ALBERT

Description: Disease relapse remains the major cause of treatment failure following hematopoietic transplantation for AML/MDS. A major goal is to develop more effective antileukemic regimens without excessive toxicity. Busulfan (Bu)-fludarabine (Flu) is a widely used preparative regimen. We demonstrated that targeting a relatively high busulfan systemic exposure pharmacokinetic (PK) dose adjustment was superior to fixed busulfan dosing. Clofarabine (Clo) has improved antileukemic activity compared to fludarabine. We previously reported a phase I/II study of different dosing combinations of busulfan with Flu and Clo; the best results were obtained with Bu with Flu 10 mg/m2 and Clo 30 mg/m2 daily for four daily doses. We performed a phase III randomized controlled trial to determine if Flu/Clo/Bu improved progression free survival compared to the Flu/Bu regimen. Busulfan was given with PK dose adjustment AUC 6000 mM x min for age

Description: Background: PR1 peptide has been established as a human myeloid leukemia-associated antigen. We studied PR1 peptide vaccine in a phase I/II clinical trial in HLA-A2 + patients with AML, MDS and CML. To address whether prior HSCT or prior use immunosuppressive drugs would prevent PR1-induce cytotoxic T lymphocyte (PR1-CTL) immunity after vaccination with PR1 peptide vaccine, we studied the outcome in 20 patients with a prior HSCT, who were treated on the PR1 vaccine trial. Methods: Twenty patients (13 with AML or MDS, 7 with CML) were vaccinated at a median time of 9.5 months (range: 1–220) after HSCT. Sixteen patients had received a prior allogeneic HSCT (12 had allogeneic related, 3 had allogeneic unrelated, and 1 had syngeneic) and 4 patients had a prior autologous HSCT. At the time of vaccination, 5 patients were in CR, and 15 had measurable disease. Patients could not receive systemic immunosuppressive therapy for at least 4 weeks prior to vaccination, and had to be free of acute or chronic GVHD requiring systemic therapy. The vaccine was given subcutaneously every 3 weeks for a total of 3 injections at one of three dose levels: 0.25, 0.5 and 1.0 mg. GM-CSF at a dose of 75 mg was injected subcutaneously into the same site. Immune response to the vaccine (IRV) was defined as 〉 2-fold increase in PR1-CTL by PR1/HLA-A2 tetramer assay. Results: After a median follow up of 56.5 months (range: 27–89), toxicity was limited to grade I/II injection site reactions in 7 (35%) patients. IRV were observed in 11/20 (55%) patients. Nine of 11 (82%) IRV+ patients versus 1 of 9 (11%) IRV- patients had clinical responses (p = .005). Median event-free survival (EFS) was 23.8 months in IRV+ patients versus 1.9 months in IRV- patients (p=0.03). Median overall survival (OS) in IRV+ patients has not yet been reached vs. 40 months in IRV- patients (p = 0.08). Only 2 patients with pre-existing, limited chronic GVHD experienced a mild exacerbation within 3 months of vaccination, which was controlled with topical steroids. PR1-CTL were enriched in central memory phenotype (TCM) that persisted up to 4 years in clinical responders. Univariate and multivariate Cox proportional hazards analyses showed a low pre-vaccine bone marrow blast count (

Description: INTRODUCTION More active high-dose regimens are needed for non-Hodgkin’s (NHL) and Hodgkin’s lymphomas (HL), where standard BEAM offers poor results in refractory or poor-risk relapsed tumors. We previously developed a regimen of infusional gemcitabine with busulfan and melphalan (Gem/Bu/Mel), exploiting the synergy between gemcitabine and alkylators based on inhibition of DNA damage repair. Gem/Bu/Mel was safe and highly active against refractory lymphomas (Nieto, BBMT 2012). To further increase its activity we combined it in preclinical experiments with SAHA, which induces relaxation of the chromatin and renders DNA more accessible to DNA-targeting agents. Concurrent exposure to SAHA and Gem/Bu/Mel resulted in markedly increased apoptosis and cytotoxicity in refractory B- and T-NHL lines, with increased PARP1 cleavage and γ-H2AX reflecting increased DNA damage (Valdez, Exp Hematol 2012). SAHA has a dose-response effect in refractory lymphoma lines up to clinically achievable levels with doses of 1,000 mg, higher than its usual dose. We wished to clinically study the concurrent combination of SAHA and Gem/Bu/Mel in refractory NHL and HL. Methods Patients ages 12-65 with refractory lymphomas and adequate end-organ function were eligible for this dose-finding study of SAHA combined with Gem/Bu/Mel. SAHA was given on days -8 to -3 at 200-1,000 mg PO daily (levels 1-11), preceding all chemotherapy. Gemcitabine was given as a loading dose of 75 mg/m2 followed by infusion at a fixed dose rate of 10 mg/m2/min over 3.5 (levels 1-5), 4 (level 6) or 4.5 hours (levels 7-11) on days -8 and -3. Each gemcitabine dose was immediately followed by the corresponding dose of busulfan or melphalan. After a test dose on day -10, busulfan was given from days-8 to -5 targeting a daily AUC of 4,000. Melphalan was infused at 60 mg/m2/day on days -3 and -2. ASCT was on day 0. Patients with CD20+ tumors received rituximab (375 mg/m2) on days +1 and +8. Dose limiting toxicities (DLT) were defined as any G4-5 nonhematological organ toxicity, or as G3 skin or G3 mucositis lasting 〉3 days at peak severity. Dose escalation followed a Bayesian design targeting a maximal DLT probability of 20%. Results Between 10/11 and 6/13, 66 patients were enrolled with DLCL, HL and T-NHL (Table 1). SAHA was escalated up to 1,000 mg PO daily, combined with full doses of Gem/Bu/Mel without encountering DLTs. There were no treatment-related deaths. The toxicity profile was manageable, including mucositis (48% G2, 31% G3), skin (11% G2, 3% G3), self-limited transaminase elevation (30% G2, 6% G3), and self-limited elevation of bilirubin not associated to VOD (22% G2, 16% G3). There were no cardiac, pulmonary, renal or CNS toxicities. There was no QT prolongation detected after SAHA. Neutrophils and platelets engrafted promptly at median days +10 (range, 8-13) and +12 (range, 8-55), respectively. This toxicity profile is undistinguishable from the one we previously described with Gem/Bu/Mel. Activity and patient outcomes at median follow-up of 8 months (1-23) are shown on Table 2 and Figures: Conclusions Concurrent administration of SAHA with high-dose GemBuMel is feasible up to a daily dose of SAHA of 1,000 mg, with no increased toxicities compared to Gem/Bu/Mel alone. Early results indicate that SAHA/Gem/Bu/Mel is highly active in refractory or poor-risk relapsed HL and DLCL and warrants further study in earlier disease stages. Longer follow-up is needed to confirm these findings. Disclosures: Nieto: Otsuka Pharmaceuticals: Research Funding. Off Label Use: Vorinostat not approved for DLCL or Hodgkin's lymphoma. Qazilbash:Otsuka Pharmaceuticals: Research Funding. Andersson:Otsuka Pharmaceuticals: Research Funding.

Description: Anti-HLA donor-specific Abs (DSAs) have been reported to be associated with graft failure in mismatched hematopoietic stem cell transplantation; however, their role in the development of graft failure in matched unrelated donor (MUD) transplantation remains unclear. We hypothesize that DSAs against a mismatched HLA-DPB1 locus is associated with graft failure in this setting. The presence of anti-HLA Abs before transplantation was determined prospectively in 592 MUD transplantation recipients using mixed-screen beads in a solid-phase fluorescent assay. DSA identification was performed using single-Ag beads containing the corresponding donor's HLA-mismatched Ags. Anti-HLA Abs were detected in 116 patients (19.6%), including 20 patients (3.4%) with anti-DPB1 Abs. Overall, graft failure occurred in 19 of 592 patients (3.2%), including 16 of 584 (2.7%) patients without anti-HLA Abs compared with 3 of 8 (37.5%) patients with DSA (P = .0014). In multivariate analysis, DSAs were the only factor highly associated with graft failure (P = .0001; odds ratio = 21.3). Anti-HLA allosensitization was higher overall in women than in men (30.8% vs 12.1%; P 〈 .0001) and higher in women with 1 (P = .008) and 2 or more pregnancies (P = .0003) than in men. We conclude that the presence of anti-DPB1 DSAs is associated with graft failure in MUD hematopoietic stem cell transplantation.

Description: Background: Relapse is the main cause of treatment failure after allogeneic stem cell transplant (SCT) in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Based on encouraging preliminary reports for S.C. 5-Azacitidine (AZA) in the post-transplant setting, we investigated whether AZA given as maintenance might improve relapse free survival (RFS). Methods: Between 2009 and 2017, 〉 900 AML/MDS aged 18-75 were screened for the randomized controlled study of post-transplant AZA if they were in complete remission after SCT. The randomization was planned with the treatment arm to receive AZA given as 32 mg/m2/day S.C. for 5 days in each of 12 cycles. The control arm (Ct.) had no intervention. The first cycle of AZA was started within 42-100 post SCT. Each cycle consisted of 28 days allowing next cycle to be started within 56 days following the previous one in the presence of toxicity. The primary outcome for treatment evaluation was RFS. The goal was to test the hypothesis that AZA, given for 12 cycles, provided at least a 50% improvement compared with Ct. in median RFS. An accrual rate of 6 pts. per month was assumed. The final analysis was to be done after 213 to 246 pts. were enrolled based on the number of events observed. However, the study was closed early due to slow accrual 8 years. Results: 187 pts were randomized to either AZA (n=93) Ct. (n=94). Of 93 patients, 87 started treatment with AZA; with a median of 62 days. There were no significant differences between the arms in age (median, 57y), race, cytogenetics, donor type, conditioning intensity, hematopoietic stem cell source, except disease status in AML and comorbidity (Table 1). The majority of the pts.in AZA arm (74.6%) did not receive the planned 12 cycles of treatment, with the number of cycles varying with a median of 4 (range, 1-12). The most common causes of discontinuation of AZA were relapse/death on AZA (46.9%), hematologic/non-hematologic toxicity (26.5%), or patient request/logistical reasons (26.5%). Median follow-up time was similar between arms; 4.6 years in AZA vs. 4.06 years in Ct. Median RFS was comparable, with 2.07 yrs. (AZA) vs. 1.28 yrs. (obs.) (p=0.43). Due to bias induced by the discontinuation of AZA, any conventional comparison analysis, such as a logrank test, would be biased. Therefore, to obtain unbiased comparisons of RFS, separate landmark analysis using logrank tests were conducted, with each including only the AZA pts. who were compliant up to the landmark time, and the comparable subset of Ct. pts. defined as those at risk of failure at the landmark time (Table 2). All landmark analysis showed no significant AZA effect on RFS. A Cox model regression analysis indicated that there was improvement in RFS with AZA beyond day 180, but this was not statistically significant. Additionally, three ad hoc comparisons of AZA to Ct. were done by stratifying AZA pts. into those who received: 1-4 cycles (group 1); , 5-8 cycles (group 2) ; ,or 9-12 cycles (group 3). Pts.in.Ct. were included in the comparative analysis for group 2 if they were at risk of failure at day 150, and for group 3 at day 270. Cox regression analyses showed improvement in RFS in AZA group if they received ≥9 cycles of AZA, but the effect was not significant (p=0.18). Overall, AZA maintenance was well-tolerated with only 1 grade 5 adverse event (AE) reported with AZA vs. 10 grade 5 AEs in the Ct . arm. Twenty grade 4 AEs were reported in AZA arm, 13 were attributed to AZA; all but one was bone marrow (BM) toxicity. All AZA attributable grade IV AEs resolved with a median of 23 days. In obs. arm, 8 grade 4 AEs were reported with 3 BM toxicity. Conclusion: The SC AZA vs. observation randomized trial conducted over 8 years demonstrated that a prospective trial in the post-transplant setting was feasible and safe but challenging. In this trial, although the aim was compare RFS between arms after 12 cycles of AZA, less than 30% of AZA pts. completed the planned 12 cycles for various reasons, including disease relapse, toxicity, compliance, and logistics for receiving the drug. Because accrual was slow, the study was terminated early. While RFS was comparable between the two arms, stratification by number of cycles of AZA received showed a trend towards improvement in RFS in AZA pts. receiving more cycles of therapy. This finding supports the notion that AZA given for 9-12 cycles as maintenance therapy warrants further study for prevention of relapse after allogeneic HSCT for AML and MDS. Figure Figure. Disclosures Oran: AROG pharmaceuticals: Research Funding; Celgene: Consultancy, Research Funding; ASTEX: Research Funding. Shpall:Affirmed GmbH: Research Funding. Rezvani:Affirmed GmbH: Research Funding. Champlin:Sanofi: Research Funding; Otsuka: Research Funding.

Description: Autologous SCT with Mel 200 mg/m2 conditioning is considered standard consolidation treatment for MM pts. However, Mel 200 results in response rates of 20–40%, with nearly all pts ultimately relapsing. A double alkylating regimen of IV Bu and Mel has been suggested as an effective and myeloablative pre-transplant conditioning regimen. The IV formulation of Bu has less pharmacokinetic variability, and results in less toxicity, specifically less hepatic and mucosal toxicity. Patients and Methods: The conditioning regimen consists of IV Bu 130 mg/m2 over 3 hr daily for 4 days, either as a fixed dose per BSA, or to target an average daily AUC of 5,000 μMol-min ± 12% determined by a test dose of IV Bu at 32 mg/m2 given 48 hours prior to the high dose regimen. After the four daily Bu doses, there is a rest day, followed by two daily doses of Mel at 70mg/m2. Stem cells are infused the following day. Dilantin is administered for seizure prophylaxis. Results: 25 pts (16 M/9 F) with median age 53 years (range 31–64) have been treated. Salmon-Durie stage at diagnosis was I (n=6), II (n=11), and III (n=8); B2M at diagnosis was available for 16 pts, median 2.8 (range 1.4–5.2). The median number of prior chemotherapy regimens was 2 (range 1–5). At time of study entry, 20 pts were in partial remission, and 5 had refractory disease. The median CD34+ cell dose infused was 5.00 × 106/kg (range 2.5–7.7). Median days to ANC ≥ 0.5 × 109/L and platelet count ≥ 20 × 109/L were 10 (range 8–13) and 9 (7–23), respectively. Eighteen pts had IV Bu delivered per test dose guidance, with a median first dose systemic Bu exposure of 4606 μMol-min (range 4008–5601), necessitating a secondary adjustment to achieve an average daily AUC of 5000 μMol-min +/−12% in 6 pts. Median Bu clearance was 94 ml/min/m2 (range 83–113). Seven pts received fixed dose Bu at 130 mg/m2. With median follow-up time of 3 months, 17 pts are evaluable for response based on EORTC consensus criteria that mandate a response maintained for at least 6 weeks (BJH1998, 102:1115): 1 complete response, 6 partial response, 1 minor response, 7 stable disease, and 2 progressive disease. The treatment was well tolerated, with grade II or III diarrhea (n=6), mucositis (n=7), and nausea (n=9) being the most common regimen-related toxicities. Transient ascites concurrent with chemotherapy administration in a pt with refractory disease and high tumor mass was the only noted possible hepatic toxicity. Carbon monoxide diffusion capacity (DLCO) was measured to evaluate for pulmonary toxicity in 16 pts. At 3 months post study, asymptomatic grade II and III pulmonary toxicity was noted in 2 and 1 pts, respectively; 1 pt was not evaluable due to concurrent pneumonia. No grade IV toxicities or deaths have been observed. Conclusion: Intravenous Bu-Mel is well tolerated, and individualized PK-directed dosing of IV Bu likely contributes to the low toxicity profile of this regimen. Although the final best response may be too early to evaluate, the preliminary response data in this group of poor prognosis MM pts suggest it is an effective conditioning regimen.

Description: Abstract 3446 Background: The achievement of a fully chimeric state, as opposed to mixed chimerism, has been associated with a more favorable outcome after allogeneic stem cell transplantation (allo-SCT) for leukemia. When using the reduced-toxicity IV Busulfan-Fludarabine (Bu-Flu) regimen (de Lima et al, BLOOD 2004;104:857-64) we were intrigued by a seemingly high incidence of early (day+30) mixed chimerism, yet a low incidence of serious toxicity, GvHD and high overall and disease-free survival, especially for patients transplanted in (any) remission (CR). We hypothesized that the introduction of highly sensitive PCR-based chimerism assessment technique, as well as separately assaying myeloid- and T-cell chimerism might provide more reliable data for assessing the prognostic value of chimerism in reference to overall (OS) and disease-free survival (DFS) after allo-SCT. Patients and methods: Chimerism assay was performed with PCR-based technique on informative loci, and multi-variate Cox models including chimerism and other covariates were fit for OS and DFS (See Table 1). Results: 206 AML/MDS patients were treated on two consecutive protocols with Flu at 40 mg/m2 daily for 4 days, each dose followed by IV Bu at 130 mg/m2 or pharmacokinetically targeted to an average systemic exposure of 6,000 mcMol-min. Recipients of an unrelated or one-Ag mismatched related graft received rabbit-ATG at a total dose of 4 mg/kg on days -3 to -1. GvHD prophylaxis was Tacrolimus with mini-dose MTX (5 mg/m2) on post-transplant days 1, 3, 6, and 11. There were 98 females and 108 males at a median age of 47 years (range 16–66). Sixty-six patients were in CR1, 48 in CR2, 18 had 1st chemotherapy-refractory relapse, 20 were in 1st or 2nd untreated relapse, 37 had primary induction failure, while 17 had high-risk MDS. One patient died before day 30, without chimerism studies, and 11 recovered with refractory leukemia. Median follow-up of patients still alive is 5.5 yrs (range 1.3–8.6). 193 patients who engrafted and were in CR on day +30 had chimerism analysis performed, 64% were full donor chimeras, and 36% had mixed chimerism (≥1% remaining host cell-derived DNA). As expected, being in CR prior to SCT and, if transplanted with active disease, to engraft and remain in CR or to achieve CR, respectively, were important predictors for survival. A cytogenetic “bad” prognostic subgroup (e.g. -5/-7), was of adverse importance. However, in the multivariate model neither higher age, up to age 65, or attainment of full vs. mixed donor chimerism by day +30 were of additional predictive value for either OS or DFS. (See Table 1). Conclusion: When the reduced-toxicity IV Bu-Flu regimen is used as conditioning therapy for AML/MDS only cytogenetic subgroup (Bad/others) and disease state (CR/No CR) at the start of conditioning therapy influenced DFS and OS. Neither patient age nor attaining complete chimerism on BMT day +30 were independently predictive of an altered prognosis in reference to OS and DFS. Disclosures: No relevant conflicts of interest to declare.