ALBERT

Description: We examined a large cohort (N=2,457) of chronic lymphocytic leukemia (CLL) patients evaluated by the CLL Research Consortium (CRC) and found 63 (2.6%) used IGHV3-21. Comparing the Ig heavy chain third complementarity determining region (HCDR3) of the IGHV3-21 cases: 25/63 cases (39.7%) had a conserved amino acid motif (motif 1: DANGMDV) in the otherwise highly variable Ig HCDR3, as described by Tobin et al. Blood 2003. All but one of these Ig heavy chains (IgH) were paired with a lambda light chain encoded by IGLV3-21. In addition, we found that 3/63 cases (4.8%) had a previously unrecognized conserved HCDR3 amino acid motif (motif 2: DPSFYSSSWTLFDY). In contrast, these IgH invariably were paired with kappa immunoglobulin light chains (IgL) encoded by IGKV3-20. Similarly to that noted for CLL cases that use IgH encoded by unmutated IGHV1-69 (Widhopf et al. Blood Epub First Edition 2007), the pairing of IgH encoded by IGHV3-21 with IgL appears governed by the HCDR3. The non-stochastic pairing of IgH with IgL argues strongly that antigen plays a role in selecting the Ig expressed in CLL. To examine for the antigen(s) recognized by the most common Ig encoded by IGHV3-21, we isolated IgH and IgL genes expressed by IGHV3-21/IGLV3-21 CLL cases and generated recombinant antibodies, which we examined for binding to antigen(s) present on microarray of self or environmental antigens. We found that Ig encoded by IGHV3-21/IGLV3-21 had apparent specific binding for protein L, a multi-domain cell-wall protein isolated from Peptostreptococcus magnus, a Gram-positive commensal bacteria that comprise a large portion of the human bacterial gut flora. Prior studies identified that protein L is a superantigen capable of binding human Ig kappa light chains encoded by IGKV genes of the I, III, and IV subgroups, but not human Ig lambda light chains. The specific binding of IGHV3-21/IGLV3-21 to protein L suggested that protein L might play a role in the development of CLL cells that express such Ig. To test this hypothesis, we examined the capacity of various recombinant antibodies to bind protein L by ELISA. We found that lambda IgL encoded by IGLV3-21 could bind to protein L with similar activity, independent of whether this lambda IgL paired with the native IgH, IgH encoded by IGHV3-21 lacking the DANGMDV HCDR3 motif, or even irrelevant IgH encoded by IGHV4-39 that are not found paired with IGLV3-21 in the Ig expressed in CLL. Moreover, Ig formed by pairing IgH encoded by IGHV3-21 that has the DANGMDV HCDR3 motif with an IgL encoded by an IGLV that was irrelevant to IGLV3-21 did not bind protein L. These results reveal a previously unrecognized capacity of human IgL encoded by IGLV3-21 to bind the protein L superantigen of Peptostreptococcus magnus, a bacteria commonly found in the human gastrointestinal tract. However, because the binding of IGLV3-21 does not depend upon the non-stochaistic pairing of IgH and IgL observed in CLL, we reason that the capacity of IGLV3-21 to bind protein L cannot account for the selected Ig repertoire expressed in CLL, suggesting that it actually does not play a role in CLL leukemogenesis. This finding suggests that caution should be exercised when defining an antigen that is found capable of binding the restricted Ig expressed in CLL as the driving factor responsible for leukemogenesis.

Description: Introduction: Fludarabine treatment has been shown to be beneficial for patients with Chronic Lymphocytic Leukemia (CLL), and fludarabine-based combinations may even further improve outcomes in patients with CLL. However, most CLL patients eventually become fludarabine refractory, a state which is associated with a relatively short survival. Treatment of fludarabine-refractory patients is challenging, with a median survival of about 10 months. Recently, 2 phase II clinical trials (Chanan-Khan et al. JCO 2006 and Ferrajoli et al. ASH 2006) demonstrated the clinical efficacy of lenalidomide, an immunomodulatory agent, in relapsed/refractory CLL patients. We conducted a subset analysis to examine the efficacy of lenalidomide in patients who are fludarabine refractory. Methods: All patients enrolled on the 2 phase II single agent lenalidomide clinical trials were evaluated and patients with fludarabine-refractory disease (progressed while on or within 6 months of fludarabine-based therapy) were assessed for clinical efficacy of lenalidomide. Lenalidomide was given orally either at 10 mg daily for 28 days followed by 5 mg increments every 28 days to a maximum dose of 25 mg or given at 25 mg on days 1–21 of each 28-day cycle. Response was assessed using the NCI-WG 1996 criteria. Results: A total of 80 patients were collectively enrolled in these clinical studies. Among these, 29 were identified to have fludarabine-refractory disease. Important clinical characteristics of these patients are reported in Table 1. The overall response rate in fludarabine-refractory patients was 34.5% (10/29). Complete remission was observed in 2 (6.8%) patients. Conclusion: Lenalidomide is a novel agent with immunomodulating properties demonstrating clinical efficacy in relapsed or refractory CLL patients. Interestingly, clinical responses to single agent lenalidomide were noted despite refractoriness to fludarabine (a subset of CLL patients with poor survival and limited therapeutic options). This observation of the clinical benefit of lenalidomide independent of responsiveness to prior fludarabine is encouraging and warrants further evaluation. Table 1 Ferrajoli et al. Chanan-Khan et al. Fludarabine-refractory (N=12) Fludarabine-refractory (N=17) ORR, overall response rate; PFS, progression-free survival; OS, overall survival. Median age, years (range) 62 (51–82) 68 (53–75) Sex, female/male 4/8 4/13 Median no. prior therapies (range) 4 (3–15) 4 (1–10) Median beta microglobulin (range) 5 (3–10) 5 (2–10) Advance Rai Stage (III/IV), n (%) 7 (58.3) 13 (76.4) ORR, n (%) 3 (25.0) 7 (41.2) Median PFS, months 12 14.9 Median OS, months All alive (range, 7–19) 23

Description: Human pentraxins are a family of proteins with a unique pentameric structure. Unlike C-reactive protein (CRP), serum amyloid P (SAP) and pentraxin-3 (PTX3) play an opposite role in tissue remodeling. PTX3 induces whereas SAP inhibits the differentiation of CD14+ monocytes into fiborcytes. While in patients with CLL CRP levels are high and were found to be associated with poor overall survival (OS) (Herishanu et al. Ann Med 2017), little is known about the plasma levels or clinical significance of other pentraxins in CLL. Therefore, we obtained plasma sample from 36 randomly chosen treatment-naïve CLL patients and 12 age-matched healthy individuals and, using an enzyme linked immuno-sorbent assay, found that PTX3, CRP and SAP plasma levels were significantly higher in CLL patients than in healthy individuals (P

Description: DAC is a potent hypomethylating agent with clinical activity in patients with myelodysplastic syndromes (MDS) and acute myelogenous leukemia (AML). VPA is a histone deacetylase inhibitor used as an antiepileptic agent. In vitro, the combination of DAC with VPA results in synergistic antileukemia activity at doses of VPA above 1mM. Based on this data, we have developed a phase I/II study of this combination for pts with leukemia. The phase I of the study followed a classic 3+3 design. The dose of DAC was fixed: 15 mg/m2 iv daily for 10 days. This was based on a previous phase I study (Blood2004;103:1635) that indicated that this schedule had an optimal toxicity-response profile in this population. Three dose levels of VPA were selected: 20, 35 and 50 mg/kg. VPA was given orally for 10 days concomitantly with DAC. 22 pts have completed the phase I portion of the study (median age 56 years, range 4–78, 20 pts AML, 2 MDS). At dose level 1 (20 mg/kg of VPA) no grade III-IV toxicity was observed. At dose level 2 (VPA 35 mg/kg), 2 out 6 pts developed grade III neurotoxicity. Both pts were receiving high doses of other neurotropic agents. After IRB approval, 3 mores pts were treated at this dose level with no significant toxicity. Subsequently, 3 pts were treated at the highest planned dose level (50 mg/kg) with no toxicity observed. This cohort was then expanded to a total of 10 pts. One pt developed grade III neurotoxicity. No other severe drug-related toxicities were observed, but 5 patients at all dose levels developed grade II sedation/somnolence. Pancytopenia was induced in all pts. At dose level 1, one pt with refractory AML achieved complete remission (CR) after the second course of therapy. This is now maintained for 5 courses. At dose level 2, a patient with HIV disease and relapsed AML achieved CR after the third course of therapy, and 2 pts with relapsed AML achieved complete marrow responses (marrow blasts less then 5%, no recovery of peripheral counts). Of 3 pts evaluable for response at dose level 3, 1 pt with MDS has achieved CR after 1 course, and 1 with relapsed AML a complete marrow response. Median free VPA levels pretreatment were 0, and 25 mg/L on both days 5 and 10 and returned to 0 prior to next course. Histone acetylation measured by Western blot was observed in 3 pts (25%), all at doses above 20 mg/kg of VPA. Reactivation of p21 expression was induced in 4 out 11 pts analyzed. Global hypomethylation measured using a bisulfite PCR LINE assay was induced in 1 out 3 pts so far studied. Based on the toxicity observed, the phase II portion of the study was initiated. This is restricted to pts with AML/MDS. Seven pts have been accrued to this phase, and 8 out the 10 pts at dose level 3 of the phase I are also evaluable. The response data of this pts will be updated at the meeting. In summary, the combination of low dose DAC and VPA up to doses of 50 mg/kg can be safely administered to pts with leukemia although it may be complicated by neurotoxicity. Clinical and biological activity was observed at all dose levels.

Description: INTRODUCTION: Most clinical trials exclude patients with poor performance, organ dysfunction, and presence of other active malignancies or comorbidities. Although some of these criteria are based on clinical reasoning, patients with such clinical features have dismal expected outcomes and limited therapeutic options and could therefore have a more favorable risk/benefit ratio if treated with a low intensity investigational intervention. The current study was designed to test whether it is feasible to treat patients not eligible for conventional studies in a clinical trial. METHODS: We conducted an initial Bayesian designed single-arm study and a subsequent randomized study for patients with AML or higher-risk MDS (intermediate-2 or high risk by IPSS) with either ECOG performance status (PS) ≥3, creatinine or bilirubin ≥2mg/dL, presence of other malignancy or other comorbidities. Primary endpoint was survival at day 60. The study included stopping rules for survival, response and toxicity. All patients received azacitidine 75mg/m2 sc daily for 5 days. Patients in the single-arm study and in the combination arm of the randomized study also received vorinostat 200mg tid for 5 days. Cycles could be repeated every 3-8 weeks. Responses were evaluated following the revised 2006 IWG criteria for patients with MDS and the IWG 2003 recommendations for patients with AML. Comorbidities were evaluated using the Adult Comorbidity Evaluation-27 (ACE-27) index. Adverse events (AEs) were assessed and graded according to the CTCAE v4 criteria. Overall survival (OS) was censored at the time of transplant. Event-free survival (EFS) was defined as the time interval between treatment start and date of resistance, progression or death. RESULTS: A total of 30 patients (16 with MDS, 14 with AML) were enrolled in the initial single-arm study. Patient characteristics and inclusion criteria are detailed in Table 1. Median age was 73 years (44-83). Median follow-up was 7.4 months (0.3-29). Sixty-day survival was 83%. Median number of cycles administered was 3.5 (1-12). The overall response rate (ORR) was 40% with 8 (27%) patients achieving CR, 4 with AML and 4 with MDS. Median OS was 7.8 months (0.3-29, CI 7.54-8.03) (Figure 1A) and median EFS was 5.1 months (0.3-15.9, CI 4.87-5.37) (Figure 1B). Stopping rules for survival and response were not met. Main adverse events (AEs) where grade 1-2 gastrointestinal toxicities. Mortality at 4 and 8 weeks was 10 and 20% respectively. A total of 79 patients were enrolled in the subsequent randomized study: 27 to azacitidine (A) and 52 to azacitidine and vorinostat (A+V). Patient characteristics and inclusion criteria are also shown in Table 1. Median age was 70 years (30-90). Forty-seven (59%) patients had MDS and 32 (41%) had AML. Median follow-up was 22.7 months (12.6-47.5). Sixty-day survival rates were 67% (A) and 85% (A+V), respectively (p=0.07). No differences in ORR (48% vs 46%, p=0.87), OS (6.1 vs 7.6 months, p=0.49) (Figure 1C) or EFS (3 vs 5.5 months, p=0.05) (Figure 1D) were observed between groups. Main AEs included grade 1-2 gastrointestinal toxicities with a higher proportion of AEs with A+V (81 vs 56%). Mortality at 4 and 8 weeks was 10% (A: 4, A+V: 4) and 19% (A: 9, A+V: 6) respectively. By univariate analysis neither PS ≥3, creatinine or bilirubin ≥2mg/dL nor presence of other malignancy were predictive for 60-day survival, OS or EFS. There were no significant differences in survival between patients with ACE-27 scores of 0-1 compared to 2-3 both in the single-arm (6.3 vs 7 months, HR=0.88, 95% CI 0.41-1.91, p=0.75) and the randomized phase of the study (A: 13.5m vs 6.1m, HR 0.93, 95% CI 0.27-3.17, p=0.9 and A+V: 12.1m vs 7.4m, HR 1.38, 95% CI 0.61-3.14, p=0.4). CONCLUSION: Most enrolled patients met the study's primary endpoint of survival at 60 days without major toxicity. Patients obtained clinical benefit with acceptable responses and survival despite their high comorbidity burden. Our results support the feasibility of treating patients with MDS or AML not eligible to other clinical trials due to poor performance status, comorbidities or organ dysfunction, with low intensity therapies within a clinical trial. These findings suggest relaxation of such criteria may likely increase the pool of clinical trial patient candidates and allow access to potential beneficial therapies for patients with otherwise dismal prognosis. Table 1 Table 1. Figure 1 Figure 1. Disclosures Jabbour: ARIAD: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Research Funding; BMS: Consultancy. DiNardo:Abbvie: Research Funding; Novartis: Research Funding; Agios: Research Funding; Daiichi Sankyo: Research Funding; Celgene: Research Funding. Cortes:ARIAD: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Teva: Research Funding. Wierda:Genentech: Research Funding; Gilead: Research Funding; Novartis: Research Funding; Acerta: Research Funding; Abbvie: Research Funding. Konopleva:Reata Pharmaceuticals: Equity Ownership; Abbvie: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Stemline: Consultancy, Research Funding; Eli Lilly: Research Funding; Cellectis: Research Funding; Calithera: Research Funding. Jain:Novimmune: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Research Funding; Pharmacyclics: Consultancy, Honoraria, Research Funding; Celgene: Research Funding; ADC Therapeutics: Consultancy, Honoraria, Research Funding; Genentech: Research Funding; Abbvie: Research Funding; Infinity: Research Funding; Incyte: Research Funding; Seattle Genetics: Research Funding; BMS: Research Funding; Novartis: Consultancy, Honoraria; Servier: Consultancy, Honoraria.

Description: Background. Lenalidomide (Len) is an immunomodulatory drug with single agent activity in patients (pts) with treatment-naïve (TN) CLL, (overall response rate (ORR) 56-65%, Chen JCO 2011, Ferrajoli Blood 2011). Given the encouraging results of the combination of Len and rituximab (R) in relapsed CLL, we explored this combination as initial therapy. TN pts could derive greater benefit than relapsed pts from Len + R given their less compromised immune function. Methods. Fifty-eight pts were enrolled between 01/2012 and the present time. All patients had treatment indications per IWCLL 2008 criteria, WHO performance status ≤2 and adequate hepatic and renal function. Patients with HIV, hepatitis B or C infection were excluded. Treatment consisted of R 375 mg/m2 IV given weekly for 4 weeks then monthly during months (mo) 3-12 and Len 10 mg PO/day from day 9 for 24 mo. Allopurinol 300 mg PO daily was given for the first 2 weeks. No pts received antibiotic or DVT prophylaxis. Use of growth factors was allowed according to ASCO guidelines. Responses were assessed (2008 IWG criteria) at mo 3, 6 and every 6mo thereafter. Results. Forty-eight patients are evaluable for response and toxicity (8 too early, 1 lost to follow-up and 1 diagnosed with metastatic colonic adenocarcinoma within 1 week of study entry). Median age was 66 yrs (42-79). 29 (59%) pts were ≥age 65. 22 pts (46%) had Rai stage III-IV disease. Median β2M level was 3.8 mg/dL (1.4-10.5). 24/37 pts (65%) had unmutated IGHV gene and 31 pts (65%) expressed ZAP-70. 4 pts (8%) had del(17p) and 15 pts (32%) del(11q). Forty pts responded (ORR 83%). 7 pts (14.6%) achieved CR (1 MRD negative) and 33 (68.8%) achieved PR (including 7 nodular PRs). Median time to CR was 11mo (range 5-27). 5 pts discontinued therapy before the 3mo evaluation (4 due to toxicity and 1 due to unrelated co-morbidities). Six pts discontinued between 3 and 6mo (4 for refractory disease and 2 for toxicity after achieving PR). ORR was similar for patients with mutated and unmutated IGHV gene (85 vs 83%, p=0.96), age ≥65 and

Description: Introduction. In the context of chemoimmunotherapy, complete remission (CR) is more common and is associated with improved survival in patients with chronic lymphocytic leukemia (CLL). CR is less frequent in CLL patients treated with ibrutinib, and the prognostic significance of achieving CR with ibrutinib is indeterminate. Methods. We prospectively analyzed 208 CLL patients treated on a phase 2 study (NCT02007044) of first-line (deletion 17p only; n=27) or salvage ibrutinib (n=181), with or without rituximab, between 12/2013 and 01/2018. Response was assessed by international workshop on CLL 2018 guidelines. Categorical variables were compared using the χ2 or Fisher exact tests. Progression-free survival (PFS) was defined as time from treatment initiation to disease progression and/or death, and Kaplan-Meier curves compared using the log-rank test. A landmark analysis at median time of CR achievement (best response) was performed for PFS. Results. After a median follow-up of 34 months (range, 3-48 months), response was evaluable in 194 patients, overall response rate (ORR) was 99%, and CR rate was 24%, with negative minimal residual disease (MRD) in 3% of patients; median time to response was 10 months (range, 3-45 months) and median time to CR was 21 months (5-45 months). None of the patients' baseline characteristics associated with achievement of CR (Table). Among the 47 patients in CR, 7 (15%) discontinued treatment, after a median time from treatment initiation of 19 months (range, 10-39); the main cause of discontinuation was toxicity (5 patients), with second cancer (metastatic melanoma) and disease progression prompting treatment discontinuation only in 2 patients. Among the 145 patients in PR, 50 (34%) discontinued treatment, after a median time from treatment initiation of 14 months (range, 4-45 months); while the main cause of discontinuation was again toxicity (26 patients), 2nd cancers and progressive disease prompted treatment discontinuation in 5 and 14 patients, respectively. Remaining causes of treatment discontinuation among patients in PR were loss to follow-up (3 patients) and consolidation therapy (2 patients). Median PFS was not reached and 28 patients (13%) progressed and/or died. Achievement of CR significantly associated with prolonged PFS (4-year PFS 98% vs 78%, p=0.03)(Figure). The association between CR and prolonged PFS was also confirmed on a landmark analysis (21 months)(p=0.05). Among baseline characteristics shown in the Table, the only factor associated with prolonged PFS was absence of complex karyotype (4-year PFS 80% vs 40%, p=0.05). Median OS has not been reached and 16 (8%) patients have died; of these, only 1 patient was in CR (and cause of death was metastatic melanoma), whereas the remaining 15 were in PR. Among patients in PR, causes of death were: infections in 7 patients, 2nd cancers in 2 patients, Richter transformation in 2 patients and other in 4 patients (small bowel obstruction, colon perforation, intracranial hemorrhage, bradyarrhythmia). Conclusions. This is the first study showing that achievement of CR is a desirable endpoint for patients with CLL treated with ibrutinib, associating with prolonged PFS. Our results support the development of future combination studies, aimed at achieving higher rates of CR in patients treated with ibrutinib. Figure. Figure. Disclosures Wierda: AbbVie, Inc: Research Funding; Genentech: Research Funding. Jain:Infinity: Research Funding; Novimmune: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding; Infinity: Research Funding; ADC Therapeutics: Research Funding; Astra Zeneca: Research Funding; Cellectis: Research Funding; Verastem: Research Funding; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Research Funding; ADC Therapeutics: Research Funding; BMS: Research Funding; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding; Pharmacyclics: Research Funding; Genentech: Research Funding; Abbvie: Research Funding; Celgene: Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Servier: Research Funding; Pharmacyclics: Research Funding; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Abbvie: Research Funding; Pfizer: Research Funding; Incyte: Research Funding; Adaptive Biotechnologioes: Research Funding; Celgene: Research Funding; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Research Funding; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Servier: Research Funding; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Cellectis: Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologioes: Research Funding; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novimmune: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees. Thompson:Adaptive Biotechnologies: Research Funding; Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Research Funding; Gilead Sciences: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.