PURPOSE: Despite advances in immunotherapies, the prognosis for adults with Philadelphia chromosomenegative, newly diagnosed (ND) or relapsed/refractory (R/R) acute lymphoblastic leukemia/acute biphenotypic leukemia (ALL/ABL) remains poor. The benzamide derivative entinostat inhibits histone deacetylase and induces histone hyperacetylation. The purine nucleoside analogue clofarabine is FDA-approved for R/R ALL in children 1-21 years of age. Low doses of clofarabine have been reported to induce DNA hypomethylation. We conducted a phase 1 study of low dose clofarabine with escalating doses of entinostat in adults with ND or R/R ALL/ABL. EXPERIMENTAL DESIGN: Adults >60 years with ND ALL/ABL or >21 years with R/R ALL/ABL received repeated cycles every 3 weeks of entinostat (4 mg, 6 mg or 8 mg orally days 1 and 8) and clofarabine (10 mg/m2/day IV for 5 days, days 3-7) (Arm A). Adults aged 40-59 years with ND ALL/ABL or age >21 years in first relapse received entinostat and clofarabine prior to traditional chemotherapy on day 11 (Arm B). Changes in DNA damage, global protein lysine acetylation, myeloid-derived suppressor cells and monocytes were measured in PBMCs before and during therapy. RESULTS: Twenty-eight patients were treated at three entinostat dose levels with the maximum administered dose being entinostat 8 mg. The regimen was well tolerated with infectious and metabolic derangements more common in the older population versus the younger cohort. There was no severe hyperglycemia and no peripheral neuropathy in this small study. There were 2 deaths (1 sepsis, 1 intracranial bleed). Overall response rate was 32 %; it was 50 % for ND ALL/ABL. Entinostat increased global protein acetylation and inhibited immunosuppressive monocyte subpopulations, while clofarabine induced DNA damage in all cell subsets examined. CONCLUSION: Entinostat plus clofarabine appears to be tolerable and active in older adults with ND ALL/ABL, but less active in R/R patients. Further evaluation of this regimen in ND ALL/ABL appears warranted.

FLT3-ITD-mutated acute myeloid leukemia (AML) remains a therapeutic challenge. FLT3 inhibition in the setting of minimal residual disease and a new immune system via allogeneic transplantation offers a promise of improved survival for these patients. We performed a prospective study of patients with FLT3-ITD AML undergoing allogeneic transplant that was conducted to evaluate the safety, tolerability, and outcome of sorafenib administered peritransplant. Sorafenib dosing was individualized, starting at 200 mg twice a day (BID), and titrated based on tolerability or toxicities until a tolerable dose was identified. Forty-four patients, with a median age of 52 years, undergoing allogeneic transplant were started on sorafenib in the peritransplant period (21 pretransplant). The median duration of post-transplant follow-up was 27.6 months (range, 5.2 to 60.4). Overall survival was 76% at both 24 and 36 months. Event-free survival at 24 and 36 months was 74% and 64%, respectively. Ten patients died in the post-transplant period, with 6 deaths due to relapsed leukemia and 4 from transplant-associated toxicity. Tolerable doses ranged from 200 mg every other day to 400 mg BID with similar exposure. Correlative studies evaluating FLT3 inhibition via a plasma inhibitory activity assay showed consistent inhibition of FLT3 at all tolerability-determined dosing levels. Sorafenib is well tolerated in the peritransplant setting irrespective of the conditioning intensity or the donor source. Our findings indicate that sorafenib dosing can be individualized in the post-transplantation setting according to patient tolerability. This approach results in effective in vivo FLT3 inhibition and yields encouraging survival results.

Pre-clinical data in non-M3 AML supports the use of differentiation therapy, but clinical activity has been limited. Myeloid growth factors can enhance anti-leukemic activity of differentiating agents in vitro. We conducted companion phase II trials investigating sargramostim (GM-CSF) 125μg/m(2)/day plus 1) bexarotene (BEX) 300mg/m(2)/day or 2) entinostat (ENT) 4-8mg/m(2)/week in patients with MDS or relapsed/refractory AML. Primary endpoints were response after at least two treatment cycles and toxicity. 26 patients enrolled on the BEX trial had a median of 2 prior treatments and 24 enrolled on the ENT trial had a median of 1. Of 13 response-evaluable patients treated with BEX, the best response noted was hematologic improvement in neutrophils (HI-N) seen in 4 (31%) patients; none achieved complete (CR) or partial remission (PR). Of 10 treated with ENT, there was 1 (10%) partial remission (PR) and 2 (20%) with HI-N. The secondary endpoint responses of HI-N with each combination were accompanied by a numerical increase in ANC (BEX: 524 to 931 cells/mm(3), p=0.096; ENT: 578 to 1 137 cells/mm(3), p=0.15) without increasing marrow blasts. Shared grade 3-4 non-hematologic toxicities included febrile neutropenia, bone pain, fatigue, and dyspnea. GM-CSF plus either BEX or ENT are well tolerated in resistant and refractory MDS and AML and showed modest clinical and biologic activity, most commonly HI-N.

Abstract Background: FLT3 ITD mutated acute myeloid leukemia remains a therapeutic challenge with very few patients experiencing prolonged disease free survival after standard therapies. FLT3 inhibitors have thus far demonstrated limited single agent activity in this disease. However, administration of FLT3 inhibitors during a state of minimal residual disease and a reconstituting immune system offers a promise of improved disease control. Methods: We designed a prospective trial for patients FLT3 ITD AML undergoing allogeneic transplant, to evaluate the safety, tolerability and outcome of the FLT3 ITD inhibitor sorafenib administered pre- and post-allogeneic transplant. To be eligible, patients needed to be in remission prior to transplant. At the discretion of the treating physician, sorafenib could be started prior to transplant after confirmation of remission and continued until three days prior to the start of the preparative regimen. Otherwise, all patients were started on sorafenib 200 mg twice a day, no earlier than Day +30 and no later than Day +120 post-transplant, after documented engraftment (Plts >50K, ANC >500). Dosing of sorafenib was based on individual patient tolerance: in tolerant patients sorafenib was escalated to 400 mg twice a day while dose reductions occurred for Grade 3 or 4 toxicities in a stepwise manner (200 mg BID, 200 mg QD, 200 mg QoD) until a tolerable dose was identified. Results: We have accrued to date 28 patients with a median age of 54, with FLT ITD AML undergoing allogeneic transplant who were started on sorafenib in the peri-transplant period (8 pre-transplant). Ten patients underwent myeloablative conditioning and received a transplant from a matched related donor (5), a matched unrelated donor (2) or a haploidentical donor (3). Eighteen patients underwent non-myeloablative conditioning and transplant using either a haploidentical donor (10), a matched sibling donor (4), a matched unrelated donor (3) or an umbilical cord blood donor (1). The median duration of post transplant follow up for active patients is 450 days (range, 107-1192 days). The median duration of sorafenib therapy for all patients is 252 days (range, 52-1081). The tolerability of sorafenib in the peri-transplant period varied among patients: 6 patients tolerated the maximum dose of sorafenib at 400 mg twice a day, 14 patients were maintained on 200 mg twice a day, seven patients were maintained on 200 mg daily and one patient was maintained on 200 mg every other day. Six patients died in the post-transplant period with three deaths due to relapsed leukemia and three from transplant-associated toxicity. No primary or secondary graft failures were observed but 9 patients developed grade 2 or higher GVHD (1-4 weeks after starting sorafenib) requiring escalation of immunosuppression therapy. Overall 5 pts have relapsed so far. Three of these patients were off therapy at the time of relapse. One patient relapsed with FLT3 ITD leukemia 117 days after stopping sorafenib at the 24 month planned stoppage time and is now back in remission after resuming sorafenib. Correlative studies evaluating FLT3 inhibition via a plasma inhibitory activity (PIA) assay showed consistent inhibition of FLT3 at all tolerability-determined dosing levels, suggesting that dosing can be safely adjusted in patients having adverse events without loss of FLT3 inhibition. Consistent with this finding was the fact that the adjusted sorafenib trough concentration exposure accounting for the active metabolite (sorafenib + (14.59*sorafenib N-oxide)) was highly variable (70% CV) and not statistically different across all dosing levels. Exploratory analysis of minimal residual disease monitoring, and of T regulatory cell populations and their relation to GVHD in the pre- and post-treatment peripheral blood, are ongoing. Conclusion: Sorafenib is well tolerated in the post-transplant setting irrespective of the conditioning intensity or the donor source. Our findings indicate that sorafenib dosing should be individualized in the post-transplantation setting according to patient tolerability. This approach results in effective in vivo FLT3 inhibition, and yields encouraging survival results, with 15 of 28 patients currently on therapy without relapse. This data supports the further study of sorafenib in a larger cohort to determine its overall effectiveness in preventing FLT3 ITD AML relapse post allogeneic transplant. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Off Label Use: Sorafenib for off label usage in Acute Myeloid Leukemia.

Farnesyltransferase inhibitors (FTI) make up a novel class of anti-cancer agents that competitively and selectively inhibit farnesyl protein transferase. Early trials of the orally bioavailable non-peptidomimetic FTI tipifarnib (ZARNESTRATM, Johnson & Johnson PRD) demonstrated both clinical responses and excellent tolerability in patients with poor-risk or refractory acute myeloid leukemia (AML). (Karp, et al. Blood97:3361, 2001). We herein report updated results of a multicenter phase 2 trial of tipifarnib in an elderly, previously untreated poor-risk AML population who refused or were deemed unfit for conventional induction chemotherapy. Tipifarnib was administered orally in the outpatient setting at a dose of 600 mg BID for 21 days, followed by a 1–3 week recovery period. Up to 4 cycles of tipifarnib were permitted in patients with complete responses (CR). The primary endpoint was overall response rate (CR + PR). Secondary endpoints included toxicity rates, measurement of markers of farnesylation (HDJ-2) in bone marrow cells, measurement of signaling intermediates ERK and AKT, and RNA microarray expression patterns. Accrual to the trial is complete. 170 patients have been enrolled, 148 of whom are evaluable for response (AML=160; high-risk MDS=4; high-risk CMML=6). The median age was 73 years (range 34–85), and 76 patients (45%) were age = 75. M/F ratio was 2:1. An unfavorable karyotype and/or antecedent MDS was present in 47% and 79% of patients, respectively. The median number of cycles received was 1, and the median number of days of drug received was 36 days. Dose reductions were implemented in 38% of patients, more commonly in cycles subsequent to cycle #1. The overall response rate (CR + PR) was 34%. CR occurred in 18% of patients. Responses were evenly distributed across study centers. In patients ≥ 75 years, the overall response rate was 30% (CR 20 %). Median CR duration was 6.4 months (range 1.5–11+ months). Median overall survival was 5.6 months for all patients. CR patients had a median survival of 14.4 months, with 63% alive at 12 months. In non-responders, median survival was 3.1 months. The incidence of grade = 3 tipifarnib-related non-hematologic adverse events was 43%, comprised mainly of infectious and gastrointestinal complications. The hospitalization rate for tipifarnib-related toxicity was 18% (median duration: 12 days). The death rate from tipifarnib-related toxicity at 6 weeks was 5%. Microarray analysis of pre-and post-treatment bone marrow samples is being performed to identify both predictive and pharmacodynamic gene markers of response to tipifarnib. In summary, tipifarnib is a novel outpatient treatment with activity in previously untreated poor-risk AML. The low hospitalization rate may reflect the low incidence of severe non-hematological toxicity.

Clinical results in AML continue to need improvement, particularly for age ≥60, prior MDS or secondary AMLs, and AMLs with adverse cytogenetics (CG) where complete remission (CR) rates are <50% and cure rates are <10%. In an attempt to improve these outcomes, we developed a TST regimen of the topoisomerase I inhibitor Topotecan with ara-C and Mitoxantrone (TAM) as induction therapy for adults with newly diagnosed AML: T, 4.5 mg/m2 IV continuous infusion (CI) over 72 hrs days (d) 1-3; A, 2 gm/m2 IV CI over 72 hrs d 3-5; and M, 40 mg/m2 IV d 10. CR patients with poor risk features received consolidation TST with T, 4.5 mg/m2 CI over 72 hrs d 1-3; A, 2 gm/m2 IV CI over 72 hrs d 3-5; and etoposide (E), 300 mg/m2 IV CI over 72 hrs d 10-12 (TAE); CR patients without poor risk features received consolidation TST with A, 2 gm/m2 CI over 72 hrs d 1-3 and 10-12; and idarubicin (I) 12 mg/m2 IV d 1,2,3 (AIA). From 04/02-2/04, 60 newly diagnosed AML patients (median age 49 yrs, 21–79) received TAM induction chemotherapy. Of 60 pts, 47 (78.5%) had at least one poor prognostic feature: age ≥60, 16 (27%); adverse CG, 28 (47%); MDS/AML, 10 (17%); secondary AML, 3 (5%); and/or WBC >25,000/μl, 23 (38.5%). Of the 41 (68.5%) pts who achieved CR, 32 (78%) received consolidation TST (22 TAE; 10 AIA). The remaining 9 pts received alloBMT (2), alternate therapy (5), or no consolidation (2) due to incomplete reversal of organ damage. Furthermore, 8 pts who finished 2 cycles of TST subsequently received alloBMT (3), autoBMT (2) and maintenance Zarnestra (3). Median overall survival (OS) for all pts is 10.1 mos, with 1yr survival 45.7% (95% CI; 32.5%–58.9%). On multivariate analysis, only antecedent MDS was a significant risk factor for poor OS (HR=2.5, 95% CI 1.13–5.65; p=0.02). For patients who achieved CR, median disease free survival (DFS) was 9.9 mos (95% CI; 5.8–18.2) with 1yr DFS 45.9% (95% CI; 29.4%–62.4%). Preceding MDS (p=0.02), adverse CG (p=0.04) and age ≥50 (p=0.06) were associated with low CR. Induction and consolidation mortality were <10%. Median time for ANC >100/μl was 28 days (22–56) and platelets >50,000/μl was 30 days (22–81) following TAM. For consolidation, median time to ANC >100/μl was 27.5 days (19–48) for TAE and 39 days (26–43) for AIA, and plts >50,000/μl 34 days (19–87) for TAE and 54 days (33–79) for AIA. Toxicities during induction and consolidation were generally ≤grade 3 and consisted of infection (bacteremias, pneumonias), oral and/or GI mucositis, transient elevation in liver function tests, reversible renal insufficiency. Pulmonary hemorrhage (1), GI bleed (3), CNS bleed/infarct (2) and decreased ejection fraction (2) occured during induction/consolidation but resolved. Causes of death during induction were sepsis/multiorgan failure (3), progressive fungal pneumonia (1), grade 5 marrow aplasia (1); during consolidation multiorgan failure (1), renal failure/sepsis (1), pulmonary hemorrhage (1). In summary, TAM induction for AML is associated with significant CR rates and acceptable toxicity, but did not appear to overcome the poor DFS and OS in a high-risk group of adults.

Purpose: Vascular endothelial growth factor (VEGF) promotes acute myelogenous leukemia (AML) cell growth and survival and may contribute to drug resistance. bevacizumab, an anti-VEGF monoclonal antibody, exhibits clinical activity against diverse malignancies when administered with cytotoxic chemotherapy. We conducted a Phase II clinical trial of bevacizumab administered after chemotherapy to adults with refractory or relapsed AML, using a timed sequential therapy (TST) approach.Experimental Design: bevacizumab 10 mg/kg was administered on day 8 after 1-beta-D-arabinofuranosylcytosine 2 g/m(2)/72 h beginning day I and mitoxantrone 40 mg/m(2) beginning day 4. In vivo laboratory. correlates included AML cell VEGF receptor-1 (FLT-1) expression, marrow microvessel density, and free serum VEGF before and during TST with bevacizumab.Results: Forty-eight adults received induction therapy. Myelosuppression occurred in all of the patients similar to other TST regimens. Toxicities were decreased ejection fraction (6%), cerebrovascular bleed (4%), and mortality of 15%. Overall response was 23 of 48 (48%), with complete response (CR) in 16 (33%). Eighteen (14 CR and 4 partial response) underwent one consolidation cycle and 5 (3 CR and 2 partial response) underwent allogeneic transplant. Median overall and disease-free survivals for CR patients were 16.2 months (64%, 1 year) and 7 months (35%, 1 year). Marrow blasts demonstrated FLT-1 staining before bevacizumab and marked decrease in microvessel density after bevacizumab. VEGF was detected in pretreatment serum in 67% of patients tested, increased by day 8 in 52%, and decreased in 93% (67% undetectable) 2 h after bevacizumab.Conclusions: In this single arm study, cytotoxic chemotherapy followed by bevacizumab yields a favorable CR rate and duration in adults with AML that is resistant to traditional treatment approaches. The clearance of marrow blasts in some patients after bevacizumab suggests that VEGF neutralization might result directly in leukemic cell death. The potential biological and clinical activity of bevacizumab in AML warrants additional clinical and laboratory study.