Multicenter, phase 1 study of etavopivat (FT-4202) treatment for up to 12 weeks in patients with sickle cell disease.

Etavopivat is an investigational, once-daily, oral, selective erythrocyte pyruvate kinase (PKR) activator. A multicenter, randomized, placebo-controlled, double-blind, 3-part, phase 1 study (https://clinicaltrials.gov/study/NCT03815695) was conducted to characterize the safety and clinical activity of etavopivat. Thirty-six patients with sickle cell disease (SCD) were enrolled into 4 cohorts: one single-dose; two multiple ascending doses; one open-label [OL]. In the OL cohort, 15 patients (median age 33.0 [range, 17‒55] years received 400-mg etavopivat once daily for 12 weeks; 14 completed treatment. Consistent with the mechanism of PKR activation, increases in ATP and decreases in 2,3 diphosphoglycerate were observed and sustained over 12 weeks' treatment. This translated clinically to an increase in hemoglobin (mean maximal increase 1.6 [range, 0.8‒2.8] g/dL), with >1 g/dL increase in 11 (73%) patients during treatment. Additionally, oxygen tension at which hemoglobin is 50% saturated was reduced (P=.0007) with concomitant shift in point-of-sickling (P=.0034) to lower oxygen tension in oxygen-gradient ektacytometry. Hemolysis markers (absolute reticulocyte count, indirect bilirubin, lactate dehydrogenase) decreased from baseline, along with matrix metalloproteinase-9 and erythropoietin. In the OL cohort, adverse events (AEs) were mostly grade 1/2, consistent with underlying SCD; 5 patients had serious AEs. Vaso-occlusive pain episode was the most common treatment-emergent AE (n=7) in the OL cohort. In this first study of etavopivat in SCD, 400 mg once daily for 12 weeks was well-tolerated, resulting in rapid and sustained increases in hemoglobin, improved RBC physiology, and decreased hemolysis.

Real-world experience of patients with sickle cell disease treated with crizanlizumab.

In 2019, crizanlizumab was approved by the Food and Drug Administration (FDA) to reduce the rate of vaso-occlusive crisis in patients with sickle cell disease (SCD). We aimed to study the real-world effectiveness of crizanlizumab in our comprehensive sickle cell center. This was a retrospective cohort analysis of patients with SCD who received at least two consecutive doses of crizanlizumab. Clinically significant improvement was captured using the patient global impression of change scale (PGI-C). As of December 2022, there were 18 patients eligible for analysis with a median age of 30.5 years. Eight patients had the HbSS genotype, 7 HbSC, and 3 HbSB null genotype. Median duration of exposure to crizanlizumab was 53.6 weeks, and 16 (88.9%) patients received crizanlizumab for ≥26 weeks. Crizanlizumab was very well tolerated with no serious adverse events (grade ≥3) related to treatment. There was no significant difference in laboratory parameters. There was a remarkable improvement in patients' subjective response to crizanlizumab infusion. The median PGI-C score of our patients was 5, signifying moderately better with slight but noticeable changes. The morphine equivalent daily doses (MEDD) were lower after crizanlizumab infusion. MEDD prior to crizanlizumab was 90; after ≥2 consecutive crizanlizumab doses, it was 60. There was also a reduction in the hospital admissions, emergency, and urgent care visit for acute pain crisis in 6 (28%) patients. This study shows that crizanlizumab was associated with improvement in patients' response, both directly and indirectly related to the reduction of opioids used, which is consistent with results from the SUSTAIN trial.

Successful Treatment of SCD-Related Priapism With Crizanlizumab: A Case Series.

Priapism, an unwanted, painful, prolonged erection that is unrelated to sexual stimulation, is a common complication of sickle cell disease (SCD). Priapic events in SCD are stuttering, meaning they occur repeatedly with intervening periods of detumescence. Without health care intervention, repeated episodes can lead to erectile dysfunction. There are limited treatment options for SCD-related priapism and no approved targeted therapies. Crizanlizumab is a monoclonal antibody that binds to P-selectin and is used to reduce the frequency of vaso-occlusive crises in patients with SCD. Here, we report the cases of 3 patients with SCD-related priapism who were treated with crizanlizumab. All patients were African American men who experienced numerous priapic episodes that interfered with their daily lives. Upon treatment with crizanlizumab, priapic events were reduced in all 3 patients. These successful cases suggest a potential role for crizanlizumab in the prevention of SCD-related priapism.

Recurrent Strokes in a Woman with a History of Thrombotic Thrombocytopenic Purpura.

Thrombotic thrombocytopenic purpura (TTP) is a microangiopathy characterized by mechanical hemolytic anemia, resulting in end-organ damage. We describe a case of TTP which presented as an ischemic stroke. The patient presented with stroke as the primary manifestation of TTP despite a normal platelet count and mildly elevated lactate dehydrogenase level (LDH). The patient underwent two transfusions of fresh frozen plasma (FFP), and ADAMTS13 levels confirmed the diagnosis of TTP after discharge. This case demonstrates the importance of maintaining a high index of suspicion for TTP in the setting of normal laboratory values and reveals the many atypical manifestations of TTP.

Patient-Reported Experiences in Voxelotor-Treated Children and Adults with Sickle Cell Disease: A Semistructured Interview Study.

Objective: Voxelotor is a first-in-class sickle hemoglobin-polymerization inhibitor that was approved in 2019 by the US Food and Drug Administration for treatment of patients with sickle cell disease (SCD) aged ≥12 years; in 2021, the approval was extended to children with SCD aged 4 to 11 years. Additionally, both the Ministry of Health and Prevention for the United Arab Emirates and the European Commission granted marketing authorization for voxelotor in September 2021 and February 2022, respectively, for treatment of SCD in adults and pediatric patients aged ≥12 years. Thus, additional information on the patient experience with voxelotor would be useful for patients, caregivers, and healthcare professionals alike. The purpose of this study was to conduct semistructured interviews in an effort to understand the experiences and perspectives of voxelotor-treated patients with SCD. Methods: One-time semistructured interviews with adults, adolescents, and children with SCD and their primary caregivers were conducted in the United States. Twenty-three adults and adolescents were recruited across 4 clinical sites, and 10 children-caregiver dyads were recruited from a single site. The interview was designed to elicit patient perspectives on symptomatic changes with voxelotor and the impact of treatment on patients' perceived health-related quality of life. Individual interview transcripts were analyzed using a thematic analytic approach, and concept saturation was assessed in both cohorts. Results: Most patients reported improvements in their SCD symptoms with voxelotor treatment, specifically regarding pain crises, jaundice, and fatigue. Almost all patients experienced improvements in self-reported health-related quality of life with voxelotor treatment. Conclusions: This study provides patient and caregiver perspectives on the symptomatic benefits of voxelotor treatment. These findings not only highlight the benefits of voxelotor treatment in improving symptoms and increasing health-related quality of life across the entire SCD population but also can inform further research on SCD-specific patient-reported outcomes.

Patient perception of voxelotor treatment benefit in sickle cell disease.

Patients with sickle cell disease (SCD) experience a range of clinical symptoms, including acute and chronic pain, fatigue, and respiratory problems, as well as chronic organ complications that can lead to disability and accelerated mortality. Voxelotor is a first-in-class therapy that targets sickle hemoglobin polymerization, the root cause of SCD. It is approved by the US Food and Drug Administration for treatment of SCD in patients aged 4 years and older and in the European Union and United Arab Emirates for the treatment of SCD in patients aged 12 years and older. Here, we report the single-center experience of both clinician-determined and patient-reported benefits of voxelotor in 27 consecutive patients treated for at least 8 weeks. Clinical Global Impression of Change and Patient Global Impression of Change rating scales were used to capture clinicians' and patients' perceptions of change in overall patient health-related quality-of-life with voxelotor treatment. Laboratory data were also collected to assess clinical response to treatment. As observed in previous clinical studies, hemoglobin concentrations and markers of hemolysis were improved in patients treated with voxelotor. Most patients reported marked improvement in disease symptoms, which correlated well with the clinicians' assessments. Although limited by the retrospective open-label study design, these findings suggest that voxelotor use has a positive impact on outcomes in patients with SCD.

Warm autoimmune haemolytic anaemia seen in association with primary sclerosing cholangitis in the setting of Klebsiella pneumoniae bacteraemia.

Warm autoimmune haemolytic anaemia mediated by warm agglutinins is a rare and heterogeneous disease which can be idiopathic or secondary to an underlying disease. Primary sclerosing cholangitis is a chronic autoimmune cholangiopathy that is very rarely associated with haemolytic anaemia. Infections can also act as triggers for immune haemolytic anaemia. Here, we report a case of a woman in her 50s with a history of primary sclerosing cholangitis and a positive direct antiglobulin test with no evidence of haemolysis who developed overt warm autoimmune haemolytic anaemia in the setting of cholangitis and Klebsiella pneumoniae bacteraemia. She was treated conservatively with appropriate antibiotics and cautious red blood cell transfusion with complete resolution of haemolysis; immunosuppression was avoided given sepsis on presentation. This case highlights a rare association of warm immune haemolytic anaemia in the setting of K. pneumoniae bacteraemia and the role of a tailored treatment approach to treat this heterogeneous disease.

Risk and protective factors for severe COVID-19 infection in a cohort of patients with sickle cell disease.

Continued investigation of comorbid conditions that increase the mortality rate of COVID-19 is necessary to provide the best care for those affected. This continued push to find answers is even more important for populations with COVID-19 comorbidities that are historically under-researched. We performed a retrospective analysis of 30 patients with sickle cell disease (SCD) who tested positive for the COVID-19 virus. An analysis of each patient's history of SCD complications, hydroxyurea usage, comorbidities, and several other factors was performed to identify the trends that will allow the practitioners to better predict the outcomes of patients with SCD before and during hospitalization for COVID-19. Through these analyses, we found that patients receiving hydroxyurea before COVID-19 infection and patients with SCD-type HbSC had significantly milder COVID-19 disease courses than those not receiving hydroxyurea or with SCD-type HbSS. A history of acute chest syndrome (ACS), a complication seen in patients with SCD, appeared to be associated with a more severe COVID-19 disease course. By creating systems to better interpret what makes a patient with SCD at high risk for a poor prognosis, practitioners are better equipped to make data-supported recommendations for prevention, risk, and treatment. These recommendations should include beginning or maintaining hydroxyurea usage in all qualifying patients with SCD, advising patients with a history of ACS to take extra precautions to prevent initial COVID-19 infection, and initiating close monitoring in the hospital for patients with HbSS and a history of ACS.

COVID-19 Presentation in Patients with Sickle Cell Disease: A Case Series.

BACKGROUND Certain health conditions have been proven to have an effect on the severity of COVID-19, the disease caused by SAR-COV-2. The list of identified comorbid conditions includes hematological diseases, with sickle cell disease (SCD) falling into this category. CASE REPORT This case series examines the history, presentation, and clinical course of 5 patients with SCD who tested positive for SAR-COV-2 during the spring and summer of 2020. These patients experienced COVID-19 severities ranging from a mild cough and congestion to 8-day hospitalizations requiring blood transfusions. CONCLUSIONS While there is still a great amount of research on the interaction between COVID-19 and SCD needed, from this study we have concluded that patients with SCD do not always present with the classic COVID-19 triad of cough, shortness of breath, and fever. Often, these patients present with symptoms of vaso-occlusive crisis (VOC), including severe leg, flank, and chest pain, as was seen in 4 of 5 of our patients. We, and several other researchers, believe that this association between COVID-19 and VOC could be due to COVID-19 triggering inflammatory cytokines (notably IL-6) leading to system-wide inflammation, which induces sickling of the red blood cells. Based on this report, we recommend that SCD patients presenting with VOC who have had exposure to SAR-COV-2 be promptly tested for SAR-COV-2 to guide treatment and reduce mortality and morbidity in this vulnerable population.

Atypical Thrombotic Thrombocytopenic Purpura Presenting as Stroke.

Here we report a case of atypical thrombotic thrombocytopenic purpura that presented as an ischemic cerebrovascular accident. A 56-year-old man with multiple cardiovascular risk factors presented with sudden left-sided weakness, slurred speech, and left facial droop. He showed mild improvement when he was treated with thrombolytic therapy according to the hospital stroke protocol. Later in the course, he developed thrombocytopenia followed by schistocytes revealed by peripheral blood smear and other lab abnormalities. Thrombotic thrombocytopenic purpura (TTP) was suspected, and he was treated with total plasma exchange that improved his condition significantly. This case shows that TTP can have unusual and atypical presentations either with the first episode or upon relapse, making diagnosis extremely difficult. Because patients may not present the expected clinical findings, it is important to be aware of variant presentations. In the early stages of the disease, platelet aggregation and thrombus formation may not be widespread, and thrombocytopenia and microangiopathic hemolytic anemia may not be clinically evident. Patients can present soon after the onset of symptoms when the typical laboratory abnormalities may not have had ample time to manifest. Although most other similar cases in the literature had a previous typical presentation of the disease before an atypical presentation, our patient's first presentation was atypical. An atypical presentation of disease in a patient with cardiovascular risk factors may therefore be extremely difficult to diagnose. We believe that TTP should be considered for any patient presenting with stroke and thrombocytopenia.

A 45-Year-Old Woman With Multiple Pulmonary Nodules and Sjögren Syndrome.

CASE PRESENTATION: A 45-year-old woman presented for evaluation for 3 months of coughing and dyspnea. A recent chest CT scan done for workup of her symptoms revealed a 2-cm right-sided pulmonary nodule. She had a medical history of Sjögren syndrome, hypertension, and obesity. She also noted a weight loss of 30 lb over the last 3 years. She denied smoking, alcohol consumption, illicit drug use, or occupational exposures. A chest radiograph done 3 years prior did not reveal any pulmonary nodules. She had no personal or family history of arteriovenous malformations, hamartomas, or any malignancies and had been up to date with her breast cancer screening. She was treated with courses of hydroxychloroquine and mycophenolate mofetil for her Sjögren syndrome and did not have a history of opportunistic pulmonary infections. She denied any recent travel or exposure to TB.

Elevated ecto-5'-nucleotidase: a missing pathogenic factor and new therapeutic target for sickle cell disease.

Although excessive plasma adenosine is detrimental in sickle cell disease (SCD), the molecular mechanism underlying elevated circulating adenosine remains unclear. Here we report that the activity of soluble CD73, an ectonucleotidase producing extracellular adenosine, was significantly elevated in a murine model of SCD and correlated with increased plasma adenosine. Mouse genetic studies demonstrated that CD73 activity contributes to excessive induction of plasma adenosine and thereby promotes sickling, hemolysis, multiorgan damage, and disease progression. Mechanistically, we showed that erythrocyte adenosine 5'-monophosphate-activated protein kinase (AMPK) was activated both in SCD patients and in the murine model of SCD. AMPK functions downstream of adenosine receptor ADORA2B signaling and contributes to sickling by regulating the production of erythrocyte 2,3-bisphosphoglycerate (2,3-BPG), a negative allosteric regulator of hemoglobin-O2 binding affinity. Preclinically, we reported that treatment of α,ß-methylene adenosine 5'-diphosphate, a potent CD73 specific inhibitor, significantly decreased sickling, hemolysis, multiorgan damage, and disease progression in the murine model of SCD. Taken together, both human and mouse studies reveal a novel molecular mechanism contributing to the pathophysiology of SCD and identify potential therapeutic strategies to treat SCD.

Echocardiographic parameters to identify sickle cell patients with cardio-pathology.

BACKGROUND: Sickle cell disease (SCD) affects millions of people and causes chronic hemolytic anemia leading to vasculopathies such as pulmonary hypertension and abnormalities in cardiac function that increase complications and mortality. It is therefore crucial to identify cardiac abnormalities in SCD. We aimed to assess the prevalence of echocardiographic parameters in SCD to help identify cardiopulmonary risk. METHODS: Ninety-one patients (53% male), median age of 30, body surface area (BSA) of 1.79 m2 , hemoglobin of 8.8 g/dL, and creatinine of 0.7 mg/dL identified. We retrospectively measured laboratory and echocardiographic parameters in patients with SCD : left ventricular (LV) dimensions, LV ejection fraction (LVEF), LV Myocardial Performance Index (MPI), LV Mass Index (MI), Left Atrial Volume Index (LAVI), Tricuspid Regurgitation Velocity (TRV), tricuspid annular plane systolic excursion (TAPSE), right heart dimensions. RESULTS: Prevalence of left heart abnormalities was 32%: increased LV end-diastolic diameter (EDD), 78%: LV MPI, 21%: diastolic dysfunction, 38%: decreased LVEF, 24%: increased LVMI, and 47%: increased LAVI. Right heart abnormalities were 39%: TAPSE, 38%: increased TRV, and 59%: increased pulmonary systolic pressure (PASP). Multivariate logistic regression analysis was significant for increased LVMI and LAVI in those with hemoglobin ≤8 g/dL (odds ratio (OR) 7.4, 95% confidence interval (CI) 2.23-24.6, P = .001) and (OR 3.32, 95% CI 1.18-9.33, P = .023). CONCLUSIONS: We confirmed increased prevalence of abnormal LVEDD, LVMI, diastolic function, LAVI, and PASP in SCD. In addition, we identified abnormal LV MPI (78%), TAPSE (29%). These parameters may be useful and readily accessible echocardiographic prognostic tools in this population.

Structural and Functional Insight of Sphingosine 1-Phosphate-Mediated Pathogenic Metabolic Reprogramming in Sickle Cell Disease.

Elevated sphingosine 1-phosphate (S1P) is detrimental in Sickle Cell Disease (SCD), but the mechanistic basis remains obscure. Here, we report that increased erythrocyte S1P binds to deoxygenated sickle Hb (deoxyHbS), facilitates deoxyHbS anchoring to the membrane, induces release of membrane-bound glycolytic enzymes and in turn switches glucose flux towards glycolysis relative to the pentose phosphate pathway (PPP). Suppressed PPP causes compromised glutathione homeostasis and increased oxidative stress, while enhanced glycolysis induces production of 2,3-bisphosphoglycerate (2,3-BPG) and thus increases deoxyHbS polymerization, sickling, hemolysis and disease progression. Functional studies revealed that S1P and 2,3-BPG work synergistically to decrease both HbA and HbS oxygen binding affinity. The crystal structure at 1.9 Å resolution deciphered that S1P binds to the surface of 2,3-BPG-deoxyHbA and causes additional conformation changes to the T-state Hb. Phosphate moiety of the surface bound S1P engages in a highly positive region close to α1-heme while its aliphatic chain snakes along a shallow cavity making hydrophobic interactions in the "switch region", as well as with α2-heme like a molecular "sticky tape" with the last 3-4 carbon atoms sticking out into bulk solvent. Altogether, our findings provide functional and structural bases underlying S1P-mediated pathogenic metabolic reprogramming in SCD and novel therapeutic avenues.

Hypoxia-mediated impaired erythrocyte Lands' Cycle is pathogenic for sickle cell disease.

Although Lands' cycle was discovered in 1958, its function and cellular regulation in membrane homeostasis under physiological and pathological conditions remain largely unknown. Nonbiased high throughput metabolomic profiling revealed that Lands' cycle was impaired leading to significantly elevated erythrocyte membrane lysophosphatidylcholine (LysoPC) content and circulating and erythrocyte arachidonic acid (AA) in mice with sickle cell disease (SCD), a prevalent hemolytic genetic disorder. Correcting imbalanced Lands' cycle by knockdown of phospholipase 2 (cPLA2) or overexpression of lysophosphatidycholine acyltransferase 1 (LPCAT1), two key enzymes of Lands' cycle in hematopoietic stem cells, reduced elevated erythrocyte membrane LysoPC content and circulating AA levels and attenuated sickling, inflammation and tissue damage in SCD chimeras. Human translational studies validated SCD mouse findings and further demonstrated that imbalanced Lands' cycle induced LysoPC production directly promotes sickling in cultured mouse and human SCD erythrocytes. Mechanistically, we revealed that hypoxia-mediated ERK activation underlies imbalanced Lands' cycle by preferentially inducing the activity of PLA2 but not LPCAT in human and mouse SCD erythrocytes. Overall, our studies have identified a pathological role of imbalanced Lands' cycle in SCD erythrocytes, novel molecular basis regulating Lands' cycle and therapeutic opportunities for the disease.

Epstein-barr virus-related hemophagocytic lymphohistiocytosis: hematologic emergency in the critical care setting.

Hemophagocytic lymphohistiocytosis (HLH) is a rare and potential life-threatening clinical syndrome that results from uncontrolled activation of the immune system. Secondary HLH, more commonly observed in adult patients, is seen in the context of underlying triggering conditions. Epstein-Barr virus (EBV) has been recognized as the leading infectious cause and is associated with a poor outcome. As clinical and laboratory features of HLH could overlap with septic shock syndrome in most patients, the diagnosis of HLH, especially in adults, is the most challenging aspect of the disease that results in delayed recognition and treatment of rapidly progressive multiorgan system failure. We report a case of Hemophagocytic lymphohistiocytosis in a patient who presented with signs of septic shock syndrome and we review the literature on the topic.

Elevated adenosine signaling via adenosine A2B receptor induces normal and sickle erythrocyte sphingosine kinase 1 activity.

Erythrocyte possesses high sphingosine kinase 1 (SphK1) activity and is the major cell type supplying plasma sphingosine-1-phosphate, a signaling lipid regulating multiple physiological and pathological functions. Recent studies revealed that erythrocyte SphK1 activity is upregulated in sickle cell disease (SCD) and contributes to sickling and disease progression. However, how erythrocyte SphK1 activity is regulated remains unknown. Here we report that adenosine induces SphK1 activity in human and mouse sickle and normal erythrocytes in vitro. Next, using 4 adenosine receptor-deficient mice and pharmacological approaches, we determined that the A2B adenosine receptor (ADORA2B) is essential for adenosine-induced SphK1 activity in human and mouse normal and sickle erythrocytes in vitro. Subsequently, we provide in vivo genetic evidence that adenosine deaminase (ADA) deficiency leads to excess plasma adenosine and elevated erythrocyte SphK1 activity. Lowering adenosine by ADA enzyme therapy or genetic deletion of ADORA2B significantly reduced excess adenosine-induced erythrocyte SphK1 activity in ADA-deficient mice. Finally, we revealed that protein kinase A-mediated extracellular signal-regulated kinase 1/2 activation functioning downstream of ADORA2B underlies adenosine-induced erythrocyte SphK1 activity. Overall, our findings reveal a novel signaling network regulating erythrocyte SphK1 and highlight innovative mechanisms regulating SphK1 activity in normal and SCD.

Feigning acute intermittent porphyria.

Acute intermittent porphyria (AIP) is an autosomal dominant genetic defect in heme synthesis. Patients with this illness can have episodic life-threatening attacks characterized by abdominal pain, neurological deficits, and psychiatric symptoms. Feigning this illness has not been reported in the English language literature to date. Here, we report on a patient who presented to the hospital with an acute attack of porphyria requesting opiates. Diligent assessment of extensive prior treatment records revealed thirteen negative tests for AIP.