Eliminating chronic myeloid leukemia stem cells by IRAK1/4 inhibitors

Leukemia stem cells (LSCs) in chronic myeloid leukemia (CML) are quiescent, insensitive to BCR-ABL1 tyrosine kinase inhibitors (TKIs) and responsible for CML relapse. Therefore, eradicating quiescent CML LSCs is a major goal in CML therapy. Here, using a G0 marker (G0M), we narrow down CML LSCs as G0M- and CD27- double positive cells among the conventional CML LSCs. Whole transcriptome analysis reveals NF-κB activation via inflammatory signals in imatinib-insensitive quiescent CML LSCs. Blocking NF-κB signals by inhibitors of interleukin-1 receptor-associated kinase 1/4 (IRAK1/4 inhibitors) together with imatinib eliminates mouse and human CML LSCs. Intriguingly, IRAK1/4 inhibitors attenuate PD-L1 expression on CML LSCs, and blocking PD-L1 together with imatinib also effectively eliminates CML LSCs in the presence of T cell immunity. Thus, IRAK1/4 inhibitors can eliminate CML LSCs through inhibiting NF-κB activity and reducing PD-L1 expression. Collectively, the combination of TKIs and IRAK1/4 inhibitors is an attractive strategy to achieve a radical cure of CML.

Active Pharmacovigilance for Primaquine Radical Cure of Plasmodium vivax Malaria in Odisha, India

Plasmodium vivax malaria elimination requires radical cure with chloroquine/primaquine. However, primaquine causes hemolysis in glucose-6-phosphate dehydrogenase-deficient (G6PDd) individuals. Between February 2016 and July 2017 in Odisha State, India, a prospective, observational, active pharmacovigilance study assessed the hematologic safety of directly observed 25 mg/kg chloroquine over 3 days plus primaquine 0.25 mg/kg/day for 14 days in 100 P. vivax patients (≥ 1 year old) with hemoglobin (Hb) ≥ 7 g/dL. Pretreatment G6PDd screening was not done, but patients were advised on hemolysis signs and symptoms using a visual aid. For evaluable patients, the mean absolute change in Hb between day 0 and day 7 was −0.62 g/dL (95% confidence interval [CI]: −0.93, −0.31) for males (N = 53) versus −0.24 g/dL (95%CI: −0.59, 0.10) for females (N = 45; P = 0.034). Hemoglobin declines ≥ 3 g/dL occurred in 5/99 (5.1%) patients (three males, two females); none had concurrent clinical symptoms of hemolysis. Based on G6PD qualitative testing after study completion, three had a G6PD-normal phenotype, one female was confirmed by genotyping as G6PDd heterozygous, and one male had an unknown phenotype. A G6PDd prevalence survey was conducted between August 2017 and March 2018 in the same region using qualitative G6PD testing, confirmed by genotyping. G6PDd prevalence was 12.0% (14/117) in tribal versus 3.1% (16/509) in nontribal populations, with G6PD Orissa identified in 29/30 (96.7%) of G6PDd samples. Following chloroquine/primaquine, notable Hb declines were observed in this population that were not recognized by patients based on clinical signs and symptoms.

Effects of Host Genetic Polymorphisms on the Efficacy of the Radical Cure Malaria Drug Primaquine

Malaria is a major cause of death in low-income countries. Malaria relapses are caused by Plasmodium vivax–induced latent liver stage hypnozoites, and relapses contribute significantly to the total disease burden. The goal of malaria elimination is threatened in countries where P. vivax is endemic and relapses remain a key aspect of concern. Targeting of the hypnozoites is crucial for radical cure and this is achieved by primaquine (PQ). In addition to its anti-hypnozoite effects, PQ also possesses gametocidal activity against all malaria causing Plasmodium species and is hence a useful tool to curtail malaria transmission. It is well known that host glucose-6-phosphate dehydrogenase (G6PD) deficiency is associated with hemolysis after treatment with PQ. Multiple other host polymorphisms impact on PQ metabolism, potentially affecting drug efficacy. Being a prodrug, PQ requires host factors cytochrome P450 2D6 (CYP2D6), cytochrome P450 NADPH: oxidoreductase (CPR) and monoamine oxidase (MAO) for its metabolism and conversion to active form. The efficacy of PQ in the host is therefore dependent on genetic polymorphisms of these three host genes. The efficacy of PQ is important for clearing reservoirs of P. vivax infection. Here, we have analyzed the known spectrum of genetic polymorphisms for host genes that enable PQ metabolism. It is vital to delineate the polymorphisms that determine the ultimate efficacy of PQ for formulating better malaria elimination strategies in countries with severe malaria burden. Thus population-based studies of these gene variants will provide new insights into the role of host genetics on PQ treatment outcomes.

Measurements of 5,6 orthoquinone, surrogate for presumed active primaquine metabolite 5-hydroxyprimaquine, in the urine of Cambodian adults

The active metabolites of primaquine, in particular 5-hydroxyprimaquine, likely responsible for clearance of dormant hypnozoites, are produced through the hepatic CYP450 2D6 (CYP2D6) enzymatic pathway. With the inherent instability of 5-hydroxyprimaquine, a stable surrogate, 5,6 orthoquinone, can now be detected and measured in the urine as part of primaquine pharmacokinetic studies. This study performed CYP450 2D6 genotyping and primaquine pharmacokinetic testing, to include urine 5,6 orthoquinone, in 27 healthy adult Cambodians, as a preliminary step to prepare for future clinical studies assessing primaquine efficacy for Plasmodium vivax infections. The CYP2D6 *10 reduced activity allele was found in 57% of volunteers, and the CYP2D6 genotypes were dominated by *1/*10 (33%) and *10/*10 (30%). Predicted phenotypes were evenly split between Normal Metabolizer (NM) and Intermediate Metabolizer (IM) except one volunteer with a gene duplication and unclear phenotype, classifying as either IM or NM. Median plasma PQ area under the curve (AUC) was lower in the NM group (460 hr*ng/mL) compared to the IM group (561 hr*ng/mL), although not statistically significant. Similar to what has been found in the US study, no 5,6 orthoquinone was detected in the plasma. The urine creatinine-corrected 5,6 orthoquinone AUC in the NM group was almost three times higher than in the IM group, with peak measurements (T max ) at 4 hours. Although there is variation among individuals, future studies examining the relationship between the levels of urine 5,6 orthoquinone and primaquine radical cure efficacy could result in a metabolism biomarker predictive of radical cure.

Safety of Weekly Primaquine in Glucose 6 Phosphatase Dehydrogenase (G6PD) Deficient Children

Aim: To assess the Safety of weekly Primaquine in Glucose 6 Phosphatase Dehydrogenase (G6PD) deficient children, for radical treatment of Plasmodium vivax malaria Study Design: cross sectional study Place and Duration: Pediatrics Out Patient Department, Liaquat University of Medical and Health Sciences Hyderabad from 11 January 2018 to 31st August 2019 (total 20 months’ duration) Methodology: A sample of 40 patients was studied during study period. Male children between 4 years to 12 years of age having confirmed vivax malaria were included in the study. If G6PD result showed decreased level of G6PD level then, they were enrolled for study. MP was checked by thick and thin slide method. 5 ml blood was taken in anticoagulant bottle for G6PD, liver function test, creatinine, complete blood count, and reticulocyte count tests. Haemoglobin < 7 g/dL, reticulocyte count > 4, SGPT > 80, G6PD Level < 60% of normal and creatinine > 1.2 was considered significant. Treatment was given with Artemether and Lumefantrine for 3 days while Primaquine, 0 .75 mg base/kg body weights once a week was given for 8 weeks. Patients were followed at OPD initially on 3rd day of therapy then every week for 8 weeks for any hemolysis. Results: There was no hemolysis during the first week and 8 weeks after therapy. Most common side effect was abdominal pain 4 (10%). Mean hemoglobin was 11.8mg/dl. Plasmodium vivax was negative on 3rd day of therapy, it was also negative on 8 week of therapy. Reticulocyte count, Liver function test, creatinine were also normal on 8 weeks of therapy. Conclusion: Primaquine 0.75mg//kg/week for total eight weeks is highly effective for the radical cure of Plasmodium vivax in G6PD deficient children. There is no recurrence of Plasmodium vivax after 8 weeks of therapy. We found this regimen safe as there was no hemolysis demonstrated in children.

Alpha-to-beta cell trans-differentiation for treatment of diabetes

Diabetes mellitus is a significant cause of morbidity and mortality in the United States and worldwide. According to the CDC, in 2017, ∼34.2 million of the American population had diabetes. Also, in 2017, diabetes was the seventh leading cause of death and has become the number one biomedical financial burden in the United States. Insulin replacement therapy and medications that increase insulin secretion and improve insulin sensitivity are the main therapies used to treat diabetes. Unfortunately, there is currently no radical cure for the different types of diabetes. Loss of β cell mass is the end result that leads to both type 1 and type 2 diabetes. In the past decade, there has been an increased effort to develop therapeutic strategies to replace the lost β cell mass and restore insulin secretion. α cells have recently become an attractive target for replacing the lost β cell mass, which could eventually be a potential strategy to cure diabetes. This review highlights the advantages of using α cells as a source for generating new β cells, the various investigative approaches to convert α cells into insulin-producing cells, and the future prospects and problems of this promising diabetes therapeutic strategy.

In vivo efficacy of anti-malarial drugs against clinical Plasmodium vivax malaria in Ethiopia: a systematic review and meta-analysis

Background Ethiopia is one of the few countries in Africa where Plasmodium vivax commonly co-exists with Plasmodium falciparum, and which accounts for ~ 40% of the total number of malaria infections in the country. Regardless of the growing evidence over many decades of decreasing sensitivity of this parasite to different anti-malarial drugs, there has been no comprehensive attempt made to systematically review and meta-analyse the efficacy of different anti-malarial drugs against P. vivax in the country. However, outlining the efficacy of available anti-malarial drugs against this parasite is essential to guide recommendations for the optimal therapeutic strategy to use in clinical practice. The aim of this study was to synthesize evidence on the efficacy of anti-malarial drugs against clinical P. vivax malaria in Ethiopia. Methods All potentially relevant, peer-reviewed articles accessible in PubMed, Scopus, Web of Science, and Clinical Trial.gov electronic databases were retrieved using a search strategy combining keywords and related database-specific subject terms. Randomized controlled trials (RCTs) and non-randomized trials aiming to investigate the efficacy of anti-malarial drugs against P. vivax were included in the review. Data were analysed using Review Manager Software. Cochrane Q (χ2) and the I2 tests were used to assess heterogeneity. The funnel plot and Egger’s test were used to examine risk of publication bias. Results Out of 1294 identified citations, 14 articles that presented data on 29 treatment options were included in the analysis. These studies enrolled 2144 clinical vivax malaria patients. The pooled estimate of in vivo efficacy of anti-malarial drugs against vivax malaria in Ethiopia was 97.91% (95% CI: 97.29–98.52%), with significant heterogeneity (I2 = 86%, p < 0.0001) and publication bias (Egger’s test = -12.86, p < 0.001). Different anti-malarial drugs showed varied efficacies against vivax malaria. The duration of follow-up significantly affected the calculated efficacy of any given anti-malarial drug, with longer duration of the follow-up (42 days) associated with significantly lower efficacy than efficacy reported on day 28. Also, pooled PCR-corrected efficacy and efficacy estimated from altitudinally lower transmission settings were significantly higher than PCR-uncorrected efficacy that estimated for moderate transmission settings, respectively. Conclusion The overall efficacy of anti-malarial drugs evaluated for the treatment of vivax malaria in Ethiopia was generally high, although there was wide-ranging degree of efficacy, which was affected by the treatment options, duration of follow-up, transmission intensity, and the confirmation procedures for recurrent parasitaemia. Regardless of evidence of sporadic efficacy reduction reported in the country, chloroquine (CQ), the first-line regimen in Ethiopia, remained highly efficacious, supporting its continuous utilization for confirmed P. vivax mono-infections. The addition of primaquine (PQ) to CQ is recommended, as this is the only approved way to provide radical cure, and thus ensure sustained efficacy and longer protection against P. vivax. Continuous surveillance of the efficacy of anti-malarial drugs and clinical trials to allow robust conclusions remains necessary to proactively act against possible emergence and spread of drug-resistant P. vivax in Ethiopia.

How radical is radical cure? Site-specific biases in clinical trials underestimate the effect of radical cure on Plasmodium vivax hypnozoites

Background Plasmodium vivax blood-stage relapses originating from re-activating hypnozoites are a major barrier for control and elimination of this disease. Radical cure is a form of therapy capable of addressing this problem. Recent clinical trials of radical cure have yielded efficacy estimates ranging from 65 to 94%, with substantial variation across trial sites. Methods An analysis of simulated trial data using a transmission model was performed to demonstrate that variation in efficacy estimates across trial sites can arise from differences in the conditions under which trials are conducted. Results The analysis revealed that differences in transmission intensity, heterogeneous exposure and relapse rate can yield efficacy estimates ranging as widely as 12–78%, despite simulating trial data under the uniform assumption that treatment had a 75% chance of clearing hypnozoites. A longer duration of prophylaxis leads to a greater measured efficacy, particularly at higher transmission intensities, making the comparison between the protection of different radical cure treatment regimens against relapse more challenging. Simulations show that vector control and parasite genotyping offer two potential means to yield more standardized efficacy estimates that better reflect prevention of relapse. Conclusions Site-specific biases are likely to contribute to variation in efficacy estimates both within and across clinical trials. Future clinical trials can reduce site-specific biases by conducting trials in low-transmission settings where re-infections from mosquito bite are less common, by preventing re-infections using vector control measures, or by identifying and excluding likely re-infections that occur during follow-up, by using parasite genotyping methods.

Current Therapeutic Strategies and Prospects for EGFR Mutation-Positive Lung Cancer Based on the Mechanisms Underlying Drug Resistance

The discovery of activating mutations in the epidermal growth factor receptor (EGFR) gene and the development of EGFR tyrosine kinase inhibitors (TKIs) have led to a paradigm shift in the treatment of non-small cell lung cancer (NSCLC). EGFR mutation-positive NSCLC is common in East Asia, and approximately 50% of adenocarcinomas harbor EGFR mutations. Undoubtedly, EGFR-TKIs, with their promising efficacy, are the mainstay of primary therapy. However, even if tumor shrinkage is achieved, most patients become resistant to EGFR-TKIs and relapse; hence, EGFR-TKIs do not achieve a radical cure. The problem of the development of resistance to targeted drugs has been a persistent challenge. After the role of EGFR T790M mutation in acquired drug resistance was reported, osimertinib, a third-generation irreversible EGFR-TKI, was designed to overcome the resistance conferred by T790M mutation. In addition, some studies have reported the mechanism of drug resistance caused by mutations other than the T790M mutation and strategies to overcome them. Elucidating the mechanism underlying drug resistance development and combining therapeutic approaches are expected to further improve NSCLC prognosis.