MPN-associated Myelofibrosis Research Articles

Ruxolitinib combined with prednisone, thalidomide and danazol in patients with myelofibrosis: Results of a pilot study.

Ruxolitinib is a safe and effective therapy of myeloproliferative neoplasm-associated (MPN) myelofibrosis. However, often there are dose reductions and/or therapy interruptions because of therapy-related adverse events (AEs), especially anemia and thrombocytopenia. We previously reported combined therapy with prednisone, thalidomide and danazol (PTD) reversed anemia and thrombocytopenia in people with MPN-associated myelofibrosis. We wondered whether adding PTD to ruxolitinib might mitigate the hematologic AEs and thereby avoid the dose reduction of ruxolitinib and improve the efficacy. To test this hypothesis, we conducted a baseline hemoglobin and platelet concentration assignment prospective observational study in 72 patients comparing 3-month dose adjustment and efficacy of ruxolitinib with (N=53, the study group) or without (N=19, the control group) PTD. According to the platelet counts, the median daily ruxolitinib doses in the study group increased from 30 to 40mg by week 12, whereas in the control group it remained at 30mg (p=0.019). In the study group 35 patients had a hemoglobin increase ≥10g/L compared with no patient receiving ruxolitinib only (p<0.001). Platelet increases >100×10E+9/L were seen in 56.6% and 5.3% of patients in the two groups, respectively (p<0.001). In patients with anemia and thrombocytopenia, 18 patients in the study group had an anemia response at week 12 and 12 had a platelet increase of ≥50×10E+9/L. No patient in the control group achieved either response (p<0.001 and p=0.078). The study group had a more spleen response than the control group (p=0.046). Peripheral edema and transaminase elevation were the main nonhematologic AEs of PTD. These AEs can be alleviated by adjusting the danazol dose. In conclusion, adding PTD to ruxolitinib improved ruxolitinib-associated anemia and thrombocytopenia, and resulted in a higher ruxolitinib dose.

Final Results of a Phase 2 Study of Sotatercept (ACE-011) for Anemia of MPN-Associated Myelofibrosis

Final Results of a Phase 2 Study of Sotatercept (ACE-011) for Anemia of MPN-Associated Myelofibrosis

Neoplastic Monocyte-Derived Osteoclasts Are Highly Proliferative, but Sub-Functional in MPN-Associated Myelofibrosis

Background: Myeloproliferative neoplasms (MPN) are clonal disorders characterized by the proliferation of myeloid progenitors. A defining hallmark of MPN-associated myelofibrosis (MF) is the deposition of fibrous tissue inside the bone marrow (BM) stroma, arising either as a primary process (PMF), or secondary to the essential thromocythemia (post-ET MF) or polycythemia vera. In at least 1/3 of cases, BM fibrosis is accompanied by the osteosclerotic thickening of the bone trabeculae. It was generally held that these changes are a reaction of mesenchymal cells to the stimuli from the malignant clone. However, the recent discovery of neoplastic monocyte-derived fibrocytes capable of directly inducing BM fibrosis in situ and in vivo has led us to hypothesize that other tissue remodeling cells of the myeloid lineage may play similar roles in the pathogenesis of MPN-associated MF. Osteoclasts (OC) are giant multinuclear cells formed by the fusion of multiple monocytic progenitors. Apart from being exclusively bone-resorbing cells, OCs have a critical role in regulating bone formation by the mesenchymal cell-derived osteoblasts (OB) and maintaining the hematopoietic BM microenvironment. The aim of this study was to examine the status of these cells in MF patients and explore the effects that the neoplastic OC progenitors exert on the development of MPN-associated osteosclerosis.Methods: In order to quantitate bone remodeling cells, trephine biopsies were obtained from patients with PMF (n = 32) and post-ET MF (n = 27), as well as healthy controls (n = 3). A tyramide signal amplification-based fluorescence IHC approach was employed using TRAP and cathepsin K as OC-specific and CD56and osterix as OB-specific markers. In addition, CD14+ low-density peripheral blood cells from the representative MF patients and healthy controls were cultured in the presence of M-CSF and RANKL. After 3 weeks mature OCs were visualized using fluorescently labeled F-actin and TRAP with DAPI as the nuclear counterstain, and the JAK2V617F allele frequency was assessed via RT-PCR. For the OC functional assay, cells were plated on a mineralized surface, which was subsequently stained using a modified von Kossa method. To assess the OC fusion capacity, two populations of progenitors labeled with different lipophilic probes were mixed in a 1:1 ratio and the colocalized signal was quantified for each mature cell. All imaging was conducted using an automated multispectral or a dual spinning disk confocal system.Results: Based on the multiplex BM imaging analysis, we observed a significant increase in the number of OCs in MF patients compared to healthy controls (median: 21.8 vs. 7.0 per 100 mm of bone perimeter; p < 0.0001) that was followed by a substantial increase in the total number of OBs and the density of trabecular bone. After inducing differentiation of JAK2+ monocytes from MF patients into mature TRAP+ OCs in vitro, these cells consistently showed a high mutant allele frequency. Compared to OCs cultured from healthy monocytes, MF patients' OCs exhibited a 40.5% decrease in the median number of nuclei per cell (p= 0.024) and a tendency to incompletely develop F-actin rings. Simultaneously, there was no change in the mean TRAP positivity between the two groups. Finally, MF OCs were significantly less apt at resorbing mineral-coated areas in contrast to healthy cells (median: 21.5% vs. 7.3%; p= 0.016), and there was a 3-fold decrease in the proportion of fused mature OCs from MF monocytes compared to healthy ones (p= 0.008).Conclusions: The development of OCs is highly skewed towards proliferation in both primary and secondary MPN-associated MF. We were able to demonstrate that neoplastic monocytic progenitors retain their aberrant genetic constitution even after differentiating into mature OCs. However, fusion of such progenitors seems to be profoundly impaired, and MF OCs are unable to fully acquire the phenotypical features associated with efficient bone resorption, particularly multinucleation and the development of actin-rich structures. At least to a certain extent, this process happens independently of the non-malignant stroma, although it seems to be impacting the OBs as well. Taken together, we show evidence that even though MF OCs are hyperproliferative, their function is intrinsically supressed due to the inherited neoplastic burden, which in turn contributes to the osteosclerotic dysplasia of the MPN-affected BM. DisclosuresVerstovsek:Blueprint Medicines Corp: Research Funding; Seattle Genetics: Research Funding; Genentech: Research Funding; Incyte: Research Funding; Galena BioPharma: Research Funding; Bristol Myers Squibb: Research Funding; Bristol Myers Squibb: Research Funding; Celgene: Research Funding; Roche: Research Funding; Pfizer: Research Funding; Lilly Oncology: Research Funding; Astrazeneca: Research Funding; Incyte: Research Funding; Promedior: Research Funding; Genentech: Research Funding; Galena BioPharma: Research Funding; Pfizer: Research Funding; Gilead: Research Funding; NS Pharma: Research Funding; Seattle Genetics: Research Funding; Astrazeneca: Research Funding; Lilly Oncology: Research Funding; Roche: Research Funding; CTI BioPharma Corp: Research Funding; NS Pharma: Research Funding; Blueprint Medicines Corp: Research Funding; Gilead: Research Funding; CTI BioPharma Corp: Research Funding; Celgene: Research Funding; Promedior: Research Funding.

Sotatercept (ACE-011) Alone and in Combination with Ruxolitinib in Patients (pts) with Myeloproliferative Neoplasm (MPN)-Associated Myelofibrosis (MF) and Anemia

Sotatercept (ACE-011) Alone and in Combination with Ruxolitinib in Patients (pts) with Myeloproliferative Neoplasm (MPN)-Associated Myelofibrosis (MF) and Anemia

Long Term Outcome of Patients with MPN-Associated Myelofibrosis Treated with Peg-Interferon-α2a, a French Intergroup of Myeloproliferative Neoplasms (FIM) Study

Myeloproliferative neoplasm (MPN)-associated myelofibrosis (MF) can occur as a de novo (Primary MF, PMF), or as secondary MF (SMF) resulting from transformation of Polycythemia Vera or Essential Thrombocythemia. In all cases, altered hematopoiesis results in abnormal blood counts (either hyperproliferation or cytopenias), splenomegaly and general symptoms related to inflammation, all of which are the intended targets of treatments.Unfortunately, few therapeutic options exist and, besides allogeneic stem cell transplantation (ASCT), none is curative. We previously reported that pegylated-interferon-a2a (Peg-Ifn-α2a ) treatment in MF was able to induce significant clinical and hematological responses (1). We now present the long-term follow-up of this prospective cohort and correlations with driver and non-driver mutations.Sixty-two MF patients (pts) treated with Peg-Ifn-α2a were included between 2006 and 2011 in a prospective observational study in 17 centers of the FIM group. Clinical and biological parameters and treatments were collected at Peg-Ifn-α2a initiation, every 3 months during two years and every 6 months thereafter. All 62 pts were genotyped for the 3 major MPN mutations (JAK2V617F, CALR, MPL), and 49 were also screened by next generation sequencing (NGS) for mutations in the whole coding sequence of 25 genes frequently mutated in chronic myeloid disorders.The median age at Peg-Ifn-α2a initiation was 64 and 70.5 years-old, in PMF (n=29) and SMF (n=33) pts, respectively. The median follow-up was 58 months (range: 9-107) after Peg-Ifn-α2a initiation and 69.6 months (range: 10-178) from MF diagnosis. Median Peg-Ifn-α2a treatment duration was 39 months (range: 6-107). At the time of analysis, 30 patients (48.4%) were still alive. The median overall survival (OS) was 7.4 years from MF diagnosis. The Lille and the DIPSS scores clearly differentiated pts in terms of OS, but median OS observed in this cohort was clearly longer than that reported in the reference cohorts used for the establishment of these prognostic scores, especially in higher risk categories: according to the Lille score (8.9 vs. 7.75 yrs for low, 5.42 vs. 2.17 yrs for intermediate and 4.46 vs. 1.08 yrs for high risks) and to the DIPSS score (6.9 vs. 4 yrs for intermediate-2 and 4.58 vs. 1.5 yrs for high-risk pts).The type of driver mutation statistically impacted survival: CALR -mutated pts had 13.5 yrs of median OS compared to 7 yrs for JAK2 -mutated pts (p<0.0001). Forty-five pts (72.6%) discontinued Peg-Ifn-α2a: 25 (55.6%) due to resistance and 20 (44.4%) due to intolerance. Patients developing intolerance to Peg-Ifn-α2a had longer median OS and leukemia-free survival (LFS) than those with resistance (p=10-5 and p=0.048, respectively). The median survival after Peg-Ifn-α2a cessation was 17 months (3-62m), but differed according to the subsequent treatment received: 22 months for those who received ruxolitinib compared to 14 months for those who received another drug (p=0.12) and 10 months for pts who underwent ASCT (p=0.003).Sequential quantification of JAK2V617F allele burden was available in 27 pts, showing a decrease of mutant allele burden of more than 50% in 10/27 pts (37%). Four pts (15%) achieved a reduction over 90% including 3 complete molecular responses. Of the 49 pts analyzed with targeted NGS, 28 (57.1%) carried at least one additional mutation. Patients who harbored at least one non-driver mutation had shorter OS (6.1 vs. not reached, p=0.06) and LFS (not reached both, p=0.026) than those with only driver mutations. The presence of “high molecular risk” mutations previously associated with poorer prognosis (in ASXL1, EZH2, SRSF2, IDH1/2) was not associated with a poorer OS or LFS than other mutations in this series of pts treated with interferon.In conclusion, this large cohort of MF pts treated with Peg-Ifn-α2a demonstrates that a long-term use of this treatment is safe, and is associated with improved OS compared to historical series as well as significant decrease in driver mutation allele burden. The presence of additional mutations remains associated with poorer prognosis. The role of interferon therapy should be discussed in pts with MF, optimal target population possibly being high-risk pts without ASCT project and with a proliferative disease. [Display omitted] DisclosuresIanotto:Novartis: Other: Grant. Laribi:MUNDIPHARMA: Research Funding; NOVARTIS: Honoraria, Research Funding; ROCHE: Research Funding; TEVA: Research Funding; HOSPIRA: Research Funding; AMGEN: Honoraria; TAKEDA: Honoraria, Research Funding. Cony-Makhoul:BMS: Speakers Bureau. Kiladjian:AOP Orphan: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Sotatercept (ACE-011) for Anemia of Myelofibrosis: A Phase 2 Study

Sotatercept (ACE-011) for Anemia of Myelofibrosis: A Phase 2 Study

PB2203 IMPROVEMENT OF THE HEMATOLOGIC TOXICITIES OF RUXOLITINIB IN PATIENTS WITH MPN‐ASSOCIATED MYELOFIBROSIS USING A COMBINATION OF THALIDOMIDE, STANOZOLOL AND PREDNISONE

Background:Anemia and thrombocytopenia are the most frequently reported adverse events of ruxolitinib in patients with MPN‐associated myelofibrosis (MPN‐MF). Although thalidomide, androgens and prednisone have previously demonstrated improvements in myelofibrosis‐associated anemia, it is unclear whether these drugs are effective in patients taking ruxolitinib.Aims:To evaluate the efficacy and tolerability of combination therapy with low dose thalidomide, stanozolol and prednisone (TSP) in patients with IPSS intermediate‐2 or high‐risk myelofibrosis (MF) who received ruxolitinib treatment.Methods:Sixty‐five patients with MPN‐MF who took ruxolitinib were enrolled in this retrospective study, of which 46 patients also took TSP while 19 did not take TSP (TSP and non‐TSP groups).Results:Within the first 24 weeks, the proportion of patients with anemia and platelet count ≥50 × 109/L were 45.7% and 67.4% in the TSP group as compared to 0% and 10.5% in the non‐TSP group (p &lt; 0.001). The mean hemoglobin level in the non‐TSP group reached the nadir after approximately 12–16 weeks of therapy, but gradually increased in the TSP group.Summary/Conclusion:In summary, TSP regime can improve anemia and thrombocytopenia during ruxolitinib treatment in patients with MPN‐MF, and the associated adverse events were manageable.image

Improvement of the hematologic toxicities of ruxolitinib in patients with MPN-associated myelofibrosis using a combination of thalidomide, stanozolol and prednisone

ABSTRACTObjective: Anemia and thrombocytopenia are the most frequently reported adverse events of ruxolitinib in patients with MPN-associated myelofibrosis (MPN-MF). Although thalidomide, androgens and prednisone have previously demonstrated improvements in myelofibrosis-associated anemia, it is unclear whether these drugs are effective in patients taking ruxolitinib.Method: We conducted a retrospective cohort study to evaluate the efficacy and tolerability of combination therapy with low dose thalidomide, stanozolol and prednisone (TSP) in patients with IPSS intermediate-2 or high-risk myelofibrosis (MF) who received ruxolitinib treatment.Results: Sixty-five patients with MPN-MF who took ruxolitinib were enrolled in this retrospective study, of which 46 patients also took TSP while 19 did not take TSP (TSP and non-TSP groups). Within the first 24 weeks, the proportion of patients with anemia response and platelet count increase ≥50 × 109/L were 45.7% and 67.4% in the TSP group as compared to 0% and 10.5% in the non-TSP group (p < 0.001). The mean hemoglobin level in the non-TSP group reached the nadir after approximately 12–16 weeks of therapy, but gradually increased in the TSP group.Conclusion: In summary, TSP regimen can improve anemia and thrombocytopenia during ruxolitinib treatment in patients with MPN-MF, and the associated adverse events were manageable.

Spliceosome Mutations Are Common in MPN-Associated Myelofibrosis with RBC-Transfusion-Dependence and Correlate with Response to Pomalidomide

Spliceosome Mutations Are Common in MPN-Associated Myelofibrosis with RBC-Transfusion-Dependence and Correlate with Response to Pomalidomide

PD-1-Mediated T Cell Exhaustion Is Prevalent Among Patients with MPN-Associated Myelofibrosis Independent of JAK1/2 Inhibition

Background: Primary myelofibrosis (PMF), post-polycythemia vera MF (post-PV MF) and post-essential thrombocythemia MF (post-ET MF) are characterized by expansion of the neoplastic clone and by progressive bone marrow (BM) fibrosis. Like in other hematologic malignancies, in most patients with MF the immune system is significantly deregulated: MF patients' plasma cytokine and chemokine levels are markedly increased and their normal T cell subset distribution is significantly altered. Although treatment with the Janus kinase (JAK)-1/2 inhibitor ruxolitinib significantly decreases cytokine/chemokine levels, reduces spleen size, and improves symptoms and quality of life, it does not reverse BM fibrosis nor does it halt the propagation of the neoplastic clone. The T cell immune checkpoint programmed cell death protein-1 (PD-1) promotes immune tolerance by binding to the tumor's cell surface PD-1 ligand (PD-L1). Whereas the importance of T cell-mediated immune tolerance in MF has been documented and trials evaluating clinical benefits of PD1/PD-L1 checkpoint inhibition are ongoing, little is known about the effect of ruxolitinib on PD-1 expression in T cell subsets. Therefore we systematically analyzed MF patients circulating T cells' surface marker expression prior to and during ruxolitinib treatment.Methods: Peripheral blood cells were obtained from well-characterized PMF, post-PV MF and post-ET MF patients prior to and during the course of treatment with ruxolitinib (n=47) and, as control, from age-matched healthy donors (n=28). The proportion of PD-1-expressing CD4+ and CD8+ cells was assessed using multiparameter flow cytometry. Naïve, central memory, effector memory, and effector T cell subsets were defined based on CD45RO and CD27 cell surface antigen expression.Results: A significantly high number of circulating T cells co-expressing CD4+/PD-1+ and CD8+/PD-1+ was found in MF patients compared to age-matched healthy individuals (5.3±4.1% vs. 3.4±1.7%, P=0.028; 7.1±4.4% vs. 3.8±2.3%, P=0.001). Whereas MF patients' naïve T cells harbored an increased number of cells co-expressing CD8+/PD-1+ (P=0.007), but not CD4+/PD-1+, their T central memory cells had a high proportion of cells co-expressing CD4+/PD-1+ and CD8+/PD-1+ (P<0.001; P<0.001). Similarly, a high proportion of circulating PD-1+ T effector memory cells (P<0.001; P<0.001), and T effector cells (P=0.013; P<0.001) was found in MF patients compared to the same cell subsets in healthy age-matched individuals. The proportions of PD-1+ T cells significantly correlated with LDH level and DIPSS score (CD4+ T cells), monocyte count (CD8+ T cells), and total leukocyte count and spleen size (both subsets). Remarkably, the percentage of PD-1+ cells within naïve and central memory CD8+ T cell populations was significantly higher in MF patients with circulating blasts (P=0.036). To determine the effects of ruxolitinib administration, we performed repeated flow cytometry analyses on MF patients' T cells prior to and during treatment (median duration: 4.3 years). Overall, no significant change in PD-1 expression levels in any of the different T cell subsets was detected over the entire treatment period. However, a significant reduction in percentage of cells co-expressing CD4+/PD-1+ and CD8+/ PD-1+ compared to treatment baseline (4.4±0.4% vs. 7.6±2.0%, P=0.011; 6.3±0.6% vs. 10.4±2.7%, P=0.021) was found in patients whose spleen size was reduced after 6 months of treatment.Conclusions: In patients with MF, circulating T cells express high levels of PD-1. While not restricted to a particular stage of T cell differentiation, the correlation between PD-1-expressing T cells and distinct clinical parameters suggests that increased PD-1 levels might induce immune exhaustion in T cell subsets in different ways. Although ruxolitinib significantly inhibits the JAK1/2 signaling pathway in a variety of hematopoietic cells, thereby lowering cytokine/chemokine levels in almost all MF patients, treatment with ruxolitinib did not affect PD-1 expression nor did it alter its distribution among the T cell subsets. Yet, the proportion of PD-1-expressing CD4+ and CD8+ cells was markedly reduced in patients who experienced a superior response to ruxolitinib as assessed by significant spleen size reduction. How disease burden and MF microenvironment affect PD-1 expression in T cells of patients with MF warrants further investigation. DisclosuresVerstovsek:Incyte: Consultancy; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees; Italfarmaco: Membership on an entity's Board of Directors or advisory committees.

A phase 2, multicenter, open-label study of the safety and efficacy of luspatercept in subjects with myeloproliferative neoplasm (MPN)-associated myelofibrosis and anemia with or without RBC transfusion dependence.

TPS7083Background: Anemia is an important complication of MPN-associated myelofibrosis. There are few effective therapies other than RBC transfusions, and responses to other therapies are typically...

Suppression oF TGF-ß signaling by ALK5 inhibition as treatment for MPN-associated myelofibrosis in mice

Suppression oF TGF-ß signaling by ALK5 inhibition as treatment for MPN-associated myelofibrosis in mice

A randomized study of pomalidomide vs placebo in persons with myeloproliferative neoplasm-associated myelofibrosis and RBC-transfusion dependence.

RBC-transfusion dependence is common in persons with myeloproliferative neoplasm (MPN)-associated myelofibrosis. The objective of this study was to determine the rates of RBC-transfusion independence after therapy with pomalidomide vs placebo in persons with MPN-associated myelofibrosis and RBC-transfusion dependence. Two hundred and fifty-two subjects (intent-to-treat (ITT) population) including 229 subjects confirmed by central review (modified ITT population) were randomly assigned (2:1) to pomalidomide or placebo. Trialists and subjects were blinded to treatment allocation. Primary end point was proportion of subjects achieving RBC-transfusion independence within 6 months. One hundred and fifty-two subjects received pomalidomide and 77 placebo. Response rates were 16% (95% confidence interval (CI), 11, 23%) vs 16% (8, 26%; P=0.87). Response in the pomalidomide cohort was associated with ⩽4 U RBC/28 days (odds ratio (OR)=3.1; 0.9, 11.1), age ⩽65 (OR=2.3; 0.9, 5.5) and type of MPN-associated myelofibrosis (OR=2.6; 0.7, 9.5). Responses in the placebo cohort were associated with ⩽4 U RBC/28 days (OR=8.6; 0.9, 82.3), white blood cell at randomization >25 × 109/l (OR=4.9; 0.8, 28.9) and interval from diagnosis to randomization >2 years (OR=4.9; 1.1, 21.9). Pomalidomide was associated with increased rates of oedema and neutropenia but these adverse effects were manageable. Pomalidomide and placebo had similar RBC-transfusion-independence response rates in persons with MPN-associated RBC-transfusion dependence.

Phase-2 Study of Sotatercept (ACE-011) in Myeloproliferative Neoplasm-Associated Myelofibrosis and Anemia

Introduction: Anemia is common in MPN-associated myelofibrosis (MF), and current therapies (e.g., erythropoiesis stimulating agents, androgens, danazol, immune modulatory drugs and corticosteroids) are unsatisfactory. Furthermore, anemia is not improved and initially worsened by ruxolitinib, an important MF therapy. New drugs with novel mechanisms of action are needed. Sotatercept is a first-in-class activin receptor type IIA (ActRIIA) ligand trap consisting of the extracellular domain of ActIIRA linked to the human IgG1 Fc domain. Sotatercept binds to and sequesters ligands of the transforming growth factor beta (TGF-ß) superfamily, thus relieving their blockade of terminal erythroid differentiation. Pre-clinically, sotatercept corrects ineffective erythropoiesis in ß-thalassemia (Dussiot, M. et al. Nat Med 2014) and its murine ortholog RAP-011 improves erythropoiesis in Diamond Blackfan anemia (Ear, J. et al. Blood 2015). Clinical trials in persons with lower risk myelodysplastic syndromes (Komrokji, R. et al. ASH 2014) and chemotherapy-induced anemia (Raftopoulos, H. et al. Support Care Cancer 2016) have shown promising results.Methods: This is an ongoing phase-2 study of sotatercept, 0.75 or 1 mg/kg subcutaneously every 3 weeks (1 cycle), in subjects with MF, whether primary (PMF) or post-polycythemia vera/essential thrombocythemia (post-PV/ET MF). Subjects must be RBC-transfusion-dependent (Gale, R.P. et al. Leuk Res 2011), have hemoglobin <10 g/dL on every determination during the 84 days preceding study entry without RBC transfusions, or have hemoglobin <10 g/dL despite intermittent RBC transfusions without fulfilling the criteria for transfusion dependence. Primary endpoints include anemia response and safety. Secondary endpoints include time to and duration of anemia response. Anemia response is a composite of RBC-transfusion-independence and hemoglobin response (increase of ≥1.5 g/dL from baseline on every determination consecutively over ≥84 days without RBC transfusions). Subjects must have received ≥5 cycles of sotatercept to be evaluable for response.Results: 18 subjects are enrolled to date. 1 subject received 6 cycles at a sub-therapeutic dose of 0.3 mg/kg and was not considered for efficacy evaluation, but was evaluable for safety. Of the remaining 17 subjects, 11 received 0.75 mg/kg and 6, 1 mg/kg. Median age was 67 years (range, 47-84 years); 10 were male and 7 female. 14 had PMF and 3, post-ET MF. 12 subjects had JAK2V617F, 1 had MPLW515L and 2 had CALR exon 9 mutations. 1 subject was triple negative and 1 subject had no JAK2 or MPL mutation but was not tested for CALR mutations. All 17 subjects had intermediate-2 or high risk disease by the Dynamic International Prognostic Scoring System. Table 1 summarizes baseline variables for these 17 subjects. Median number of cycles of sotatercept received is 5 (range, 1-13).14 of the 17 subjects received ≥5 cycles and were evaluable for response. The 3 other subjects received 1, 2 and 2 cycles and discontinued due to unrelated medical problems, hypertension and stem cell transplant (SCT), respectively. 5 of 14 (36%) evaluable subjects have responded; 4 of whom continue on study in ongoing response. All responders are female and all female subjects evaluable for response responded. Responses occurred across phenotypic driver mutation categories and in both transfusion-dependent (n=3) and -independent (n=2) subjects. 40% and 25% of evaluable patients responded in the 0.75 mg/kg and 1 mg/kg dose cohorts, respectively. Most adverse events (AEs) were grades 1 or 2. The only AEs possibly attributable to sotatercept include grade 3 hypertension leading to discontinuation, and grade 1 myalgia, bone pain, pain in extremity and injection site reaction. 5 subjects remain on study. 12 have discontinued because of no response (5), SCT (2), unrelated medical problems (1), hypertension (1), disease progression (1), transformation to AML (1) and withdrawal of consent (1).Conclusion: Sotatercept improves anemia and RBC-transfusion-dependence in persons with MF and is well-tolerated. Enrollment to the trial is ongoing; updated results will be presented. A separate cohort of subjects receiving ruxolitinib has been added and will also be discussed. Based on the preponderance of responses at the 0.75 mg/kg dose, this dose has been selected for the combination cohort. [Display omitted] DisclosuresDaver:Incyte: Consultancy, Other: Advisory board, Research Funding. Jabbour:ARIAD: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Research Funding; BMS: Consultancy.

A randomized study of pomalidomide vs placebo in persons with myeloproliferative neoplasm-associated myelofibrosis and RBC-transfusion dependence

RBC-transfusion dependence is common in persons with myeloproliferative neoplasm (MPN)-associated myelofibrosis. The objective of this study was to determine the rates of RBC-transfusion independence after therapy with pomalidomide vs placebo in persons with MPN-associated myelofibrosis and RBC-transfusion dependence. Two hundred and fifty-two subjects (intent-to-treat (ITT) population) including 229 subjects confirmed by central review (modified ITT population) were randomly assigned (2:1) to pomalidomide or placebo. Trialists and subjects were blinded to treatment allocation. Primary end point was proportion of subjects achieving RBC-transfusion independence within 6 months. One hundred and fifty-two subjects received pomalidomide and 77 placebo. Response rates were 16% (95% confidence interval (CI), 11, 23%) vs 16% (8, 26%; P=0.87). Response in the pomalidomide cohort was associated with ⩽4 U RBC/28 days (odds ratio (OR)=3.1; 0.9, 11.1), age ⩽65 (OR=2.3; 0.9, 5.5) and type of MPN-associated myelofibrosis (OR=2.6; 0.7, 9.5). Responses in the placebo cohort were associated with ⩽4 U RBC/28 days (OR=8.6; 0.9, 82.3), white blood cell at randomization >25 × 109/l (OR=4.9; 0.8, 28.9) and interval from diagnosis to randomization >2 years (OR=4.9; 1.1, 21.9). Pomalidomide was associated with increased rates of oedema and neutropenia but these adverse effects were manageable. Pomalidomide and placebo had similar RBC-transfusion-independence response rates in persons with MPN-associated RBC-transfusion dependence.

Increased plasma nicotinamide phosphoribosyltransferase is associated with a hyperproliferative phenotype and restrains disease progression in MPN-associated myelofibrosis.

Myeloproliferative neoplasm (MPN)-associated myelofibrosis is a clonal, neoplastic disorder of the hematopoietic stem cells, in which inflammation and immune dysregulation play an important role. Extracellular nicotinamide phosphoribosyltransferase (eNAMPT), also known as visfatin, is a cytokine implicated in a number of inflammatory and neoplastic diseases. Here plasma levels of eNAMPT in patients with MPN-associated myelofibrosis and their effects on disease phenotype and outcomes were examined. The concordance of eNAMPT levels with the marker of general inflammation high-sensitivity C-reactive protein (hs-CRP) was also studied. A total of 333 MPN-associated myelofibrosis patients (187 males and 146 females) and 31 age- and gender-matched normal-weight healthy subjects were enrolled in the study main body. Levels of eNAMPT and hs-CRP were simultaneously assayed in 209 MPN-associated myelofibrosis patients. Twenty-four polycythemia vera or essential thrombocythemia patients were used as controls. eNAMPT was over expressed in MPN-associated myelofibrosis, and eNAMPT expression was correlated with higher white blood cell count, higher hemoglobin, and higher platelet count, suggesting that eNAMPT is an indispensable permissive agent for myeloproliferation of MPN-associated myelofibrosis. The lack of correlation between eNAMPT and hs-CRP revealed that eNAMPT in MPN-associated myelofibrosis does not behave as a canonical inflammatory cytokine. In addition, higher levels of eNAMPT predicted longer time to blast transformation, and protected against progression toward thrombocytopenia and large splenomegaly. In conclusion, in MPN-associated myelofibrosis high levels of eNAMPT mark the myeloproliferative potential and, at variance with a high number of cancers, are protective against disease progression. Am. J. Hematol. 91:709-713, 2016. © 2016 Wiley Periodicals, Inc.

What Is the True Response Rate to Ruxolitinib in Persons with Myeloproliferative Neoplasm (MPN)-Associated Myelofibrosis (MF) Needing Therapy for Splenomegaly ?

Data from COMFORT-I and COMFORT-II trials indicate that the JAK1/JAK2 inhibitor ruxolitinib is effective in reducing splenomegaly and reversing symptoms in patients with MPN-associated MF (Verstovsek S. et al, NEJM 2012;366:799; Harrison C. et al. NEJM 2012;366:787). However, not all subjects in these studies needed therapy for splenomegaly according newly-reported criteria (Barosi et al, Leuk Res 2014;38:155). Moreover, splenomegaly response was defined as 35% reduction in spleen volume by magnetic resonance imaging, which does not always correspond to a clinically relevant response as defined by the IWG-MRT/ELN revised response criteria (Tefferi et al. Blood 2012;122:1395).We evaluated response in 57 subjects with a spleen > 10 cm from the costal margin or with a progressive splenomegaly. Patients had been enrolled in clinical trials, or in individual patient care. The majority of patients were males (32/57, 56.1%), and the median patient age was 57 years (range: 30–81 years). The disease conditions included primary MF in 45 patients (78.9%), post-ET or post- PV MF (12 patients, 21.1%). Genotype was JAK2V617F in 37, 26 with > 50% (45.6%) and 11 (19.3%) with 50% or less allele burden. Fifteen (26.3%) had a CALR mutation, 4 a MPL mutation (7%), and 1 no detectable mutation. Starting dose of ruxolitinib given twice daily was: 20 mg in 32, 15 mg in 22, and 10 mg in 3. Doses were adjusted as appropriate. Median actuarial follow-up was 23.3 months. Thirteen subjects (37%) had a dose-reduction at a median time of 34 days (range 8-510 days). Twenty-eight (49.1%) discontinued therapy at a median of 17. months: 3-month and 1-,2-, and 3-year discontinuation rates were 22%, 40%, 55%, and 67%, respectively. Reasons for therapy-discontinuation were lack of response/progression (N=14), or toxicity/adverse events (N=14).Nineteen subjects (33%) responded according to the IWG-MRT/ELN response criteria at a median time of 3.9 months (range, 12 days - 21 months). However, 7 subsequently lost their response after a median time of 2.3 months (range, 1-35 months). 3-year continuous response rate was 24%.We next estimated failure-free survival (FFS), defined as continuing on ruxolitinib, no start of another therapy for splenomegaly, and/or no disease progression. This composite endpoint is more relevant than the individual components, but its validity after ruxolitinib in MF has not been evaluated. Actuarial FFS was 84% at 3 months, 71% at 6 months, 61% at 12 months, 44% at 2 years, and 36% at 3 years. Subjects with a JAK2V617F allele burden >50%, or with a liver <5 cm="" had="" significantly="" longer="" ffs="" log="" rank="" test="" p=".05," and="" respectively="" multivariate="" analysis="" identified="" jak2v617f="" allele="" burden="">50% as independently associated with FFS. Relative failure risk of subjects with >50% JAK2V617F allele burden was 0.28 (95% CI = 0.12 to 0.66), P=0.003 relative to all other genotypes (Figure). There was no significant association between FFS and age, gender, type of MF, hemoglobin concentration, white blood cells, platelet count, reason for starting therapy, spleen size, CD34+ levels, starting dose, or dose reductions.In conclusion, ruxolitinib produced a 3-year IWG-MRT/ELN response rate of 24% in persons needing therapy for splenomegaly. However, actuarial 3-year FFS was 36%. Patients with JAK2V617F and more than 50% allele burden had significantly better FFS than other genotypes, perhaps reflecting a greater sensitivity to inhibition of JAK1/JAK2 by ruxolitinib. These results may help define which persons with MPN-associated MF and splenomegaly needing therapy are most likely to benefit from ruxolitinib. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Comparison of the Impact of Two Different Definitions of Red-Cell Transfusion Dependence on the Natural History of Myeloproliferative Neoplasm (MPN)-Associated Myelofibrosis (MF)

The current definitions of red-cell transfusion dependence (TD) for MPN-associated MF are based on expert opinion. The optimal definition of TD, and its impact on the natural history of MF is not well studied. We evaluated the impact of two definitions of red-cell TD on the natural history of 306 patients (pts.) with WHO/IWG-MRT-defined primary MF (PMF, n=202, 66%), post-polycythemia vera MF (PPV-MF, n=45, 15%) or post-essential thrombocythemia MF (PET-MF, n=59, 19%).Red-cell TD was defined according to IWG-MRT 2006 criteria (Tefferi et al, Blood, 2006), and on the results of the expert consensus RAND-Delphi panel (Gale et al, Leukemia Research, 2011). The IWG-MRT criteria require patients to have received ≥2 Units (U) packed red blood cells (PRBC) in the preceding 28 days for hemoglobin (Hb) <85 g/l. On the other hand, the more stringent Gale definition requires patients to receive ≥2 U of PRBC per month over 3 months without any specification for the Hb level. Patients were evaluated for disease risk stratification according to dynamic international prognostic scoring system (DIPSS), co-morbidities according to ACE-27, and red-cell TD at their first presentation to Princess Margaret Cancer Center or diagnosis.The study cohort was divided in 4 groups (gp.): Non-transfusion dependent (NTD) pts. with Hb ≥100 g/dl (gp1, n=156, 51%); patients with Hb <100 g/dl, but no transfusion in preceding 12 weeks (gp2, n=65, 21%); pts. qualifying IWG-MRT 2006 criteria of TD, but not qualifying Gale definition (gp3, n=41, 13%); and pts. qualifying the Gale definition of TD (gp4, n=44, 14%). There was no significant difference among the 4 groups with relation to age, disease distribution (primary vs. secondary), cytogenetics, blasts%, and ACE-27 co-morbidity scores. There was significant difference in the gp1, gp2, gp 3, and gp4 in relation to constitutional symptoms (35% vs. 45% vs. 46% vs.64%, p=0.006), median WBC count (x109/L) (11.5 vs. 8.3 vs. 6.8 vs. 6.5, p<0.0001), platelets (x109/l) (317 vs. 154 vs. 124 vs. 127, p<0.0001), and Int-2/high DIPSS (24% vs. 82% vs. 90% vs. 82%, p<0.0001).In a univariate analysis, probability of survival among the 4 groups at 3-years was 80%, 55%, 68%, 30%, respectively (Fig 1, p=0.0016). No difference in leukemic transformation was observed among the 4 groups (p=0.68). In a multivariate analysis, after adjusting for DIPSS and co-morbidity scores, hazard ratios among the gp2, gp3, and gp 4 were 1.58 (95% CI 0.78-3.19, p=0.21), 2.17 (95% CI 0.88-5.34, p=0.09), 2.82 (95% CI 1.29-6.16, p=0.009) in comparison to gp 1 (ref. group). There was no significant difference between NTD patients with Hb <100 vs. TD patients according to IWG-MRT 2006 criteria, but not meeting Gale Criteria (p=0.47). DIPSS was the only other independent prognostic factor for survival.Our study shows the independent prognostic impact of TD on survival defined according to Gale criteria, but not according to previous IWG-MRT 2006 definition, which does not meet Gale criteria. No impact of anemia or TD was observed on leukemic transformation. [Display omitted] DisclosuresSchuh:Celgene: Membership on an entity’s Board of Directors or advisory committees.

Use of the Functional Assessment of Cancer Therapy−Anemia in Persons with Myeloproliferative Neoplasm-Associated Myelofibrosis and Anemia

BackgroundAnemia is common in myeloproliferative neoplasm (MPN)−associated myelofibrosis. The Functional Assessment of Cancer Therapy (FACT) measurement system is a patient-reported outcomes instrument that documents symptoms of the diverse aspects of cancer treatment. One FACT version, FACT-Anemia (FACT-An), documents symptoms of anemia related to cancer. The FACT-An has been validated in diverse cancer populations, but not in MPN-associated myelofibrosis. ObjectiveOur aim was to evaluate the relationship between anemia response to therapy with pomalidomide with or without corticosteroids and patient-reported outcomes using the FACT-An instrument. MethodsData were obtained from a Phase II, randomized, double-blind Bayesian pick-the-winner trial of prednisone and pomalidomide in patients with MPN-associated myelofibrosis and anemia (red blood cell−transfusion dependence). Details of the study, including definitions of anemia, anemia response, red blood cell−transfusion, red blood cell−transfusion dependence, and red blood cell−transfusion independence, are reported. Change in quality of life from randomization to the last cycle of therapy was evaluated using the FACT-An Physical Well Being, Functional Well Being, Trial Outcome Index, and Anemia domains. Clinically important differences were used to determine the smallest difference in scores that patients perceived as beneficial in the FACT-An domains of interest. Patients were classified as meeting clinically important differences for responsiveness if their change score from baseline was >1 SEM, indicating improvement. ResultsEighty-five patients were studied. Thirty-one patients (37%) were classified as anemia responders by prospectively defined criteria. Across all FACT-An domains, anemia responders showed greater improvement in Physical Well Being, Functional Well Being, and Trial Outcome Index scores than did nonresponders. This improvement began at the second 28-day cycle of therapy and was sustained. ConclusionsWe show a correlation between anemia response and improved quality of life measured by the FACT-An instrument in patients with MPN-associated myelofibrosis and anemia.

Pomalidomide In MPN–associated Myelofibrosis With Cytopenia: Results Of The Mpnsg 01-09 Study

BackgroundPomalidomide (POM) in a 1-arm phase-1/-2 study and a randomized 4-arm phase-2 study in MPN-associated myelofibrosis improved anemia. Pomalidomide was evaluated at doses of 0.5 and 2.0 mg/d. AimsTo evaluate efficacy of POM alone at two different doses and combined with prednisolone (PRED) in patients with MPN-associated myelofibrosis and cytopenia (ClinicalTrials.gov No. NCT00949364). MethodsMain inclusion criteria were RBC-transfusion-dependence or hemoglobin <100 g/L and/or platelets <50/nL and/or neutrophils <1/nL. Treatment of the 1st cohort was POM, 2mg/d. PRED, 30mg/d was added in non-responders at 4 months (mo). Treatment of the 2nd cohort was POM, 0.5mg/d. Subjects were randomized to receive PRED, 30 mg/d, starting at 4 or 7 mo in non-responders. The primary endpoint was response assessed by IWG-MRT criteria and RBC-transfusion response (Gale RP et al., Leuk Res. 2011). Patients with proliferative disease could receive concomitant hydroxyurea. Acetylsalicylic acid, 100 mg/d, was given to prevent thrombosis. The study-design used Simon's optimal 2-stage design for the 1st cohort and a one-stage design for the 2nd cohort. Results38 patients were treated in cohort-1 and 58 in cohort-2 (N=27, PRED-mo-4; N=31; PRED-mo-7). Median follow-up was 30 mo in cohort-1 and 10 mo in cohort-2. Median age was 72 y (range, 49-85 y). 34% were female, 72% had primary MF. Disease-stage at study-entry (DIPSS) was high-risk, 24%, intermediate-2 risk, 65% and intermediate-1 risk 12%; JAK2V617Fand MPLW515L were detected in 58% and 6% of patients; 76% of patients were RBC- and 17% platelet-transfusion-dependent. There were no significant differences in pretreatment characteristics between cohort-1 and cohort-2 or between the 2 arms of cohort-2. Median durations of POM treatment were 12, 8, and 4 mo, respectively. PRED was added in cohort-1 and in the PRED-month-4 as well as PRED-month-7 arms of cohort-2 in 50%, 59% and 26% of patients. Response-rates were: 34% (95%-CI, 21-50%), 19% (95%-CI, 8-37%) and 16% (95%-CI, 7-33%), respectively; p=0.086. Responses occurred after 6 mo (range, 1-15 mo), 7 mo (range, 1-12 mo) and 4 mo (range, 3-7 mo). Anemia responses were observed more frequently in cohort-1 (29% [95%-CI, 17-45%]) compared to cohort-2 (14% [95%-CI, 7-25%]; p=0.059). Platelet response in patients with platelets<50/nL were 27% (95%-CI, 10-57%) and 11% (95%-CI, 3-33%; p=0.34). In patients with platelets 50-100/nL, stable platelets>100/nL were achieved in 56% (95%-CI, 27-81%) and 25% (95%-CI, 9-53%; p=0.20). 13 patients (12 high risk) experienced blastic transformation; 4 patients developed solid neoplasms. ConclusionsResponse rate to POM at a dose of 2mg/d was higher compared to 0.5 mg/d. Early addition of PRED at 4 mo compared to 7 mo was associated with longer treatment duration. Disclosures:Schlenk:Novartis: Research Funding; Amgen: Research Funding; Chugai: Research Funding; Pfizer: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Ambit: Honoraria. Off Label Use: Pomalidomide in Myelofibrosis. Reiter:Sanofi: Honoraria. Gattermann:Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Hochhaus:Novartis: Consultancy, Honoraria, Research Funding, Travel Other; BMS: Consultancy, Honoraria, Research Funding; ARIAD: Consultancy, Honoraria; Pfizer: Consultancy. Platzbecker:Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Heidel:Novartis Inc.: Research Funding; Novartis Inc.: Honoraria.