Krisstina L. Gowin

Emerging therapies for the treatment of chronic Philadelphia chromosome-negative myeloproliferative neoplasm-associated myelofibrosis.

Introduction: Chronic Philadelphia chromosome-negative myeloproliferative neoplasm-associated myelofibrosis significantly impacts afflicted patients with cytopenia, splenomegaly, debilitating constitutional symptoms and decreased survival. Approval of the first Janus kinase 2 (JAK2) inhibitor therapy, ruxolitinib, has improved splenomegaly, symptomatic burden, survival and perhaps fibrosis in some treated patients; however, other patients remain symptomatic and are in need of alternate therapeutic strategies. Areas covered: A review of recent literature via PubMed and meeting abstracts has revealed many studies investigating new treatment approaches for chronic Philadelphia chromosome-negative myeloproliferative neoplasms. Multiple additional JAK2 inhibitors (fedratinib, pacritinib and momelotinib) are well into single agent development, as well as multiple combination approaches with ruxolitinib. Efforts to combine JAK2 inhibition with agents to improve cytopenia, marrow fibrosis, additional pathway inhibitors and even allogeneic transplant are planned or ongoing. Additionally, Phase III trials of immunomodulation with pomalidomide are ongoing. Expert opinion: This article discusses investigational therapies for the treatment of Philadelphia chromosome-negative myeloproliferative neoplasms, particularly those in Phase II clinical trials, employing new JAK2 inhibitors, novel multi-agent therapeutic approaches and innovative new drug targets. Additionally, the future era of Philadelphia chromosome-negative myeloproliferative neoplasms is addressed with potentially expanded niches for JAK2 inhibition.

The new landscape of therapy for myelofibrosis

The landscape of therapy for myelofibrosis (MF) is evolving at a pace not previously seen for this clonal myeloproliferative neoplasm. The discovery of the JAK2 V617F mutation in 2005 has led to the rapid development of therapy specifically developed for afflicted MF patients. Indeed, the successful phase III studies of ruxolitinib demonstrating improved symptomatic burden, splenomegaly and survival led to the first approved myelofibrosis drug in the United States and Europe. Multiple additional JAK2 inhibitors are currently in or nearing phase III testing, including SAR302503 (fedratinib), SB1518 (pacritinib) and CYT387 (momelotinib), seeking to offer incremental benefits to ruxolitinib in regards to cytopenias or other disease features. In parallel, phase III testing of pomalidomide is ongoing, with the goal of solidifying the role of immunomodulatory therapy in MF-associated anemia. Multiple single agents strategies are ongoing with histone deacetylase inhibitors, hedgehog inhibitors and hypomethylation agents. Incremental advances are further sought, either in additive or synergistic fashion, from combination strategies of ruxolitinib with multiple different approaches ranging from allogeneic stem cell transplant to current therapies mitigating anemia and further impacting the bone marrow microenvironment or histology. Transitioning from a pre-2011 era devoid of approved MF therapies to one of multiple agents that target not only disease course but symptomatic burden has indeed changed the platform from which MF providers are able to launch individualized treatment plans. In this article, we discuss the diagnostic and therapeutic milestones achieved through MF research and review the emerging pharmacologic agents on the treatment horizon.

Profile of pomalidomide and its potential in the treatment of myelofibrosis

Myelofibrosis, a Philadelphia-negative myeloproliferative neoplasm, is in a new treatment era after the discovery of the JAK2V617F mutation in 2005. JAK inhibitors boast improvements in disease-related symptoms, splenomegaly, and overall survival; however, treatment of myelofibrosis remains a challenge, given the lack of improvement in cytopenias with these agents. Second-generation immunomodulatory agents, such as pomalidomide, have shown efficacy in myelofibrosis-associated anemia within multiple clinical trials. Five major pomalido-mide clinical trials have been completed to date, and demonstrate tolerability and efficacy with low-dose pomalidomide (0.5 mg/day) in the treatment of myelofibrosis, and no clinical benefit of elevated dosing regimens (≥2.5 mg/day). Anemia responses ranged from 17% to 36% as per the International Working Group for Myelofibrosis Research and Treatment consensus guidelines, while improvements in splenomegaly were rare, and observed in <1% of most clinical trials. In comparison with earlier immunomodulatory agents, pomalidomide was associated with an improved toxicity profile, with substantially lower rates of myelosuppression and neuropathy. Given the low overall response rate to pomalidomide as a single agent, combination strategies are of particular interest for future studies. Pomalidomide is currently being tested in combination with ruxolitinib, and other novel combinations are likely on the horizon.

Pegylated interferon alpha – 2a is clinically effective and tolerable in myeloproliferative neoplasm patients treated off clinical trial

Polycythemia vera, essential thrombocytosis, and myelofibrosis are chronic Philadelphia-negative myeloproliferative neoplasms that are characterized by clonal hematopoiesis, splenomegaly, risk of hemorrhagic and thrombotic sequelae, and profound symptom burden. We review the outcomes of 75 myeloproliferative neoplasm patients treated with pegylated interferon alpha 2a off study at an academic medical center. In the 56 treated polycythemia vera and essential thrombocytosis patients, a complete or partial response was obtained in 78.6% of patients per ELN/IWG-MRT revised criteria, with >80% of polycythemia vera patients becoming phlebotomy independent and 60% of essential thrombocytosis patients having platelet normalization with therapy. In the 19 treated myelofibrosis patients, stable disease was seen in 63.2% of patients. Vascular events occurred in 2/75 (2.6%) of treated patients while on therapy. Grade 3 toxicity was uncommon with leukopenia noted in 1 patient (1.3%). The most common adverse event overall was grade 1 fatigue in 18.7%. This retrospective single center analysis demonstrates pegylated interferon alpha 2a is active and well-tolerated therapy outside the support of a clinical trial. These results substantiate the previously reported efficacy of pegylated interferon alpha 2a in myeloproliferative neoplasms. Further prospective and randomized clinical trial data is required to better delineate pegylated interferon alpha 2as use in myeloproliferative disease, with emphasis placed on comprehensive molecular characterization, allelic burden quantification, and measurement of histologic response.

Multicenter phase 2 study of combination therapy with ruxolitinib and danazol in patients with myelofibrosis

Myelofibrosis is a myeloproliferative neoplasm that is characterized by splenomegaly, profound symptom burden, and cytopenias. JAK inhibitor therapy offers improvements in splenomegaly, symptom burden, and potentially survival; however, cytopenias remain a significant challenge. Danazol has previously demonstrated improvements in myelofibrosis-associated anemia. We conducted a phase II clinical trial evaluating the efficacy and tolerability of combination therapy with ruxolitinib, an oral JAK inhibitor, and danazol. Fourteen intermediate or high-risk MF patients were enrolled at 2 institutions. Responses per IWG-MRT criteria were stable disease in 9 patients (64.2%) clinical improvement in 3 (21.4%) all of which were spleen responses, partial response in 1 (7.1%) and progressive disease in 1 (7.1%). Despite limited IWG-MRT response, stabilization of anemia and thrombocytopenia was demonstrated. In JAK inhibitor naïve patients, 4/5 (80%) had stable or increasing hemoglobin. Of the 9 patients on prior JAK inhibitor, 5 patients (55.5%) and 8 patients (88.9%) had stable or increasing hemoglobin or platelet levels, respectively. Adverse events possibly related included grade 3 or greater hematologic toxicity in ten patients (71.4%) and non-hematologic toxicity in two patients (14.3%). Although combination therapy did not lead to increased hematologic response per IWG-MRT criteria, hematologic stabilization was observed and may be clinically useful.

Physical Activity as a Nonpharmacological Symptom Management Approach in Myeloproliferative Neoplasms Recommendations for Future Research

Purpose: Essential thrombocythemia, polycythemia vera, and myelofibrosis are rare chronic hematological malignancies known as myeloproliferative neoplasms (MPNs) and are characterized by deregulated myeloid lineage cell production, splenomegaly, and heterogeneous symptom profiles. MPN patients suffer from a significant symptom burden (eg, fatigue, depressive symptoms, early satiety) and an impaired overall quality of life (QoL). Current treatments typically include pharmacological approaches, which may come with additional side effects and may be limited by treatment-associated toxicities (ie, cytopenias). Nonpharmacological approaches such as physical activity may be beneficial for reducing symptom burden and improving QoL. To date, no studies have examined physical activity as a nonpharmacological approach in MPN patients despite preliminary evidence supporting its benefit in other hematological cancers. The purpose of this article is to (1) review the literature related to physical activity and specific hematological cancer subtypes and to (2) make suggestions for future research involving physical activity in MPN patients as a symptom management strategy. Methods: A brief review of studies examining physical activity in leukemias, lymphomas, and myelomas (excluding stem-cell transplant patients) was conducted. Results: There is preliminary evidence to suggest that physical activity may be an effective approach to improve patient-reported outcomes (fatigue, depression, anxiety, sleep), physical fitness (cardiovascular fitness, balance, body composition), and overall QoL in other hematological cancers. Conclusions: Based on encouraging findings in other hematological cancers, future research should examine the feasibility and effectiveness of physical activity in MPN patients.

Limitations of fibrosis grade as diagnostic criteria for post polycythemia vera and essential thrombocytosis myelofibrosis

BACKGROUND The clinical phenotype of patients with myeloproliferative neoplasms (MPNs) including primary myelofibrosis (PMF), polycythemia vera (PV), and essential thrombocytosis (ET) whom manifest WHO grade 1 marrow fibrosis is poorly defined. Current IWG-MRT criteria require 2+ marrow fibrosis for diagnosis of post PV/ET myelofibrosis (MF). In contrast, the 2008 WHO definition of PMF does not require a minimum fibrosis threshold. METHODS We retrospectively analyzed the clinical characteristics of 91 MPN patients with 1+ marrow fibrosis. We compared the clinical phenotype of sub threshold fibrosis PV/ET with that manifested by PMF. We applied the IWG-MRT criteria for post-PV/ET MF with the fibrosis component omitted and evaluated for percentage of criteria fulfillment. RESULTS When IWG-MRT criteria were applied to the PV/ET group, 38/58 (66%) of patients fulfilled criteria for diagnosis of post-PV/ET myelofibrosis except for the 2+ fibrosis requirement. Comparison of sub threshold fibrotic PV/ET clinical phenotype to PMF revealed similar characteristics including heavy symptomatic burden (57% and 52%), presence of splenomegaly (43% and 55%), leukoerythroblastic blood smear (38% and 45%), and median hemoglobin (12.8g/dL and 11.1g/dL). CONCLUSION MPN progression represents a biological spectrum and definitions of progression in ET/PV may benefit from criteria not restricted by degree of fibrosis.

Management of thrombocythemia

Essential thrombocythemia is a clonal myeloproliferative neoplasm characterized by an elevated platelet count, the potential for both microvascular and macrovascular sequelae, and a risk for transformation to myelofibrosis or acute myeloid leukemia. A systematic and detailed initial analysis is essential for accurate diagnosis of essential thrombocythemia, as many etiologies are reactive and benign. Once a diagnosis has been made, risk stratification and symptom assessment are vital to guide the subsequent therapy. Treatment may be required in high-risk disease, such as in cases of advanced age or prior thrombotic events. Systemic therapy is aimed at reducing the thrombotic risk and includes daily low dose aspirin and in some patients, cytoreductive therapy. Currently, the first line cytoreductive therapy includes hydroxyurea or pegylated interferon, with a phase III clinical trial underway comparing these two important agents. Anagrelide and clinical trials are reserved for refractory or intolerant patients. Looking to the future, new therapies including Janus kinase 2 (JAK2) and telomerase inhibitors are promising and may become valuable to the treatment armamentarium for those afflicted with essential thrombocythemia.

Feasibility study of online yoga for symptom management in patients with myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) including polycythemia vera (PV), essential thrombocythemia (ET), and myelofibrosis (MF) are clonal, progressive, hematological malignancies resulting in the risk of vascular events, splenomegaly, and significant symptom burden, with a high prevalence of fatigue.[

Predictive models for splenic response to JAK-inhibitor therapy in patients with myelofibrosis

Abstract JAK inhibitors for myelofibrosis (MF) reduce spleen size, control constitutional symptoms, and may improve survival. We studied the clinical characteristics of 548 MF patients treated with JAK inhibitors from 2008 to 2016 to better understand predictors of splenic response. Response was defined as a 50% decrease in spleen size at early (3–4 months on therapy) and late (5–12 months) timepoints after therapy initiation. Early response positively correlated with higher doses of JAK inhibitor, baseline spleen size 5–10 cm, and hemoglobin. Early response negatively correlated with baseline spleen size >20 cm and high WBC. The strongest predictor of late response was whether a patient had a response at the earlier timepoint (OR 8.88). Our response models suggest that clinical factors can be used to predict which patients are more likely to respond to JAK inhibitors, and those who do not achieve an early response, i.e. within 3–4 months, should consider alternative treatments.