Assessing efficacy in myelofibrosis treatment: a focus on JAK inhibition

Development of a symptom assessment in patients with myelofibrosis: qualitative study findings

BACKGROUND

The goal of the research reported here was to understand the patient experience of living with myelofibrosis (MF) and establish content validity of the Modified Myeloproliferative Neoplasm Symptom Assessment Diary (MPN-SD).

METHODS

Qualitative interviews were performed in patients with MF, including both concept elicitation and cognitive debriefing. Patients with MF were asked to spontaneously report on their signs, symptoms, and impacts of MF, as well as their understanding of the MPN-SD content, and use of the tool on an electronic platform. A supplementary literature review and meetings with MF experts were also performed.

RESULTS

Twenty-three patients with MF participated in qualitative interviews. Signs and symptoms most commonly reported by ruxolitinib-experienced patients (n = 16) were: fatigue and/or tiredness (n = 16, 100%), shortness of breath (n = 11, 69%), pain below the ribs on the left side and/or stomach pain and/or abdominal pain (n = 9, 56%), and enlarged spleen (n = 9, 56%) and for ruxolitinib-naïve patients (n = 7) were: fatigue and/or tiredness (n = 6, 86%), pain below the ribs on the left side (n = 6, 86%), enlarged spleen (n = 4, 57%), full quickly/filling up quickly (n = 4, 57%), night sweats and/or general sweats (n = 4, 57%), and itching (n = 4, 57%). Patients demonstrated that they were able to read, understand, and provide meaningful responses to the MPN-SD. The final version of the MPN-SD includes the 10 most commonly reported concepts from the MF patient interviews.

CONCLUSIONS

The findings demonstrate the comprehensiveness of the MPN-SD in assessing MF symptoms in both ruxolitinib-experienced and ruxolitinib-naïve patients, while remaining easy for patients to understand and complete.

Myelofibrosis patients in Belgium: disease characteristics

OBJECTIVE

To date, only a small number of epidemiological studies on myelofibrosis have been performed. The current study aimed to characterize the myelofibrosis patient population in Belgium according to pre-defined disease parameters (diagnosis, risk categories, hemoglobin <10 g/dl, spleen size, constitutional symptoms, platelet count, myeloblast count), with a view to obtaining a deeper understanding of the proportion of patients that may benefit from the novel myelofibrosis therapeutic strategies.

METHODS

A survey was used to collect data on prevalence and disease parameters on all myelofibrosis patients seen at each of 18 participating hematologic centers in 2011. Aggregated data from all centers were used for analysis. Analyses were descriptive and quantitative.

RESULTS

A total of 250 patients with myelofibrosis were captured; of these, 136 (54%) were male and 153 (61%) were over 65 years old. One hundred sixty-five (66%) of myelofibrosis patients had primary myelofibrosis and 85 (34%) had secondary myelofibrosis. One hundred ninety-three myelofibrosis patients (77%) had a palpable spleen. About a third of patients (34%) suffered from constitutional symptoms. Two hundred twenty-two (89%) myelofibrosis patients had platelet count ≧50 000/μl and 201 (80%) had platelet count ≧100 000/μl. Of 250 patients, 85 (34%) had a myeloblast count ≧1%. Six (2%) patients had undergone a splenectomy. Thirteen (5·2%) patients had undergone radiotherapy for splenomegaly.

CONCLUSIONS

The results of this survey provide insight into the characteristics of the Belgian myelofibrosis population. They also suggest that a large proportion of these patients could stand to benefit from the therapies currently under development.

MLS-2384, a new 6-bromoindirubin derivative with dual JAK/Src kinase inhibitory activity, suppresses growth of diverse cancer cells

Janus kinase (JAK) and Src kinase are the two major tyrosine kinase families upstream of signal transducer and activator of transcription (STAT). Among the seven STAT family proteins, STAT3 is constitutively activated in many diverse cancers. Upon activation, JAK and Src kinases phosphorylate STAT3, and thereby promote cell growth and survival. MLS-2384 is a novel 6-bromoindirubin derivative with a bromo-group at the 6-position on one indole ring and a hydrophilic group at the 3'-position on the other indole ring. In this study, we investigated the kinase inhibitory activity and anticancer activity of MLS-2384. Our data from in vitro kinase assays, cell viability analyses, western blotting analyses, and animal model studies, demonstrate that MLS-2384 is a dual JAK/Src kinase inhibitor, and suppresses growth of various human cancer cells, such as prostate, breast, skin, ovarian, lung, and liver. Consistent with the inactivation of JAK and Src kinases, phosphorylation of STAT3 was inhibited in a dose-dependent manner in the cancer cells treated with MLS-2384. STAT3 downstream proteins involved in cell proliferation and survival, such as c-Myc and Mcl-1, are downregulated by MLS-2384 in prostate cancer cells, whereas survivin is downregulated in A2058 cells. In these two cancer cell lines, PARP is cleaved, indicating that MLS-2384 induces apoptosis in human melanoma and prostate cancer cells. Importantly, MLS-2384 suppresses tumor growth with low toxicity in a mouse xenograft model of human melanoma. Taken together, MLS-2384 demonstrates dual JAK/Src inhibitory activity and suppresses tumor cell growth both in vitro and in vivo. Our findings support further development of MLS-2384 as a potential small-molecule therapeutic agent that targets JAK, Src, and STAT3 signaling in multiple human cancer cells.