ALBERT

Description: Background: Treatment with rhu-Epo ameliorates anemia in a subset of LR-MDS patients, however, effective salvage therapy is limited. LEN promotes erythroid lineage competence and expansion of primitive erythroid precursors in vitro. In the MDS-002 and MDS-005 trials, treatment with LEN improved erythropoiesis, yielding RBC transfusion-independence in 26% of azanucleoside-naïve, transfusion-dependent (TD) LR, non-del(5q) MDS patients for a median of 10.2 and 7.75 months, respectively. We previously reported that LEN restores Epo-responsiveness in MDS progenitors by inducing formation of lipid rafts enriched for signaling competent JAK2/Epo-receptor complexes and excluding large isoforms of the JAK2/lyn kinase-phosphatase CD45 (McGraw K, et. al. PLoS One 2014; Basiorka A, et. al. Cancer Res 2016). In a pilot study of Epo-refractory MDS patients, addition of EA yielded erythroid responses in 28% of patients who were unresponsive to LEN alone, suggesting that LEN may overcome resistance and augment response to rhEpo (Komrokji R, et. al. Blood 2012). To test this hypothesis, we performed a randomized phase III trial comparing treatment with LEN to LEN+EA in LR non-del(5q) MDS patients who were refractory to, or not candidates for treatment with rhEpo. Methods: Patients with Low or Intermediate-1 (Int-1) risk IPSS MDS with hemoglobin 2 units/mo) with serum Epo 〉500mU/mL were eligible for study. Patients were stratified by serum Epo level and prior rhEpo (EA vs. darbepoetin vs. none) then randomized to treatment with LEN 10 mg/d x21d q4wk (Arm A) or LEN + EA 60,000U SC/wk (Arm B). Primary endpoint was IWG 2006 major erythroid response (MER) rate after 4 cycles. Arm A non-responders were offered cross-over to combined therapy. Secondary endpoints included analysis of response biomarkers. Results: Between April 2009 and May 2016, 248 patients were enrolled and 195 were randomized and will be included in the primary analysis. Interim analysis of 163 patients (Arm A, 81; B, 82) accrued before July 2015 showed that the study met predefined stopping criteria. Baseline characteristics were balanced between arms. Median age was 74 years (range, 47-89) receiving a median of 2 RBC units/mo (0-8). Overall, 64 (39%) patients had Low IPSS risk and 90 (55%) Int-1 risk. Among these, 150 received prior rhuEpo (92%) and 27, azanucleosides (17%). In an ITT analysis, MER rate was significantly higher with combination therapy, Arm B 25.6% (n=21) vs. Arm A 9.9% (n=8) (P=0.015). Among 116 patients evaluable at week 16, 33.3% (20/60) and 14.3% (8/56) achieved MER, respectively (P=0.018), with a median response duration of 25.4 months vs. not reached in Arm A responders. Response to combined treatment was associated with baseline CD45-isoform distribution in erythroid precursors. Patients achieving MER had a significantly lower CD45 RA+RB:RO ratio (median, 1.51) compared to non-responders (median, 4.21; P=0.04), favoring homo-dimerization of the short CD45-RO isoform and inhibition of phosphatase activity. MER rate in Arm B patients with a low isoform ratio (〈 median) was 72.7% vs. 18.2% in the high ratio group (P=0.03). Thirty-four Arm A non-responders crossed over to combination-therapy with only 1 MER. There was no difference in the frequency or distribution of 〉Grade 3, non-hematologic AEs. Conclusions: LEN restores sensitivity to rhEpo in Epo-refractory LR-non-del(5q) MDS patients to yield durable and significantly higher rates of erythroid response to combination treatment without added toxicity. Erythroid CD45 isoform profile may serve as a response biomarker for selection of candidates for combination therapy. Disclosures Bennett: Celgne: Membership on an entity's Board of Directors or advisory committees. Altman:Syros: Honoraria; Janssen: Honoraria; BMS: Honoraria; Novartis: Honoraria. Komrokji:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Speakers Bureau. Schiffer:Teva: Other: DSMB member; BMS: Research Funding; Ariad: Research Funding; Pfizer: Other: DSMB member.

Description: Abstract 634 FLT3, a transmembrane receptor tyrosine kinase constitutively activated via mutation in blasts of patients (pts) with AML, is an important therapeutic target. Blasts from approximately 25% of pts have a length or internal tandem duplication (ITD) mutation in the juxtamembrane region or tyrosine kinase domain (TKD1) of FLT3, which is associated with reduced disease-free survival and overall survival (OS), particularly in pts with normal cytogenetics. Blasts from 5–10% of pts have a point mutation (typically D835Y) in the tyrosine kinase domain (TKD); the effect of this mutation on prognosis is uncertain. Midostaurin (PKC412) is a multi-targeted kinase inhibitor with demonstrated clinical activity in FLT3-mutant (FLT3–mut) and FLT3-wild-type (FLT3–wt) AML (peripheral blood blast reduction in 70% and 30% of pts, respectively) but rarely produces complete remissions). Preclinical studies demonstrated synergy between FLT3 inhibitors and chemotherapy. We conducted a Phase 1b trial to investigate the feasibility of administering daunorubicin (60 mg/m2 IV, days 1–3) and cytarabine (100 mg/m2 IVCI, days 1–7) induction and high-dose cytarabine post-remission therapy (3 gm/m2 over 3h every 12h, days 1, 3, and 5 for 3 cycles) plus oral midostaurin at 100 mg or 50 mg each twice daily on days 8–21 (sequentially) or days 1–7, 15–21 (concomitantly) with all chemo cycles in newly diagnosed pts under age 61 with de novo AML. Whereas 100 mg of midostaurin plus induction chemotherapy was poorly tolerated due to nausea and vomiting, the 40 pts who received 50 mg of midostaurin orally twice daily ( 20 each on the sequential and concomitant schedules; 27 FLT3–wt; 13 FLT3–mut [9 with an ITD]), tolerated the combination well. Median midostaurin exposure was 133 days (range 21–975) for the FLT3–mut pts and 90 days (range 7–1016) for FLT3–wt pts. Maintenance therapy with midostaurin was allowed with investigator discretion and was received by 5 pts (3 FLT3–mut, 2 FLT–wt). The median ages for the FLT3–wt and FLT3–mut pts were 50 years (range 25–60) and 46 years (range 20–65), respectively. 77% of the FLT3–mut pts displayed normal, 15% adverse and 8% other intermediate cytogenetics compared with 18.5%, 26%, and 26%, respectively, for FLT3-wt (also 18.5% favorable; 11% unknown). Complete response occurred in 32/40 (80%) of all pts (20/27 [74%] of FLT3–wt patients, 12/13 [92%] of FLT3–mut pts). Patients were censored at the last date they were known to be alive with a median post treatment follow-up for FLT3-mut pts of 1059 days and 1086 days for FLT3-wt. Even accounting for their differing cytogenetics and ages, the OS of the FLT3–mut subgroup was expected to be inferior to that of the FLT3–wt subgroup. However, we report that the 1 and 2 year OS for the pts with FLT3–mut AML was 85% and 62%, respectively, and was comparable to that of the FLT3–wt subgroup (81% and 59%, respectively). Although based on small numbers and not stratified for type of FLT3 mutation (TKD, ITD, ITD length, location, or allelic ratio), these long-term results suggest that combination therapy with a FLT3 inhibitor and chemotherapy might be effective enough to obviate the perceived need for allogeneic stem cell transplantation for FLT3–mut AML pts in first complete remission. Moreover, these data support the rationale for the ongoing international phase 3 study of induction, post-remission intensification, and maintenance with midostaurin (50 mg po bid) or placebo. Disclosures: Stone: Novartis: Research Funding, ad hoc consultancy; Cephalon: ad hoc consultancy. Off Label Use: midostaurin with chemothereapy for AML. Paquette:Novartis: Honoraria, Research Funding, Speakers Bureau. Schiller:Novartis: Research Funding, Speakers Bureau; Millenium: Research Funding, Speakers Bureau; Genzyme: Research Funding; Vion: Research Funding; Centocor: Research Funding; Eli Lilly: Research Funding; Celgene: Research Funding. Schiffer:Novartis: Consultancy, Research Funding; Genzyme: Consultancy. Ehninger:Novartis: Honoraria, Research Funding. Cortes:Novartis: Research Funding; Bristol-Myers Squibb: Research Funding; Wyeth: Research Funding. Kantarjian:Novartis: Research Funding. DeAngelo:Bristol-Myers Squibb: Speakers Bureau; Celgene: Speakers Bureau; Enzon: Speakers Bureau; Novartis: Speakers Bureau. Huntsman-Labed:Novartis: Employment, Equity Ownership. Dutreix:Novartis: Employment, Equity Ownership. Rai:Novartis: Employment, Equity Ownership. Giles:Novartis: Research Funding; Merck: Research Funding; Bristol-Myers Squibb: Research Funding; Vion: Research Funding.

Description: Background: Only a small subset of Lower risk (LR) MDS patients benefit from treatment with rhu-Erythropoietin (Epo). We previously reported that lenalidomide (LEN) restores sensitivity to Epo in MDS progenitors by inducing the formation of lipid rafts that are enriched for signaling competent, JAK2/Epo-receptor complexes (McGraw K, et. al. PLoS One 2014; Basiorka A, et. al. Cancer Res 2016). In the MDS-002 and MDS-005 trials, treatment with LEN monotherapy gave rise to RBC transfusion-independence (TI) in 26% of azanucleoside-naïve, transfusion-dependent (TD) LR, non-del(5q) MDS patients for a median of 10.2 and 7.75 months, respectively. In a pilot study of Epo-refractory LR-MDS patients, the addition of epoetin alfa (EA) to LEN treatment yielded erythroid responses in 28% of patients who were unresponsive to LEN alone, suggesting that LEN may overcome clinical resistance to augment response to rhEpo (Komrokji R, et. al. Blood 2012). To test this hypothesis, we performed a randomized phase III trial comparing treatment with LEN to LEN+EA in LR non-del(5q) MDS patients who were refractory to, or not candidates for treatment with rhEpo. Methods: Patients with Low or Intermediate-1 IPSS risk MDS with hemoglobin 2 units/month) with serum Epo 〉500mU/mL were eligible. Patients were stratified by serum Epo level and prior rhEpo (EA vs. darbepoetin vs. none) then randomized to treatment with LEN 10 mg/d x21d q4wk (Arm A) or LEN + EA 60,000U SC/wk (Arm B). The primary endpoint was major erythroid response (MER) at week 16 which was defined according to transfusion status at baseline: (1) achievement of RBC-TI for ≥ 8 consecutive weeks AND a sustained ≥1 g/dL hemoglobin rise compared to mean pre-transfusion baseline value in TD patients; and (2) a 〉2 g/dL rise in hemoglobin without transfusion for ≥ 8 consecutive weeks in non-TD patients (Grade 3, non-hematologic adverse events between treatment arms. Two patients progressed to AML while on study (Arm A), and no thromboembolic events were reported. Conclusions: LEN restores sensitivity to rhEpo in otherwise refractory, LR-non-del(5q) MDS patients to yield a significantly higher frequency of durable major erythroid responses compared to LEN alone. The addition of LEN to EA treatment is an effective strategy for the management of Epo-refractory patients with a potential duration of benefit extending to years. Disclosures List: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Verma:Janssen: Research Funding; BMS: Research Funding; Stelexis: Equity Ownership, Honoraria; Acceleron: Honoraria; Celgene: Honoraria. Maciejewski:Novartis: Consultancy; Alexion: Consultancy. Komrokji:JAZZ: Speakers Bureau; Novartis: Speakers Bureau; JAZZ: Consultancy; Agios: Consultancy; Incyte: Consultancy; DSI: Consultancy; celgene: Consultancy; pfizer: Consultancy. Luger:Onconova: Research Funding; Pfizer: Honoraria; Seattle Genetics: Research Funding; Cyslacel: Research Funding; Biosight: Research Funding; Ariad: Research Funding; Agios: Honoraria; Genetech: Research Funding; Jazz: Honoraria; Daichi Sankyo: Honoraria; Kura: Research Funding; Celgene: Research Funding. Mattison:Pfizer: Membership on an entity's Board of Directors or advisory committees. Altman:Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Theradex: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Glycomimetics: Consultancy, Honoraria, Other: Data Safety and Monitoring Committee; Agios: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; France Foundation: Speakers Bureau; Daiichi Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; prIME Oncology: Speakers Bureau; PeerView: Speakers Bureau; Cancer Expert Now: Consultancy; Novartis: Consultancy; Biosight: Other: US Lead. Claxton:Astellas Pharma: Other: Pharma support of clinical studies; Merck Sharp & Dohme Corp.: Other: Pharma support of clinical studies; Cyclacel Pharmaceuticals, Inc.: Other: Pharma support of clinical studies; Medimmune Inc.: Other: Pharma support of clinical studies; Novartis Pharmaceuticals: Other: Pharma support of clinical studies; Celgene Corporation: Other: Pharma support of clinical studies; Incyte Corporation: Other: Cyclacel Pharmaceuticals, Inc; Daiichi Sankyo Co. and Ambit Biosciences Corp: Other: Pharma support of clinical studies. Artz:Miltenyi: Research Funding. Tallman:Daiichi-Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Research Funding; Oncolyze: Consultancy, Membership on an entity's Board of Directors or advisory committees; Tetraphase: Consultancy, Membership on an entity's Board of Directors or advisory committees; UpToDate: Patents & Royalties; Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cellerant: Research Funding; Rigel: Consultancy, Membership on an entity's Board of Directors or advisory committees; KAHR: Consultancy, Membership on an entity's Board of Directors or advisory committees; Biosight: Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Nohla: Consultancy, Membership on an entity's Board of Directors or advisory committees; Orsenix: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Delta Fly Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; BioLineRx: Consultancy, Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Lenalidomide used for treatment non-del 5q myelodysplastic syndromes.

Description: Background: Treatment of chronic myeloid leukemia (CML) with a tyrosine kinase inhibitor (TKI) offers significant improvements over previous treatments in terms of survival and toxicity yet has been associated with reduced health-related quality of life and very high cost. Discontinuing TKIs with regular monitoring is safe, but little is known about the impact of discontinuation on patient-reported outcomes (PROs). In the largest U.S. study to date, we evaluated molecular recurrence of CML and PROs after TKI discontinuation. Methods: The Life After Stopping TKIs (LAST) study was a prospective single-group longitudinal study. Key inclusion criteria were age 〉 18 years, patient on TKI therapy (imatinib, dasatinib, nilotinib, or bosutinib) for 〉 3 years with documented BCR-ABL 〈 0.01% by PCR for 〉 2 years, and no previous TKI resistance. We monitored disease outcome (PCRs by central lab) and PROs (PROMIS computerized adaptive tests via REDCap) monthly for the first 6 months, every 2 months until 24 months, then every 3 months until 36 months. Molecular recurrence was defined as 〉 0.1% BCR-ABL IS by central lab (loss of major molecular response [MMR]). We considered 3 points to be clinically meaningful and hypothesized that by 6 months after TKI discontinuation, fatigue, depression, sleep disturbance, and diarrhea would improve by at least 3 points each, corresponding to a standardized effect size of 0.3. Given reports of a withdrawal syndrome of musculoskeletal pain in some patients after discontinuation, pain was an additional outcome of particular interest. For each PRO domain, we estimated a polynomial piecewise linear mixed effects model that specified one nonlinear trajectory after TKI discontinuation and, for those with molecular recurrence, another trajectory after TKI restart. The models included patient-level random effects for the intercepts and linear slopes. Results: From 12/2014 to 12/2016, 172 patients enrolled from 14 U.S. sites. Median age was 60 years (range 21-86) and 89 (52%) were female. The median time on TKI prior to enrollment was 81 months (IQR 54-123). With a minimum follow-up of 24 months, 107 (62%) patients remained in a treatment free remission (TFR). Reasons for restarting therapy were: loss of MMR by central (n=56) or local (n=2) lab, patient decision (n=4), and withdrawal syndrome (n=3). Missing PRO data was minimal (〈 5%) with 〉 2000 assessments completed. For patients in TFR at 6 months, the average estimated improvement in fatigue was 2.6 points (95% CI 2.5-2.7), depression was 1.9 points (95% CI 1.8-1.9), sleep disturbance was 0.9 points (95% CI 0.8-1.0), and diarrhea was 2.7 points (95% CI 2.6-2.7). The average estimated worsening in pain interference (i.e., the extent to which pain affects daily life) was 0.4 points (95% CI 0.3-0.5). The figure shows the distribution of estimated change for each domain at 6 months. All patients showed improvements in depression, diarrhea, and fatigue. About 1 in 6 patients (17%) experienced a clinically meaningful (i.e., at least 3 points) improvement in fatigue and/or diarrhea at 6 months. Conclusion: The LAST study is the largest US TKI discontinuation study to date, and the first to include comprehensive PRO measurement. For patients in TFR at 6 months, TKI discontinuation conferred modest benefits in fatigue and diarrhea on average, with a negligible increase in pain interference. Some patients experienced more notable improvements in fatigue and diarrhea. Planned secondary analyses will include change over time up to 3 years and evaluation of additional PRO domains, including anxiety, physical function, social function, and sexual function. Our results provide important new evidence to support shared patient-provider clinical decision making regarding TKI discontinuation for patients with CML. Figure. Disclosures Radich: Novartis: Other: RNA Sequencing; TwinStrand Biosciences: Research Funding. Mauro:Pfizer: Consultancy; Takeda: Consultancy; Novartis Oncology: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy. Pinilla Ibarz:Sanofi: Speakers Bureau; Abbvie: Consultancy, Speakers Bureau; Teva: Consultancy; Janssen: Consultancy, Speakers Bureau; Novartis: Consultancy; Takeda: Consultancy, Speakers Bureau; Bayer: Speakers Bureau; TG Therapeutics: Consultancy; Bristol-Myers Squibb: Consultancy. Larson:Celgene: Consultancy; Novartis: Honoraria, Other: Contracts for clinical trials; Agios: Consultancy. Oehler:Blueprint Medicines: Consultancy; NCCN: Consultancy; Pfizer Inc.: Research Funding. Deininger:Humana: Honoraria; Incyte: Honoraria; Blueprint: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Research Funding; Ascentage Pharma: Consultancy, Honoraria; TRM: Consultancy; Sangoma: Consultancy; Fusion Pharma: Consultancy; Adelphi: Consultancy; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Sangamo: Consultancy. Shah:Bristol-Myers Squibb: Research Funding. Ritchie:Tolero: Other: Advisory board; Celgene: Other: Advisory board; Celgene, Novartis: Other: travel support; Jazz Pharmaceuticals: Research Funding; Celgene, Incyte, Novartis, Pfizer: Consultancy; AStella, Bristol-Myers Squibb, Novartis, NS Pharma, Pfizer: Research Funding; Ariad, Celgene, Incyte, Novartis: Speakers Bureau; Genentech: Other: Advisory board; Pfizer: Other: Advisory board, travel support; agios: Other: Advisory board. Silver:PharmEssentia: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Cortes:Sun Pharma: Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Forma Therapeutics: Consultancy, Honoraria, Research Funding; BiolineRx: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Daiichi Sankyo: Consultancy, Honoraria, Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding; Biopath Holdings: Consultancy, Honoraria; Immunogen: Consultancy, Honoraria, Research Funding; Merus: Consultancy, Honoraria, Research Funding; Astellas Pharma: Consultancy, Honoraria, Research Funding. Atallah:Jazz: Consultancy; Helsinn: Consultancy; Pfizer: Consultancy; Takeda: Consultancy, Research Funding; Jazz: Consultancy; Helsinn: Consultancy; Novartis: Consultancy.

Description: Background Clonal proliferation of T/NK cells has been noted after the treatment of CML patients with dasatinib. Previous reports have suggested that persistent expansion of clonal cytotoxic T cells or NK cells in dasatinib-treated patients may be associated with higher response rates and increased occurrence of pleural effusions. This retrospective study analyzed the incidence of lymphocytosis and its association with response, progression-free survival (PFS) and overall survival (OS), and pleural effusion in a large sample of dasatinib-treated patients. Methods Analyses were conducted using dasatinib-treated patients from three large studies with ≥3 years of follow-up: CA180-056 (DASISION), which included 258 dasatinib-treated patients with newly diagnosed CML in chronic phase (CML-CP); CA180-034, which included 662 dasatinib-treated patients with CML-CP who were previously treated with imatinib; and CA180-035, which included 316 dasatinib-treated patients with CML in accelerated phase (CML-AP) and 148 dasatinib-treated patients with CML in myeloid blast phase (CML-MBP) who were previously treated with imatinib. Results Lymphocytosis, as defined by ≥2 consecutive lymphocyte counts 〉 3600/µl after 28 days of treatment, was present in 33% of patients (85/258) with newly diagnosed CML-CP in DASISION (median time to onset, 4.6 months) and 31% of patients (206/662) with imatinib-resistant or -intolerant CML-CP in CA180-034 (median time to onset, 3.0 months). The median on-treatment follow-up times were 36.8 months and 29.3 months for DASISION and CA180-034, respectively. For CA180-035, the median on-treatment follow-up time was 6.1 months, and lymphocytosis developed in 35% of patients (110/316) with CML-AP and 34% of patients (51/148) with CML-MBP. Lymphocytosis persisted for 〉12 months in 64% of patients (54/85) with newly diagnosed CML-CP, in 52% of patients (107/206) with imatinib-resistant or -intolerant CML-CP, in 42% (46/110) with CML-AP, and in 18% (9/51) with CML-MBP. The proportion of newly diagnosed patients with complete cytogenetic response (CCyR) or major molecular response (MMR) at any time was higher among those with vs. without lymphocytosis: 89% (76/85) vs. 80% (138/173) for confirmed CCyR and 74% (63/85) vs. 67% (116/173) for MMR. Patients who developed lymphocytosis during treatment with second-line dasatinib were more likely to achieve CCyR, regardless of disease phase; the proportion of patients who achieved CCyR with vs. without lymphocytosis was 62% (127/206) vs. 49% (222/456) for CML-CP, 46% (51/110) vs. 27% (55/206) for CML-AP, and 31% (16/51) vs. 14% (14/97) for CML-MBP. In landmark analyses of patients with CML-CP in DASISION who were still on first-line dasatinib at 3 or 8 months, lymphocytosis status did not significantly affect PFS or OS. Similar results were found in the second-line studies, when considering patients with CML-CP, -AP, or -MBP who were still on study treatment (second-line dasatinib) at 3 months. Pleural effusions (all grades) developed more often in newly diagnosed patients with lymphocytosis (28% [24/85] vs. 16% [27/173] without lymphocytosis) and in imatinib-resistant or -intolerant patients with CML-CP (38% [79/206] vs. 30% [136/456]) or CML-AP (53% [58/110] vs. 31% [64/206]). The proportion of patients with CML-MBP developing pleural effusions was 27%, regardless of the presence of lymphocytosis (14/51 with lymphocytosis and 26/97 without lymphocytosis). Conclusions Lymphocytosis develops very commonly after treatment with dasatinib and persists for 〉1 year in an appreciable fraction of patients. Immunophenotyping was not done, but it can be presumed that this represents a large granular lymphocyte proliferation in most patients, based on other studies. Lymphocytosis was associated with higher CCyR rates in all stages of CML, as well as higher rates of pleural effusions in CML-CP and -AP. Lymphocytosis was also associated with higher MMR rates in patients with CML-CP receiving first-line dasatinib. There appears to be no significant association, however, between lymphocytosis and PFS or OS in this analysis. Prospective studies are warranted to more carefully characterize the functional activity of these cells and to help assess whether an immunologic effect against CML is detectable in some patients, particularly advanced phase patients with unexpected long responses to treatment with dasatinib alone. Disclosures: Schiffer: Novartis: Consultancy, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Research Funding; Teva: Consultancy; Eisai: Consultancy; Ariad: Research Funding; Pfizer: Research Funding. Cortes:Ariad: Consultancy, Grant to institution Other, Honoraria; BMS: Grant to institution, Grant to institution Other; Novartis: Grant to institution, Grant to institution Other; Pfizer: Consultancy, Grant to institution, Grant to institution Other, Honoraria; Teva: Consultancy, Grant to institution Other, Honoraria; Tragara: Membership on an entity’s Board of Directors or advisory committees; Ambit: Grants/grants pending for institution Other; Astellas: Grants/grants pending for institution, Grants/grants pending for institution Other; Incyte: Grants/grants pending for institution, Grants/grants pending for institution Other; Arog: Grants/grants pending for institution Other; Celgene: Grants/grants pending for institution, Grants/grants pending for institution Other; sanofi: Grants/grants pending for institution, Grants/grants pending for institution Other. Saglio:Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria; ARIAD: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. le Coutre:Novartis: Honoraria, Research Funding; BMS: Honoraria; Pfizer: Honoraria. Porkka:BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Mustjoki:BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Mohamed:BMS: Employment, Stock/stock options; travel/accommodations/meeting expenses unrelated to activities listed Other. Shah:BMS: Consultancy, Grants/grants pending to institution for costs related to clinical research Other; Ariad: Consultancy, Grants/grants pending to institution for costs related to clinical research, Grants/grants pending to institution for costs related to clinical research Other.

Description: FLT3 (fms-like tyrosine kinase) activating mutations, either an ITD (repeat of 3-〉100 amino acids in the juxtamembrane region) or a point mutation in the activation loop, occur in blasts from 30% of AML patients (pts). ITD mutations are associated with a relatively poor prognosis. PKC412 is a multi-targeted kinase inhibitor that has clinical activity in mutant (reduction in peripheral blasts in 70%) and wild type (reduction in peripheral blast in 30%) FLT3 AML, but rarely produces complete remissions (Stone et al, Blood 2005; Estey et al, ASH 2003). We conducted a phase Ib trial with DA (daunorubicin 60 mg/m2 d 1–3 and cytarabine 100 mg/m2/d by IVCI x 7d) induction and post-remission therapy (cytarabine 3 gm/m2/3h q 12h, d1,3, and 5 for 3 cycles) plus PKC412 at 100 mg bid po continuously beginning on day 8 (arm 1) or day 1 (arm 2) (n=15) or an amended schedule: day 8–21 (arm 1) or day 1–7, 15–21 (arm 2) (n=15) in previously untreated adult AML pts ≤ age 60. Results demonstrated safety, but poor tolerability due to nausea and vomiting (Giles, et al, ASH 2004). The study was then amended to include the same chemotherapy, but with 50 mg PKC412 po bid (previously shown to lead to plasma levels sufficient to inhibit FLT3) on day 8–21 (arm 1) or day 1–7, 15–21 (arm 2); tolerability improved to acceptable levels with no patients withdrawing due to nausea, vomiting, or diarrhea (Stone at al, ASH 2005). The study has completed accrual (40 pts enrolled after the PKC412 50 mg po bid amendment) with 38 pts (26 with wild type FLT3 (FLT3wt) blasts and 12 with mutated FLT3 (FLT3mut) blasts) evaluable for efficacy and 37 pts for safety. Complete response (CR) occurred in 27/38 (71%). The CR rate in FLT3wt pts was 18/26 (69%); 9/13 (69%) pts achieved CR in each of the arms. CR occurred in 11/12 (92%) FLT3mut pts. CR rate in FLT3mut pts was 7/7 (100%) in Arm 1 and, 4/5 (80%) in arm 2. 4/11 CR pts relapsed after 7, 7, 10 and 15 months; 7 pts remain in first CR for 3–15 months. No drug-related deaths were reported. One patient withdrew due to Grade 4 increase in alkaline phosphatase. The most common serious Grade 3–4 side effects reported to date include thrombocytopenia 6/19 (31.5%), anemia 5/19 (26%) and neutropenia 5/19 (26%) in pts on arm 1; thrombocytopenia 2/18 (11%), anemia 1/18 (5.5%) and neutropenia 2/18 (11%) in pts on arm 2. All Grade 3–4 events were transient and/or reversible. No Grade 3 or 4 nausea and vomiting occurred in either arm. In conclusion, PKC412 at 50 mg po bid can be given safely and tolerably in newly diagnosed adult AML pts ≤ 60 years old in combination with DA and high dose cytarabine. The CR rate and preliminary DFS in FLT3mut pts is encouraging. A phase III study of chemotherapy +/− PKC 412 at 50 mg po bid on d8–21 per cycle in newly diagnosed pts ages 18–60 with mutant FLT3 AML is planned.

Description: Background Imatinib is effective in L-CP CML patients (Pts), but response duration is unknown. From 12/1999 to 05/2000, the Novartis study STI571A110 recruited 454 Pts with confirmed diagnosis of CP CML. Pts were hematologically (n=133) or cytogenetically resistant/refractory (n=160) or intolerant (n=161) to IFN. Median time since diagnosis was 34 months (m). Pts were evaluated for best major and complete cytogenetic response (MCyR and CCyR), time to progression to accelerated phase (AP) or blast crisis (BC), and overall survival (OS). This abstract includes data up to 56 m after the first patient and more than 48 m after last patient started treatment. Results: Median drug exposure as of 31-Jul-04 was 50 m. The initial daily dose was 400 mg. Dose increases after a median of 14 m were reported in 227 (50%) Pts. The table below summarizes discontinuation reasons, best responses observed and the estimated long-term outcomes at 48 m. n=454 (%) [95% Conf intervals] Still on Treatment 269 (59.3) Discontinued 185 (40.7) Progression/deaths from any cause 105 (23.1) AEs/toxicities 32 (7.0) BMT 5 (1.1) Withdrew consent/Lost/Admin. problems 43 (9.5) Pts achieving MCyR (includes CCyR) 301 (66.3) Pts achieving CCyR 248 (54.6) % Pts free of progression to AP/BC at 48 m (74.6) [70.4–78.9] OS at 48 m (82.4) [78.9–86.0] Median time to CCyR was 8.3 m [8.3–8.6 m]; 45 of the 248 Pts achieved CCyR after dose increase. The yearly risk of progression to AP/BC did not increase when considering all patients (7.8%, 6.0%, 7.2% and 7.1% within year 1,2,3,4 respectively). The corresponding risk rates for patients in MCyR at 3 m were 2.7%, 0.7%, 2.2%, 2.4%. Using the 3-m (and 12 m) landmark (n=446 or 421), Pts with CCyR, PCyR and minor CyR had an estimated OS at 48 m of 94(94)%, 93(94) %, 86(92) %, whereas Pts with only minimal CyR or no CyR had estimated 4-year OS of 85(78) % and 77(71) %, respectively. Among Pts who achieved MCyR and arrived to 48m of follow-up, 79% [74–84] maintain it; this value compares with 86% [80–92] for Pts with MCyR within 3 m. The following figure shows the duration of MCyR according to the time when MCyR was reached. Pts who had MCyR by the 3rd m did significantly better than the other groups (p= 0.02). However a MCyR obtained at a late time point (〉12 m) has a duration similar to the entire cohort. Half of the Pts who lost MCyR did not progress to AP while on study. Conclusion: Imatinib treatment for L-CP CML Pts failing IFN therapy is effective and produces durable cytogenetic responses and survival, with more than 80% Pts alive at 48 m and no evident increase in progression rate over time. Even Pts who failed to achieve any CyR reached OS of 71%. Obtaining a MCyR at 3–12 m resulted in 〉90% OS. Duration of MCyR was longer in Pts who responded within 3m, than in the other groups. The results will be updated for the meeting including 60-m data up to 31-July-05. Figure Figure