Inhibition of c-Kit signaling is associated with reduced heat and cold pain sensitivity in humans

The tyrosine kinase receptor c-Kit is critically involved in the modulation of nociceptive sensitivity in mice. Ablation of the c-Kit gene results in hyposensitivity to thermal pain, while c-Kit activation produces hypersensitivity to the noxious heat, without altering sensitivity to innocuous mechanical stimuli. In this study we investigated the role of c-Kit signalling in human pain perception. We hypothesized that subjects treated with Imatinib or Nilotinib, potent inhibitors of tyrosine kinases including c-Kit, but also Abl1, PDFGFR{alpha}, and PDFGFR{beta}, that are used to treat chronic myeloid leukemia (CML), would experience changes in thermal pain sensitivity. We examined 31 asymptomatic CML patients (14 male, 17 female) under Imatinib/Nilotinib treatment and compared them to 39 age- and sex-matched healthy controls (12 male, 27 female). We used cutaneous heat and cold stimulation to test normal and noxious thermal sensitivity, and a grating orientation task to assess tactile acuity. Thermal pain thresholds were significantly increased in the Imatinib/Nilotinib-treated group, while innocuous thermal and tactile thresholds were unchanged compared to the control group. In conclusion, our findings suggest that the biological effects of c-Kit inhibition are comparable in mice and humans in that c-Kit activity is required to regulate thermal pain sensitivity, but does not affect innocuous thermal and mechanical sensation. The effect on experimental heat pain observed in our study is comparable to that of several common analgesics, thus modulation of the c-Kit pathway can be used to specifically modulate noxious heat and cold sensitivity in humans

The recurrent atypical e8a2 BCR::ABL1 transcript with insertion of an inverted 55 base pair ABL1 intron 1b sequence: a detailed molecular analysis

Atypical BCR::ABL1 transcripts are found in approximately 2% of cases of chronic myeloid leukemia. It is important to detect them, since affected patients benefit from tyrosine kinase inhibitor therapy, similar to patients with typical BCR::ABL1 variants. In the rare e8a2 atypical BCR::ABL1 transcript two out-of-frame exons are fused, thus, interposed nucleotides are usually found at the fusion site to restore the reading frame. In approximately half of previously reported e8a2 BCR::ABL1 cases an inserted 55 bp sequence homologous to an inverted sequence from ABL1 intron 1b was detected. The generation of this recurrent transcript variant is not obvious. This work describes the molecular analysis of such an e8a2 BCR::ABL1 translocation from a CML patient. The genomic chromosomal breakpoint is identified, and the formation of this transcript variant is theoretically explained. The clinical course of the patient is reported, and recommendations are provided for the molecular analysis of future e8a2 BCR::ABL1 cases

Impact of early remission by induction therapy on allogeneic stem cell transplantation for acute myeloid leukemia with an intermediate risk karyotype in first complete remission

For patients with acute myeloid leukemia (AML) early achievement of remission during induction treatment is an important predictor for long-term outcome irrespective of the type of consolidation therapy employed. Here, we retrospectively examined the prognostic impact of early remission (ER) versus delayed remission (DR) in a cohort of 132 AML patients with an intermediate risk karyotype undergoing allogeneic stem cell transplantation (alloSCT) in first complete remission (CR1). In contrast to patients showing DR, patients achieving ER had a significantly higher 3-year overall survival (OS) and disease-free survival (DFS) of 76% versus 54% (p=0.03) and 76% versus 53% (p=0.03). Likewise, three years after alloSCT the cumulative incidence of relapse (CI-R) was significantly lower in the ER subgroup as compared to patients achieving DR, i.e. 10% versus 35% (p=0.004), whereas non-relapse mortality (NRM) did not differ significantly. Multivariate analysis identified DR as an independent prognosticator for an inferior DFS (HR 3.37, p=0.002) and a higher CI-R (HR 3.55, p=0.002). Taken together, these data may indicate that the rapid achievement of remission predicts a favorable outcome in patients with intermediate risk AML undergoing alloSCT in CR1. In turn, the adverse effect of DR may not be fully overcome by alloSCT

Thyroid dysfunction caused by second-generation tyrosine kinase inhibitors in Philadelphia chromosome-positive chronic myeloid leukemia

BACKGROUND: Thyroid dysfunction is a well-known adverse effect of first-generation tyrosine kinase inhibitors (TKIs), like sunitinib. The aim of this study was to investigate the effect of second-generation TKIs on thyroid function. METHODS: We retrospectively assessed the effect of the first-generation TKI imatinib and the second-generation TKI nilotinib and dasatinib on thyroid function tests in 73 Philadelphia chromosome-positive (Ph-positive) chronic myeloid leukemia patients. RESULTS: Overall, 33 of 73 (45%) had one or more thyroid function test abnormalities during follow-up. Hypothyroidism or hyperthyroidism were found in 18 of 73 (25%) and 21 of 73 (29%) cases after a median of 6 and 22 weeks, respectively. In most patients (29 of 39, 74%) thyroid dysfunction was transient without clinical symptoms. Therapy of hypo-/hyperthyroidism was required in three patients. Thyroid dysfunction never resulted in the discontinuation of TKI therapy. Under treatment with imatinib, nilotinib, and dasatinib, thyroid abnormalities were detected in 25%, 55%, and 70%, respectively. Four of 55 patients (7%) treated with nilotinib had evidence for an autoimmune thyroiditis (antibody positive in 3 of 4 patients) with an episode of hyperthyroidism preceding hypothyroidism. CONCLUSIONS: Thyroid dysfunction is a common adverse event with second-generation TKI therapy in patients with Ph-positive chronic myeloid leukemia. Although the mechanism is still unclear, the high frequency of thyroid abnormalities, including autoimmune thyroiditis, warrants regular and long-term monitoring of thyroid function in these patients

Long-term observation of the frequency of secondary colorectal cancer and other malignancies in tyrosine kinase inhibitor treated chronic myeloid leukemia patients and controls

In this analysis, we examined the risk of secondary malignancies for tyrosine kinase inhibitor (TKI) therapy in chronic myeloid leukemia (CML) patients. We also collected data on specific risk factors for colorectal cancer. Ninety-one patients with CML and 76 controls were included and in total 4 (4.4%) secondary malignancies were found in patients and 8 (10.5%) in controls. The risk for secondary malignancies was not significantly elevated for CML patients (p = 0.141). Two (2.2%) CML patients developed colorectal cancer compared to 4 (5.3%) in the reference group. A higher risk for CML patients for colorectal cancer could not be found (p = 0.414)

The Alternating Access Transport Mechanism in LacY

Lactose permease of Escherichia coli (LacY) is highly dynamic, and sugar binding causes closing of a large inward-facing cavity with opening of a wide outward-facing hydrophilic cavity. Therefore, lactose/H+ symport via LacY very likely involves a global conformational change that allows alternating access of single sugar- and H+-binding sites to either side of the membrane. Here, in honor of Stephan H. White’s seventieth birthday, we review in camera the various biochemical/biophysical approaches that provide experimental evidence for the alternating access mechanism

Moxetumomab pasudotox in heavily pre-treated patients with relapsed/refractory hairy cell leukemia (HCL): long-term follow-up from the pivotal trial

Background: Moxetumomab pasudotox is a recombinant CD22-targeting immunotoxin. Here, we present the long-term follow-up analysis of the pivotal, multicenter, open-label trial (NCT01829711) of moxetumomab pasudotox in patients with relapsed/refractory (R/R) hairy cell leukemia (HCL). Methods: Eligible patients had received ≥ 2 prior systemic therapies, including ≥ 2 purine nucleoside analogs (PNAs), or ≥ 1 PNA followed by rituximab or a BRAF inhibitor. Patients received 40 µg/kg moxetumomab pasudotox intravenously on Days 1, 3, and 5 of each 28-day cycle for up to six cycles. Disease response and minimal residual disease (MRD) status were determined by blinded independent central review. The primary endpoint was durable complete response (CR), defined as achieving CR with hematologic remission (HR, blood counts for CR) lasting > 180 days. Results: Eighty adult patients were treated with moxetumomab pasudotox and 63% completed six cycles. Patients had received a median of three lines of prior systemic therapy; 49% were PNA-refractory, and 38% were unfit for PNA retreatment. At a median follow-up of 24.6 months, the durable CR rate (CR with HR > 180 days) was 36% (29 patients; 95% confidence interval: 26–48%); CR with HR ≥ 360 days was 33%, and overall CR was 41%. Twenty-seven complete responders (82%) were MRD-negative (34% of all patients). CR lasting ≥ 60 months was 61%, and the median progression-free survival without the loss of HR was 71.7 months. Hemolytic uremic and capillary leak syndromes were each reported in ≤ 10% of patients, and ≤ 5% had grade 3–4 events; these events were generally reversible. No treatment-related deaths were reported. Conclusions: Moxetumomab pasudotox resulted in a high rate of durable responses and MRD negativity in heavily pre-treated patients with HCL, with a manageable safety profile. Thus, it represents a new and viable treatment option for patients with R/R HCL, who currently lack adequate therapy. Trial registration: ClinicalTrials.gov identifier: NCT01829711; first submitted: April 9, 2013. https://clinicaltrials.gov/ct2/show/NCT0182971