Blinatumomab and Inotuzumab Ozogamicin Sequential Use for the Treatment of Relapsed/Refractory Acute Lymphoblastic Leukemia: A Real-Life Campus All Study.

BACKGROUND: Blinatumomab (Blina) and inotuzumab ozogamicin (InO) has improved the outcome of relapsed/refractory B-lymphoblastic leukemia (R/R B-ALL). However, little is known about the outcome after recurrence and re-treatment with immunotherapy. METHODS: We describe 71 R/R B-ALL patients treated for different relapses with Blina and InO. Blina was the first treatment in 57 patients and InO in 14. Twenty-seven patients had a previous allogeneic hematopoietic stem cell transplantation (allo-HSCT). RESULTS: In the Blina/InO group, after Blina, 36 patients (63%) achieved a complete remission (CR), with 42% of negative minimal residual disease (MRD-); after InO, a CR was achieved in 47 patients (82%, 34 MRD-). In the InO/Blina group, after InO, 13 cases (93%) reached a CR (6 MRD-); after Blina, a CR was re-achieved in 6 cases (43%, 3 MRD-). Twenty-six patients proceeded to allo-HSCT. In the Blina/InO group, the median overall survival (OS) was 19 months; the disease-free survival (DFS) after Blina was 7.4 months (11.6 vs. 2.7 months in MRD- vs. MRD+, p = 0.03) and after InO, 5.4 months. In the InO/Blina group, the median OS was 9.4 months; the median DFS after InO was 5.1 months and 1.5 months after Blina (8.7 vs. 2.5 months in MRD- vs. MRD+, p = 0.02). With a median follow-up of 16.5 months from the start of immunotherapy, 24 patients (34%) are alive and 16 (22%) are alive in CR. CONCLUSION: In our series of R/R B-ALL, Blina and InO treatment demonstrate efficacy for subsequent relapses in terms of MRD response, OS and DFS, and as a bridge to allo-HSCT.

Pegaspargase-modified risk-oriented program for adult acute lymphoblastic leukemia: results of the GIMEMA LAL1913 trial.

Pediatric-inspired chemotherapy is the standard of care for younger adults with Philadelphia chromosome-negative acute lymphoblastic leukemia/lymphoma (Ph- ALL/LL). In LAL1913 trial, the Gruppo Italiano Malattie EMatologiche dell'Adulto added pegaspargase 2000 IU/m2 to courses 1, 2, 5, and 6 of an 8-block protocol for patients aged from 18 to 65 years, with dose reductions in patients aged >55 years. Responders were risk stratified for allogeneic hematopoietic cell transplantation (HCT) or maintenance per clinical characteristics and minimal residual disease (MRD). Of 203 study patients (median age, 39.8 years), 91% achieved a complete remission. The 3-year overall survival, event-free, and disease-free survival (DFS) rates were 66.7%, 57.7%, and 63.3%, respectively, fulfilling the primary study end point of a 2-year DFS >55%. Although based on the intention-to-treat, the DFS being 74% and 50% in the chemotherapy (n = 94) and HCT (n = 91) assignment cohorts, respectively, a time-dependent analysis proved the value of HCT in patients who were eligible (DFS HCT 70% vs no HCT 26%; P <.0001). In multivariate analysis, age and MRD were independent factors predicting DFS rates of 86% (age ≤ 40 and MRD-negative), 64%-65% (MRD-positive or age > 40) and 25% (age > 40 and MRD-positive); P < .0001. Grade ≥2 pegaspargase toxicity was mainly observed at course 1, contributing to induction death in 2 patients but was rare thereafter. This program improved outcomes of patients with Ph- ALL/LL aged up to 65 years in a multicenter national setting. This trial was registered at www.clinicaltrials.gov as #NCT02067143.

Multicenter retrospective analysis of clinical outcome of adult patients with mixed-phenotype acute leukemia treated with acute myeloid leukemia-like or acute lymphoblastic leukemia-like chemotherapy and impact of allogeneic stem cell transplantation: a Campus ALL study.

Mixed-phenotype acute leukemia (MPAL) is a rare disease. Treatment is often similar to that of acute lymphoblastic leukemia (ALL), but the outcome in adults and the role of allogeneic stem cell transplantation (AlloSCT) are not well defined. We report on 77 adult patients diagnosed with MPAL over the last 10 years and treated with a curative intent. Median age was 49 years; 7.6% of cases had a BCR::ABL1 rearrangement. Thirty patients (39%) were treated with an acute myeloid leukemia (AML)-like induction and 47 (61%) with an ALL-like scheme. The complete remission (CR) rate was 67.6% and an ALL-like therapy was associated with a better CR rate (P = 0.048). The median OS was 41.9 months; age ≤ 60 years was associated with a better OS (67 vs 26 months, P = 0.014). An AlloSCT was performed in 50 patients (65%). The 5-year OS of transplanted patients was 54%. The OS post-AlloSCT was better in patients who were minimal residual disease (MRD)-negative prior to transplant (75.8% vs 45.2%, P = 0.06). This study shows that MPAL patients respond better to an ALL-like induction therapy; that consolidation therapy should include, whenever possible, an AlloSCT and that MRD negativity should be a primary endpoint of treatment.

Incidence, treatment and outcome of central nervous system relapse in adult acute lymphoblastic leukaemia patients treated front-line with paediatric-inspired regimens: A retrospective multicentre Campus ALL study.

Within the Campus ALL network we analyzed the incidence, characteristics, treatment and outcome of a central nervous system (CNS) relapse in 1035 consecutive adult acute lymphoblastic leukemia (ALL) patients treated frontline with pediatric-inspired protocols between 2009 and 2020. Seventy-one patients (6.8%) experienced a CNS recurrence, more frequently in T- (28/278; 10%) than in B-ALL (43/757; 5.7%) (p = 0.017). An early CNS relapse-< 12 months from diagnosis-was observed in 41 patients. In multivariate analysis, risk factors for early CNS relapse included T-cell phenotype (p = <0.001), hyperleucocytosis >100 × 109 /L (p<0.001) and male gender (p = 0.015). Treatment was heterogeneous, including chemotherapy, radiotherapy, intrathecal therapy and novel agents. A complete remission (CR) was obtained in 39 patients (55%) with no differences among strategies. After CR, 26 patients underwent an allogenic transplant, with a significant overall survival benefit compared to non-transplanted patients (p = 0.012). After a median observation of 8 months from CNS relapse, 23 patients (32%) were alive. In multivariate analysis, the time to CNS relapse was the strongest predictor of a lower 2-year post-relapse survival (p<0.001). In conclusion, in adult ALL the outcome after a CNS relapse remains very poor. Effective CNS prophylaxis remains the best approach and allogenic transplant should be pursued when possible.

Digital Droplet PCR Is a Reliable Tool to Improve Minimal Residual Disease Stratification in Adult Philadelphia-Negative Acute Lymphoblastic Leukemia.

Digital droplet PCR (ddPCR) is an implementation of conventional PCR, with the potential of overcoming some limitations of real-time quantitative PCR (RQ-PCR). To evaluate if ddPCR may improve the quantification of disease levels and refine patients' risk stratification, 116 samples at four time points from 44 (35 B-lineage and 9 T-lineage) adult Philadelphia-negative acute lymphoblastic leukemia patients enrolled in the GIMEMA LAL1913 protocol were analyzed by RQ-PCR and ddPCR. A concordance rate between RQ-PCR and ddPCR of 79% (P < 0.0001) was observed; discordances were identified in 21% of samples, with the majority being RQ-PCR-negative (NEG) or positive not quantifiable (PNQ). ddPCR significantly reduced the proportion of PNQ samples-2.6% versus 14% (P = 0.003)-and allowed disease quantifiability in 6.6% of RQ-PCR-NEG, increasing minimal residual disease quantification in 14% of samples. Forty-seven samples were also investigated by next-generation sequencing, which confirmed the ddPCR results in samples classified as RQ-PCR-PNQ or NEG. By reclassifying samples on the basis of the ddPCR results, a better event-free survival stratification of patients was observed compared to RQ-PCR; indeed, ddPCR captured more true-quantifiable samples, with five relapses occurring in three patients who resulted RQ-PCR-PNQ/NEG but proved ddPCR positive quantifiable. At variance, no relapses were recorded in patients whose follow-up samples were RQ-PCR-PNQ but reclassified as ddPCR-NEG. A broader application of ddPCR in acute lymphoblastic leukemia clinical trials will help to improve patients' stratification.

INCB84344-201: Ponatinib and steroids in frontline therapy for unfit patients with Ph+ acute lymphoblastic leukemia.

Tyrosine kinase inhibitors have improved survival for patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). However, prognosis for old or unfit patients remains poor. In the INCB84344-201 (formerly GIMEMA LAL 1811) prospective, multicenter, phase 2 trial, we tested the efficacy and safety of ponatinib plus prednisone in newly diagnosed patients with Ph+ ALL ≥60 years, or unfit for intensive chemotherapy and stem cell transplantation. Forty-four patients received oral ponatinib 45 mg/d for 48 weeks (core phase), with prednisone tapered to 60 mg/m2/d from days-14-29. Prophylactic intrathecal chemotherapy was administered monthly. Median age was 66.5 years (range, 26-85). The primary endpoint (complete hematologic response [CHR] at 24 weeks) was reached in 38/44 patients (86.4%); complete molecular response (CMR) in 18/44 patients (40.9%) at 24 weeks. 61.4% of patients completed the core phase. As of 24 April 2020, median event-free survival was 14.31 months (95% CI 9.30-22.31). Median overall survival and duration of CHR were not reached; median duration of CMR was 11.6 months. Most common treatment-emergent adverse events (TEAEs) were rash (36.4%), asthenia (22.7%), alanine transaminase increase (15.9%), erythema (15.9%), and γ-glutamyltransferase increase (15.9%). Cardiac and vascular TEAEs occurred in 29.5% (grade ≥3, 18.2%) and 27.3% (grade ≥3, 15.9%), respectively. Dose reductions, interruptions, and discontinuations due to TEAEs occurred in 43.2%, 43.2%, and 27.3% of patients, respectively; 5 patients had fatal TEAEs. Ponatinib and prednisone showed efficacy in unfit patients with Ph+ ALL; however, a lower ponatinib dose may be more appropriate in this population. This trial was registered at www.clinicaltrials.gov as #NCT01641107.

MYB rearrangements and over-expression in T-cell acute lymphoblastic leukemia.

We investigated MYB rearrangements (MYB-R) and the levels of MYB expression, in 331 pediatric and adult patients with T-cell acute lymphoblastic leukemia (T-ALL). MYB-R were detected in 17 cases and consisted of MYB tandem duplication (tdup) (= 14) or T cell receptor beta locus (TRB)-MYB (= 3). As previously reported, TRB-MYB was found only in children (1.6%) while MYB tdup occurred in both age groups, although it was slightly more frequent in children (5.2% vs 2.8%). Shared features of MYB-R T-ALL were a non-early T-cell precursor (ETP) phenotype, a high incidence of NOTCH1/FBXW7 mutations (81%) and CDKN2AB deletions (70.5%). Moreover, they mainly belonged to HOXA (=8), NKX2-1/2-2/TLX1 (=4), and TLX3 (=3) homeobox-related subgroups. Overall, MYB-R cases had significantly higher levels of MYB expression than MYB wild type (MYB-wt) cases, although high levels of MYB were detected in ~ 30% of MYB-wt T-ALL. Consistent with the transcriptional regulatory networks, cases with high MYB expression were significantly enriched within the TAL/LMO subgroup (P = .017). Interestingly, analysis of paired diagnosis/remission samples demonstrated that a high MYB expression was restricted to the leukemic clone. Our study has indicated that different mechanisms underlie MYB deregulation in 30%-40% of T-ALL and highlighted that, MYB has potential as predictive/prognostic marker and/or target for tailored therapy.

A multicenter total therapy strategy for de novo adult Philadelphia chromosome positive acute lymphoblastic leukemia patients: final results of the GIMEMA LAL1509 protocol.

The GIMEMA LAL1509 protocol, designed for adult (≥18-60 years) de novo Ph+ acute lymphoblastic leukemia patients, was based on a dasatinib plus steroids induction - with central nervous system prophylaxis - followed by dasatinib alone in patients in complete molecular response or chemotherapy and/or allogeneic transplantation in patients not reaching a complete molecular response. Sixty patients (median age 41.9 years) were enrolled: 33 were p190+, 18 p210+ and 9 p190/p210+. At the end of induction (day +85), 58 patients (97%) achieved a complete hematologic remission. No deaths in induction were recorded. Eleven patients (18.3%) obtained a complete molecular response. Among non-complete molecular responders (n=47), 22 underwent an allogeneic transplant. Seventeen hematologic relapses occurred (median 7 months, range 3-40.1), 13 during consolidation and 4 post-transplant. ABL1 mutations (5 T315I, 3 V299L, 1 E281K and 1 G254E) were found in 10/13 relapsed cases. With a median follow-up of 57.4 months (range: 4.2-75.6), overall survival and disease-free survival are 56.3% and 47.2%. A better diseasefree survival was observed in patients who obtained a molecular response at day +85 compared to cases who did not. The presence of additional copy number aberrations - IKZF1 plus CDKN2A/B and/or PAX5 deletions - was the most important unfavorable prognostic factor on overall and disease-free survival (p=0.005 and p=0.0008). This study shows that in adult Ph+ ALL long-term survivals can be achieved with a total-therapy strategy based on a chemo-free induction and, in complete molecular responders, also without further systemic chemotherapy. Finally, the screening of additional copy number aberrations should be included in the diagnostic work-up. EudraCT 2010-019119-39.

Philadelphia-like acute lymphoblastic leukemia is associated with minimal residual disease persistence and poor outcome. First report of the minimal residual disease-oriented GIMEMA LAL1913.

Early recognition of Ph-like acute lymphoblastic leukemia cases could impact on the management and outcome of this subset of B-lineage ALL. To assess the prognostic value of the Ph-like status in a pediatric-inspired, minimal residual disease (MRD)-driven trial, we screened 88 B-lineage ALL cases negative for the major fusion genes (BCR-ABL1, ETV6-RUNX1, TCF3-PBX1 and KTM2Ar) enrolled in the GIMEMA LAL1913 front-line protocol for adult BCR/ABL1-negative ALL. The screening - performed using the BCR/ABL1-like predictor - identified 28 Ph-like cases (31.8%), characterized by CRLF2 overexpression (35.7%), JAK/STAT pathway mutations (33.3%), IKZF1 (63.6%), BTG1 (50%) and EBF1 (27.3%) deletions, and rearrangements targeting tyrosine kinases or CRLF2 (40%). The correlation with outcome highlighted that: i) the complete remission (CR) rate was significantly lower in Ph-like compared to non-Ph-like cases (74.1% vs 91.5%, p=0.044); ii) at time point 2 (TP2), decisional for transplant allocation, 52.9% of Ph-like cases vs 20% of non-Ph-like were MRD-positive (p=0.025); iii) the Ph-like profile was the only parameter associated with a higher risk of being MRD-positive at TP2 (p=0.014); iv) at 24 months, Ph-like patients had a significantly inferior event-free and disease-free survival compared to non-Ph-like patients (33.5% vs 66.2%, p=0.005 and 45.5% vs 72.3%, p=0.062, respectively). This study documents that Ph-like patients have a lower CR rate, EFS and DFS, as well as a greater MRD persistence also in a pediatric-oriented and MRD-driven adult ALL protocol, thus reinforcing that the early recognition of Ph-like ALL patients at diagnosis is crucial to refine risk-stratification and to optimize therapeutic strategies.

Adolescent and young adult acute lymphoblastic leukemia. Final results of the phase II pediatric-like GIMEMA LAL-1308 trial.

Adolescents and young adults (AYA) with acute lymphoblastic leukemia (ALL) represent a unique patient population with specific characteristics and needs. Growing evidences suggest that pediatric-inspired approaches improve the outcome in AYA. These results prompted the design of a pediatric AIEOP-BFM ALL 2000-based regimen - the GIMEMA LAL-1308 protocol - for newly diagnosed AYA (range 18-35 years) with Philadelphia negative (Ph-) ALL. The protocol included minimal residual disease (MRD) analysis at two different time-points (TP), that is, at the end of induction IA and consolidation IB, and a modulation in post-consolidation intensity according to MRD. Seventy-six patients were eligible between September 2010 and October 2014. The regimen was well tolerated, with 2.7% induction deaths and no deaths in the post-consolidation phase. The complete response (CR) rate was 92%; the 48-month overall survival (OS) and disease-free survival (DFS) were 60.3% and 60.4%. Both OS and DFS were significantly better in T-ALL than B-ALL. A molecular MRD <10-3 at TP1 was associated with a significantly better OS and DFS (77% vs 39% and 71.9% vs 34.4%, respectively);similar results were documented at TP2 (OS and DFS 74.5% vs 30.6% and 71.5% vs 25.7%, respectively). The LAL-1308 results were compared to those from similar historic AYA populations undergoing the two previous GIMEMA LAL-2000 and LAL-0904 protocols. Both OS and DFS improved significantly compared to the two previous protocols. These results indicate that this pediatric-inspired and MRD-oriented protocol is feasible and effective for Ph- AYA ALL patients, and underline the prognostic value of MRD determinations at specific TPs.

Dasatinib-Blinatumomab for Ph-Positive Acute Lymphoblastic Leukemia in Adults.

BACKGROUND: Outcomes in patients with Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL) have improved with the use of tyrosine kinase inhibitors. Molecular remission is a primary goal of treatment. METHODS: We conducted a phase 2 single-group trial of first-line therapy in adults with newly diagnosed Ph-positive ALL (with no upper age limit). Dasatinib plus glucocorticoids were administered, followed by two cycles of blinatumomab. The primary end point was a sustained molecular response in the bone marrow after this treatment. RESULTS: Of the 63 patients (median age, 54 years; range, 24 to 82) who were enrolled, a complete remission was observed in 98%. At the end of dasatinib induction therapy (day 85), 29% of the patients had a molecular response, and this percentage increased to 60% after two cycles of blinatumomab; the percentage of patients with a molecular response increased further after additional blinatumomab cycles. At a median follow-up of 18 months, overall survival was 95% and disease-free survival was 88%; disease-free survival was lower among patients who had an IKZF1 deletion plus additional genetic aberrations (CDKN2A or CDKN2B, PAX5, or both [i.e., IKZF1 plus]). ABL1 mutations were detected in 6 patients who had increased minimal residual disease during induction therapy, and all these mutations were cleared by blinatumomab. Six relapses occurred. Overall, 21 adverse events of grade 3 or higher were recorded. A total of 24 patients received a stem-cell allograft, and 1 death was related to transplantation (4%). CONCLUSIONS: A chemotherapy-free induction and consolidation first-line treatment with dasatinib and blinatumomab that was based on a targeted and immunotherapeutic strategy was associated with high incidences of molecular response and survival and few toxic effects of grade 3 or higher in adults with Ph-positive ALL. (Funded by Associazione Italiana per la Ricerca sul Cancro and others; GIMEMA LAL2116 D-ALBA EudraCT number, 2016-001083-11; ClinicalTrials.gov number, NCT02744768.).

Nelarabine as salvage therapy and bridge to allogeneic stem cell transplant in 118 adult patients with relapsed/refractory T-cell acute lymphoblastic leukemia/lymphoma. A CAMPUS ALL study.

The outcome of relapsed or refractory (R/R) T-cell acute lymphoblastic leukemia/lymphoma (T-ALL/T-LBL) in adults is poor, with less than 20% of patients surviving at 5 years. Nelarabine is the only drug specifically approved for R/R T-ALL/T-LBL, but the information to support its use is based on limited available data. The aim of this observational phase four study was to provide recent additional data on the efficacy and safety of nelarabine in adults with R/R T-ALL/T-LBL and to evaluate the feasibility and outcome of allogeneic hematopoietic stem cell transplant (SCT) after salvage with nelarabine therapy. The primary endpoints were overall response rate (ORR) and overall survival (OS). Additional endpoints were safety, SCT rate and post-SCT OS. Between May 2007 and November 2018, 118 patients received nelarabine salvage therapy at 27 Italian hematology sites. The median age was 37 years (range 18-74 years), 73% were male, 77 had a diagnosis of T-ALL and 41 of T-LBL, and 65/118 (55%) had received more than two lines of therapy. The median number of nelarabine cycles was two (range 1-4); 43/118 (36%) patients had complete remission (CR), 16 had partial remission (14%) and 59 (50%) were refractory, with an ORR of 50%. The probability of OS, from the first dose of nelarabine, was 37% at 1 year with a median survival of 8 months. The OS at 1 year was significantly better for the 47 patients (40%) who underwent SCT after nelarabine salvage therapy (58% vs 22%, log-rank P < .001). The probability of OS at 2 and 5 years from SCT was 46% and 38%, respectively. Seventy-five patients (64%) experienced one or more drug-related adverse events (AE). Grade III-IV neurologic toxicities were observed in 9/118 (8%) of cases and thrombocytopenia or/and neutropenia (grade III-IV) were reported in 41% and 43% of cases, respectively. In conclusion, this is one of the largest cohorts of adult patients with R/R T-ALL/T-LBL treated in real life with nelarabine. Taking into account the poor prognosis of this patient population, nelarabine represents an effective option with an ORR of 50% and a CR rate of 36%. In addition, 40% of cases following nelarabine salvage therapy could undergo SCT with an expected OS at 2 and 5 years of 46% and 38%, respectively. The safety profile of nelarabine was acceptable with only 8% of cases showing grade III-IV neurological AE.

Design of a Comprehensive Fluorescence in Situ Hybridization Assay for Genetic Classification of T-Cell Acute Lymphoblastic Leukemia.

T-cell acute lymphoblastic leukemia (T-ALL) results from deregulation of a number of genes via multiple genomic mechanisms. We designed a comprehensive fluorescence in situ hybridization (CI-FISH) assay that consists of genomic probes to simultaneously investigate oncogenes and oncosuppressors recurrently involved in chromosome rearrangements in T-ALL, which was applied to 338 T-ALL cases. CI-FISH provided genetic classification into one of the well-defined genetic subgroups (ie, TAL/LMO, HOXA, TLX3, TLX1, NKX2-1/2-2, or MEF2C) in 80% of cases. Two patients with translocations of the LMO3 transcription factor were identified, suggesting that LMO3 activation may serve as an alternative to LMO1/LMO2 activation in the pathogenesis of this disease. Moreover, intrachromosomal rearrangements that involved the 10q24 locus were found as a new mechanism of TLX1 activation. An unequal distribution of cooperating genetic defects was found among the six genetic subgroups. Interestingly, deletions that targeted TCF7 or TP53 were exclusively found in HOXA T-ALL, LEF1 defects were prevalent in NKX2-1 rearranged patients, CASP8AP2 and PTEN alterations were significantly enriched in TAL/LMO leukemias, and PTPN2 and NUP214-ABL1 abnormalities occurred in TLX1/TLX3. This work convincingly shows that CI-FISH is a powerful tool to define genetic heterogeneity of T-ALL, which may be applied as a rapid and accurate diagnostic test.

Minimal Residual Disease in Acute Lymphoblastic Leukemia: Technical and Clinical Advances.

Introduction: Acute lymphoblastic leukemia (ALL) is the first neoplasm where the assessment of early response to therapy by minimal residual disease (MRD) monitoring has proven to be a fundamental tool to guide therapeutic choices. The most standardized methods to study MRD in ALL are multi-parametric flow cytometry (MFC) and polymerase chain reaction (PCR) amplification-based methods. Emerging technologies hold the promise to improve MRD detection in ALL patients. Moreover, novel therapies, such as monoclonal antibodies, bispecific T-cell engagers, and chimeric antigen receptor T cells (CART) represent exciting advancements in the management of B-cell precursor (BCP)-ALL. Aims: Through a review of the literature and in house data, we analyze the current status of MRD assessment in ALL to better understand how some of its limitations could be overcome by emerging molecular technologies. Furthermore, we highlight the future role of MRD monitoring in the context of personalized protocols, taking into account the genetic complexity in ALL. Results and Conclusions: Molecular rearrangements (gene fusions and immunoglobulin and T-cell receptor-IG/TR gene rearrangements) are widely used as targets to detect residual leukemic cells in ALL patients. The advent of novel techniques, namely next generation flow cytometry (NGF), digital-droplet-PCR (ddPCR), and next generation sequencing (NGS) appear important tools to evaluate MRD in ALL, since they have the potential to overcome the limitations of standard approaches. It is likely that in the forthcoming future these techniques will be incorporated in clinical trials, at least at decisional time points. Finally, the advent of new powerful compounds is further increasing MRD negativity rates, with benefits in long-term survival and a potential reduction of therapy-related toxicities. However, the prognostic relevance in the setting of novel immunotherapies still needs to be evaluated.

Phase II trial with sequential clofarabine and cyclophosphamide for refractory and relapsed philadelphia-negative adult acute lymphoblastic leukemia. Results of the GIMEMA LAL 1610 protocol.

Clofarabine (CLO) and cyclophosphamide (CY) combinations were tested in late stage refractory/relapsed (R/R) acute lymphoblastic leukemia (ALL) with disappointing results and high-grade toxicity. We designed a sequential 5-day combination of CLO 40 mg/m2/d plus CY 400 mg/m2/d as first salvage for Philadelphia-negative ALL patients refractory or relapsed until 24 months from complete remission (CR). Primary endpoint was an overall response rate (ORR) ≥ 40%. Among 26 study patients (median age 40.5 years) ORR was 57.6% (CR with complete [n = 8] or incomplete [n = 7] hematologic recovery). Despite severe myelotoxicity, no dose-limiting toxicity suggested de-intensification of CLO schedule. With a median follow-up of 17.0 months, median and 1-year overall and disease-free survival were 6.5 months and 28.6%, and 3.7 months and 28.1%, respectively. This association was tolerable and more effective in patients younger than 40 years with B-precursor ALL, longer first CR, not previously transplanted and achieving CR with full hematological recovery.