Multicenter evaluation of the addition of eltrombopag to immunosuppressive therapy for adults with severe aplastic anemia

Eltrombopag has been shown to improve response rates when added to standard therapy in adults with severe aplastic anemia in controlled trial settings. However, outcomes in real-world populations have mostly been examined in small retrospective studies. This robust, multicenter, retrospective cohort study across six academic health systems compared outcomes in patients who received immunosuppressive therapy with or without eltrombopag. The study included 82 patients who received front-line therapy from January 2014 to August 2021. Overall response rates at 6 months did not differ significantly for patients receiving eltrombopag versus immunosuppressive therapy alone (58% v. 65%, p = 0.56). However, complete response rates at 6 and 12 months were over two times higher in the eltrombopag arm (29% v. 12%, p = 0.06 and 48% v. 18%, p = 0.005). Rates of hepatotoxicity were similar across both arms. Eltrombopag addition did not impact overall survival (median not reached in either arm at 2 years, p = 0.86) or disease-free survival (median not reached v. 13.3 months at 2 years, p = 0.20). Eltrombopag may not produce as large of a benefit in real-world settings compared to controlled trial settings but may offer patients deeper responses with similar rates of toxicity to immunosuppressive therapy alone.

Outcomes with high dose cytarabine and mitoxantrone induction for adults with mixed phenotype acute leukemia

The optimal induction strategy for mixed phenotype acute leukemia (MPAL) is unknown, though retrospective data has shown improved remission rates and overall survival with acute lymphoblastic leukemia (ALL)-based regimens. At Memorial Sloan Kettering Cancer Center (MSKCC), the most utilized induction regimen for MPAL is high dose cytarabine plus mitoxantrone ("ALL-2"), though outcomes with this regimen are not well described. In this study, outcomes to first-line induction chemotherapy in 24 patients at MSKCC with MPAL classified by 2016 World Health Organization criteria are reported. The overall response rate was 94 % (16 of 17) in patients receiving ALL-2, including 86 % (6 of 7) in patients with extramedullary disease. Thirteen patients who received ALL-2 induction proceeded to allogeneic hematopoietic cell transplant (allo-HCT). The most common toxicity associated with ALL-2 was febrile neutropenia, documented in 12 patients. With a median follow-up of 37 months, median overall survival was not reached in the ALL-2 cohort, and 3-year overall survival was 62 %. In multivariate analysis, age ≥ 60 years and MPAL with isolated extramedullary disease were associated with significantly worse overall survival (P = .009 and P = .01, respectively). These results support further prospective investigation of ALL-2 as a front-line induction regimen for adults with MPAL.

Real-world management of targeted therapies in chronic lymphocytic leukemia

The advent of novel targeted therapies, including B-cell receptor (BCR) pathway and B-cell lymphoma 2 (BCL2) inhibitors, has substantially changed the treatment paradigm for chronic lymphocytic leukemia (CLL). Although targeted therapies have improved outcomes compared to traditional chemoimmunotherapy in the front-line and relapsed or refractory settings, they are associated with resistance mutations and suboptimal outcomes in certain high-risk patients. Additionally, targeted therapies are associated with drug interactions and unique adverse effect profiles which can be challenging for patients and clinicians to manage. Ongoing studies continue to address questions regarding optimal sequencing of therapies, the role of treatment combinations, and the efficacy of next-generation novel agents. This review provides a comprehensive overview regarding the clinical management of targeted therapies for CLL and applies current literature to clinical practice.

Real-world comparison of immune checkpoint inhibitors in non-small cell lung cancer following platinum-based chemotherapy

Purpose

Immunotherapy is a relatively new treatment modality for advanced non-small cell lung cancer following platinum-based chemotherapy. Nivolumab, pembrolizumab, and atezolizumab demonstrated superior outcomes and improved tolerability compared to standard treatment in randomized controlled trials; however, these studies vary significantly in inclusion criteria and study design. To our knowledge, the efficacy and safety of nivolumab and atezolizumab following platinum-based chemotherapy have not been directly compared to one another in a real-world clinic setting.

Methods

We retrospectively compared immunotherapy response rates and toxicity in patients with stage IV or recurrent non-small cell lung cancer following progression during or after platinum-based chemotherapy.

Results

Among 124 eligible patients, the objective response rate was 14.8% in the nivolumab group (n = 81) vs. 13.9% in the atezolizumab group (n = 43) (p = 0.897). Median overall survival was 8.4 months with nivolumab (95% confidence interval (CI), 6.3 to 11.2) vs. 6.5 months with atezolizumab (95% CI, 4.7 to not reached). Median progression free survival was 2.2 months (95% CI, 1.7 to 2.8) and 2.0 months (95% CI, 1.8 to 2.7) in the nivolumab and atezolizumab groups, respectively. Treatment-related adverse events occurred in 70.4% of patients in the nivolumab group and 65.1% in the atezolizumab group.

Conclusions

There was no statistically significant difference in efficacy outcomes in patients with non-small cell lung cancer who received atezolizumab or nivolumab after progression during or after platinum-based chemotherapy. Response rates in this study were numerically lower than response rates observed in the landmark randomized controlled trials leading to approval of immunotherapy in this setting. Rates of treatment-related adverse events were similar between groups.

Different inhibition patterns of tedisamil for fast and slowly inactivating transient outward current in rat ventricular myocytes

Tedisamil has been described as a selective inhibitor of a fast inactivating transient outward current (i(to,f)) in rat ventricular myocytes. Because recent reports demonstrated the existence of a second slowly inactivating transient component (i(to,s)) we investigated i(to,s) and differentiated the effects of tedisamil on both transient outward current components and their influence on action potential duration. Standard electrophysiological techniques were used for whole cell recordings at 24-26 degrees C from enzymatically isolated myocytes. Inhibition of i(to,f) by tedisamil was the result of an acceleration of inactivation at positive test potentials with a concentration for half-maximal inhibition (EC50) of 4-7 micromol/l, which is confirmatory to reports from other investigators. Our new results show that i(to,s) is more sensitive to tedisamil with an EC50 of 0.5 micromol/l. Furthermore the pattern of i(to,s) inhibition is different compared with i(to,f), because inactivation of i(to,s) is not accelerated by tedisamil. Instead the amplitude of the steady state inactivation curve of i(to,s) is attenuated which indicates a reduction of maximally available current. I(to,s) was evaluated by three different methods as time-dependently inactivating current (7.5 s test pulse duration), voltage-dependently inactivated current and tedisamil-sensitive current. All approaches yield similar inactivation curves. The potential for halfmaximal inactivation of i(to,s) lies about 35 mV more negative than that for i(to,f) and the slope factor (K = -23 mV) is different to that of i(to,f) (K = -3 mV). Effectiveness of tedisamil-induced modulation of i(to,f) and i(to,s) on action potential repolarization was tested. Action potentials stimulated at 0.5 Hz were not prolonged by 1 micromol/l tedisamil (dominant i(to,s) block) at a repolarization level of 0 mV but prolonged to about 120% of control at -70 mV. This indicates that i(to,f) was sufficient to guarantee a regular early repolarization whereas decrease of i(to,s) delayed the final repolarization. In conclusion, the observation that tedisamil inhibits i(to,f) and i(to,s) differently supports the hypothesis that the two i(to)-components are related to two different channel populations expressed in rat ventricular myocytes.

Effects of 17beta-estradiol on action potentials and ionic currents in male rat ventricular myocytes

This study describes electrophysiological effects of estrogens in isolated male rat ventricular myocytes. According to the literature these cells do not express the nuclear estrogen receptor. Action potentials or membrane currents were recorded in the whole-cell configuration with standard techniques. Action potential durations (APD) measured at a level of 0 mV (APD 0) and -70 mV (APD -70) were prolonged by 17beta-estradiol (0.5 Hz stimulation frequency, 24-26 degrees C). Threshold concentration was 1 micromol/l. At the highest concentration used (30 micromol/l) no saturation of the response was reached and APD 0 was 162% and APD -70 was 230% of the respective control. The resting potential remained unaffected in most cells. The prolongation induced by 17beta-estradiol developed fast and reached a steady state 10 min after start of hormone superfusion. Effects of estrogen were completely reversible during 10-15 min wash-out with hormone-free solution. The extent of prolongation (10 micromol/l 17beta-estradiol) was frequency dependent. Expressed as percentage of the respective control APD 0 (or APD -70) was 115% (188%) at 0.05 Hz, 118% (163%) at 0.5 Hz and 99% (129%) at 5 Hz stimulation frequency. The response was stereoselective, because 30 micromol/l 17alpha-estradiol did not prolong action potentials (APD 0: 101%, APD -70: 104% of the respective control, 0.5 Hz stimulation frequency). The endogenous estrogens estrone and estriol were less effective than 17beta-estradiol. With 30 micromol/l estrone (0.5 Hz stimulation frequency) APD 0 was 103% and ADP-70 148% of control and with 30 micromol/l estriol APD 0 was 135% and APD -70 137% of control. The prolongation of action potentials can be explained by inhibition of transient outward current which, in rat ventricle, is composed of fast (i[to,f]) and slowly (i[to,s]) inactivating components. At 30 micromol/l 17beta-estradiol i(to,f) was reduced to 50% and i(to,s) to 43% of their maximal amplitudes. The voltage sensor of i(to,f) or i(to,s) was hardly affected. Additionally, 17beta-estradiol decreased the calcium current (i[Ca,L]) to 76% (10 micromol/l) and 38% at 30 micromol/l. The inwardly rectifying potassium current (i[K1]) was reduced partly with 30 micromol/l 17beta-estradiol and its amplitude was 72% of control at -90 mV (inward current flow) and 65% at -40 mV (outward current flow). These results show that 17beta-estradiol is active in cardiac cells which do not express the nuclear estrogen receptor. The hormone exerts class III activity and reduces calcium inward current. These effects, however, occur in vitro with concentrations above the physiological level and therefore may be without significance in vivo.

Inhibition of pacemaker current by the bradycardic agent ZD 7288 is lost use-dependently in sheep cardiac Purkinje fibres

The inhibition of the pacemaker current (if) in sheep cardiac Purkinje fibers by ZD 7288 [4-(N-ethyl-N-phenylamino)-1,2-dimethyl-6-(methylamino)pyrimidinium++ + chloride] is lost use-dependently. This disinhibition of if was investigated by using the two-microelectrode voltage-clamp technique. The pulse protocol consisted of a rest period (holding potential of about -50 mV, 1-10 micromol/l ZD 7288) followed by a train of test pulses (potential negative to -100 mV, stimulation frequency 0.05 Hz). At the beginning of the first test pulse there was an immediate reduction of if but inhibition was lost during continued stimulation. Activation of if is sigmoidal and the early delay in current activation was prolonged from 33 ms (no ZD 7288) to 424 ms (10 micromol/l ZD 7288). Therefore hardly any disinhibition occurred during short test pulses (0.5s). During longer test pulses (5 s, -120 mV, 10 micromol/l) disinhibition developed with a time constant of about 2 s. The inhibition of if by ZD 7288 was lost voltage-dependently. With 10 micro mol/l ZD 7288 the half-maximal disinhibition occurred at -92 mV and the slope factor of the disinhibition/voltage curve (Boltzmann relation) was 4.8 mV. The voltage-dependent disinhibition could be abolished largely by extracellular application of protease (0.5 mg/ml, 7 min). After prior disinhibition, reinhibition at the holding potential (about -50 mV) followed a bi-exponential time course indicating that inhibition may be produced by a fast (tau=0.7 min) and a slow component (tau=20-30 min). Increasing ZD 7288 concentration from 1 to 10 mu mol/l accelerated reinhibition, mainly by an increase of the amplitude (A) of the fast component. The ratio Afast/Aslow was 0.399 at 1 micromol/l and 2.65 at 10 micromol/l ZD 7288. The reinhibition of if was unchanged by shifting the holding potential from -50 mV to -20 mV. Trials to wash out the effects of 10 micromol/l ZD 7288 gave two results. The inhibition of if was slightly reversed after a wash-out of 1.5 h with drug-free solution. A second effect of the drug, the fast reinhibition, could be completely removed by wash-out. In summary if is inhibited by ZD 7288 at membrane potentials at which the virtual if gate is closed. Disinhibition occurs during long-lasting hyperpolarization but will hardly be operative in unclamped fibres under physiological conditions.