ALBERT

Description: Introduction Pegaspargase (PEG) is a critical component of therapy for pediatric acute lymphoblastic leukemia (ALL); however, complete asparaginase treatment may be hampered by the development of hypersensitivity reactions. Inadequate exposure to asparaginase has been shown to result in inferior outcomes (Gupta 2020). Although Erwinia asparaginase can be utilized as a replacement in patients with PEG allergy, recent shortages of Erwinia leave some patients who develop allergy to PEG without an alternative. Premedication with antihistamines and corticosteroids, as well as decreasing the pegaspargase infusion rate have been proposed as approaches to reduce hypersensitivity reactions (Cooper 2019, Bade 2019, Stock 2019). We evaluated the episodes of hypersensitivity reactions to PEG during three time periods with differing premedication and infusion practices at a single institution. Methods We utilized pharmacy records to conduct a retrospective chart review on PEG administration at Children's Healthcare of Atlanta from June 2017 to May 2020. Abstraction captured data on clinical hypersensitivity reactions to PEG over 3 time periods. PEG 2500 units/m2 was delivered as an intravenous infusion according to the schedules used in Children's Oncology Group ALL protocols. In the first time period (P1, June 22, 2017 to June 21, 2018) PEG was infused over 1 hour without premedication. In the second period (P2, June 22, 2018 to May 19, 2019) PEG was infused over 1 hour following premedication with ranitidine and diphenhydramine. In the final period (P3, May 20, 2019 to May 19, 2020) PEG was infused over 2 hours with normal saline piggyback intravenous fluids following premedication with ranitidine (or famotidine), diphenhydramine and hydrocortisone. Asparaginase activity was measured 7-10 days after PEG doses in consolidation and subsequent phases in P1 and P2, and also after induction in P3. Silent inactivation was defined as asparaginase activity

Description: Key Points A novel clinical syndrome of CSA, B-cell immunodeficiency, periodic fevers, and developmental delay is described. Bone marrow transplant resulted in complete and durable resolution of the hematologic and immunologic manifestations.

Description: We prove that the SH2-containing tyrosine phosphatase 1 (SHP-1) plays a prominent role as resistance determinant of imatinib (IMA) treatment response in chronic myelogenous leukemia cell lines (sensitive/KCL22-S and resistant/KCL22-R). Indeed, SHP-1 expression is significantly lower in resistant than in sensitive cell line, in which coimmunoprecipitation analysis shows the interaction between SHP-1 and a second tyrosine phosphatase SHP-2, a positive regulator of RAS/MAPK pathway. In KCL22-R SHP-1 ectopic expression restores both SHP-1/SHP-2 interaction and IMA responsiveness; it also decreases SHP-2 activity after IMA treatment. Consistently, SHP-2 knocking-down in KCL22-R reduces either STAT3 activation or cell viability after IMA exposure. Therefore, our data suggest that SHP-1 plays an important role in BCR-ABL–independent IMA resistance modulating the activation signals that SHP-2 receives from both BCR/ABL and membrane receptor tyrosine kinases. The role of SHP-1 as a determinant of IMA sensitivity has been further confirmed in 60 consecutive untreated patients with chronic myelogenous leukemia, whose SHP-1 mRNA levels were significantly lower in case of IMA treatment failure (P 〈 .0001). In conclusion, we suggest that SHP-1 could be a new biologic indicator at baseline of IMA sensitivity in patients with chronic myelogenous leukemia.

Description: Key Points Nilotinib induced deeper molecular responses than continued imatinib in patients with minimal residual disease on long-term imatinib. These deeper responses may enable more patients to benefit from treatment-free remission trials.

Description: Abstract 3283 Donor-derived regulatory T cells (Treg) and natural killer (NK) cells can respectively improve stem cell transplant (SCT) outcome by reducing graft versus host disease (GVHD) severity and exerting a graft-versus-leukemia effect. High frequencies of donor Treg are associated with less GVHD, and low doses of interleukin-2 (IL-2) can expand both NK and Treg after allogeneic SCT. To explore the feasibility of improving the quality of peripheral blood SCT donations, we evaluated the safety and the tolerability of ultra-low dose IL-2 administration to volunteers with the aim of preferentially expanding Treg and NK cells. Twelve healthy volunteers (mean age 34 years; range 22–57) received 0.1 or 0.2 million U/m2/day IL-2 subcutaneously for 5 days (NIH protocol 11-H-0268). Blood samples were collected before and 1, 2, 3, 4, 7 and 28 days after IL-2 injection. Samples were analyzed by multiplex techniques including whole transcriptome gene expression with HumanGene 1.0ST microarrays; serum levels of 69 cytokines and chemokines by Luminex assay; and lymphocyte phenotyping by flow cytometry, to comprehensively characterize the cellular and molecular immune response to IL-2 (“IL-2 immunome”). Treg subsets were determined within the CD4+ T cell population using FoxP3, Helios, CD45RA and CD31 to identify thymus-derived natural Treg (nTreg), induced Tregs (iTreg) and their recent thymic emigrants (RTE). NK cell subsets were determined within CD56+CD3- population using NKG2A, KIR2DL1, KIR2DL2/3, KIR3DL1 and CD57 to identify CD56bright, CD56dim NKG2A+KIR-, and CD56dim KIR+CD57+ cells. All subjects tolerated ultra-low dose IL-2 with minimal adverse events (mainly grade 1–2 injection site reactions). The fraction of FoxP3+Treg in CD4 rose significantly above baseline peaking at 4 days (3.7% vs 5.8%; p=0.0004) after the first dose of IL-2. Treg subset analysis demonstrated that the fraction of nTreg and RTE nTreg in CD4 expanded significantly in the lower dose cohort compared to the higher dose cohort (p=0.004 and p=0.005 respectively). %CD56bright NK significantly increased at 7 days (p=0.008), whereas CD56dimNKG2A+KIR-, and CD56dimKIR+CD57+ NK cells remained at baseline. The Ki67 proliferation marker further verified a significant in vivo expansion of CD56bright NK cells with ultra-low dose IL-2. Cytokine and chemokine profiling demonstrated significant increase circulating level of IP-10 (P=0.0018) through day 2 to 4 after IL-2 injections. In contrast, circulating levels of IL-2, IL-6, IL-10, IL-15 and IL-17 remained unchanged after IL-2 injection. Gene expression microarray studies revealed significant changes in 24 genes (P value 〈 0.1 corrected by false discovery rate (FDR) for multiple testing), including up-regulation of IL-2RA and FOXP3 as early as 2 days after IL-2 injections. Gene Set Analysis (GSA) revealed significant changes (P value 〈 0.1 after FDR) in innate immune response pathways, including Toll-like receptor signaling and interferon signaling. This is the first study to show that ultra-low dose IL-2 could be safely administrated to healthy volunteers to expand thymic-derived natural Treg and CD56bright NK cells. These results raise the possibility of using ultra-low dose IL-2 to boost Treg and NK cells in stem cell donors. Disclosures: No relevant conflicts of interest to declare.

Description: Key Points IL-3 receptor α (CD123) expression is elevated in CML progenitor and stem cells compared with healthy donors. CD123 monoclonal antibody targeting represents a novel, potentially clinically relevant approach to deplete CML progenitor and stem cells.

Description: Background The efficacy and safety of subsequent TKIs in pts who have experienced failure of dasatinib is not fully known. Ponatinib, a pan-BCR-ABL inhibitor, was evaluated in a phase 2, international, open-label clinical trial (PACE). This post-hoc analysis explored the efficacy and safety of ponatinib following failure of dasatinib in CP-CML pts in the PACE trial. Methods The PACE trial enrolled 449 pts, including 270 with CP-CML. Pts had to be resistant or intolerant to dasatinib or nilotinib, or they had to have the T315I mutation at baseline. The primary endpoint in CP-CML was major cytogenetic response (MCyR) at any time within 12 months after treatment initiation. The trial is ongoing. Data as of 1 April 2013 are reported, with a minimum follow-up of 18 months for pts remaining on study. The efficacy and safety of ponatinib (45 mg QD) in 107 CP-CML pts following failure of dasatinib as the most recent prior therapy, irrespective of other TKI therapy, is presented (Group D). Eighteen pts who experienced failure of dasatinib but received ≥1 anticancer therapy, other than hydroxyurea or anagrelide, prior to ponatinib treatment were excluded from the analyses. Data are also presented for 2 subsets of Group D: 52 pts whose only TKI therapy was imatinib followed by dasatinib (Group I-D), and 46 pts whose only TKI therapy was imatinib, then nilotinib, and then dasatinib (Group I-N-D). An analysis of cross-intolerance was also conducted in 69 pts with prior dasatinib treatment at any time who discontinued dasatinib due to intolerance. Results Baseline characteristics are shown in the table. Group I-D tended to be younger, with less time since diagnosis versus Group I-N-D. At the time of analysis, 60%, 65%, and 54% of pts in Groups D, I-D, and I-N-D remained on study. The most common reasons for discontinuation were adverse events (AEs; 16%, 15%, 17%) and progressive disease (9%, 6%, 11%) in Groups D, I-D, and I-N-D. Efficacy end points are shown in the table. In Group D, MCyR was seen in pts with the following dasatinib-resistant mutations at baseline: V299L, 3/4 (75%); T315I, 17/23 (74%); F317L, 3/10 (30%). The most common treatment-related AEs were thrombocytopenia (44%, 37%, 57%), rash (39%, 39%, 39%), and dry skin (39%, 29%, 52%) in Groups D, I-D, and I-N-D. Serious cardiovascular, cerebrovascular, and peripheral vascular AEs occurred in 6%, 3%, and 3% of pts in Group D (treatment-related: 3%, 1%, 0%). Seventy-three of 217 pts receiving prior dasatinib at any time discontinued dasatinib due to intolerance. Of these 73 pts, 27 experienced the same AE(s) with ponatinib that led to dasatinib intolerance; 12 pts had grade 3/4 thrombocytopenia, 6 pts had other grade 3/4 AEs (3 with neutropenia, 1 each with pleural effusion, dyspnea, pulmonary hypertension), 8 pts had grade 1/2 AEs. Six of these 27 pts discontinued ponatinib due to the same AE that led to dasatinib intolerance. Thrombocytopenia was the primary AE involved in cross-intolerance (4 pts); congestive cardiac failure (grade 5) and pleural effusion each occurred once. Conclusions Ponatinib has substantial activity in pts with CP-CML following failure of dasatinib, with a safety profile reflective of this heavily pretreated population. Cross-intolerance between dasatinib and ponatinib was infrequent. Disclosures: Hochhaus: Ariad, Novartis, BMS, MSD, Pfizer: Research Funding; Novartis, BMS, Pfizer: Honoraria. Cortes:Ariad, Pfizer, Teva: Consultancy; Ariad, BMS, Novartis, Pfizer, Teva: Research Funding. Kim:BMS, Novartis,IL-Yang: Consultancy; BMS, Novartis, Pfizer,ARIAD,IL-Yang: Research Funding; BMS, Novartis,Pfizer,IL-Yang: Honoraria; BMS, Novartis,Pfizer: Speakers Bureau; BMS, Pfizer: Membership on an entity’s Board of Directors or advisory committees. Pinilla-Ibarz:Novartis, Ariad: Research Funding; Novartis, Ariad, BMS and Pfizer: Speakers Bureau. le Coutre:Novartis: Research Funding; Novatis, BMS, Pfizer: Honoraria. Paquette:ARIAD, BMS, Novartis: Consultancy, Honoraria, Speakers Bureau. Chuah:Novartis, Bristol-Myers Squibb: Honoraria. Nicolini:Novartis, Ariad and Teva: Consultancy; Novartis & Bristol Myers Squibb: Research Funding; Novartis, BMS, Teva, Pfizer, Ariad: Honoraria; Novartis, BMS, Teva: Speakers Bureau; Novartis, Ariad, Teva, Pfizer: Membership on an entity’s Board of Directors or advisory committees. Apperley:Novartis: Research Funding; Ariad, Bristol Myers Squibb, Novartis, Pfizer, Teva: Honoraria. Talpaz:Ariad, BMS, Sanofi, INCYTE: Research Funding; Ariad, Novartis: Speakers Bureau; Ariad, Sanofi, Novartis: Membership on an entity’s Board of Directors or advisory committees. DeAngelo:Araid, Novartis, BMS: Consultancy. Abruzzese:BMS, Novartis: Consultancy. Rea:BMS, Novartis, Pfizer, Ariad, Teva: Honoraria. Baccarani:Ariad, Novartis, BMS: Consultancy; Ariad, Novartis, BMS, Pfizer, Teva: Honoraria, Speakers Bureau. Müller:Novartis, BMS, Ariad: Consultancy, Honoraria; Novartis, BMS: Research Funding. Gambacorti-Passerini:Pfizer: Research Funding; Pfizer, BMS: Honoraria. Lustgarten:ARIAD: employees of and own stock/stock options in ARIAD Pharmaceuticals, Inc Other, Employment. Rivera:ARIAD: Employment. Clackson:ARIAD: employees of and own stock/stock options in ARIAD Pharmaceuticals, Inc Other, Employment. Turner:ARIAD: Employment. Haluska:ARIAD: employees of and own stock/stock options in ARIAD Pharmaceuticals, Inc Other, Employment. Deininger:BMS, ARIAD, NOVARTIS: Consultancy; BMS, NOVARTIS, CELGENE, GILEAD: Research Funding; ARIAD, NOVARTIS: Advisory Boards, Advisory Boards Other. Hughes:Novartis, BMS, ARIAD: Honoraria, Research Funding. Goldman:Ariad: Honoraria. Shah:Ariad, Bristol-Myers Squibb: Consultancy, Research Funding. Kantarjian:RIAD, Novartis, BMS, Pfizer: Research Funding.

Description: Abstract 1690 Background: We have previously identified that low OCT-1 activity (OA) is a poor prognostic indicator in CP-CML patients treated with imatinib (IM). Importantly, a very low OA (OA≤4ng/200,000 cells) is associated with a significant risk of poor molecular response, kinase domain mutations and transformation. The TIDEL II strategy of early intervention, via dose escalation and/or switch to nilotinib (NIL) may reduce the incidence of poor response/therapeutic failure in CP-CML patients, particularly those with very low OA. Methods: Patients in Cohort I (n=105) of the TIDEL II trial were switched to NIL for either IM intolerance, or failure to demonstrate a clinical benefit from IM dose escalation which was triggered by failure to achieve time dependent molecular targets: ≤10% BCR-ABL by 3 m, ≤1% BCR-ABL by 6 m or ≤0.1% BCR-ABL by 12 m. In Cohort II (n=105) patients failing to achieve these molecular targets were switched directly to NIL without prior IM dose intensification. All patients, where possible, had OA measured at diagnosis. Only therapeutic changes prior to 24 months, and patients with a minimum of 6 months exposure to NIL are considered in this analysis. Results: (Table 1) Cohort I: Median follow-up 30 months. The overall rate of major molecular response (MMR) by 12 months was 66%. There was a significant difference in the rate of MMR between patients with low OA (n=49) compared to those with higher OA (n= 54): 49% vs 76%, p=0.007. The overall rate of MMR by 24 months was 81%. Again, patients with low OA (n=46) achieved MMR at a significantly lower rate compared to those with higher OA (n=54): 65% vs 91%, p= 0.003. Thirty patients have switched to NIL, 19/30 because of IM intolerance (av. time on IM 8.5m.) and 11/30 because of molecular target failure (av. time on IM 12.8m). 14/14 intolerant patients not in MMR at the time of switch have achieved MMR on NIL with an average log reduction of 2.8, and 9/18 have achieved CMR. In contrast, 1/9 patients switched for molecular target failure has achieved MMR on NIL, with an average log reduction of 0.65. Importantly, 3/19 withdrew from study due to CML related events. Cohort II: Median follow-up 12 months. To date, 22/105 patients have switched to NIL and have a minimum of 6 months follow-up: 11 for intolerance and 11 for molecular target failure. All patients switched for intolerance achieved and/or maintained MMR on nilotinib, with an average log reduction of 2.89. In contrast, 1/11 patients switched for molecular target failure achieved MMR, with an average log reduction of 0.95 and CCyR has been achieved in 5/10 patients not previously in CCyR. 2/11 of these patients have withdrawn from study. There was a significant difference in the time of switch to NIL, and the length of imatinib exposure between the 2 cohorts for intolerance, and a significant difference between the cohorts in the length of IM exposure for patients with target failure. However, this did not translate to a significant difference in molecular response between the 2 cohorts, suggesting the length of prior IM exposure is not a determinant of subsequent NIL response. Importantly in both cohorts, the OA of those patients switched to NIL based on molecular target failure was significantly lower than that of those who switched for intolerance (p=0.007 and p=0.003) and those patients remaining on IM (p=0.004). Conclusion: Switch to NIL significantly improves response in IM intolerant patients. The majority of patients who switch for molecular target failure on IM do not subsequently achieve MMR on NIL. This suggests that a low OA may delineate a group of CP-CML patients intrinsically insensitive to TKI therapy, for whom switch to NIL either following IM dose intensification (Cohort 1) or as a primary strategy (Cohort II) may not result in an improvement in response. A different first-line strategy may be more effective for this poor risk subgroup. Disclosures: White: Novartis Pharmaceuticals: Honoraria, Research Funding; BMS: Honoraria, Research Funding. Slader:Novartis Pharmaceuticals: Employment, Equity Ownership. Yeung:Novartis Pharmaceuticals: Research Funding; BMS Oncology: Research Funding. Osborn:Novartis Pharmaceuticals: Research Funding; BMS Oncology: Research Funding. Mills:Novartis Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Sponsorship to professional meetings; BMS Oncology:. Hughes:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; ARIAD: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Description: Abstract 2291 Background: Nilotinib is a potent and the most selective inhibitor of BCR-ABL. In the phase 3 ENESTnd trial, nilotinib demonstrated superior efficacy vs imatinib with higher and faster molecular responses and a significantly lower rate of progression on treatment to accelerated or blast phases of CML. Nilotinib has been previously shown to prolong the QT interval. The cardiac safety profile of nilotinib was previously described in pts with imatinib-resistant and -intolerant CML-CP enrolled in phase 2 clinical trials. Here, we report cardiac safety data on nilotinib 300 and 400 mg twice daily (bid), and imatinib, in pts with newly diagnosed CML-CP from the ENESTnd trial. Methods: A total of 836 pts were included in the safety analysis of ENESTnd (279, 277, and 280 pts in the nilotinib 300 mg bid, nilotinib 400 mg bid, and imatinib arms, respectively) with a median follow-up of 18 months. Pts were excluded from study participation if they had known uncontrolled or medically significant cardiac disease, left ventricular ejection fraction (LVEF) 〈 45%, or QTcF interval 〉 450 msec. Prospective cardiac monitoring was conducted throughout the study for QT prolongation (via electrocardiogram) and LVEF (via echocardiogram) at regular intervals. Results: QTcF increases of 〉 30 msec from baseline occurred in 26% of pts in each nilotinib arm and in 18% of pts in the imatinib arm. QTcF increases of 〉 60 msec from baseline were uncommon, occurring in 〈 1% of pts in all three arms (Table). The highest mean changes from baseline in QTcF interval were 10.4, 12.4, and 7.9 msec in nilotinib 300 mg bid, nilotinib 400 mg bid, and imatinib arms, respectively, which occurred between months 3–6 of therapy in all arms. Furthermore, there was a modest linear correlation between nilotinib serum concentration and QTcF change from baseline that was similar to previously reported results. No pt in any treatment arm demonstrated an absolute QTcF interval 〉 500 msec. Analysis was conducted to identify any potential case of clinically symptomatic QT prolongation. Only events of syncope were identified (1 pt in each arm with drug-related events) by this analysis and none of these could be attributed to QT prolongation; there were no episodes of torsades de pointes in any treatment arm. Additionally, there was no decrease from baseline in mean LVEF observed anytime on treatment in any arm (Table). No patient in any treatment arm had a LVEF of 〈 45% on treatment or an absolute reduction from baseline in LVEF of 〉 15%. Importantly, no pt discontinued therapy due to QT prolongation or LVEF change. An analysis of grouped adverse event terms was performed to identify cases consistent with ischemic heart disease (IHD) or left ventricular dysfunction. A total of 11 pts in all treatment arms experienced IHD events after median treatment duration of 18 months: 3 (1%) on nilotinib 300 mg bid, 6 (2%) on nilotinib 400 mg bid, and 2 (〈 1%) on imatinib. Of these 11 pts, 10 had preexisting cardiac disease or risk factors and only 1 pt discontinued treatment due to an IHD event. Nine pts reported angina pectoris. Two pts experienced myocardial infarction (MI) and 1 of these pts died during coronary artery bypass surgery (perisurgical MI). A total of 7 pts in all treatment arms with events consistent with left ventricular dysfunction were identified: 1 (〈 1%) on nilotinib 300 mg bid, 4 (1%) on nilotinib 400 mg bid, and 2 (〈 1%) on imatinib. Of these 7 pts, 4 pts experienced reduction in LVEF (3 were asymptomatic grade 1/2) and 3 pts experienced cardiac failure/congestive failure; 5 of these 7 pts had prior history of cardiovascular disease and/or preexisting cardiovascular risk factors. None of these 7 pts discontinued treatment due to events with left ventricular dysfunction. There were no sudden deaths reported on study. Conclusions: Overall, QT prolongation, changes in LVEF, and clinical cardiac events were uncommon in all arms and seldom led to discontinuation. There was no cumulative effect of nilotinib exposure on cardiac safety with a median of 18 months follow-up. Nilotinib at both doses had a favorable cardiac safety profile that was similar to imatinib in pts with newly diagnosed CML-CP. Disclosures: Larson: Novartis: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding. Hochhaus: Novartis: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding. Saglio: Novartis: Consultancy, Honoraria; Bristol Myers Squibb: Consultancy, Honoraria. Rosti: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bristol Myers Squibb: Honoraria, Speakers Bureau; Roche: Speakers Bureau. Lopez: Novartis: Consultancy; Bristol Myers Squibb: Consultancy. Goldberg: Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau. Gallagher: Novartis Pharma AG: Employment, Equity Ownership. Hoenekopp: Novartis: Employment. Ortmann: Novartis: Employment. Hughes: Novartis: Honoraria, Research Funding, Speakers Bureau; Bristol Myers Squibb: Honoraria, Research Funding; Ariad: Honoraria. Kantarjian: Novartis: Consultancy, Research Funding; Bristol Myers Squibb: Research Funding; Pfizer: Research Funding.

Description: Abstract 2288 Previous studies have demonstrated that the achievement of an imatinib (IM) trough level of 1000ng/ml in CP-CML patients is associated with a better response. The aim of this sub-study was to perform a detailed assessment of IM plasma levels in the TIDEL II trial, in which patients are treated with IM 600mg/day upfront with subsequent dose escalation to 400mg BID, or switch to nilotinib if pre-determined molecular milestones are not met. Patients failing to achieve a trough level of 〉1000ng/ml 22 days after the commencement of IM were scheduled to dose escalate to 400mg BID or maximum tolerated dose (MTD). 105 patients were enrolled in Cohort I of this trial. Plasma for trough IM PK testing was collected at day 8 and day 22, then at 3, 6, and 12 months, and IM levels were measured via HPLC. The median IM PK at day 22 was 1550ng/ml (R 0–4680) (Table 1). 21% (22/103 evaluable) of patients failed to achieve 1000g/ml at day 8, 20% (21/103) at day 22, 20% (18/91) at 3 mths, 29% (23/80) at 6 mths and 24% (13/55) at 12 mths. Overall 56/103 patients (54%) failed to achieve plasma IM levels of 〉1000ng/ml at least once over the study period. In the majority of cases these reductions in IM level were transient. However, detection of an IM level