Steensma, David P.

Abstract Abstract 2778 Introduction: Lenalidomide is approved for the treatment of del(5q) MDS in US and Japan. In Low to Intermediate-1 (Int-1) risk non-del(5q) MDS, lenalidomide treatment is less effective with a lower response rate (25%) and shorter response duration [Raza A. et al, Blood, 2008.111,1]. Ezatiostat, a glutathione S-transferase P1-1 (GST P1-1) inhibitor, activates Jun kinase, promoting the growth and maturation of hematopoietic progenitors while inducing apoptosis in malignant cells. Based on the novel mechanism of action, response rates, non-overlapping toxicities, and tolerability observed in a single agent ezatiostat Phase 2 study in MDS, a study of the combination of ezatiostat and lenalidomide was conducted to determine the safety and efficacy of ezatiostat with lenalidomide in non-del(5q) Low to Int-1 risk MDS. Methods: In this multicenter Phase 1 dose-ranging study, ezatiostat was given at a starting dose of 2000 mg in combination with lenalidomide at 10 mg, days 1–21 of a 28-day cycle. In stage 1, 3–6 patients in a standard 3+3 design were treated before escalation to the ezatiostat/lenalidomide 2500/10 mg dose level. Treatment was given until lack of MDS response or unacceptable toxicity. Hematologic improvement-erythroid (HI-E) rates were determined by the MDS International Working Group (IWG; 2006) criteria. Results: Eighteen pts (median age 73 yrs; range 57–82; 72% male), with World Health Organization classifications: 4 refractory anemia (RA), 2 RA with excess blasts-1, 4 refractory cytopenia with multilineage dysplasia (RCMD), 5 RCMD with ring sideroblasts, 2 MDS-unclassified, 1 MDS/myeloproliferative disorder-U were enrolled. Thirteen pts (72%) were Int-1 risk, 5 (28%) Low risk; 4 pts (22%) had abnormal cytogenetics. Twelve RBC transfusion-dependent pts (67%) required a median of 6 units (range 4–10)/8-weeks. Two pts (11%) were platelet transfusion dependent. A total of 67 treatment cycles were given (median 3.5 cycles/pt [range 1–11]) and only 6 cycles (9%) required dose reductions and 8 (12%) dose delays. Two of 6 pts reported DLTs (Grade 3 diarrhea and Grade 3 rash) at 2500/10 mg, with 9 additional pts receiving the recommended combination dose of 2000/10 mg. Eleven of 18 pts were evaluable (4 at 2500/10 mg and 7 at 2000/10 mg), and 3 pts are still on therapy with insufficient treatment duration to be evaluable. The HI-E rate was 43% (3/7; 95% CI, 10%–82%) for pts at the recommended 2000/10 mg dose and 6 pts are continuing therapy at the time of analysis. Three of 8 (38%; 95% CI, 9%–76%) RBC transfusion-dependent evaluable pts achieved transfusion independence including 1 responder who did not respond to prior lenalidomide. In responders, the median increase in hemoglobin level was 3.4 g/dL (from 7.9 g/dL). In 2 of 4 thrombocytopenic pts, a HI-platelet (HI-P) response was observed. A bilineage (HI-E and HI-P) response in 2 of 4 pts with anemia and thrombocytopenia was reported. One RBC and platelet transfusion-dependent pt who had a poor response to prior anti-thymocyte globulin treatment achieved complete RBC and platelet transfusion independence. The combination was generally well tolerated with no unexpected toxicities. Most common treatment-related non-hematologic adverse events (AEs) were Grades 1 and 2 including: fatigue (6%, 28%), swelling (0%, 11%), anorexia (11%, 6%), rash (0%, 6%), skin odor (11%, 6%), nausea (39%, 11%), diarrhea (22%,17%), vomiting (28%,17%), upper abdominal pain (5.6%, 5.6%), and constipation (11%, 0%). Grade 3 events were rash (11%), nausea (6%), diarrhea (17%), and vomiting (6%). Most common hematologic-related AEs were Grades 1 and 2 thrombocytopenia (11%, 6%) and neutropenia (0%, 11%). Grade 3–4 AEs were thrombocytopenia (11%, 17%), neutropenia (17%, 11%), anemia (6%, 6%), and febrile neutropenia (11%, 0%). Conclusions: Ezatiostat is the first GST P1-1 inhibitor to cause clinically significant reductions in RBC and platelet transfusions, including RBC and platelet transfusion independence. Since ezatiostat is non-myelosuppressive, it is a good candidate for combination with lenalidomide and in this study, the combination was well tolerated. Interestingly, ezatiostat may also have the potential to enhance lenalidomide's efficacy. The recommended doses of this combination regimen for future studies is the ezatiostat/lenalidomide 2000/10 mg. Disclosures: Off Label Use: Lenalidomide was used off-label in patients with non-del5q MDS. Mulford:Celgene: Speakers Bureau. Brown:Telik, Inc.: Employment, Equity Ownership. Meng:Telik, Inc.: Employment, Equity Ownership. Lyons:Incyte: Research Funding; Telik: Research Funding; Alexion: Consultancy, Honoraria; Novartis: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding. Sekeres:Celgene: Consultancy, Honoraria, Speakers Bureau. Mesa:NS Pharma: Research Funding; Astra Zeneca: Research Funding; SBio: Research Funding; Lilly: Research Funding; Incyte: Research Funding; Celgene: Research Funding.

Abstract Acquired hemoglobin H (HbH) disease (α thalassemia) can arise in the setting of marrow neoplasia, especially the myelodysplastic syndrome (MDS). This association has been termed α thalassemia-MDS (ATMDS, MIM #300448). Recently, we have linked ATMDS to acquired point mutations in the ATRX gene, which encodes an X-linked chromatin-associated factor whose precise normal cellular function is unknown (Steensma et al, Blood2004;103:2019, and Gibbons et al, Nature Genetics2003;34:446). We now describe a novel acquired splicing mutation in the helicase domain of the ATRX gene in a 71 year-old man of southern Italian descent. The patient, who previously had normal blood indices, presented with a 6-month history of microcytic anemia (Hb 7.7 g/dL, MCV 73.7 fL, reticulocytes 0.2%; WBC 11,800/uL with 29% circulating blasts). Peripheral smear demonstrated marked anisopoikilocytosis and the presence of poorly hemoglobinized ghost cells, while a marrow aspirate and biopsy revealed dysplastic features including atypical megakaryocytes, and approximately 20% blasts, consistent with a diagnosis of MDS in leukemic transformation. On supravital staining, approximately 30% of circulating erythrocytes contained HbH inclusions. The α/β globin transcript ratio measured by quantitative real-time PCR ranged between 0.11 and 0.39, compared with the mean ratio for 11 normals (α/β ratios in normals ranged between 0.8–1.2 fold of the mean). Despite this evidence of α thalassemia, no gross rearrangements of the α globin cluster were detected on Southern blotting or by FISH, and sequencing of the α globin genes was unremarkable. Screening of the entire coding region of the ATRX gene by denaturing high-performance liquid chromatograpy showed no abnormalities. Amplification and sequencing of cDNA made from the patient’s blood, however, revealed loss of ATRX exon 28 (in the middle of the putative helicase domain), resulting in a frame shift and generation of a premature stop codon. The causative mutation at the genomic level remains unknown, despite sequencing of the consensus splice sites framing both ATRX exon 28 and the surrounding regions. A clonally restricted mutation in a distant cryptic splice enhancer or inhibitor is suspected. Following treatment with idarubicin and Ara-C, the patient achieved a complete remission with normalization of red cell morphology and indices, and HbH was no longer detectable. This case emphasizes the need to search carefully for abnormal mRNA splicing when screening for ATRX mutations and provides further support for a link between ATRX mutations and ATMDS. Among 20 ATMDS patients analyzed molecularly, we have now characterized ATRX missense, null, and nonsense mutations in 9 patients, found a codon substitution of uncertain significance in 1 patient, and detected ATRX splicing mutations in 3 patients, including the present case. Additionally, one patient had an acquired α globin deletion limited to the neoplastic clone (Steensma et al, Blood2004; 103:1518). The molecular defect remains unknown in 6 cases. Since RNA is not available from these 6 archival cases, it is possible that they have ATRX splicing mutations as well.

Abstract Abstract 3814 Poster Board III-750 Introduction The 1997 IPSS remains the most widely used prognostic scoring system for patients with MDS, and it has important strengths, but several other prognostic systems have been proposed recently to overcome some of the well-recognized IPSS limitations. These systems include a new risk model for patients with MDS and CMML – including previously treated patients and those with secondary (treatment-related) MDS – proposed by Kantarjian and colleagues at the MD Anderson Cancer Center (MDACC) (Cancer 2008; 113:1351), as well as the WPSS, proposed by Malcovati and colleagues in Europe (J Clin Oncol 2007; 25:3503) To date, the MDACC risk model has not been validated in a large external independent cohort or directly compared to the WPSS. We assessed the performance of the MDACC model compared to the WPSS and the IPSS in a 12-year Mayo Clinic MDS/CMML cohort. Patients and Methods We reviewed the medical records of 1,503 adult patients (pts; 984 males; median age 71 years, range 17-98) with MDS (n=1,249) or CMML (n=254) evaluated at Mayo Clinic between January 1996 and December 2007. Pediatric pts (age ≤16 and pts with ≥30% marrow blasts were excluded. IPSS and WPSS scores were calculated, and data collected for MDACC risk model assignment (age, performance score, platelet count, hemoglogbin, marrow blast proportion, white blood cell count, karyotype, and transfusion history). Data were analyzed using Kaplan-Meier survival analysis and Cox proportional hazards regression models. Results The overall median survival was 17.8 months (mos) – 13.7 mos for CMML, 19.1 mos for WHO-defined MDS, and 9.6 mos for RAEB-t – similar to the 14.1 mos observed in the test cohort used to derive the MDACC risk model. Follow-up was complete until death in 1,122 (74.7%) pts. Pts excluded from the cohort stratified using IPSS included 122 patients with CMML and leukocytosis (>12 × 109/L), and 176 pts with secondary MDS/CMML (there were 12 pts with secondary CMML with leukocytosis) – total excluded, 286 pts. Patients excluded from the WPSS cohort included 27 pts with RAEB-t, 254 pts with CMML, and 148 pts with secondary MDS – total excluded, 429 pts. Survival by IPSS risk group was 38.9 mos for Low (n=413), 17.9 mos for Int-1 (n=541), 9.6 mos for Int-2 (n=206), and 6.6 mos for High (n=57). Survival by WPSS risk group was 39.0 months for Very Low (n=352), 26.6 months for Low (n=276), 15.9 months for Intermediate (n=185), 11.2 mos for High (n=221), and 4.9 months for Very High (n=40). Survival by MDACC risk group was 45.6 mos for Low (n=426), 20.0 mos for Int-1 (n=552), 12.3 mos for Int-2 (n=325), and 4.9 mos for High (n=200). When the MDACC risk model was used to classify only the 1,074 pts with conditions for which the WPSS has been validated, survival was 51.4 mos for Low (n=336), 21.2 mos for Int-1 (n=411), 13.3 mos for Int-2 (n=213), and 4.6 mos for High (n=114) (p<0.001 for all comparisons). In a multivariable proportional hazards model, all of the MDACC risk model components except WBC>20 × 109/L retained independent prognostic significance. Conclusions All 3 systems stratify patients accurately, but the MDACC risk model best identifies the lowest-risk patients, and also classifies the broadest group of patients (i.e., primary and secondary MDS, and primary and secondary CMML with or without leukocytosis). The revised IPSS that is currently in development should include the patient factors accounted for by the MDACC risk model, with the possible exception of leukocytosis. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 630 Introduction: Erythropoiesis stimulating agents (ESAs) improve hemoglobin (Hb) levels and reduce red blood cell (RBC) transfusion requirements in patients (pts) with chemotherapy-associated anemia (CAA), but many pts with CAA do not respond to ESAs. Functional iron deficiency due to inflammation-related hepcidin production and pathological sequestration of bioavailable iron may be an important reason for lack of ESA response in iron-replete pts. The common clinical practice of co-administering oral iron with ESAs does not appear to alter the disordered iron processing in CAA. We conducted a prospective trial to evaluate whether parenteral iron might overcome functional iron deficiency and benefit iron-replete pts with CAA undergoing ESA treatment. Patients and Methods: Eligible pts were receiving chemotherapy for a non-myeloid neoplasm and had Hb level <11.0 g/dL, ferritin >20 ng/mL, transferrin saturation <60%, and ECOG performance score ≤2. All pts received darbepoetin alfa (DA) 500 mcg subcutaneously q3wks until Hb reached >11 g/dL, and thereafter DA 300 mcg q3wks; DA was held for Hb >13 g/dL until Hb fell to <12 g/dL, then restarted with 25% dose reduction. Pts were randomized 1:1:1 to receive either sodium ferric gluconate complex in sucrose (Ferrlecit) 187.5 mg intravenously q3wks (total dose 1,125 mg), oral ferrous sulfate 325 mg once daily, or oral placebo. Quality of life (QOL) was measured using the Symptom Distress Scale, Brief Fatigue Inventory, FACT-An, and LASA instruments. The primary endpoint was the proportion of patients achieving Hb ≥12.0 g/dL or ≥2.0 g/dL Hb increment from baseline by the end of the 16-week study. Secondary endpoints included transfusion requirements. changes in QOL, changes in iron parameters, and adverse events (AEs). Results: Planned enrollment was 582 pts, but the study met an early stopping rule due to an excess of serious AEs in the IV iron arm; 502 pts enrolled at 14 MCCRC sites between February 2006 and December 2008. The median age of the 490 evaluable pts was 64 years; 65% were female and 94% white; 6% had hematological neoplasms (lymphoma or multiple myeloma), 25% had severe anemia (Hb <9.5 g/dL), 48% received platinum-containing therapy, and 66% completed all 16 weeks of the study. Baseline characteristics were comparable between groups. With respect to the primary endpoint, 69.5% of IV iron-treated pts achieved a Hb response (median Hb increase from baseline to end of study, 2.7 g/dl), compared to 66.9% with oral iron (median increase, 2.4 g/dL) and 65.0% with placebo (median increase 2.3 g/dl) (p=0.73). There were no significant differences in the proportion of patients requiring RBC transfusion (12.8% for IV iron, 12.9% for oral iron, 13.5% for placebo; p=0.87) or QOL changes. A total of 17 pts (3%) died on study–8 in the IV iron arm, 6 oral iron, 3 placebo (p=0.22). Grade 3 or higher AEs occurred in 54% of IV iron pts compared to 43% for oral iron and 45% placebo (p=0.03). The end-of-study ferritin level was higher in the IV iron arm (median 501 ng/mL) compared to the oral iron (229 ng/mL) and placebo (193 ng/mL) arms (p=0.0022). The median total DA dose administered was similar between arms (p=0.71). Conclusions: Co-administration of DA with intravenous ferrous gluconate q3wks did not result in improvement in Hb levels, reduce transfusions, improve QOL endpoints, or allow lower doses of DA, compared with DA + oral iron or DA + placebo. IV iron increased AEs. The reason for discordant results with 5 previous smaller studies is unclear. Disclosure: The study was supported by a grant from Amgen (Thousand Oaks, CA) to the MCCRC. Disclosures: Off Label Use: Ferrlecit, chemotherapy-associated anemia.

Abstract Background: Erythropoiesis-stimulating agents (ESAs) reduce anemia in cancer patients; however, there are concerns that ESAs increase mortality in some patients. Within the framework of an international collaboration we thus conducted a patient-level meta-analysis to assess the effects of ESAs on mortality in cancer patients. Methods: We performed a meta-analysis, based on the intention-to-treat principle, of cancer patients enrolled in randomized controlled trials comparing epoetin alfa, epoetin beta or darbepoetin alfa plus red blood cell transfusions as needed versus transfusion alone, for prophylaxis or treatment of anemia while or after receiving anticancer therapy. Patient-level data were obtained and analyzed by independent statisticians at two academic departments. Primary endpoints were on-study mortality and overall survival in patients receiving chemotherapy, defined as all patients from studies in which =/> 70% of study population received chemotherapy, and in all cancer patients regardless of anticancer therapy. On-study mortality was defined as death from any cause between date of randomization and 28 days after end of active study phase. Overall survival was defined as death from any cause between date of randomization and longest follow up available. Hazard ratios (HR) and 95% confidence intervals (CIs) were calculated per study and meta-analyzed with fixed-effects and random-effects models. Stratified multivariable Cox-regression analyses were conducted to assess the impact of baseline imbalances. Tests for interactions were used to identify differences in effect across pre-specified subgroups. All analyses were pre-specified in a peer-reviewed protocol (Bohlius et al. 2008). An independent steering committee consisting of clinicians and methodologists agreed on all analyses and interpretations. Independent investigators and representatives from manufacturers contributing data offered advice, but had no decision-making authority. Results: Data from 13,933 cancer patients enrolled in 53 studies were included in the analysis; 38 trials including 10,441 patients used mainly chemotherapy. Including all cancer patients ESAs increased on-study mortality by 17% (HR 1.17; 95% CI 1.06–1.30), with little evidence for a difference between chemotherapy and other trials (p for interaction=0.42), and worsened overall survival by 6% (HR 1.06; 95% CI 1.00–1.12). In the chemotherapy population on-study mortality was increased by 10% (HR 1.10, 95% CI 0.98–1.24) and overall survival was worsened by 4% (HR 1.04; 95% CI 0.97–1.11). Adjusting for known prognostic factors had little effect on the overall estimates. There was no conclusive evidence for effect modification by patient level characteristics such as age, sex, Hb and Hct at baseline, Hb ceiling, type and stage of tumor or study level characteristics (anticancer treatment, ESA treatment schedules, study design and quality) for the outcomes tested. Conclusion: ESA treatment in cancer patients increased on-study mortality by 17% and worsened overall survival by 6%. For patients undergoing chemotherapy the increase was less pronounced, but could not be excluded. In clinical practice, risks of ESAs must be balanced against benefits of ESAs depending on the clinical circumstances of the individual patient.

Abstract Abstract 4094 Background: Our group has previously reported the benefits of thalidomide-prednisone based regimens for improvement of anemia, thrombocytopenia, and splenomegaly for patients with MF; both primary myelofibrosis (PMF), and arising from essential thrombocythemia and polycythemia (Post ET/PV MF). We sought to evaluate the overall efficacy of these commonly used regimens by evaluating long-term outcomes and applying the IWG-MRT response criteria (Tefferi et. al. Blood 2006) which arose after completion of these trials. Methods: We retrospectively analyzed the long-term outcomes, and assessed the initial therapeutic responses using IWG-MRT criteria from three parallel completed trials of MF using a thalidomide (THAL-50 mg/day) and prednisone (3 month taper beginning at 40mg, stopped at 3 months) backbone. The trials had identical eligibility criteria including adequate organ function and need for MF therapy (defined as symptomatic: anemia and/or splenomegaly). The trials were 1) THAL-PRED alone, THAL only after 3 months 2) THAL-PRED-etanercept (ETAN - TNF- alpha inhibitor at 25 micrograms subcutaneously twice a week), THAL and ETAN only after 3 months and 3) THAL-PRED – oral cyclophosphamide (CTX 25mg daily orally), THAL alone after 3 months. Results: Patients: A total of 50 pts were enrolled in these 3 trials (Males n=36, 72%) with median age of 68.5 years (Range 43–85), with 79% having PMF. Patients had advanced disease in general with 88% having intermediate 2 or high risk MF by IWG criteria (Cervantes et. al. Blood 2009), 62% patients with red cell transfusion dependence and 50% with an abnormal karyotype. Therapy initial results: 80 % of patients reached the three month juncture on the trials, with 40% reaching 6 months. Initial toxicity was myelosuppression with 3 cases of grade 3 anemia, 3 cases of grade 3 neutropenia and 4 cases of grade 3 thrombocytopenia. There were no grade 4 or higher hematological toxicities noted. Initial neuropathy was uncommon and seen in only 4% of patients. No complete responses were observed and only 1 patient had partial response (by IWG-MRT criteria). 14 patients (28% overall) met the new IWG-MRT criteria for clinical improvement; 11 for anemia (22%), 2 for thrombocytopenia (4%) and 3 for splenomegaly (6%). Responses occurred relatively quickly at an overall median of 8 weeks (range 4–12) after enrollment. Long Term Outcomes: After a median follow-up of 36 months across this cohort we observed an overall median duration of response of 8.5 months (range 3–42). Responses to THAL based regimens can lead to periods of prolonged stabilization after cessation of therapy. We observed an overall median time to institution of next therapy of 3 months (range 1–50). At the time of this analysis 14 patients (28%) have expired of their MF and median survival across the entire cohort was 36 months (3-106). Comparison of Regimens: Comparison of these three independent trials (Table 1) suggests greater toxicity and inferior response rate, duration of response, and time to next therapy with the cyclophosphamide containing regimen. Conclusion: THAL-PRED based regimens are active in a subset of MF patients for therapy primarily of anemia, and for some patients a response of good duration (even after cessation of therapy) may be obtained. IWG-MRT response assessment demonstrates utilizing additional agents to a THAL-PRED regimen do not appear to augment (and may detract from responses). Newer agents such as pomalidomide may have similar to greater efficacy without neuropathy and less myelosuppression. Disclosures: Off Label Use: There is no FDA approved agent in Myelofibrosis. All the drugs discussed; Thalidomide, Prednisone, Etanarcept and Cyclophosphamide are off-label. Mesa:SBio: Research Funding; Novartis: Research Funding; Celgene: Research Funding; Incyte: Research Funding; Roche: Research Funding; eisai: Research Funding; telik: Research Funding.

Abstract Abstract 2919 Background: Sideroblastic anemias can be either hereditary due to congenital mutations in factors critical for iron processing or heme biosynthesis, or acquired; acquired sideroblastic anemias may be induced by alcohol or medications, but are usually idiopathic. Pyridoxine, a form of vitamin B6, plays a critical role in heme synthesis as a cofactor for δ-aminolevulinic acid synthetase (ALAS). Some subtypes of congenital sideroblastic anemia, such as those associated with mutations in the ALAS2 gene encoding the erythrocyte-expressed isoform of ALAS, may respond to pyridoxine therapy at doses ranging from 5–500 mg/day. Anecdotal reports of improvement with pyridoxine therapy in cases of acquired idiopathic sideroblastic anemia (AISA) have led to widespread clinical use of this agent in patients with refractory anemia with ring(ed) sideroblasts (RARS) and refractory cytopenia with multilineage dysplasia associated with ring sideroblasts (RCMD-RS). However, there are no systematic studies of the effectiveness of pyridoxine in AISA. Methods: We reviewed clinical and laboratory data from 231 adult patients with marrow aspirate-proven AISA (i.e., RARS or RCMD-RS, based on 2001 WHO criteria) evaluated at our institution between 1994 and 2007. Responses to pyridoxine were assessed using 2006 International Working Group (IWG) standardized criteria for MDS (erythroid response with hemoglobin increase by '1.5 mg/dl). The relationship between response to pyridoxine and disease subtype or International Prognostic Scoring System (IPSS) stratification was assessed using χ2 test, using a p-value limit of <0.05 for statistical significance. Results: 86 of the 231 patients (42%) were treated with pyridoxine for an average of 19 months (range 1–114 months) at a mean dose of 167 mg/day (range 50–600 mg/day). Sufficient follow-up data to allow response evaluation were available from 74 (86%) of the 86 patients who received pyridoxine. Only 5/86 patients (6.8%) receiving pyridoxine met IWG response criteria for hematological improvement, but 3 of these 5 patients also received erythropoetin and 1 also received prednisone concomitantly with pyridoxine therapy. Therefore, only 1/86 (1.4%) patient's improvement in hemoglobin could be attributed to pyridoxine monotherapy. ALAS2 genotype data were not available from these 5 patients. The dose of pyridoxine was not associated with response to therapy (187.5 mg daily in responders vs. 157 mg daily in non-responders (p=0.60). Patients with RCMD-RS were more likely to be treated with vitamin B6 compared to patients with RARS (p=<0.001), possibly because of more severe anemia, but response to pyridoxine did not differ significantly between subtypes (3/49 vs. 2/25, response in RARS vs. RCMD-RS; p=0.76). Among the 74 evaluable patients, 3/46 patients in the low IPSS risk group responded to pyridoxine, compared to 2/24 of patients in the Intermediate-1 risk group and 0/4 in the Intermediate-2 risk group (p=0.82). Adverse effects associated with pyridoxine included new onset of irreversible symptomatic peripheral neuropathy in 2/86 patients (2.3%). Conclusions: Pyridoxine is commonly prescribed to patients with AISA in clinical practice, and this agent is often continued for a long period of time despite lack of evidence of objective response. Pyridoxine is an ineffective therapy in AISA that induces symptomatic peripheral neuropathy in some patients. Therefore, pyridoxine therapy should be limited to patients with known or suspected congenital mutations that confer pyridoxine responsiveness, and therapeutic trials should be brief to avoid adverse effects. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 3008 Poster Board II-984 Introduction: The erythropoiesis-stimulating agents (ESAs) epoetin alfa (EA) and darbepoetin alfa (DA) increase hemoglobin (Hb) levels and reduce red blood cell (RBC) transfusion requirements in patients (pts) with cancer chemotherapy-associated anemia (CAA). Extended-interval ESA dosing (i.e., administration less than once weekly) is a common practice with DA, which is FDA approved for dosing once every 3 weeks (q3wks); a previous study of the North Central Cancer Treatment Group suggested that EA can also be given less often than the FDA-approved once weekly schedule (Steensma DP et al, J Clin Onc 2006; 24:1079). The present study compared 2 different q3wks extended-interval EA regimens with weekly fixed-dose EA and with q3wks DA in pts with CAA. Patients and Methods: Eligible pts were receiving chemotherapy for a non-myeloid malignancy and had Hb <10.5 g/dL, ferritin >20 ng/mL, weight >40 kg and <150 kg, and ECOG performance score £2. Pts were randomized 1:1:1:1 to receive EA 40,000 Units subcutaneously (SC) once weekly (40K arm), EA 80,000 Units SC q3wks (80K arm), EA 120,000 Units SC q3wks (120K arm), or DA 500 mcg SC q3wks (DA arm), for 15 weeks. EA and DA were held for Hb >12 g/dL and restarted at a lower dose when Hb fell to '11.5 g/dL. All pts received ferrous sulfate 325 mg orally once daily, if tolerated. Quality of life (QOL) was measured using the Symptom Distress Scale (SDS), Brief Fatigue Inventory (BFI), FACT-An, and Linear Analogue Self Assessment (LASA) tools. The primary endpoint was the proportion of pts achieving Hb≥11.5 g/dL or increment of Hb>2.0 g/dL from baseline. Secondary endpoints included RBC transfusion requirements, adverse events (AEs), and QOL. Results: 239 pts (236 evaluable) enrolled at 10 MCCRC sites between Feb. 2007 and Dec. 2008; 62% of pts completed all study interventions. The median age of enrolled pts was 66 years; 42.4% were men, 91.5% had solid tumors, 26.7% had severe anemia (Hb <9.5 g/dL), and 44.9% were receiving platinum-containing regimens. Baseline characteristics were balanced between study arms, with the exception of gender (39% female for 40K, 60% for 80K, 43% for 120K, 26% for DA). There were no significant differences between treatment arms in the proportion of pts achieving a Hb response (68.9% for 40K, 61.7% for 80K, 65.5% for 120K, and 66.7% for DA; p>0.41 for all comparisons), but the median Hb increment from baseline was higher in the 40K and DA arms compared to the 2 extended dosing EA arms (40K-2.8 g/dL, 80K-2.0 g/dL, 120K-2.1 g/dL, DA-2.6 g/dL; p=0.005 for 40K vs 80K). Hb response was achieved more quickly in the weekly EA arm, but the difference was not significant (40K-32 days, 80K-50 days, 120K-49 days, DA-49 days; p>0.13). The proportion of patients transfused was similar between arms (40K-27.9%, 80K-33.3%, 120K-22.4%, DA-29.8%; p>0.49). There were no significant differences in QOL changes. Deaths were also similar between arms (40K-5 pts, 80K-7 pts, 120K-7 pts, DA-1 pt, p>0.10) and were primarily due to disease progression. AEs and serious AEs were comparable between study groups; grade 3/4 AEs were observed in 22% of pts in the 40K arm, 22% on 80K, 17% on 120K, and 13% on DA; p>0.56. The median total dose of EA used was highest in the 120K arm (40K-265,000 U; 80K-240,000 U; 120K-360,000 U; p=0.0009 for 40K vs 120K), while pts on the 40K arm were more likely to omit a dose due to a high Hb (40K-63.9% of pts omitted at least one dose; 80K-30.0%; 120K-34.5%; DA-43.6%, p<0.0001 for 40K vs 80K). Conclusion: Although there was no significant difference in the proportion of responding pts (the primary endpoint), Hb increments from baseline were moderately higher with the 2 FDA-approved regimens – weekly EA 40,000 Units, and q3wk DA 500 mcg – than with the extended dosing regimens. This study was supported by a grant from Centocor Ortho Biotech, Inc. to the MCCRC. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 460 Background: SF3B1 mutations were recently reported to occur in myelodysplastic syndromes (MDS), especially in the presence of ring sideroblasts (RS) (Papaemmanuil et al. Leukemia Research 2011, Volume 35, Supplement 1, page S18). We sought to accurately define the interaction between SF3B1 mutations, bone marrow morphology, karyotype and prognosis in MDS with ≥15% RS (MDS-RS). Methods: Mayo Clinic databases and cell banks were queried to identify patients with MDS and ≥15% RS (MDS-RS). All study patients were required to have undergone bone marrow examination and cytogenetic evaluation at diagnosis. Pathology slides, including iron stains, were centrally re-reviewed to accurately quantify bone marrow RS percentage and confirm World Health Organization (WHO) morphologic categories. Detailed analysis of clinical and cytogenetic parameters was performed to risk stratify patients according to the revised International Prognostic Scoring System (IPSS-R) (Greenberg et al. Leukemia Research 2011, Volume 35, Supplement 1, page S6). All patients were annotated for their mutational status involving JAK2, MPL and IDH. PCR sequencing was used to identify SF3B1 mutations. Results I: Baseline patient information: The study is currently ongoing; to date, results are availab1e in 88 patients (median age 72 years, 69% males) including 36 (41%) patients with refractory anemia with RS (RARS), 36 (41%) with refractory cytopenia with multilineage dysplasia and ≥15% RS (RCMD-RS), 11 (12%) with refractory anemia with excess blasts (RAEB)-1 and ≥15% RS (RAEB1-RS) and 5 (6%) with RAEB2-RS. Median (range) values were 9.1 g/dL (5.8–15.7) for hemoglobin, 4.1 × 109/L (1.2–35.2) for leukocytes and 164 × 109/L (6–585) for platelets. IPSS-R risk categories were 20% very good, 49% good, 11% intermediate, 3% poor and 16% very poor. Karyotype was normal in 60%, other very good/good risk 16%, intermediate-risk 2%, and poor/very poor in 22%; 14% had monosomal karyotype (MK). Six (7%), four (5%) and zero (0%) patients displayed IDH, JAK2 or MPL mutations. Red cell transfusion need was documented in 27 (31%) patients. Results II: Prevalence and distribution of SF3B1 mutations and clinical correlates: SF3B1 mutations (all heterozygous) were detected in 40 (∼46%) of all 88 study patients: 25 (63%) K700E, 6 (15%) K666N/Q/R, 3 (8%) E622D, 2 (5%) H662D/Q, 2 (5%) Y623C, 1 (3%) R625C, and 1 (3%) T663I. One patient each displayed both SF3B1K700E and IDH2R140Q or SF3B1K700E and JAK2V617F. SF3B1 mutational frequencies were 69% for RARS, 36% for RCMD-RS, 18% for RAEB1-RS and 0% for RAEB2-RS (p=0.0007). SF3B1 mutations clustered with normal (59%) and other very good/good risk (57%) karyotype and were infrequent in poor/very poor karyotype (5%; p=0.0004). Additional significant correlations were noted between SF3B1 mutations and lower IPSS-R risk category (p=0.0004), advanced age (p=0.006), higher platelet count (p=0.0003). Results II: SF3B1 mutations and prognostic relevance in MDS-RS: To date, 68 (∼77%) deaths and 10 (∼11%) leukemic transformations have been documented. Median follow-up for living patients was 82 months. Univariate survival analysis considering all 88 study patients identified the following as strongly significant risk factors: IPSS-R (p<0.0001), WHO morphologic categories (p<0.0001), cytogenetic risk categories (p<0.0001), and transfusion need (p=0.0003). In multivariable analysis, only IPSS-R and transfusion need remained significant. In univariate analysis, the presence of SF3B1 mutations was significantly associated with better overall (p=0.04) and leukemia-free (p=0.03) survival; however, in both instances, significance was completely accounted for by WHO morphologic risk categorization and the morphology-adjusted p values were 0.6 and 0.2, respectively. In other words, when RARS and RCMD were analyzed separately, there was no additional prognostic value from the presence or absence of SF3B1 mutations (Figures 1 and 2; p=0.67 and 0.44, respectively). Conclusions: SF3B1 mutations are prevalent in RARS and RCMD-RS but do not provide additional, WHO morphology-independent or IPSS-R-independent, prognostic information. Disclosures: No relevant conflicts of interest to declare.

Abstract BACKGROUND: We have previously reported on the therapeutic value of low-dose thalidomide in combination with prednisone (THAL-PRED) for the treatment of both anemia and thrombocytopenia in MMM (Blood2003;101:2534), with response rates of 62% and 75% for each cytopenia respectively. Alkylators have long been shown to have palliative benefit in MMM, however are used judiciously as long-term use could increase likelihood of leukemic transformation. Additionally, oral cyclophosphamide has been shown to synergize with thalidomide and steroids in the treatment of myeloma (Garcia-Sanz et. al. Leukemia2004;18:856–863). In the current study, we investigated the value of adding oral cyclophosphamide to THAL-PRED for MMM (TPC). METHODS: Study eligibility criteria included a histologically confirmed diagnosis of MMM and either severe anemia (hemoglobin < 10 g/dL) or symptomatic splenomegaly. Protocol treatment was initiated with 50 mg of oral thalidomide (THAL) daily, oral cyclophosphamide (CTX) 25 mg daily for three months, and a three month prednisone taper starting at 0.5 mg/kg/day for the first month followed by a 50% reduction for the second months and a further 50% reduction for the third and final month of treatment with prednisone. Patients with a demonstrable clinical response after three months were able to remain on thalidomide alone as maintenance. Responses were assessed by the International Working Group for Myelofibrosis Research and Treatment (IWG-MRT) criteria for MMM clinical responses (Tefferi et. al. Blood 2006; epub May 2006). RESULTS: 13 patients were enrolled to the trial (median age 73 years, range, 46–80; 7 males). Six patients (46%) completed the planned three cycles (i.e. 12 weeks) of treatment, the remaining seven patients discontinued treatment early for the following reasons: progression (n=3), patient choice (n=2), other medical problem (n=1) and died on study (n=1). After the initial 3 months of treatment, 3/13 (23%) patients evidenced a response (n = 1) or stable disease (n = 2) and continued on an additional three months of THAL alone. At enrollment, nine patients (69%) were anemic (8 of whom (62%) were red cell transfusion dependent). Ten patients (77%) were at least moderately thrombocytopenic (platelet count < 100 x 109//L). Eight patients (62%) had palpable hepatomegaly/splenomegaly, and five patients (38%) had severe constitutional symptoms (night sweats). According to IWG-MRT criteria for MMM the best responses observed from therapy was a CI (clinical improvement) in 2 individuals (one each for anemia (1/9 patients (11%); and thrombocytopenia (1/10 patients (10%)). No clear responses in organomegaly or constitutional symptoms were observed. The regimen overall was well tolerated with toxicities in excess of grade 2 all being related to myelosuppression (anemia (n=2), neutropenia (n=2), and thrombocytopenia (n=3)). CONCLUSIONS: This phase II study of combination therapy with thalidomide-prednisone-cyclophosphamide in patients with MMM strongly suggests that the addition of the alkylator cyclophosphamide largely negates the clinical benefits of THAL-PRED. This observation supports the potential immunologic mechanism of THAL-PRED benefit in MMM, and cautions against potential combinations of immunological and cytotoxic therapy in this disorder.