Activation of pyruvate kinase as therapeutic option for rare hemolytic anemias:Shedding new light on an old enzyme

Novel developments in therapies for various hereditary hemolytic anemias reflect the pivotal role of pyruvate kinase (PK), a key enzyme of glycolysis, in red blood cell (RBC) health. Without PK catalyzing one of the final steps of the Embden-Meyerhof pathway, there is no net yield of adenosine triphosphate (ATP) during glycolysis, the sole source of energy production required for proper RBC function and survival. In hereditary hemolytic anemias, RBC health is compromised and therefore lifespan is shortened. Although our knowledge on glycolysis in general and PK function in particular is solid, recent advances in genetic, molecular, biochemical, and metabolic aspects of hereditary anemias have improved our understanding of these diseases. These advances provide a rationale for targeting PK as therapeutic option in hereditary hemolytic anemias other than PK deficiency. This review summarizes the knowledge, rationale, (pre)clinical trials, and future advances of PK activators for this important group of rare diseases.</p

Mitapivat improves ineffective erythropoiesis and iron overload in adult patients with pyruvate kinase deficiency

Pyruvate kinase (PK) deficiency is a rare, hereditary disease characterized by chronic hemolytic anemia. Iron overload is a common complication regardless of age, genotype, or transfusion history. Mitapivat, an oral, allosteric PK activator, improves anemia and hemolysis in adult patients with PK deficiency. Mitapivat’s impact on iron overload and ineffective erythropoiesis was evaluated in adults with PK deficiency who were not regularly transfused in the phase 3 ACTIVATE trial and long-term extension (LTE) (#NCT03548220/#NCT03853798). Patients in the LTE received mitapivat throughout ACTIVATE/LTE (baseline to week 96; mitapivat-to-mitapivat [M/M] arm) or switched from placebo (baseline to week 24) to mitapivat (week 24 to week 96; placebo-to-mitapivat [P/M] arm). Changes from baseline in markers of iron overload and erythropoiesis were assessed to week 96. Improvements in hepcidin (mean, 4770.0 ng/L; 95% confidence interval [CI], −1532.3 to 11 072.3), erythroferrone (mean, −9834.9 ng/L; 95% CI, −14 328.4 to −5341.3), soluble transferrin receptor (mean, −56.0 nmol/L; 95% CI, −84.8 to −27.2), and erythropoietin (mean, −32.85 IU/L; 95% CI, −54.65 to −11.06) were observed in the M/M arm (n = 40) from baseline to week 24, sustained to week 96. No improvements were observed in the P/M arm (n = 40) to week 24; however, upon transitioning to mitapivat, improvements similar to those observed in the M/M arm were seen. Mean changes from baseline in liver iron concentration by magnetic resonance imaging at week 96 in the M/M arm and the P/M arm were −2.0 mg Fe/g dry weight (dw; 95% CI, −4.8 to −0.8) and −1.8 mg Fe/g dw (95% CI, −4.4 to 0.80), respectively. Mitapivat is the first disease-modifying pharmacotherapy shown to have beneficial effects on iron overload and ineffective erythropoiesis in patients with PK deficiency

Cognitive Profile of Adults with Sickle Cell Disease - Cluster Analysis

International audienceAbstract Background: Published literature on cognitive functioning in adults with sickle cell disease (SCD) is sparse when compared to children. A few reports describe deficits in processing speed and executive functioning. Some studies suggest that these deficits are more severe in patients with silent cerebral infarcts (SCI). Even in the absence of radiological evidence of ischemic injury, some cognitive deficits have been depicted in adults . We hypothesize that in SCD adults, the cognitive profile varies with the presence of ischemic injury (SCI or overt stroke). The aims of this study were 1) to describe the neuropsychological profiles of SCD adults, and 2) to characterize clusters of patients with similar cognitive profiles. Methods: We conducted a retrospective analysis of all consecutive SCD adults who underwent comprehensive neuropsychological assessment during routine care at the UMGGR clinic at Henri Mondor Hospital, Créteil (France), between January 2017 and April 2021. The Montreal Cognitive Assessment (MoCA) and Hospital Anxiety and Depression Scale (HADS) were used for cognitive disorder, anxiety and depression screening, respectively. The cognitive battery combined standardized neuropsychological tests with established clinical utility and validity. Educational attainment was scored based on the number of years of schooling for the highest completed diploma. Principal component analysis was performed. ANOVA was used to compare patients' characteristics between clusters. Results: 80 patients, median age 36.5 [range 19-63] years were included. 40 (50.0%) were male. Genotype distribution was 62 patients (77.5%) with SS/Sbeta 0, 12 (15.0%) with SC and 6 (7.5%) with Sbeta +. On Principal Component Analysis, a 5-factor model presented the best fit (Bartlett's sphericity test (χ²(171)=1174; p&lt;0.001)), explaining 71.8% of the variance in neuropsychological scores. The first factor encompassed tests specifically assessing visual attention/visual organization (right hemisphere). The second included tests for mental/cognitive control (frontal lobe), the third tests of selective inhibition/attention (fronto-parietal), the fourth tests for language/memory (left temporal lobe) and the last referred to shifting skill (sub-cortical loop). On hierarchical classification, 3 different clusters emerged: 32 patients in cluster 1, 32 in cluster 2 and 16 in cluster 3. Cluster 1 had a lower mean educational level (F(2,77) = 15,65; p&lt;0,001). Cluster 1 showed the lowest mean MoCA score (20.0/30.0), relative to cluster 2 and 3 (24.6 and 26.4; p&lt;0.001 and p&lt;0.001, respectively). Cluster 1 patients presented deficits on all five factors. Cluster 2 patients compared to cluster 3 were altered in 4 factors (factors 1-4), but to a lesser extent than cluster 1. Processing speed was slower and some frontal-executive deficits were present in cluster 2 compared to cluster 3. There was no statistical difference between clusters in terms of ethnic origins. There was a trend for the presence of more cerebral vasculopathy in cluster 1 (chi2; p=0.06). Regarding stroke, 70% occurred during childhood in cluster 1, whereas 70% during adulthood in cluster 2, and 100% during adulthood in cluster 3. Conclusions: Overall, these results suggest at least three different cognitive profiles in adults with SCD: 1) few or no cognitive deficits (cluster 3), 2) some cognitive impairment with a sub-cortical cognitive profile (cluster 2) and 3) more global cognitive impairment with cortical/sub-cortical profile and specific deficits of memory, language and constructional praxis, depending on the location of prior overt neurological events (cluster 1). To reduce the long-term cognitive morbidity of SCD, patients can be identified by their distinct cognitive profiles and neurorehabilitation tailored to their unique profile should be applied. The large proportion of childhood stroke in patients with global cognitive impairment in contrast with majority of those with milder to no cognitive impairment having had their stroke in adulthood emphasize the crucial importance of preventing early childhood stroke and implementing early neurorehabilitation. Disclosures Forté: Canadian Hematology Society: Research Funding; Pfizer: Research Funding; Novartis: Honoraria. Kuo: Pfizer: Consultancy, Research Funding; Bluebird Bio: Consultancy; Novartis: Consultancy, Honoraria; Apellis: Consultancy; Alexion: Consultancy, Honoraria; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy; Bioverativ: Membership on an entity's Board of Directors or advisory committees. Bartolucci: Jazz Pharma: Other: Lecture fees; AGIOS: Consultancy; Emmaus: Consultancy; GBT: Consultancy; F. Hoffmann-La Roche Ltd: Consultancy; Hemanext: Consultancy; INNOVHEM: Other: Co-founder; Bluebird: Consultancy, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Lecture fees, Steering committee, Research Funding; Fabre Foundation: Research Funding; Addmedica: Consultancy, Other: Lecture fees, Research Funding

Evidence of Educational Bias in Cognitive Screening of Adults with Sickle Cell Disease: Comparison of Available Tools and Possible Strategies for Mitigation

International audienceBackground: Cognitive impairment is a dreaded complication of sickle cell disease (SCD) that impacts quality of life, school performance and employment. In 2020, the American Society of Hematology issued a strong recommendation that clinicians supervising the care of adults with SCD conduct surveillance for cognitive impairment using simplified signaling questions (DeBaun, 2020). However, guidance on the optimal screening strategy is lacking and several available tools are biased by language and education. The Rowland Universal Dementia Assessment Scale (RUDAS) was specifically designed for cognitive screening in multicultural populations (Storey, 2004). In the general elderly population, RUDAS is less biased by education than the Montreal Cognitive Assessment (MoCA) (Naqvi, 2015). Hypothesis: In adults with SCD, performance on the RUDAS is less influenced by educational attainment when compared to the MoCA. Our primary aim was to estimate the prevalence of suspected cognitive impairment using RUDAS and MoCA in adult SCD patients. The secondary aims were to examine for the presence of educational bias and to develop mitigation strategies in case of such a bias. Methods: Study design: cross-sectional study at UMGRR clinic at Henri Mondor Hospital, Créteil (France). Inclusion criteria: out-patients ≥18 years-old; all SCD phenotypes. Exclusion criteria: inability to obtain informed consent and/or follow study instructions. Intervention: Cognitive screening was performed using the RUDAS (translated to French by Philippe Desmarais), MoCA (third alternative version) and an additional visuospatial task of copying overlapping triangles (from the French BEC96 assessment). RUDAS and MoCA scores &lt;28 and &lt;26, respectively, were considered suggestive of cognitive impairment per previous studies (Basic, 2009 and Nasredinne, 2005) and patients were referred for definite neuropsychological evaluation. Survey on demographics and screening for depression and anxiety using Hospital Anxiety Depression Scale (HADS) were completed by the participants. Educational attainment was scored based on the number of years of schooling for the highest completed diploma. Statistical plan: linear regression was performed to identify possible associations between RUDAS, MoCA and social determinants of health. Results: Among the first 45 consecutive adult SCD patients undergoing routine cognitive screening, the median age was 39 (range 19-67). RUDAS and MoCA scores suggestive of mild cognitive impairment were found in 33/45 (73.3%) and 29/45 (64.4%) participants, respectively. There was a strong correlation between both tests (r=0.48, p=0.001). Both RUDAS and MoCA scores increased significantly with increasing level of education (r=0.36, p=0.015 and r=0.39, p=0.007, respectively), but were not significantly influenced by the HADS score. RUDAS and MoCA test items most biased by education were visuoconstructional tasks. Tasks assessing executive functioning and language were also biased in MoCA. Substituting the 3D visuospatial task of the RUDAS by a 2D task reduced the educational bias (r=0.20, p=0.045). Adding 1 point for highest level of education £ 12 years after kindergarten did significantly mitigate the effect of education on the RUDAS but only partially for the MoCA (r=0.23, p=0.131 and r=0.30, p=0.047). Conclusions: Overall, these results suggest there is an educational bias in the neurocognitive screening of adult SCD patients using available tools such as the RUDAS and MoCA. Although RUDAS was less biased overall, visuospatial assessment remained biased. The task often considered more "culture-fair" is still subject to the impact of educational potential (Statucka, 2019). We provide different strategies to mitigate education bias when assessing with RUDAS. Thus, the RUDAS adjusted by the educational level allows to systematically identify SCD patients in need of comprehensive neurocognitive testing. Prospective validation is ongoing. Disclosures Forté: Canadian Hematology Society: Research Funding; Pfizer - Global Medical Grants: Research Funding. Soulieres:Novartis: Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees. Kuo:Pfizer: Consultancy, Research Funding; Celgene: Consultancy; Alexion: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Bioverativ: Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bluebird Bio: Consultancy; Apellis: Consultancy. Bartolucci:Roche: Consultancy; Innovhem: Other; AGIOS: Consultancy; Bluebird: Consultancy; Emmaus: Consultancy; Addmedica: Research Funding; Fabre Foundation: Research Funding; Novartis: Research Funding; Bluebird: Research Funding; GBT: Consultancy; ADDMEDICA: Consultancy; HEMANEXT: Consultancy; Novartis: Consultancy

Corrigendum to “Activation of pyruvate kinase as therapeutic option for rare hemolytic anemias: Shedding new light on an old enzyme” [Blood Rev. 2023 Sep:61:101103] (Blood Reviews (2023) 61, (S0268960X23000644), (10.1016/j.blre.2023.101103))

The authors regret that in the published article, a part of Table 2 titled ‘Main clinical study results of subjects treated with PK activators in hereditary hemolytic anemia’ was missing. A correction has therefore been made to Table 2 with the addition of the last three columns and some abbreviations in the legend. The original article has been updated. The authors would like to apologise for any inconvenience caused