Effect of Romiplostim in Patients (pts) with Low or Intermediate Risk Myelodysplastic Syndrome (MDS) Receiving Azacytidine

Abstract

Romiplostim is an investigational Fc-peptide fusion protein (peptibody) that stimulates platelet production by a mechanism similar to endogenous thrombopoietin. MDS pts receiving hypomethylating agents such as azacytidine frequently develop clinically significant thrombocytopenia. This is an ongoing phase 2 multicenter, randomized, double-blind, placebo-controlled study evaluating the effect of romiplostim on the incidence of clinically significant thrombocytopenia in pts with low or intermediate risk MDS receiving azacytidine. Eligible pts were randomized (stratified by baseline [BL] platelet count [≥ or <50 × 109/L]) 1:1:1 to 3 treatment groups to receive placebo or romiplostim at 500μg or 750μg weekly, by subcutaneous (s.c.) injection. All pts received 4 cycles of azacytidine 75mg/m2/day by s.c. injection for the 1st 7 days of each 28-day treatment cycle. The primary endpoint was the incidence of clinically significant thrombocytopenic events, defined as platelet counts <50 × 109/L after Week 3 of treatment or receipt of platelet transfusions (txns) at any time during the treatment period. Secondary endpoints included the incidence of platelet txns and platelet nadir during azacytidine treatment cycles. Safety of romiplostim in combination with azacytidine was evaluated. Forty pts were randomized and treated. The 3 groups were balanced for the stratification factor, but some MDS disease characteristics were imbalanced including IPSS score >1 (54%, placebo vs 23% and 29% romiplostim 500μg and 750μg). Results presented are from a planned interim analysis after all pts had completed or withdrawn from the treatment period. Overall pt incidence of clinically significant thrombocytopenic events was 85%, 62% and 71% for the placebo, romiplostim 500μg and 750μg groups, respectively. In a summary by azacytidine treatment cycle, the pt incidence of thrombocytopenic events per cycle was higher in the placebo group (50%–85% of pts) than in the romiplostim 500μg (44%–69% of pts) and 750μg (18%–64% of pts) groups, respectively. The pt incidence of platelet txns was 69% for placebo vs 46% and 36% for romiplostim 500μg and 750μg groups. Platelet counts on the 1st day of each azacytidine cycle and at the nadir of each 28-day cycle (Table) were lower in the placebo than the romiplostim groups. All pts (100%) had ≥1 adverse event (AE). Serious AEs (SAEs) were observed in 77%, 46%, and 71% of placebo, romiplostim 500μg and 750μg groups, respectively. Two pts in the romiplostim groups experienced ≥1 treatment-related SAE (1 arthralgia, romiplostim 500μg; 1 rash and hypersensitivity, romiplostim 750μg). Two pts in the placebo group had grade 3 or above bleeding events (1 pulmonary hemorrhage and 1 hemorrhage) vs 1 pt in the romiplostim 500μg group (epistaxis) and none in the romiplostim 750μg group. Two pts died in the placebo group (1 fungal pneumonia, 1 pulmonary hemorrhage) vs none in the romiplostim groups. One case of disease progression from MDS to AML was observed in the 500μg group. In summary, romiplostim reduced pt incidence of clinically significant thrombocytopenic events and platelet txns, and improved platelet nadir in MDS pts receiving azacytidine in this study. These findings are consistent with increased platelet counts over time. Romiplostim in combination with azacytidine appears to be well tolerated in this pt population. Azacytidine Treatment Cycle Placebo (N=13) 500μg Romiplostim (N=13) 750μg Romiplostim (N=14) n Cycle BLa Platelet nadirb N Cycle BLa Platelet nadirb n Cycle BLa Platelet nadirb aMedian of platelet count (×109/L) on 1st day of each azacytidine treatment cycle bMedian of lowest platelet count (×109/L) during each azacytidine treatment cycle BL = baseline 1 13 25 14 13 40 33 14 37 32 2 11 48 16 10 121 63 13 115 53 3 11 54 33 10 73 43 11 222 116 4 10 88 40 9 60 53 10 315 91

Alternative agents to prophylactic platelet transfusion for preventing bleeding in people with thrombocytopenia due to chronic bone marrow failure: a meta-analysis and systematic review

“…Seven trials that were excluded for being in the wrong participant group (Archimbaud 1999; Geissler 2003; Han 2015; Higby 1974; Miao 2012; Moskowitz 2007; Schiffer 2000) were included in a separate review assessing alternatives, and adjuncts, to prophylactic platelet transfusion for people with haematological malignancies undergoing intensive chemotherapy or stem cell transplantation (Desborough 2016b). In total, seven studies in 25 references were deemed eligible for inclusion (Fricke 1991; Giagounidis 2014; Greenberg 2013; Kantarjian 2010; Mannucci 1986; Platzbecker 2015; Wang 2012). The four ongoing trials are expected to be reported (EudraCT 2010-022890-33; EudraCT 2014-000174-19; NCT02099747; NCT02158936).…”

“…Seven trials were published as full-text articles (published in 25 papers) between 1986 and 2015 (Fricke 1991; Giagounidis 2014; Greenberg 2013; Kantarjian 2010; Mannucci 1986; Platzbecker 2015; Wang 2012). All seven were published in English.…”

Development of thrombopoietin receptor agonists for clinical use

“…Recently, Kantarjian et al. reported the results of a phase 2 trial for romiplostim in patients with low‐ and intermediate‐risk MDS receiving azacytidine [35]. Interim analysis indicated that romiplostim decreased the incidence of platelet transfusions and thrombocytopenic events compared with placebo [35].…”

Treatment of MDS: something old, something new, something borrowed…

“…Now, at the time of publication, three drugs-azacitidine, lenalidomide, and decitabine [1][2][3] -are approved by the U.S. Food and Drug Administration (FDA) specifically for MDSrelated indications, along with at least five hematopoietic growth factors that can potentially be used for patients with MDS: epoetin, darbepoetin, filgrastim, sargramostim, and pegfilgrastim. While the thrombopoietin agonists romiplostim and eltrombopag have activity in MDS, 4,5 their use is currently restricted to patients with immune thrombocytopenia. Other active therapies used off-label for treating MDS include cytotoxic agents (such as cytarabine and clofarabine) and those with immune-modulating mechanisms of action (such as thalidomide and antithymocyte globulin).…”

“…Current and future iterations of lenalidomide-based studies are exploring combination therapy with ESAs, TPO agonists, and DNA methyltransferase inhibitors and use of the drug in higherrisk populations of MDS and AML patients. 5,39 DNA methyltransferase inhibitors themselves are being combined with a panoply of agents, ranging from growth factors and histone deacetylase inhibitors, which maximize chromatin remodeling (particularly in an Eastern Cooperative Oncology Group trial), 40 to gemtuzumab ozogamicin, in a Southwest Oncology Group trial. Most importantly, future survival studies will become de rigeur, as azacitidine has set the bar for measurement of "hard" outcomes in MDS.…”