BACKGROUND Patients with transfusion-dependent β-thalassemia need regular red-cell transfusions. Luspatercept, a recombinant fusion protein that binds to select transforming growth factor β superfamily ligands, may enhance erythroid maturation and reduce the transfusion burden (the total number of red-cell units transfused) in such patients. METHODS In this randomized, double-blind, phase 3 trial, we assigned, in a 2:1 ratio, adults with transfusion-dependent β-thalassemia to receive best supportive care plus luspatercept (at a dose of 1.00 to 1.25 mg per kilogram of body weight) or placebo for at least 48 weeks. The primary end point was the percentage of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 plus a reduction of at least 2 red-cell units over this 12-week interval. Other efficacy end points included reductions in the transfusion burden during any 12-week interval and results of iron studies. RESULTS A total of 224 patients were assigned to the luspatercept group and 112 to the placebo group. Luspatercept or placebo was administered for a median of approximately 64 weeks in both groups. The percentage of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 plus a reduction of at least 2 red-cell units over this 12-week interval was significantly greater in the luspatercept group than in the placebo group (21.4% vs. 4.5%, P<0.001). During any 12-week interval, the percentage of patients who had a reduction in transfusion burden of at least 33% was greater in the luspatercept group than in the placebo group (70.5% vs. 29.5%), as was the percentage of those who had a reduction of at least 50% (40.2% vs. 6.3%). The least-squares mean difference between the groups in serum ferritin levels at week 48 was −348 μg per liter (95% confidence interval, −517 to −179) in favor of luspatercept. Adverse events of transient bone pain, arthralgia, dizziness, hypertension, and hyperuricemia were more common with luspatercept than placebo. CONCLUSIONS The percentage of patients with transfusion-dependent β-thalassemia who had a reduction in transfusion burden was significantly greater in the luspatercept group than in the placebo group, and few adverse events led to the discontinuation of treatment. (Funded by Celgene and Acceleron Pharma; BELIEVE ClinicalTrials.gov number, NCT02604433; EudraCT number, 2015-003224-31.)

Introduction: β-thalassemia is an inherited hemoglobinopathy associated with an erythroid maturation defect characterized by ineffective erythropoiesis and impaired RBC maturation. Luspatercept is a first-in-class erythroid maturation agent under development to treat patients with β-thalassemia. Luspatercept binds to select TGFβ superfamily ligands to reduce aberrant Smad2/3 signaling and enhance late-stage erythropoiesis (Suragani RN, et al. Nat Med. 2014;20:408-14). We report the results of a phase 3, randomized, double-blind, placebo-controlled study to determine the efficacy and safety of luspatercept in adult β-thalassemia patients requiring regular RBC transfusions. ClinicalTrials.gov identifier: NCT02604433. Methods: Eligible patients were aged ≥ 18 years; had β-thalassemia or hemoglobin (Hb) E/β-thalassemia (compound β-thalassemia mutation and/or multiplication of α-globin genes was allowed); and required regular transfusions of 6-20 RBC units in the 24 weeks prior to randomization with no transfusion-free period ≥ 35 days during that time. Patients were randomized 2:1 to receive either luspatercept, at a starting dose level of 1.0 mg/kg with titration up to 1.25 mg/kg, or placebo, subcutaneously every 3 weeks for ≥ 48 weeks. Patients in both treatment arms continued to receive RBC transfusions and iron chelation therapy to maintain the same baseline Hb level. The primary endpoint was a ≥ 33% reduction in transfusion burden (with a reduction of ≥ 2 RBC units) during weeks 13-24, when compared with a 12-week baseline period. Key secondary endpoints included: ≥ 33% reduction in RBC transfusion burden at weeks 37-48, ≥ 50% reduction in transfusion burden at weeks 13-24, ≥ 50% reduction in transfusion burden at weeks 37-48, and mean change in transfusion burden at weeks 13-24. Achievement of ≥ 33% reduction in RBC transfusion burden over any consecutive 12 weeks on study was also evaluated. Results: † A total of 336 patients were randomized, of whom 332 were treated. Median age was 30 years (range 18-66) and 58% of patients were female. Patients received a median of 6 RBC units in the 12 weeks prior to treatment. 58% of patients in each arm had undergone splenectomy. B0/B0 genotype (classification according to the HbVar database) was observed in 68 of 224 (30.4%) and 35 of 112 (31.3%) patients in the luspatercept and placebo arms, respectively. 48 of 224 (21.4%) patients in the luspatercept arm achieved the primary endpoint versus 5 of 112 (4.5%) patients receiving placebo (odds ratio 5.79, P < 0.0001). 44 of 224 (19.6%) patients receiving luspatercept achieved a ≥ 33% reduction in RBC transfusion burden at weeks 37-48 compared with 4 of 112 (3.6%) patients receiving placebo (P < 0.0001). Of 224 patients receiving luspatercept, 17 (7.6%) and 23 (10.3%) achieved a ≥ 50% reduction in RBC transfusion burden at weeks 13-24 and 37-48, respectively, compared with 2 (1.8%) and 1 of 112 (0.9%) patients receiving placebo (P = 0.0303 and P = 0.0017, respectively). The difference of mean change from baseline in transfusion burden from week 13 to week 24 was 1.35 units (P < 0.0001). 158 of 224 (70.5%) patients receiving luspatercept achieved a ≥ 33% RBC transfusion reduction over any consecutive 12 weeks compared with 33 of 112 (29.5%) patients receiving placebo (P < 0.0001); statistically significant differences were also noted for all other transfusion burden reduction endpoints. Adverse events (AEs) observed in the study were generally consistent with previously reported phase 2 data. Treatment-emergent AEs leading to dose delay or dose reduction were similar between treatment arms. No patient deaths were reported for those treated with luspatercept. Conclusions: Treatment with luspatercept resulted in significant reductions in RBC transfusion burden in adults with transfusion-dependent β-thalassemia. Luspatercept was generally well tolerated in this patient population. † As of May 11, 2018, cutoff date. Disclosures Cappellini: Celgene Corporation: Membership on an entity's Board of Directors or advisory committees; Sanofi/Genzyme: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Vifor: Membership on an entity's Board of Directors or advisory committees. Viprakasit:F. Hoffmann-La Roche Ltd: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Agios: Consultancy, Research Funding; Protagonist Therapeutics: Consultancy, Research Funding. Taher:Protagonist Therapeutics: Consultancy; Novartis: Consultancy, Honoraria, Research Funding; Ionis Pharmaceuticals: Consultancy; La Jolla Pharmaceutical: Research Funding; Celgene Corp.: Research Funding. Georgiev:Alnylam: Consultancy. Coates:Celgene Corp.: Consultancy; ApoPharma: Consultancy, Honoraria; Vifor Pharma: Consultancy; Sangamo: Consultancy, Honoraria. Voskaridou:Acceleron: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corp: Membership on an entity's Board of Directors or advisory committees, Research Funding. Forni:Novartis: Research Funding; Roche: Research Funding; Celgene: Research Funding. Perrotta:Acceleron Pharma: Research Funding; Novartis: Research Funding. Lal:Celgene Corporation: Research Funding; Bluebird Bio: Research Funding; La Jolla Pharmaceutical Company: Consultancy, Research Funding; Insight Magnetics: Research Funding; Novartis: Research Funding; Terumo Corporation: Research Funding. Kattamis:ApoPharma: Honoraria; Vifor Pharma: Consultancy; CELGENE: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Vlachaki:Novartis: Honoraria. Origa:Cerus Corporation: Research Funding; Bluebird Bio: Consultancy; Novartis: Honoraria; Apopharma: Honoraria. Aydinok:TERUMO: Research Funding; Protagonist: Other: SSC; CRISPR Tech: Other: DMC; Cerus: Honoraria, Research Funding; La Jolla Pharmaceuticals: Research Funding; Novartis: Research Funding, Speakers Bureau; Celgene: Research Funding. Ho:Takeda: Honoraria, Other: travel to meeting; Novartis: Honoraria; Janssen: Honoraria; Amgen: Honoraria; Celgene: Other: Travel to meeting. Chew:Celgene: Research Funding. Tantiworawit:Celgene: Honoraria, Research Funding, Speakers Bureau. Shah:Novartis: Honoraria, Speakers Bureau; Sobi/Apotex: Honoraria; Celgene Corp: Other: Steering committee; Roche: Other: Advisory board meeting. Neufeld:Celgene Corp.: Consultancy, Other: Steering committee; Acceleron Pharma: Consultancy. Laadem:Celgene: Employment, Equity Ownership. Shetty:Celgene: Employment, Equity Ownership. Zou:Celgene Corporation: Employment, Equity Ownership. Miteva:Celgene Corporation: Employment, Other: grants. Zinger:Celgene Corporation: Employment. Linde:AbbVie: Equity Ownership; Abbott Laboratories: Equity Ownership; Fibrogen: Equity Ownership; Acceleron Pharma: Employment, Equity Ownership. Sherman:Acceleron Pharma: Employment, Equity Ownership. Hermine:AB Science: Consultancy, Equity Ownership, Honoraria, Research Funding; Celgene Corporation: Research Funding; Hybrigenics: Research Funding; Erythec: Research Funding; Novartis: Research Funding. Porter:Cerus: Honoraria; Agios: Honoraria; Novartis: Consultancy. Piga:La Jolla: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bluebird Bio: Honoraria; Apopharma: Honoraria, Research Funding; Celgene Corp: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Acceleron: Research Funding.

show significant differences of primary outcomes between G and TC in any subgroup except for TP53. Patients with identified baseline TP53 mutations did worse on G vs TC while those without identified TP53 mutations had a more favorable outcome on G vs TC. Both treatment arms showed overall similar safety profiles with slightly higher but not significant serious AEs incidence (81% vs 75.5%) and Grade  3 AEs (91.5% vs 87.5%) on G vs TC respectively. There was no difference in AEs leading to death (28.7% for G vs 29.8% for TC). Summary/Conclusion: The trial did not achieve its primary endpoints of statistically significant superiority of G vs TC for CR or OS. However due to the large sample size and narrow 95% CI for OS difference, the trial suggests that G is an active drug with an overall similar efficacy and safety profiles to standard therapy. Potential benefit of G vs TC was observed in patients who were able to receive adequate treatment (>3 cycles), and those who achieved any CR. The significance of TP53 mutations needs to be further explored.

Pregnancy in CML patients (pts) is becoming a reality due to the increase in information from published cases or larger multicentric database (GIMEMA and ELN). Interferon (IFN) has been used during pregnancy, but little is known about the use of tyrosine kinase inhibitors (TKIs), which should be stopped early due to their teratogenic effects. Female pts can ideally plan a pregnancy if they are in a deep, stable, molecular response (DMR=MR≥ 4, ≤0.01%IS) and treatment free remission (TFR) parameters are satisfied. Molecular remission can be maintained throughout the pregnancy, but how to proceed if the remission is rapidly lost, or if the patient is not in DMR, or when CML is discovered during pregnancy? To address these questions, we analyzed more than 300 pregnancies registered through the ELN database. Pts completing pregnancy were grouped as follow: 1) pts diagnosed with CML while pregnant 2) pts in DMR 3) pts with ≤MR3 (≥ 0.1%IS) In 47 patients CML was diagnosed during pregnancy, 21 during the 1st trimester, 15 in the 2nd , and 11 in the 3rd (range 3-38 wk). Sixteen patients were not treated until delivery, 15 were treated with IFN; 19 with Imatinib (IM), 12 in the 2nd trimester (&gt;16 wk), and 7 in the 3rd. Forty-eight children were born (one set of twins). Three were preterm (35-37 wk), and one pregnancy is ongoing. No births defects were observed. Seven newborns had a low birth weight (&lt; 2.5 Kg) 6 of them were exposed to IM at late pregnancy and 3 were preterm. Follow-up was uneventful. The majority of pts achieved ≥ MR3 after starting TKI. Two pts died: 1 in blast crisis (BC) after 9 years, but she was not adherent to treatment; 1 of transplant complication (resistant to&gt;2TKI). Seventy five pts had 80 pregnancies in DMR. Six were in TFR (no therapy) for more than 12 mo, while 8 stopped TKI in order to conceive (2-8 mo before conception). Twenty two pts were treated during pregnancy: 12 with TKI (8 IM, 4 nilotinib, NIL) 1 in the 1st trimester (never stopped IM), 7 in the 2nd and 4 in the 3rd; 10 pts received IFN. Eighty one children were born (6 patients had 2 pregnancies, 1 had twins) with one baby born preterm (wk 35). No births defects were observed and two pregnancies are ongoing. Fifty eight pregnancies were carried without any CML treatment. Twenty six maintained DMR, 28 ≤ MR3 and considered in "treatment free pregnancy" (TFP), and 5 had &gt;10% transcript levels at delivery, considered as high tumor burden (HTB). None of the patients progressed after pregnancy, 4 patients maintained TFR. Four patients did not return to MR3 &lt;12 months after restarting TKI; 3 were switched to a more potent TKI rapidly achieving ≥ MR3, while 1 pt, who did not, is in hematologic remission after 3 years. Pts belonging to ≤MR3 do not satisfy TFR criteria, and were discouraged from starting a pregnancy. However 95 pregnancies (90 pts) were reported; 29 had stopped TKI prior to conception (5 of them had HTB at pregnancy onset). Fifty eight (61%) were treated with IFN (20), TKIs (35), or HU (3). Thirteen patients were treated with IM during 1st trimester (10 throughout the pregnancy). Among the untreated pts, 6 were surprisingly in DMR at delivery, 20 were in TFP, and 11 had HTB. Two babies were born with polydactyly and hypospadias (IFN treatment since 1st trimester), and 2 exhibited a non-closed foramen ovale (IM during 2-3rd trimester) which was considered unlikely to be related to treatment. Four pts progressed in BC and died after pregnancy but all were not compliant to therapy. This is the first, large, multicenter report focusing on treatment during pregnancy. Results suggest that CML patients can pursue a normal life including planning a family, with several caveats. Based on the different situations examined, treatment with IFN is confirmed safe. In contrast TKIs should not be used during pregnancy. Selected TKIs, specifically IM and NIL which have little placental transfer, can be started after organogenesis. Pts at onset can delay therapy without jeopardizing the future CML outcome. If therapy during pregnancy is deemed necessary, IFN can induce and maintain hematologic remission, or, if introduced earlier, preserve molecular remission after TKI interruption, while TKIs can reduce HTB. Caution should be taken when considering stopping TKI prior to conception due to the possibility of losing response, while an early stop (at first positive pregnancy test, 4-5 wk) could be considered. Detailed results, mother and child follow up and practical management will be presented. Disclosures Abruzzese: BMS: Consultancy; Incyte: Consultancy; Novartis: Consultancy; Pfizer: Consultancy. Turkina:Pfizer: Consultancy; Bristol Myers Squibb: Consultancy; Novartis: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; fusion pharma: Consultancy. Apperley:Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Kim:Novartis: Research Funding; BMS: Research Funding; Pfizer: Research Funding; Il-Yang co.: Research Funding; Takeda: Research Funding. Garcia-Gutiérrez:Novartis: Honoraria, Other: Advisory Committees. Mauro:Novartis Oncology: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy; Pfizer: Consultancy; Takeda: Consultancy. Milojkovic:Novartis: Honoraria, Speakers Bureau; Incyte: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; BMS: Honoraria, Speakers Bureau. Moriaghi:novartis: Speakers Bureau; BMB: Speakers Bureau; Takeda: Speakers Bureau. Nicolini:Incyte Biosciences: Honoraria, Research Funding, Speakers Bureau; Novartis: Research Funding, Speakers Bureau; Sun Pharma Ltd: Consultancy. Rea:Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria; Incyte Biosciences: Honoraria. Rousselot:Pfizer: Research Funding; Incyte: Research Funding. Shacham:novartis: Consultancy. Trawinska:Novartis: Consultancy, Honoraria. Chelysheva:Fusion Pharma: Consultancy; Novartis: Consultancy, Honoraria. OffLabel Disclosure: informations on the use of interferon and/or TKIs (imatinib, nilotinib) during pregnancy.

Objective: Mutations of the nucleophosmin (NPM1) gene are considered as the most frequent acute myeloid leukemia (AML)-associated genetic lesion, reported with various incidences in different studies, and type A (NPM1-A) is the most frequent type. However, since most series in the literature report on the features of all patients regardless of the type of mutation, NPM1-A(+) cases have not been well characterized yet. Therefore, we evaluated the prevalence of NPM1-A in Bulgarian AML patients and searched for an association with clinical and laboratory features. Materials and Methods: One hundred and four adults (51 men, 53 women) were included in the study. NPM1-A status was determined using allele-specific reverse-transcription polymerase chain reaction with co-amplification of NPM1-A and β-actin and real-time quantitative TaqMan-based polymerase chain reaction. Patients received conventional induction chemotherapy and were followed for 13.2±16.4 months.Results: NPM1-A was detected in 26 (24.8%) patients. NPM1-A mutation was detected in all AML categories, including in one patient with RUNX1-RUNX1T1. There were no differences associated with the NPM1-A status with respect to age, sex, hemoglobin, platelet counts, percentage of bone marrow blasts, splenomegaly, complete remission rates, and overall survival. NPM1-A(+) patients, compared to NPM1-A(-) patients, were characterized by higher leukocyte counts [(75.4±81.9)x109/L vs. (42.5±65.9)x109/L; p=0.049], higher frequency of normal karyotype [14/18 (77.8%) vs. 26/62 (41.9%); p=0.014], higher frequency of FLT3-ITD [11/26 (42.3%) vs. 8/77 (10.4%); p=0.001], and lower incidence of CD34(+) [6/21 (28.8%) vs. 28/45 (62.2%); p=0.017]. Within the FLT3-ITD(-) group, the median overall survival of NPM1-A(-) patients was 14 months, while NPM1-A(+) patients did not reach the median (p=0.10). Conclusion: The prevalence of NPM1-A mutation in adult Bulgarian AML patients was similar to that reported in other studies. NPM1-A(+) patients were characterized by higher leukocyte counts, higher frequency of normal karyotypes and FLT3-ITD, and lower incidence of CD34(+), supporting the idea that the specific features of type A mutations might contribute to the general clinical and laboratory profile of NPM1(+) AML patients.