Erythrocyte Mean Corpuscular Volume Research Articles

CDK4/6 Inhibitor-Associated Mean Corpuscular Volume Change: A Potential Parameter for Predicting Survival in Metastatic Breast Cancer?

To evaluate the impact of CDK4/6 inhibitors on erythrocyte mean corpuscular volume (MCV) change and its possible correlation with progression-free survival (PFS) and overall survival (OS). Observational study. Place and Duration of the Study: Department of Medical Oncology, Kahramanmaras Necip Fazil City Hospital, Kahramanmaras, Turkiye, between January 2020 and 2023. The data of 74 patients with HR (+) HER2 (-) metastatic breast cancer were analysed retrospectively. MCV and other complete blood count metrics were noted before and after the treatment. The first post-treatment evaluation was performed at three months. The median ΔMCV values at the third month after treatment-baseline were calculated. The patients were all females, with a median age of 55 years (between 35 and 80). Prior to the therapy, the baseline median MCV level was 90.4 (min-max: 77.3-113.2). After three months, the median MCV level was 95 (min-max: 84.3-115.3). Moreover, 7.15 was the median ΔMCV level. Regarding PFS (16.53 vs. 15.26 months) (p = 0.13) and OS (21.46 vs. 17.83 months) (p = 0.08), there was no statistically significant difference seen between the group with ΔMCV ≥7.15 and the group with ΔMCV <7.15. CDK4/6 inhibitors led to an increase in MCV but there was no significant difference between PFS or OS and the increase in MCV. To figure out whether the rise in MCV represents a prognostic or predictive marker, further research is required. Breast cancer, CDK4/6 inhibitors, Mean corpuscular volume, Prognosis.

Dantu Blood Group Erythrocytes Form Large Plasmodium falciparum Rosettes Less Commonly.

Dantu erythrocytes, which express a hybrid glycophorin B/A protein, are protective against severe malaria. Recent studies have shown that Dantu impairs Plasmodium falciparum invasion by increasing erythrocyte membrane tension, but its effects on pathological host-parasite adhesion interactions such as rosetting, the binding of uninfected erythrocytes to P. falciparum-infected erythrocytes, have not been investigated previously. The expression of several putative host rosetting receptors-including glycophorin A (GYPA), glycophorin C (GYPC), complement receptor 1 (CR1), and band 3, which complexes with GYPA to form the Wrightb blood group antigen-are altered on Dantu erythrocytes. Here, we compare receptor expression, and rosetting at both 1 hour and 48 hours after mixing with mature trophozoite-stage Kenyan laboratory-adapted P. falciparum strain 11019 parasites in Dantu and non-Dantu erythrocytes. Dantu erythrocytes showed lower staining for GYPA and CR1, and greater staining for band 3, as observed previously, whereas Wrightb and GYPC staining did not vary significantly. No significant between-genotype differences in rosetting were seen after 1 hour, but the percentage of large rosettes was significantly less in both Dantu heterozygous (mean, 16.4%; standard error of the mean [SEM], 3.2) and homozygous donors (mean, 15.4%; SEM, 1.4) compared with non-Dantu erythrocytes (mean, 32.9%; SEM, 7.1; one-way analysis of variance, P = 0.025) after 48 hours. We also found positive correlations between erythrocyte mean corpuscular volume (MCV), the percentage of large rosettes (Spearman's rs = 0.5970, P = 0.0043), and mean rosette size (rs = 0.5206, P = 0.0155). Impaired rosetting resulting from altered erythrocyte membrane receptor expression and reduced MCV might add to the protective effect of Dantu against severe malaria.

Association of iron deficiency with chronic suppurative otitis media in adults

Background Chronic suppurative otitis media (CSOM) is a prevalent chronic inflammatory disease globally. Current research suggests a possible association between anaemia and the development of CSOM. Objectives The objective of this trial was to investigate the relationship between iron metabolism and chronic suppurative otitis media (CSOM) in adults aged 20–60 years. Materials and methods A consecutive sampling case-control study was used. The study participants were divided into a case group (42 children diagnosed with CSOM) and a control group (42 children with normal ears). Haemoglobin (Hb), Hematocrit (Hct), mean corpuscular volume of erythrocytes (MCV), serum iron level (SI), unsaturated iron-binding capacity (UIBC), total iron-binding capacity (TIBC), transferrin (TF), ferritin (Fer) were tested in all the participants, and the results were compared with the normal ranges of the World Health Organization (WHO). The comparative analysis of cases and controls was performed using the Fisher extract test, independence t-test, or Mann–Whitney U test. p-value <.05 was considered statistically significant for correlation. Results There were 61 patients with CSOM and 61 controls included in the study. In the case group, 16 out of 61 patients (26.2%) had low ferritin levels and in the control group, 1 out of 61 patients (1.6%) had low ferritin levels (p < .001). In the case group, 6 (9.8%) of 61 patients had IDA, and in the control group, there were no patients with IDA among 61 patients (p = .027). There were significant differences in SI, UIBC, and Fer parameters between the groups. Conclusions In adult patients, the incidence of iron deficiency was higher in CSOM patients than in controls. Iron deficiency may be considered a potential risk factor for chronic suppurative otitis media, and serum iron parameters should be evaluated in these CSOM patients and further studies should be conducted to better understand the potential link between iron deficiency and CSOM.

Diagnostics of anemia and iron deficiency in patients with chronic heart failure

According to the recommendations of the European Society of Cardiology (ESC) 2021 for the management of patients with chronic heart failure (CHF), it is necessary to take into account the iron level in the diagnosis of all patients with firstly diagnosed heart failure (HF). Also the practical recommendations indicate that the assessment of iron deficiency is also carried out in patients with already confirmed CHF, especially if the symptoms of HF persist against the background of optimal treatment of the underlying disease, which necessitates knowledge of the diagnosis of anemia and iron deficiency in patients with CHF. The aim was review literature illustrating current data about diagnostics of iron deficiency and anemia in patients with CHF. In the work 28 sources from the Web of Science database and 7 sources from the PubMed database were analyzed. Anemia is diagnosed by hemoglobin levels. As criteria for iron deficiency, two parameters are used in clinical practice – ferritin level and transferrin saturation. The mean corpuscular volume of erythrocytes and the mean hemoglobin content in them were not reliable markers of iron deficiency and are not recommended for assessing iron deficiency in patients with HF. Depletion of iron stores in the bone marrow is a highly specific for iron deficiency, as it is not affected by inflammation and therefore the test for iron stores in the bone marrow is the gold standard for diagnosis, however its use in clinical practice is limited due to invasiveness and high cost. Diagnostic markers such as levels of hepsidin, dissolved transferrin receptor and ferritin index have low availability in laboratories. Since timely diagnosis followed by treatment of anemia and iron deficiency in patients with CHF impoves the quality of life of patients, therefore, increasing the diagnostic value of tests to identify iron deficiency remains a question for active research.

Effect of Iron-Erythrocyte Metabolism-Related Indexes on Posttraumatic Growth in Patients on Maintenance Hemodialysis (MHD).

To investigate the effect of iron-erythrocyte metabolism-related indexes on posttraumatic growth in MHD patients and their caregivers. A total of 170 pairs of MHD patients and their caregivers in Shanghai Changhai Hospital were enrolled in this research, which used sociodemographic characteristics, the Posttraumatic Growth Inventory (PTGI), the Perceived Social Support Scale (PSSS), and the Medical Coping Modes Questionnaire (MCMQ). The test data of 141 patients were retrieved from the hospital database. Single-factor analysis showed that the PTGI score of patients with a mean corpuscular erythrocyte volume ≥ 100 fL was 85.4 ± 19.8 and those with a mean corpuscular erythrocyte volume lower than 100 fL were 70.6 ± 24.7; the PTGI scores of patients with reticulocytes >1.5% were 68.8 ± 25.8, and those with reticulocytes <1.5% were 78.4 ± 21.1; the PTGI scores of the caregivers whose serum iron was >10.6 µmol /L were 78.2 ± 21.6, and those with serum iron <10.6 µmol /L were 67.9 ± 22.8. The difference in MCMQ scores between the caregivers with transferrin saturation>50% and with transferrin saturation<20% was 18.9 ± 8.4. For the correlation test of serum iron, reticulocyte and PTGI scores for patients, the Pearson correlation coefficients were 0.239 and -0.193, respectively, and the correlation test between erythrocyte distribution width SD and the score of caregivers MCMQ scale, the Pearson correlation coefficient was 0.225; p for all was< 0.05, with significant differences. There was no significant difference in the scores of different scales for total iron binding capacity (TIBC) at different levels. The indexes related to iron erythrocyte metabolism in MHD patients are correlated with ruminant meditation of patients and their caregivers and promotion of posttraumatic growth. Good nutritional status, adequate hematopoietic material, and normal erythrocyte count and function are also important for them.

Succinate dehydrogenase inversely regulates red cell distribution width and healthy life span in chronically hypoxic mice.

Increased red cell distribution width (RDW), which measures erythrocyte mean corpuscular volume (MCV) variability (anisocytosis), has been linked to early mortality in many diseases and in older adults through unknown mechanisms. Hypoxic stress has been proposed as a potential mechanism. However, experimental models to investigate the link between increased RDW and reduced survival are lacking. Here, we show that lifelong hypobaric hypoxia (~10% O2) increased erythrocyte numbers, hemoglobin, and RDW, while reducing longevity in male mice. Compound heterozygous knockout (hKO) mutations in succinate dehydrogenase (Sdh; mitochondrial complex II) genes Sdhb, Sdhc, and Sdhd reduced Sdh subunit protein levels, reduced RDW, and increased healthy life span compared with WT mice in chronic hypoxia. RDW-SD, a direct measure of MCV variability, and the SD of MCV showed the most statistically significant reductions in Sdh hKO mice. Tissue metabolomic profiling of 147 common metabolites showed the largest increase in succinate with elevated succinate/fumarate and succinate/oxoglutarate (2-ketoglutarate) ratios in Sdh hKO mice. These results demonstrate that mitochondrial complex II level is an underlying determinant of both RDW and healthy life span in hypoxia and suggest that therapeutic targeting of Sdh might reduce high RDW–associated clinical mortality in hypoxic diseases.

Novel Insights into Alcoholic Liver Disease: Iron Overload, Iron Sensing and Hemolysis.

The liver is the major target organ of continued alcohol consumption at risk and resulting alcoholic liver disease (ALD) is the most common liver disease worldwide. The underlying molecular mechanisms are still poorly understood despite decades of scientific effort limiting our abilities to identify those individuals who are at risk to develop the disease, to develop appropriate screening strategies and, in addition, to develop targeted therapeutic approaches. ALD is predestined for the newly evolving translational medicine, as conventional clinical and health care structures seem to be constrained to fully appreciate this disease. This concept paper aims at summarizing the 15 years translational experience at the Center of Alcohol Research in Heidelberg, namely based on the long-term prospective and detailed characterization of heavy drinkers with mortality data. In addition, novel experimental findings will be presented. A special focus will be the long-known hepatic iron accumulation, the somewhat overlooked role of the hematopoietic system and novel insights into iron sensing and the role of hepcidin. Our preliminary work indicates that enhanced red blood cell (RBC) turnover is critical for survival in ALD patients. RBC turnover is not primarily due to vitamin deficiency but rather to ethanol toxicity directly targeted to erythrocytes but also to the bone marrow stem cell compartment. These novel insights also help to explain long-known aspects of ALD such as mean corpuscular volume of erythrocytes (MCV) and elevated aspartate transaminase (GOT/AST) levels. This work also aims at identifying future projects, naming unresolved observations, and presenting novel hypothetical concepts still requiring future validation.

Sunitinib-Induced Elevation of Mean Corpuscular Volume (MCV)-Exploring Its Possible Clinical Relevance in Cancer Patients.

Sunitinib is a broad-spectrum multitargeted tyrosine kinase inhibitor mainly used as second-line therapy for non-resectable gastrointestinal stromal or first-line treatment option of metastatic renal cell carcinoma (mRCC), and as an “off-label” option in pediatric oncology. It has been previously reported that sunitinib elevates the mean corpuscular volume of erythrocytes (MCV) in treated subjects. The aim of this study was to assess time-dependent changes of this effect and evaluate its possible clinical relevance. In this study, 179 adult and 21 pediatric patients with solid tumors treated with sunitinib were retrospectively analyzed. The laboratory and treatment-related data were collected for each treatment period. The regression model with a broken-line relationship was used to fit time dependence of the MCV. In the adult group, the MCV was increasing during the first 21.6 weeks (median) of treatment in a median level of 99.8 fL, where it stabilized. MCV increase was faster in the patients who suffered from treatment-related adverse events (21.3 vs. 24.6 weeks, p = 0.010). In the pediatric cohort, the MCV dynamics were similar to adults. In conclusion, MCV changes during sunitinib treatment in pediatric and adult patients may be of clinical utility in monitoring sunitinib treatment course.

OA26 Erythrocyte mean corpuscular volume as a surrogate marker for methotrexate polyglutamation during early treatment in rheumatoid arthritis

Abstract Background/Aims The long-term outcomes for patients with rheumatoid arthritis (RA) depend on early and effective disease control. Methotrexate remains the key first-line disease-modifying therapy for the majority of patients. The gradual onset of action of methotrexate has been proposed to be linked to the build-up of intracellular stores of the drug, achieved through the process of polyglutamation. This is a complex and expensive assay. Recent work has shown an association between the increase in mean corpuscular volume (MCV) of erythrocytes and improvements in disease activity. This study seeks to relate intracellular methotrexate and 5-methyl-tetrahydrofolate polyglutamate concentrations with changes in MCV and their association with early ‘steroid free’ remission in RA patients. Methods 68 drug-naïve, newly diagnosed RA patients were recruited form the Newcastle Early Arthritis Clinic (NEAC). These patients were followed up for 6 months with serial blood sampling and quantification of the erythrocyte methotrexate and 5-methyl-tetrahydrofolate polyglutamate levels by liquid chromatography-mass spectrometry (LC-MS). This was then related to the contemporaneous erythrocyte MCV values from the clinical monitoring bloods on those occasions and the treatment outcome at 6 months. The outcome measure used was 4 component DAS28CRP remission (&amp;lt;2.4) with only the baseline intramuscular steroid permitted for the definition of remission. Results The majority of patients displayed a gradual increase in MCV over the first 6 months of treatment (MCV change from patient baseline used to normalise the data). When grouped by the ‘steroid free’ remission outcome, there was a divergence in MCV change with greater MCV increases observed in those achieving remission from 4 months of treatment onward (p &amp;lt; 0.05). In the same patient group, the accumulation of longer chain methotrexate polyglutamates (chain length 3 to 5) was observed to follow a similar trend to MCV with higher polyglutamate concentrations in those achieving the remission outcome from 2 months of treatment (P &amp;lt; 0.05). When the contemporaneous MCV and MTX polyglutamate samples were compared, an association was observed between the longer chain MTX polyglutamates and the change in MCV values (R2 = 0.39, p &amp;lt; 0.001), but not between intracellular 5-methyl-tetrahydrofolate and MCV (R2 = 0.01, p = NS). Conclusion Change in MCV shows an association with early remission induction with MTX therapy in treatment-naïve RA patients. This change in MCV appears to be associated with the accumulation of intracellular MTX metabolites, rather than via depletion of intracellular folates. MCV may therefore represent a tractable proxy measure of methotrexate polyglutamation for application in larger studies or for the purpose of drug monitoring. Disclosure P.M. Brown: None. A.G. Pratt: None. A.E. Anderson: None. A.W. Morgan: None. J.D. Isaacs: None.

Erythrocyte Indices and Long-Term Blood Pressure Variability in Military Males.

Severe microcytic anemia has been associated with BP changes. Whether the erythrocyte indices are associated with long-term BPV is unknown. This study aimed to investigate the association of hemoglobin levels and erythrocyte size with long-term blood pressure variability (BPV) in young males. This study included 1,112 healthy military males, averaging 32 years of age, in Taiwan. All participants took a measurement of systolic and diastolic BP (SBP and DBP) every two-year from 2012 to 2018 (2012-14, 2014-15, 2015-16, 2016-18). Levels of hemoglobin and mean corpuscular volume (MCV) of erythrocytes were obtained at the first visit. Long-term BPV was assessed by the standard deviation (SD) and average real variability (ARV). Multivariate linear regression analysis with adjustment for the baseline BP levels and other covariates was used to elucidate the association. Hemoglobin levels were borderline positively correlated with SD DBP (β and standard errors = 0.016 (0.009), P =0.06). In those with hemoglobin levels of 10.0-13.9 g/dL, hemoglobin was negatively correlated with SDSBP (β= -0.039 (0.018), P =0.03). In contrast, MCV levels were borderline positively correlated with SDSBP (β =0.085 (0.052), P =0.09). In those with MCV levels <80 fL, MCV was positively correlated with SDSBP and ARVSBP (β= 0.445 (0.210) and 0.286 (0.149), p = 0.03 and 0.05, respectively). There were inconsistent patterns for the associations of erythrocyte indices with longterm BPV. We found a U-shaped relationship of hemoglobin levels with systolic BPV, whereas there was a positive linear relationship of hemoglobin and MCV levels with diastolic BPV, respectively.

Demographic and Clinical Characteristics of Individuals with Mild Cognitive Impairment Related to Grade of Alcohol Consumption

Introduction: While alcohol overconsumption is regarded as a risk factor for Alzheimer’s disease, the specific relationship between alcohol consumption and cognitive impairment remains unclear and poorly understood. Our primary objective is to investigate whether alcohol consumption is associated with lower cognitive performance at an early phase of the development of cognitive impairment (mild cognitive impairment [MCI] stage) and second to present the clinical and demographic characteristics depending on the grade of alcohol consumption. Methods: This is a cross-sectional observational study, including 251 subjects with the diagnosis MCI, having caregiving contact with Memory Clinic, Karolinska University Hospital, under year 2015. We compared subgroups with different levels of alcohol consumption, concerning social parameters, cognitive, radiological, laboratory profile as well as comorbidities and burden of drugs. Results: Mini-mental State Examination score was not associated with alcohol consumption. Light to moderate drinkers were significantly higher educated. There were significantly more subjects using antianxiety medications among heavy drinkers in comparison with light to moderate drinkers. Finally, never/rare drinkers had significantly lower levels of erythrocyte mean corpuscular volume in their blood tests. Discussion/Conclusion: Alcohol consumption was not correlated with a more pronounced cognitive deficit or a distinct clinical severity at an early stage of cognitive impairment apart from higher usage of antianxiety medications. We are planning to follow up all individuals to ascertain if heavy drinkers have a different outcome compared with the other groups.

Pathological features in ‘humanized’ neonatal pig

Cytidine monophosphate-Nacetylneuraminic acid (Neu5Ac) hydroxylase (CMAH) and glycoprotein, alpha1, 3-galactosyltransferase (GGTA1) double knockout (DKO) pig models were produced to reduce immune reaction for xenotransplantation. However, the role of Neu5Gc and α-Gal in pigs has not been fully elucidated and it is necessary to consider the after-effect of inactivation of GGTA1 and CMAH in pigs. Hematological profiles of DKO pigs were analyzed through complete blood count (CBC). Histology of liver and spleen of DKO were investigated, and lectin blotting and mass spectrometry (MS) were performed to explore glycosylation changes in red blood cell (RBC) membranes of DKO pigs. DKO pigs showed common clinical signs such as weakness (100%), dyspnea (90%) and constipation (65%). DKO pigs revealed a significant decrease in RBC, hemoglobin (HGB) and hematocrit (HGB), and an increase in white blood cell (WBC), lymphocyte (LYM), monocyte (MON), and erythrocyte mean corpuscular volume (MCV). DKO piglets showed swollen liver and spleen, and exhibited raised deposition of hemosiderin and severe bleeding. Lectin assay and MS proved variations in glycosylation on RBC membranes. GGTA1/CMAH DKO pigs developed pathological features which are similar to anemic symptoms, and the variations in glycosylation on RBC membranes of DKO pigs may be attributed to the pathologies observed.

Prognostic role of hematologic parameters of metastatic renal cell carcinoma treated with sunitinib.

Hemochrome parameters at the diagnosis of metastatic renal cell carcinoma (mRCC) and the development of macrocytosis during sunitinib therapy are considered prognostic. To evaluate the prognostic role of hematologic parameters and macrocytosis in mRCC treated with sunitinib. We analyzed clinical data of 100 patients with mRCC treated with sunitinib as first-line therapy in a retrospective multicenter study. We calculated neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) at baseline and erythrocyte mean corpuscular volume (MCV) during therapy. We considered the following cutoffs: NLR >3, PLR >150, LMR <3, and MCV >100 fl. Clinical data histology, prior nephrectomy, Fuhrman grading, metastatic sites, Memorial Sloan-Kettering Cancer Center score, and Heng score were collected. Overall survival (OS) and progression-free survival (PFS) were calculated. Univariate and multivariate analysis using Cox regression model with time-dependent (macrocytosis) covariate were applied. At the univariate analysis, low LMR was associated with shorter PFS and OS (p = 0.02 and p = 0.06, respectively). High PLR was associated with worse PFS (p = 0.005); median OS was 23 vs 28 months (p = 0.13). At the multivariate analysis, poor risk (Heng score), low LMR, and high PLR were associated with shorter PFS (hazard ratio 7.1, 1.5, and 2, respectively); poor PS and poor risk (Heng score) were related to worst OS. Macrocytosis was observed in 26 patients and was not prognostic of survival. In our cohort of patients with mRCC treated with sunitinib, low LMR (>3) and high PLR (>150) were associated with shorter PFS. Macrocytosis was not prognostic.

Changes in complete blood count parameters influenced by endocrine disorders.

Complete blood count is one of the most common diagnostic methods used in everyday practice. Hormonal status is known to affect blood count parameters. The aim of this study is to summarize changes in blood count that may indicate endocrine disorders, based on a literature review. Red cell parameters deteriorate in thyroid disorders including autoimmune thyroiditis and tend to resolve with appropriate treatment implementation. The most frequent form of anaemia associated with thyroid dysfunction is normocytic anaemia. Macrocytic anaemia is more typical of autoimmune thyroiditis-induced hypothyroidism, while microcytic anaemia is more common in hyperthyroidism. Unexplained anaemia or an increase in red cell distribution width should prompt the investigation of thyroid disorders. Cushing's disease may manifest as an increase in white blood cells and platelets. In the blood smear, neutrophilia is often present, while lymphocytes and eosinophils may be within the lower normal range. Hypercortisolism may induce both hyperaemia and anaemia. In hypopituitarism, a decrease in red blood cell count, haemoglobin, haematocrit, and platelets is observed. Acromegaly may be accompanied by an increase in mean corpuscular volume of erythrocytes. Testosterone deficiency is manifested by a decrease in red cell parameters, whereas hyperandrogenism may lead to polycythaemia. In polycystic ovary syndrome an increase in white blood cell count reflects an underlying inflammatory state. Complete blood count analysis is an easily available and cost-effective additional tool in the diagnosis and treatment monitoring of endocrine disorders.

MO539HEMATOLOGIC EFFICACY OF VADADUSTAT FOR ANEMIA IN PATIENTS WITH KIDNEY FAILURE ON DIALYSIS

Abstract Background and Aims Vadadustat is a small-molecule inhibitor of hypoxia-inducible factor prolyl hydroxylase being developed for treatment of anemia associated with chronic kidney disease (CKD). The vadadustat phase 3 program includes four efficacy and cardiovascular safety outcome trials of vadadustat versus the erythropoiesis-stimulating agent (ESA) darbepoetin alfa. Here we describe detailed results on hematologic efficacy in two of the four phase 3, randomized, open-label, sponsor-blind trials (the INNO2VATE trials) in adult patients with dialysis-dependent (DD) CKD and anemia, where vadadustat met prespecified noninferiority criteria compared with darbepoetin alfa with respect to cardiovascular safety and correction/maintenance of hemoglobin (Hb) target concentrations. Method The mean screening Hb range for the incident DD-CKD trial (NCT02865850) was 8.0-11.0 g/dL; for the prevalent DD-CKD trial (NCT02892149), it was 8.0-11.0 g/dL in the United States (US) and 9.0-12.0 g/dL for non-US. Patients in the incident and prevalent DD-CKD trials had initiated dialysis within &amp;lt;16 weeks with limited or no prior ESA exposure and &amp;gt;12 weeks with established ESA treatment prior to screening, respectively. Vadadustat starting dose was 300 mg/day for all patients, whereas initial darbepoetin alfa dose depended on each patient’s prior dose or product label. Both vadadustat and darbepoetin alfa doses were titrated according to prespecified dosing algorithms to achieve target Hb concentrations (US: 10-11 g/dL; non-US: 10-12 g/dL) during the primary evaluation period (PEP; weeks 24-36) and the secondary evaluation period (SEP; weeks 40-52). Herein, we present topline results from PEP and SEP endpoints, as well as other, more detailed hematologic erythrocyte parameters. Results A total of 3923 patients (369 with incident DD-CKD and 3554 with prevalent DD-CKD) were randomized 1:1 to vadadustat or darbepoetin alfa. Vadadustat was noninferior to darbepoetin alfa in achieving target-range Hb concentrations (primary efficacy endpoint) among patients who were new to, or established on, dialysis. The respective proportions of patients (vadadustat vs. darbepoetin alfa) with an average Hb value within the geography-specific target range in the PEP and SEP were 43.6% versus 56.9% and 39.8% versus 41.0% in the incident trial and 49.2% versus 53.2% and 44.3% versus 50.9% in the prevalent dialysis trial. The proportion of patients who achieved an Hb increase &amp;gt;1.0 g/dL from baseline to week 52 was assessed only for the incident trial and was 84.0% (95% CI: 77.8%, 89.0%) for vadadustat versus 89.9% (95% CI: 84.7%, 93.8%) for darbepoetin alfa. Hematologic erythrocyte parameters at time points within the PEP and SEP are presented in Table 1. In the incident trial, reticulocyte count was slightly increased from baseline at 28 and 52 weeks for vadadustat, whereas for darbepoetin alfa, reticulocyte count was slightly decreased or unchanged in both trials. Erythrocyte mean corpuscular volume and erythrocyte mean corpuscular Hb showed increases by week 52 for both groups. Conclusion Vadadustat demonstrated similar profiles across erythrocyte parameters compared with darbepoetin alfa in the treatment of anemia associated with CKD in adults in both incident dialysis and prevalent dialysis settings.

MO541HEMATOLOGIC EFFICACY OF VADADUSTAT FOR ANEMIA IN PATIENTS WITH NON--DIALYSIS-DEPENDENT CHRONIC KIDNEY DISEASE

Abstract Background and Aims Vadadustat is a small-molecule inhibitor of hypoxia-inducible factor prolyl hydroxylases under development to treat anemia associated with chronic kidney disease (CKD). The vadadustat phase 3 program includes four efficacy and cardiovascular safety outcome trials of vadadustat versus the erythropoiesis-stimulating agent (ESA) darbepoetin alfa. Here we describe detailed results on hematologic efficacy in two phase 3, randomized trials (the PRO2TECT trials) in adult patients with non–dialysis-dependent (NDD) CKD and anemia, in which vadadustat met prespecified noninferiority criteria compared to darbepoetin alfa, with respect to hematologic efficacy (correction/maintenance of hemoglobin [Hb] target concentrations). Method The mean screening Hb level for the ESA-untreated NDD-CKD trial (NCT02648347) had to be &amp;lt;10.0 g/dL, and for the ESA-treated NDD-CKD trial (NCT02680574), the range had to be from 8.0-11.0 g/dL in the United States (US) and from 9.0-12.0 g/dL non-US. In the ESA-untreated trial, patients received no ESA within 8 weeks before randomization; in the ESA-treated trial, patients were maintained on ESA therapy, with ≥1 dose received within 6 weeks prior to or during screening. The vadadustat starting dose was 300 mg/day for all patients, whereas the initial darbepoetin alfa dose depended on each patient’s prior dose or the product label. Both vadadustat and darbepoetin alfa doses were titrated according to prespecified dosing algorithms to achieve target Hb concentrations (US: 10-11 g/dL; non-US: 10-12 g/dL) both during the primary (PEP; weeks 24-36) and secondary (SEP; weeks 40-52) evaluation periods. Herein, we present topline results from the PEP and SEP endpoints, in addition to more detailed erythrocyte parameters. Results A total of 3,476 patients (1751 ESA-untreated and 1725 ESA-treated) were randomized 1:1 to vadadustat or darbepoetin alfa. In both trials, vadadustat was noninferior to darbepoetin alfa with regard to the difference of mean change in Hb concentrations between baseline and PEP, as well as between baseline and SEP. The respective proportions of patients (vadadustat vs. darbepoetin alfa) with an average Hb value within the geography-specific target range in the PEP and SEP were 50.4% versus 50.2% and 43.1% versus 43.5% in the ESA-untreated trial and 60.1% versus 60.7% and 50.7% versus 49.0% in the ESA-treated trial. The proportion of patients (vadadustat vs darbepoetin alfa) who achieved an Hb increase &amp;gt;1.0 g/dL from baseline to week 52 was assessed only for the ESA-untreated trial and was 87.7% (95% CI: 85.4%, 89.8%) for vadadustat versus 88.0% (95% CI: 85.6%, 90.0%) for darbepoetin alfa. Hematologic parameters at time points within the PEP and SEP are presented in Table 1. In both the ESA-untreated and ESA-treated trials, the reticulocyte count trended up from baseline through week 52 for vadadustat and trended down from baseline for darbepoetin alfa. Trends in erythrocyte mean corpuscular volume and erythrocyte mean corpuscular Hb were largely unremarkable by week 52 in both treatment groups. Conclusion Vadadustat demonstrated similar profiles across erythrocyte parameters compared with darbepoetin alfa in the treatment of adults with anemia in CKD not on dialysis, whether ESA-untreated or ESA-treated at study entry.

The synergistic efficacy of hydroxychloroquine with methotrexate is accompanied by increased erythrocyte mean corpuscular volume.

ObjectivesTo determine whether concomitant HCQ modulates the increase in erythrocyte mean corpuscular volume (MCV) caused by MTX therapy, and whether this is associated with improved clinical response in RA.MethodsA retrospective observational analysis was conducted on two independent hospital datasets of biologic-naïve, early-RA patients who started oral MTX. Baseline characteristics, DAS28-ESR and monthly MCV after starting MTX were obtained. Conventional and machine-learning statistical approaches were applied to the discovery cohort (Cohort 1, 655 patients) and results validated using Cohort 2 (225 patients).ResultsHCQ therapy with MTX was associated with a 2-fold increase in the likelihood of response defined in this study as clinical remission or low disease activity at 6 months (P <0.001). The improved clinical outcome of combination HCQ and MTX therapy was associated with an accelerated rise in MCV from 2 months after commencing therapy. The increase in MCV at 3 months was equivalent to the contemporaneous reduction in the DAS (DAS28-ESR) in predicting clinical response at 6 months. Using latent class mixed modelling, five trajectories of MCV change over 6 months from baseline were identified. The odds ratio of response to treatment was 16.2 (95% CI 5.7, 46.4, P <0.001) in those receiving combination therapy classified within the MCV elevation >5 fl class, which contained the most patients, compared with MTX alone.ConclusionOur data provide mechanistic insight into the synergistic clinical benefit of concomitant HCQ with MTX, boosting the rise in MCV, which could serve as a companion biomarker of treatment response.

O07 The increase in erythrocyte mean corpuscular volume by methotrexate is potentiated by hydroxychloroquine and is an early indicator of clinical response in rheumatoid arthritis

Background/Aims Rheumatologists are facing a significant challenge in the management of early rheumatoid arthritis (RA) due to limitations placed on outpatient visits during the COVID-19 pandemic. Frequent clinical assessments of disease activity are recommended during implementation of the treat to target strategy to achieve remission. A biomarker indicating response to methotrexate during the early phase of therapy could complement clinical examination. Methotrexate increases erythrocyte mean corpuscular volume (MCV), which is measured routinely, prompting us to investigate whether changes in MCV could act as an early indicator of response. Methods Patients with early RA who were started on methotrexate therapy were included from two independent cohorts. The larger cohort (discovery cohort, n = 655) was used to build the model and the second cohort (validation cohort, n = 225) was applied to test the prediction of the model. Conventional statistical, and machine learning approaches were adopted to identify key determinants that influence the potential relationship between MCV and clinical response, defined as attainment of remission or low disease activity, at six months after starting methotrexate. Results A LASSO penalised logistic regression model was built with the discovery cohort [area under the receiver operating characteristics (AUROC) curve = 0.76], where change of MCV from three months [Odds ratio (OR) 1.53 (95% CI 1.38-1.70)], concomitant use of hydroxychloroquine [OR 2.16 (95% CI 1.52 - 3.07, p < 0.001)], and seropositivity [OR 1.83 (95% CI 1.12 - 3.03, p = 0.02)] were associated with favourable methotrexate response [accuracy 81% (95% CI 76%-86%) of the model testing against discovery model]. Different machine learning classification methods were applied. Random forest exhibited the maximum accuracy and AUROC (89%, and 86%, respectively), confirming the above three predictors as the most significant. Two latent classes (class 1: smaller MCV increase and class 2: greater MCV increase) were identified based on the MCV changes over six months. Class 1 had fewer responders and a lower number of patients on hydroxychloroquine compared to class 2. The earliest time point of significant difference of MCV between responders and non-responders was three months [mean difference 1.43 (95% CI 0.57-2.3)]. Combination hydroxychloroquine and methotrexate caused the greatest increase in MCV with a difference between responders and non-responders at 2 months. Change of MCV at three months showed AUROC of 0.75 to predict treatment response to the combination of methotrexate and hydroxychloroquine at six months with an optimal cut-point of MCV 3.5 fL (95% CI 3.5-3.6) with 71% sensitivity and 75%, specificity. Conclusion Our data provides mechanistic insight into the synergistic clinical benefit of concomitant hydroxychloroquine with methotrexate, boosting the rise in erythrocyte MCV which could serve as an early biomarker of treatment response. Disclosure M.R. Shipa: Grants/research support; Versus arthritis. S. Yeoh: Grants/research support; Royal College of Physicians, Rosetrees Trust, NIHR University College London Hospitals Biomedical Research Centre, UCLH Charities. A. Embleton-Thirsk: None. D. Mukerjee: None. M.R. Ehrenstein: Grants/research support; University College London Hospital Biomedical Research Centre.

Lactate and glucose as additional considerations to the plasma sodium level-corrected erythrocyte mean corpuscular volume report when using the Sysmex XE-2100

BackgroundMean corpuscular volume (MCV) can be artefactually inflated, by variation in sodium concentration, on the Sysmex XE-2100. We report that severe hyperglycemia and modest lactic acidemia can also spuriously increase MCV. To catch and correct such inaccurate MCV measurements, we propose to flag them using commonly assayed biomarkers. Materials and MethodsWe examined the relationship between delta MCV (uncorrected MCV minus corrected MCV), plasma osmolality, and levels of plasma glucose, lactate, and sodium in 60 samples from emergency room patients. Based on these biomarkers, we developed and tested a preliminary composite flag system to identify high delta MCV on 105 ER samples. Finally, we evaluated a revised composite flagging system optimized to improve the positive predictive value. ResultsPlasma osmolality, glucose and lactate are each correlated with delta MCV. The revised composite flag system – based on ≥ 5.0 mmol/L of plasma lactate, > 32 mmol/L of glucose, or > 150 mmol/L of sodium – identified twice as many patients with spuriously elevated MCV as the vendor recommended MCHC flagging system. The associated positive predictive value of 31%, while lower than the vendor flagging system (62%), was considered adequate for implementation in our laboratory. ConclusionsWe recommend reporting clinically significant corrected MCVs, based on sample pre-dilution with the Sysmex buffer, when the proposed composite metabolic flag is triggered.

Evidence in the UK Biobank for the underdiagnosis of erythropoietic protoporphyria

PurposeErythropoietic protoporphyria (EPP), characterized by painful cutaneous photosensitivity, results from pathogenic variants in ferrochelatase (FECH). For 96% of patients, EPP results from coinheriting a rare pathogenic variant in trans of a common hypomorphic variant c.315-48T>C (minor allele frequency 0.05). The estimated prevalence of EPP derived from the number of diagnosed individuals in Europe is 0.00092%, but this may be conservative due to underdiagnosis. No study has estimated EPP prevalence using large genetic data sets. MethodsDisease-associated FECH variants were identified in the UK Biobank, a data set of 500,953 individuals including 49,960 exome sequences. EPP prevalence was then estimated. The association of FECH variants with EPP-related traits was assessed. ResultsAnalysis of pathogenic FECH variants in the UK Biobank provides evidence that EPP prevalence is 0.0059% (95% confidence interval [CI]: 0.0042–0.0076%), 1.7–3.0 times more common than previously thought in the UK. In homozygotes for the common c.315-48T>C FECH variant, there was a novel decrement in both erythrocyte mean corpuscular volume (MCV) and hemoglobin. ConclusionThe prevalence of EPP has been underestimated secondary to underdiagnosis. The common c.315-48T>C allele is associated with both MCV and hemoglobin, an association that could be important both for those with and without EPP.