine the overall response rate of clofarabine in combination with mitoxantrone as reinduction therapy in children, adolescents and young adults with refractory/relapsed acute leukemia. To determine the percent of minimal residual disease (MRD) following reinduction with mitoxantrone and clofarabine reinduction therapy. To further characterize the biology of childhood, adolescent and young adult refractory/relapsed acute leukemia. DESIGNProspective, multi-center, treatment-based, non-randomized, open label, uncontrolled, single group assignment, safety and efficacy study (NCT01842672). Patients 0-30.99yr old with ALL or AML with relapse OR primary induction failure were given 1 to 3 cycles of clofarabine (established MTD 35mg/m2/day) Day 1-5, in combination with mitoxantrone 12mg/m2/day on Day 3-6 (MITCL). Dexrazoxane was given prior to Mitoxantrone. CNS prophylaxis was achieved with intrathecal liposomal cytarabine. Patients were allowed subsequent cycles pending response and anthracycline exposure. The majority of patients were planned to undergo allogeneic hematopoietic stem cell transplantation upon achieving CR/MRD negative remission. MRD was defined by flow cytometry (≥ 0.01%) RESULTSTo date 14 patients have been enrolled at the established RP2D of clofarabine (six patients during Phase I, 8 patients during Phase II). Median Age is 6yrs (2-22yrs). Patient characteristics include 9 ALL (5=Induction Failure, 3=Relapse 1, 1=Relapse 2) and 5 AML (3=Induction Failure, 2=Relapse 1). The reinduction regimen was well tolerated. There has been 1 patient with Grade IV prolonged myelosuppression following therapy. For the remaining patients, median time to neutrophil recovery was 24 days. Eleven of 14 (79%) patients achieved a CR after 1 cycle of therapy. Of these patients, 100% achieved MRD negativity (<0.1%). Three patients died of progressive disease after 1 cycle of therapy. All 11 patients achieving CR went on to receive an allogeneic HSCT with no documented transplant associated toxicities attributed to prior MITCL therapy. Baseline and post treatment echocardiograms were compared in patients who achieved CR. No patient had clinical evidence of deterioration of left ventricular systolic function prior to proceeding with AlloHSCT. One patient developed MRD (2.6%) at Day +270 post HSCT. The remaining 10 patients demonstrated continued complete remission with MRD negativity at a median follow up time of 321 days (range 113-1150 days). The overall and event free survival for patients who responded to therapy is 91%. (Figure 1) CONCLUSIONThe combination of clofarabine and mitoxantrone reinduction therapy for relapsed or refractory acute leukemia has been demonstrated to be safe and well tolerated in children, adolescents and young adults with poor risk acute leukemias. Hematopoietic recovery continues to be rapid and complete. Data from the first 14 patients enrolled at the RP2D of this combination is encouraging with 79% MRD negative CR rate in leukemic patients allowing patients to safely proceed to AlloHSCT. Longer follow up and a larger cohort is planned and ongoing. [Display omitted] DisclosuresOesterheld:Shire Pharmaceuticals: Speakers Bureau. Cairo:Jazz Pharmaceuticals: Speakers Bureau.

Treatment of High Risk (HR) Smoldering Multiple Myeloma (SMM) with Carfilzomib, Lenalidomide, and Dexamethasone (KRd) Followed By Lenalidomide Maintenance (-R): A Phase 2 Clinical and Correlative Study

Treatment of High Risk (HR) Smoldering Multiple Myeloma (SMM) with Carfilzomib, Lenalidomide, and Dexamethasone (KRd) Followed By Lenalidomide Maintenance (-R): A Phase 2 Clinical and Correlative Study

Three Year Update of the Phase II ABT-199 (Venetoclax) and Ibrutinib in Mantle Cell Lymphoma (AIM) Study

Background: The phase II AIM trial (Tam et al, NEJM 2018; NCT02471391), using combination BTK inhibitor ibrutinib (IB) and BCL-2 inhibitor venetoclax (VEN) therapy achieved excellent 16 week complete remission rates (CRR) (primary endpoint; 62%) in patients (pts) with poor prognosis mantle cell lymphoma (MCL), higher than currently approved second line IB monotherapy. Additionally, overall response rate (ORR) by PET of 71%, with attainment of minimal residual disease (MRD) negativity was reported. At the time of primary endpoint analysis (median follow up 15.9 months), median progression free survival (PFS), duration of response (DOR), time to progression (TTP) and overall survival (OS) had not been reached. Herein, we update our results with an additional 21.6 months of follow-up and report the outcomes of pts who electively interrupted treatment. Methods: Pts with MCL who had relapsed or refractory disease (R/R; n=23) or were treatment naïve but inappropriate for chemotherapy (n=1) were enrolled. Pts commenced treatment with IB 560mg/d for 4 weeks, followed by weekly ramp-up of VEN to 400mg/d. Initially, pts were intended to continue IB and VEN until progressive disease or unacceptable toxicity; a later amendment allowed pts to electively interrupt both drugs if MRD-negative CR was reached. Pts who elected to interrupt therapy were closely monitored by peripheral blood flow MRD testing and regular CT scans, and were allowed to recommence both study drugs at MRD recrudescence or clinical progression. Results: Median age was 68 years (range, 47-81), median number of previous treatments was 2 (range, 0 to 6), and 50% had aberrations of TP53. As previously reported, the flow MRD-negative and ASO-PCR MRD-negative rates were 67% and 38%, respectively. For the current analysis, the median follow-up was 37.5 months (range, 1.4-45.3).The median DOR and TTP had not been reached and were estimated to be 74% and 60% at 30 months, respectively. The median PFS was 29 months (95% CI of 13-NE) (Figure 1), and the median OS was 32 months (95% CI of 27-NE) (Figure 2). For pts with TP53 aberrant MCL (n=12), the CRR was 50% (95% CI 21-79) with and without PET. In this group the ORR was 58% (95% CI 28-85) without PET and 50% (CI 21-79%) with PET. The DOR in 6 responders with TP53 aberrant MCL (excluding one pt with CRu) was 12+, 24+, 26+, 35+, 36+ and 38+ months from study commencement. In contrast, pts with ATM aberrant MCL (n=10) the CRR was 90% (95% CI 55-100) with and without PET, and the ORR was 90% (95% CI 55-100) with and without PET. Of the 9 responders with ATM aberrant MCL, the DOR was 9+, 9+, 12+, 24+, 31+, 35+, 36+, 37+ and 38+ months from study commencement. Of 13 deaths, 8 were due to PD. Of the other 5 deaths, 2 were due to infection, and 1 each to cardiac failure, glioblastoma, and graft versus host disease after an allograft that occurred after PD on trial. Five pts in MRD negative PET-confirmed CR electively interrupted treatment after a median 18.5 months (range 18-33) of therapy: one pt had radiological progression after 7 months, and the other 4 remained free of clinical or MRD progression after 6, 13, 17 and 18 months off therapy. Conclusions: The median PFS for the IB-VEN combination was 29 months. Treatment interruption was feasible for pts in MRD-negative complete remissions, raising the prospect of limited duration targeted-agent therapy in the management of R/R MCL. Disclosures Handunnetti: Gilead: Honoraria; Abbvie: Other: Travel Grant. Anderson:Walter and Eliza Hall Institute: Employment, Patents &amp; Royalties: Institute receives royalties for venetoclax, and I receive a fraction of these.. Hicks:Clarity: Research Funding; Ipsen: Research Funding; Telix Pharmaceuticals: Equity Ownership. Bressel:Regeneron Pharmaceuticals: Consultancy. Koldej:NanoString Technologies: Other: Travel grant. Ritchie:Amgen: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy; BMS: Research Funding; Takeda: Research Funding; Beigene: Research Funding; Imago: Research Funding; Novartis: Honoraria; Sanofi: Honoraria. Seymour:Roche: Consultancy, Research Funding, Speakers Bureau; Acerta: Consultancy; Takeda: Consultancy; Janssen: Consultancy, Research Funding; Celgene: Consultancy, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Research Funding, Speakers Bureau. Roberts:Walter and Eliza Hall Institute: Patents &amp; Royalties: Institute receives royalties for venetoclax, and I receive a fraction of these.; AbbVie: Other: Unremunerated speaker for AbbVie, Research Funding; Janssen: Research Funding; Australasian Leukaemia and Lymphoma Group: Membership on an entity's Board of Directors or advisory committees; BeiGene: Research Funding. Tam:AbbVie: Honoraria, Research Funding; Roche: Honoraria; BeiGene: Honoraria; Novartis: Honoraria; Pharmacyclics LLC, an AbbVie company: Honoraria; Janssen: Honoraria, Research Funding. OffLabel Disclosure: While ibrutinib is FDA approved for use in relapsed and refractory mantle cell lymphoma, venetoclax and combination venetoclax and ibrutinib are not licensed for use in mantle cell lymphoma. The use of venetoclax and ibrutinib for this indication is investigational.

Clinical Factors Associated with Improved Survival Following Allogeneic HSCT after CD19 CAR Therapy in Adult Patients with Relapsed B-ALL

Introduction: Autologous chimeric antigen receptor (CAR) T cell therapy has shown to be effective in CD19+ relapsed or refractory (R/R) B-ALL patients (pts). However, relapses are common and the role of post-CAR allogeneic hematopoietic stem cell transplant (alloHSCT) remains unclear, particularly in adults with relapsed B-ALL. We previously reported that there was no survival benefit with post-CAR alloHSCT in overall adult ALL population (Park J et al. NEJM 2018), but it is unclear whether there is a subset of pts who may benefit the most from post-CAR alloHSCT. Therefore, we sought to identify clinical features that are associated with a better long-term survival in adult B-ALL pts treated with CD19 CAR T cells followed by alloHSCT. Methods: We performed a retrospective chart review of adult pts with R/R ALL treated with 19-28z CAR T therapy at MSKCC (NCT01044069), with a particular focus on pts who achieved minimal residual disease (MRD) negative CR to the CAR therapy and subsequently proceeded to alloHSCT. Clinical data was updated with the data cutoff date of July 15, 2019. We examined the association between overall survival and the following clinical factors: impact of age, prior HSCT status, presence of Philadelphia chromosome (Ph), disease status at the time of CAR therapy (MRD vs. morphologic), severity of cytokine release syndrome (CRS) and neurotoxicity (NTX) experienced during CAR therapy. Survival was calculated from the time of CAR T cell infusion. Continuous variables were analyzed univariately using cox PH models. Categorical variables were analyzed using Kaplan Meier methodology and log rank tests. Results: Of the 53 pts who received 1928z CAR T cells, 16 pts proceeded to alloHSCT after achieving MRD negative CR to the CAR therapy. The median age of these pts was 38 (range, 23-66), and baseline disease and pt characteristics as well as response and toxicity to CAR T therapy are listed in Table 1. Of the 16 pts, 6 pts remain alive in remission; 4 pts died of relapse (median time to relapse: 104.5 days, 57-194), and 6 pts died of transplant-related mortality (TRM) in remission (n=4, infection; n=1, pulmonary VOD; n=1, respiratory failure of unclear etiology). Detailed disease and treatment characteristics by the outcome categories are listed in Table 2. For those pts who are alive in remission, the median survival is 47.5 months (range, 39.7-92.4). Among the examined clinical variables, we found younger age and no severe NTX (i.e. grade 0-2) after CAR therapy to be significantly associated with improved overall survival (p=0.014 and 0.05, respectively) but prior lines of therapy, time to HSCT, prior HSCT, Ph chromosome, disease status at the time of T cell therapy and severity of CRS did not impact the survival after alloHSCT. Conclusions: In this retrospective analysis, we found that younger age and no severe NTX to CD19 CAR therapy were associated with improved overall survival following alloHSCT. Number of relapses following alloHSCT (4 of 16 pts) appears to be lower compared to the previously reported number of relapse in the adult ALL cohort without alloHSCT (17 of 26 pts). However, the occurrence of TRM due to infection is high, likely a reflection of heavily pretreated pt population and possibly further immunosuppression from CAR + alloHSCT. The link between severe NTX and worse survival is unclear but could be related to prolonged corticosteroid use and high disease burden. While no definitive conclusion can be drawn due to a small sample size, our data suggests a certain subset of adult pts with R/R B-ALL may benefit more from alloHSCT as a consolidation therapy following CD19 CAR T cells, and acute and late infectious complications following alloHSCT should be carefully monitored. These findings should be validated prospectively and compared between different CAR constructs. Disclosures Park: Allogene: Consultancy; Amgen: Consultancy; AstraZeneca: Consultancy; Autolus: Consultancy; GSK: Consultancy; Incyte: Consultancy; Kite Pharma: Consultancy; Novartis: Consultancy; Takeda: Consultancy. Riviere:Fate Therapeutics: Consultancy; Juno Therapeutics: Consultancy, Equity Ownership, Research Funding; Memorial Sloan Kettering Cancer Center: Employment. Sadelain:Memorial Sloan Kettering Cancer Center: Employment; Fate Therapeutics: Consultancy, Patents &amp; Royalties; Juno Therapeutics: Consultancy, Patents &amp; Royalties, Research Funding. Brentjens:JUNO Therapeutics: Consultancy, Patents &amp; Royalties, Research Funding; Celgene: Consultancy.

Minimal residual disease negativity in elderly patients with acute myeloid leukemia may indicate different postremission strategies than in younger patients.

In the present analysis, we evaluated whether in elderly acute myeloid leukemia (AML) patients (>60years), minimal residual disease (MRD) assessed by flow cytometry may have a role in guiding choice of postremission strategies. We analyzed 149 young and 61 elderly adults who achieved morphological CR after induction course of EORTC/GIMEMA protocols. Elderly patients reached a postconsolidation MRD negative status less frequently than younger ones (11 vs 28%, p = 0.009). MRD negativity resulted in a longer 5-year disease-free survival (DFS) both in elderly (57 vs 13%, p = 0.0197) and in younger patients (56 vs 31%, p = 0.0017). Accordingly, 5-year cumulative incidence of relapse (CIR) of both elderly (83 vs 42%, p = 0.045) and younger patients (59 vs 24% p = NS) who were MRD positive doubled that of MRD negative ones. Nevertheless, CIR of MRD negative elderly patients was twofold higher than that of younger MRD negative ones (42 vs 24%, p = NS). In conclusion, elderly patients in whom chemotherapy yields a MRD negative CR have duration of DFS and rate of CIR significantly better than those who remain MRD positive. Nonetheless, the high CIR rate observed in the elderly suggests that MRD negativity might have different therapeutic implications in this population than in the younger counterpart.

Immune Status In Patients with Chronic Lymphocytic Leukemia and Sustained Complete Remission: A Multiparametric Analysis

AbstractAbstract 1389Although chronic lymphocytic leukemia (CLL) is considered incurable, a proportion of patients treated with modern therapy achieve complete remission (CR) with minimal residual disease (MRD) negative status, which translates into a better outcome. In addition, survival curves for allogeneic stem cell transplant (alloSCT) appear to plateau, suggesting possible cure. Profound immune disturbances are a major cause of morbidity and mortality in CLL and can be exacerbated by therapy. We studied the immune status of 26 patients with CLL with a sustained (median 8 years, range 2.2 to 17) CR following treatment (4 patients received fludarabine, cyclophosphamide and mitoxantrone [FCM], 6 autologous SCT [autoSCT]) and 16 allogeneic stem cell transplantation [alloSCT]. Lymphocyte subsets were studied using multiparameter flow cytometry and compared to healthy controls. CD8+ T cell response to cytomegalovirus (CMV) was assessed using a pentameric HLA-A2 binding CMV pp65-derived peptide and functionality was confirmed by interferon gamma (IFNγ) ELISPOT. Immunoglobulin subtypes, complement proteins, and β2-microglobulin (B2M) were quantified by standard techniques, interleukin 10 (IL-10) and vascular endothelial growth factor (VEGF) by flow-based cytometric bead array technology, and B cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) serum levels by commercial ELISA. Median age at the time of study was 57 years (55 for the alloSCT, 54 for the autoSCT and 63 for the FCM patients). Two alloSCT patients had chronic graft-versus host disease (cGVHD) at sample collection and were receiving immunosuppression. In addition, three patients experienced autoimmune cytopenia after alloSCT, but had responded to therapy at the time of the study. Detectable residual CLL cells (> 10-4) in peripheral blood were found in six patients (3 alloSCT, 3 FCM). The 20 patients in MRD negative CR had a significantly higher absolute B cell count compared to normal controls comprised of both CD19+CD5- cells (154 cells/mm3vs. 76 cells/mm3, p=0.005) and CD19+CD5+ cells (22 cells/mm3vs. 1 cell/mm3, p=0.002). Normal serum levels of immunoglobulin were present in 17 patients whereas 9 had persistent hypogammaglobulinemia (4 were MRD positive, 2 were on immunosuppression for cGVHD and 1 patient had received rituximab). Thus only 2 patients had unexplained hypogammaglobulinemia despite being in MRD negative-CR. T cell abnormalities were also common in these patients. An abnormal CD4:CD8 ratio was present in 9 patients, and CD4+ cells had failed to recover to >400 cells/mm3 in an additional 5 patients. An increase in CD8+ cells (620 cells/mm3vs. 379 cells/mm3 in normal controls) was mostly comprised of cells with a chronically activated phenotype, CD8+DR+ (220 cells/mm3vs. 78 cells/mm3 in normal controls, p=0.062). Furthermore, in CMV+/HLA-A2 patients, an elevated cytotoxic CD3+CD8+CD45RA population was seen (200 cells/mm3vs. 51 cells/mm3, p=0.037). In all cases, cytotoxic T cells expansions secrete IFNγ in response to pp65. As regards T regulatory cells, CD4+CD25+FOXP3+ cells were significantly increased in patients after alloSCT compared to normal controls (4.1% of CD4+ cells vs. 2.05% in normal, p=0.023). In contrast, patients who received either FCM or autoSCT had Treg levels equivalent to our normal samples (2.45% of CD4+ cells), including the three patients who were MRD positive after FCM. B2M was elevated in 7 patients. No differences were found in levels of complement proteins C3 and C4, direct Coombs test, IL-10 and VEGF. Nevertheless, patients showed median BAFF serum levels significantly higher than healthy controls, even when those patients with conditions considered likely to elevate BAFF and APRIL were excluded (cGVHD, autoimmune cytopenia) (p<0.0001). As for APRIL, serum levels were only significantly increased in patients who had received an alloSCT (p<0.001). These results indicate that characteristic immunological defects associated with CLL (i.e, hypogammaglobulinemia, expansion of CD8+CD45RA cells, abnormal levels of cytokines) may persist in patients with CLL in sustained MRD-negative CR independent of therapy. However, T regulatory cells are increased in patients who had received an alloSCT, a finding which may relate to the persistence of an immunologically tolerant environment necessary to permit successful allografting. Disclosures:No relevant conflicts of interest to declare.

CLL2007FMP, a Phase III Randomized Multicentric Trial of the French Cooperative Group On CLL and WM (FCGCLL/MW) and the “Groupe Ouest-Est D'etudes Des LeuceÃŒmies Aigües Et Autres Maladies Du Sang” (GOELAMS): Immunochemotherapy with Fludarabine (F), Cyclophosphamide (C), and Rituximab (R) (FCR) Yields a Significantly Better Response Than Fludarabine (F), Cyclophosphamide (C) and MabCampath (Cam) (FCCam) In Previously Untreated B-Chronic Lymphocytic

AbstractAbstract 698 Introduction:Between 11/2007 and 01/2009, the FCGCLL/MW and the GOELAMS conducted a multicenter phase III trial, CLL2007FMP, to evaluate the efficacy of FCCam versus FCR in previously untreated medically fit patients. PFS was the primary-end-point of this trial. The trial was discontinued after randomisation of 165 patients for unacceptable toxicity in the FCCam arm. PFS and OS are not yet evaluable but as a sensitive 6 color flow cytometry technique was used to assess MRD in blood and bone marrow at month 9, we were able to evaluate the quality of the response in both arms. Methods and patients:A cohort of 178 medically fit patients (cumulative illness rating scale (CIRS) score < or = 6 and creatinine clearance ≥ 60 ml/min), younger than 65 years old, were enrolled. 165 patients were randomized to receive six oral courses of FC (F 40mg/m2 d1-3 and C 250 mg/m2 d1–3; q 28 days) in combination with either R (n=83; 375 mg/m2 i.v. d 0 at first cycle and 500 mg/m2 d1 all subsequent cycles; q 28 days) or Cam (n=82; 30 mg s/c d1-3; q 28 days). Patients were stratified according to IGHV mutational status and presence of 11q deletion. Cases with 17p deletion were excluded. The trial recruitment was discontinued because of an excess of mortality in the FCCam arm (6 deaths versus 0 in FCR arm), and the last 13 patients enrolled were not randomized. Clinical response was evaluated based on IWCLL criteria.We established a sensitive and specific approach for the evaluation of minimal residual disease (MRD) at month 9, using a 6-color flow cytometry technique with 3 combinations including characteristic markers and light chain expression. We determined the limit of detection (LOD) of the assay by studying normal blood samples, LOD varied from 0.5 to 0.7×10-5 depending on the combination considered. Result:The Overall Response Rate (ORR) was 91% in the FCR arm and 85% in the FCCam arm (ns). Clinical responses were as follows: CR (FCR: 56/80=70%, FCCam: 45/79 =59%, ns), CR I (FCR:13/FCCam: 11), PR (FCR:5/FCCam:15), and stable and progressive cases (FCR: 6/FCCam:8). When considering together CR and CR I, response rate appeared significantly higher in the FCR arm (86%) than in FCCam arm (70%) (p=0.03). MRD was assessed both in blood and bone marrow at month 9, and was undetectable in 58% patients in blood and only in 36 % in bone marrow. No patient had an undetectable MRD in marrow when detectable in blood. Similarly, MRD was detectable in bone marrow in 15 cases with histologically normal bone marrow biopsy, whereas no nodal PR had undetectable MRD. Therefore, flow cytometry MRD in bone marrow appears as the most sensitive technique for the evaluation of response. Of note, 9 patients had a very good PR with presence of a residual lymphnode, and had undetectable blood and bone marrow MRD (4 in FCCAm arm and 5 in FCR arm). When considering MRD independently from clinical response, the number of MRD negative cases was not significantly different between the two arms (FCR: 45%/FCCam: 26 %) arm. But when combining MRD negativity with clinical complete response, the number of MRD negative CR was significantly higher with FCR (40%) than with FCCam (15%)(p= 0.029). The number of courses of chemotherapy received was slightly but significantly lower in the FCCam arm. Nonetheless, this difference was not accountable for the difference in the quality of response as the number of MRD negative CR remained significantly higher with FCR than with FCCam when considering only the patients having received at least 4 courses of either chemotherapy. The quality of response was not influenced by either presence of deletion11q or mutational status as well. In conclusion, detection of MRD in bone marrow by flow cytometry is a sensitive technique for the evaluation of minimal residual disease. Combining clinical CR with flow cytometry bone marrow MRD allows detecting the best responders. In this randomized phase III trial, besides leading to a lower rate of toxicity, the FCR regimen yielded a significantly higher rate of MRD negative CR than FCCam, and therefore had a positive impact on the quality of the response. Disclosures:Veronique:roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; mundipharma: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; genzyme: Membership on an entity's Board of Directors or advisory committees; celgene: Membership on an entity's Board of Directors or advisory committees; jansen: Membership on an entity's Board of Directors or advisory committees.

Alemtuzumab and Rituximab for Therapy of Patents with Early Stage High Risk CLL: Report of a Planned Interim Analysis.

The standard of care for CLL is to treat only patients with obvious clinical progression because earlier intervention is not of proven benefit. The discovery of more accurate prognostic markers for CLL could change that paradigm. The predictors of more aggressive disease include 17p13 deletion (17p13−), 11q22-3 deletion (11q22−), unmutated (UM) immunoglobulin heavy-chain variable region (IgVH), and expression of ZAP-70 and CD38. In addition, monoclonal antibody (MoAb) therapies provide effective treatment with less toxicity than chemotherapy and are likely to be most efficacious in early stage CLL. The combination of alemtuzumab (ALEM) and rituximab (RIT) is of interest because of non-overlapping mechanisms of action. ALEM is also effective therapy for patients with defects in the p53 apoptotic pathway that are more resistance to purine analogue therapy. We tested the hypothesis that MoAb therapy with ALEM and RIT will eliminate/greatly decrease the high risk clone characterized by 17p13−, 11q22−, or UM IgVH plus either ZAP70+ or CD38+, in early stage CLL.Methods This trial will enroll a maximum of 30 patients and be considered promising if ≥ 19 patients respond. All patients with previously untreated CLL (Rai stage 0 −II) not meeting NCI-WG 1996 treatment criteria and with a high risk CLL clone were evaluated for enrollment. Treatment duration was 30 days (subcutaneous ALEM dose escalation, 3 mg - 10 mg - 30 mg on days 1–3) then 30 mg Monday, Wednesday and Friday for 4 weeks. RIT (375 mg/m2/dose IV x 4) was administered weekly staring on day 8. All patients received PCP and herpes virus prophylaxis and had CMV viral DNA testing for 7 months. Response was evaluated using NCI-WG 1996 criteria and minimal residual disease (MRD) was measured in peripheral blood using sensitive flow cytometry (1:104) for CD19+/CD5+/CD79b− lymphocytes.Results Since January 2005, 17 patients have been enrolled and the interim analyses are for the first 11 patients accrued. Median age was 62 years (29 – 75) with 6 males and 5 females. The qualifying high risk features were 17p13− (n = 4), 11q22− (n = 3), and UM IgVH + CD38+ +/− ZAP-70+ (n = 4). Median time from diagnosis to treatment was 11 months (2–72). Clinical stage (Rai) was 0 in 3 patients, I in 5 patients and II in 3 patients. Median absolute lymphocyte count was 25.6 x 109/L (15.9 – 81.8), Hgb 14.4 g/dL (12 – 15.8), and platelet count 171 x 109/L (125 – 312). Two patients had serious adverse reactions requiring intervention (CMV reactivation responsive to treatment; febrile drug reaction to sulfamethoxazole/trimethoprim). Grade 3–4 adverse reactions not requiring interventions were leukopenia (n = 4), neutropenia (n = 2), anemia (n = 1), elevated ALT (n = 1), and skin reaction to ALEM (n =1). There were no “first dose” reactions. All patients responded to therapy with 5 CR (4 of these MRD negative), 3 nodular PR, and 3 PR. Median duration of response has not yet been reached at median follow up of 11.7 months (6.5 – 14.9). Patients with a MRD negative CR had recurrence of detectable MRD at 120 – 210 days after completing therapy but all remain in CR. One patient died off study of complications of a myeloablative allogeneic transplant for progressive CLL.Discussion ALEM and RIT is effective and tolerable therapy for early stage high risk CLL. All patients responded with 36% achieving a MRD negative CR but serial MRD assays showed that the CLL clone was not deleted. This promising, treatment requires further improvement.

Combination Chemotherapy with Fludarabine, Cyclophosphamide and Mitoxantrone (FCM) Induces a High Response Rate in Previously Untreated CLL.

Treatment with FCM results in responses rates of 60% in relapsed or refractory CLL patients. Against this background, we started a trial of FCM in untreated patients diagnosed with CLL younger than 65 yrs. FCM consisted of fludarabine 25 mg/m2 i.v. on days 1 to 3, cyclophosphamide 200 mg/m2 on days 1 to 3, and mitoxantrone 6 mg/m2 i.v. on day 1, given at a 4-week intervals up to six courses. Patients received support with G-CSF and prophylaxis with cotrimoxazole. Response was assessed two months after treatment and included bone marrow and minimal residual disease (MRD) analysis by four-color flow cytometry and PCR. Out the 64 evaluable patients (74% male, median age 58 years), 83% were in advanced (B and C) Binet's clinical stage and 62% had increased (>20%) ZAP-70 expression. FISH analysis disclosed del(13q) in 25%, +12 in 22%, del(17p) in 10% of cases and del(11q) in 23%. Eighty-three per cent of the patients received the entire planed treatment. Overall response rate was of 88%. MRD-negative CR was obtained in 24%, MRD-positive CR in 23%, nPR 22% and PR 11%. Two out of 14 nPR cases were MRD-negative. Duration of response was 55% at 36 months. Initial parameters associated with CR achievement were the presence of del(17p) (p=0.003), increased serum LDH (P=0.014), and splenomegaly (p=0.04). Hematological toxicity was mild, with grade III-IV neutropenia in 8% of the cases, and moderate infections in 12%. Two patients developed fulminant B hepatitis, one of them dying as a direct consequence of it. In conclusion, in untreated CLL patients, FCM induces a high CR rate, including an important number of MRD negative CR. This places FCM among the most effective regimens for CLL and serves to build up a new immunochemotherapy regimen for CLL (R-FCM) currently under investigation.

Optimising alemtuzumab therapy for refractory B cell chronic lymphocytic leukaemia (CLL)

6522 Background: Approximately half of CLL patients do not respond to alemtuzumab and others progress after responding to alemtuzumab. We report here factors predictive for lack of response and approaches to achieve the best outcome for these patients. Methods: 91 patients with relapsed or refractory CLL received alemtuzumab aiming for minimal residual disease (MRD) negativity. Factors correlated with response were reviewed and strategies for overcoming resistance or relapse are reported. Results: The chance of response was associated with lymph node size (p <0.0001): High dose methyl prednisolone (HDMP; 1g/m2/day x5 every 4 weeks; 4 patients) or CHOP (1) were used to reduce bulky nodes prior to alemtuzumab. 2 of 5 had a resolution of lymph nodes with both achieving MRD negative remissions with alemtuzumab. The other 3 did not respond to HDMP or alemtuzumab. 8 patients refractory to alemtuzumab, due to bulky lymph nodes, received alemtuzumab with concurrent fludarabine and 6 responded (2 MRD negative, 2 CR, 2 PR). In addition, 9 patients relapsing after a median of 23 months (range 8–46) from alemtuzumab were retreated of which 5 responded (1 MRD negative, 2 CR, 2 PR): 2 of the non-responders then received alemtuzumab combined with fludarabine with 1 achieving MRD negativity. One patient was treated on relapse directly with the alemtuzumab/fludarabine combination and achieved a MRD negative CR. Thus 11 refractory patients received combined alemtuzumab and fludarabine with 8 responding (4 MRD negative, 2 CR, 2 PR). Conclusions: Gross lymphadenopathy predicts for poor response to alemtuzumab but therapy with HDMP or CHOP followed by alemtuzumab can be effective in achieving MRD negative CR. The majority of alemtuzumab refractory patients (8/11) respond to the addition of fludarabine. Retreatment with alemtuzumab was effective for 3 of 7 relapsing patients. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Ilex Oncology Ltd. Ilex Oncology Ltd. Ilex Oncology Ltd.

Optimising alemtuzumab therapy for refractory B cell chronic lymphocytic leukaemia (CLL)

6522 Background: Approximately half of CLL patients do not respond to alemtuzumab and others progress after responding to alemtuzumab. We report here factors predictive for lack of response and approaches to achieve the best outcome for these patients. Methods: 91 patients with relapsed or refractory CLL received alemtuzumab aiming for minimal residual disease (MRD) negativity. Factors correlated with response were reviewed and strategies for overcoming resistance or relapse are reported. Results: The chance of response was associated with lymph node size (p <0.0001): High dose methyl prednisolone (HDMP; 1g/m2/day x5 every 4 weeks; 4 patients) or CHOP (1) were used to reduce bulky nodes prior to alemtuzumab. 2 of 5 had a resolution of lymph nodes with both achieving MRD negative remissions with alemtuzumab. The other 3 did not respond to HDMP or alemtuzumab. 8 patients refractory to alemtuzumab, due to bulky lymph nodes, received alemtuzumab with concurrent fludarabine and 6 responded (2 MRD negative, 2 CR, 2 PR). In addition, 9 patients relapsing after a median of 23 months (range 8–46) from alemtuzumab were retreated of which 5 responded (1 MRD negative, 2 CR, 2 PR): 2 of the non-responders then received alemtuzumab combined with fludarabine with 1 achieving MRD negativity. One patient was treated on relapse directly with the alemtuzumab/fludarabine combination and achieved a MRD negative CR. Thus 11 refractory patients received combined alemtuzumab and fludarabine with 8 responding (4 MRD negative, 2 CR, 2 PR). Conclusions: Gross lymphadenopathy predicts for poor response to alemtuzumab but therapy with HDMP or CHOP followed by alemtuzumab can be effective in achieving MRD negative CR. The majority of alemtuzumab refractory patients (8/11) respond to the addition of fludarabine. Retreatment with alemtuzumab was effective for 3 of 7 relapsing patients. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Ilex Oncology Ltd. Ilex Oncology Ltd. Ilex Oncology Ltd.