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Smart LR, Charles M, McElhinney KE, Dong M, Power-Hays A, Howard T, Vinks AA, Ambrose EE, Ware RE. Hydroxyurea pharmacokinetics and precision dosing in low-resource settings. Front Mol Biosci 2023; 10:1130206. [PMID: 37325474 PMCID: PMC10267409 DOI: 10.3389/fmolb.2023.1130206] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/22/2023] [Indexed: 06/17/2023] Open
Abstract
Introduction: Hydroxyurea is effective disease-modifying treatment for sickle cell anemia (SCA). Escalation to maximum tolerated dose (MTD) achieves superior benefits without additional toxicities, but requires dose adjustments with serial monitoring. Pharmacokinetic (PK)-guided dosing can predict a personalized optimal dose, which approximates MTD and requires fewer clinical visits, laboratory assessments, and dose adjustments. However, PK-guided dosing requires complex analytical techniques unavailable in low-resource settings. Simplified hydroxyurea PK analysis could optimize dosing and increase access to treatment. Methods: Concentrated stock solutions of reagents for chemical detection of serum hydroxyurea using HPLC were prepared and stored at -80C. On the day of analysis, hydroxyurea was serially diluted in human serum, then spiked with N-methylurea as an internal standard and analyzed using two commercial HPLC machines: 1) standard benchtop Agilent with 449 nm detector and 5 micron C18 column; and 2) portable PolyLC with 415 nm detector and 3.5 micron C18 column. After validation in the United States, the portable HPLC and chemicals were transported to Tanzania. Results: A calibration curve using hydroxyurea 2-fold dilutions ranging from 0 to 1000 µM was plotted against the hydroxyurea:N-methylurea ratio. In the United States, both HPLC systems yielded calibration curves with R2 > 0.99. Hydroxyurea prepared at known concentrations confirmed accuracy and precision within 10%-20% of the actual values. Both HPLC systems measured hydroxyurea with <10% variance from the prepared concentrations, and paired analysis of samples on both machines documented <15% variance. Serial measurements of 300 and 100 μM concentrations using the PolyLC system were precise with 2.5% coefficient of variance. After transport to Tanzania with setup and training, the modified PolyLC HPLC system produced similar calibration curves with R2 > 0.99. Conclusion: Increasing access to hydroxyurea for people with SCA requires an approach that eases financial and logistical barriers while optimizing safety and benefits, especially in low-resource settings. We successfully modified a portable HPLC instrument to quantify hydroxyurea, validated its precision and accuracy, and confirmed capacity building and knowledge transfer to Tanzania. HPLC measurement of serum hydroxyurea is now feasible in low-resource settings using available laboratory infrastructure. PK-guided dosing of hydroxyurea will be tested prospectively to achieve optimal treatment responses.
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Affiliation(s)
- Luke R Smart
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Global Health Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Mwesige Charles
- Department of Laboratory Sciences, Bugando Medical Centre, Mwanza, Tanzania
| | - Kathryn E McElhinney
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Min Dong
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Division of Clinical Pharmacology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Alexandra Power-Hays
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Global Health Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Thad Howard
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Alexander A Vinks
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Division of Clinical Pharmacology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Emmanuela E Ambrose
- Department of Paediatrics and Child Health, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
- Department of Paediatrics and Child Health Bugando Medical Centre, Mwanza, Tanzania
| | - Russell E Ware
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Global Health Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
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Smart LR, Ambrose EE, Balyorugulu G, Songoro P, Shabani I, Komba P, Charles M, Howard TA, McElhinney KE, O'Hara SM, Odame J, Nakafeero M, Adams J, Stuber SE, Lane A, Latham TS, Makubi AN, Ware RE. Stroke Prevention with Hydroxyurea Enabled through Research and Education: A Phase 2 Primary Stroke Prevention Trial in Sub-Saharan Africa. Acta Haematol 2022; 146:95-105. [PMID: 35977532 PMCID: PMC10100573 DOI: 10.1159/000526322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 07/01/2022] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Stroke is a severe complication of sickle cell anemia (SCA), with devastating sequelae. Transcranial Doppler (TCD) ultrasonography predicts stroke risk, but implementing TCD screening with suitable treatment for primary stroke prevention in low-resource environments remains challenging. SPHERE (NCT03948867) is a prospective phase 2 open-label hydroxyurea trial for SCA in Tanzania. METHODS After formal training and certification, local personnel screened children 2-16 years old; those with conditional (170-199 cm/s) or abnormal (≥200 cm/s) time-averaged mean velocities (TAMVs) received hydroxyurea at 20 mg/kg/day with dose escalation to maximum tolerated dose (MTD). The primary study endpoint is change in TAMV after 12 months of hydroxyurea; secondary endpoints include SCA-related clinical events, splenic volume and function, renal function, infections, hydroxyurea pharmacokinetics, and genetic modifiers. RESULTS Between April 2019 and April 2020, 202 children (average 6.8 ± 3.5 years, 53% female) enrolled and underwent TCD screening; 196 were deemed eligible by DNA testing. Most had numerous previous hospitalizations and transfusions, with low baseline hemoglobin (7.7 ± 1.1 g/dL) and %HbF (9.3 ± 5.4%). Palpable splenomegaly was present at enrollment in 49 (25%); average sonographic splenic volume was 103 mL (range 8-1,045 mL). TCD screening identified 22% conditional and 2% abnormal velocities, with hydroxyurea treatment initiated in 96% (45/47) eligible children. CONCLUSION SPHERE has built local capacity with high-quality research infrastructure and TCD screening for SCA in Tanzania. Fully enrolled participants have a high prevalence of elevated baseline TCD velocities and splenomegaly. SPHERE will prospectively determine the benefits of hydroxyurea at MTD for primary stroke prevention, anticipating expanded access to hydroxyurea treatment across Tanzania.
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Affiliation(s)
- Luke R. Smart
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Global Health Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Emmanuela E. Ambrose
- Catholic University of Health & Allied Sciences, Mwanza, Tanzania
- Bugando Medical Centre, Mwanza, Tanzania
| | | | | | - Idd Shabani
- Catholic University of Health & Allied Sciences, Mwanza, Tanzania
- Bugando Medical Centre, Mwanza, Tanzania
| | | | | | - Thad A. Howard
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Global Health Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Kathryn E. McElhinney
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Sara M. O'Hara
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Jodie Odame
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Global Health Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Maria Nakafeero
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Janet Adams
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Susan E. Stuber
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Adam Lane
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Teresa S. Latham
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Abel N. Makubi
- Catholic University of Health & Allied Sciences, Mwanza, Tanzania
- Bugando Medical Centre, Mwanza, Tanzania
| | - Russell E. Ware
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Global Health Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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Ambrose EE, Smart LR, Charles M, Hernandez AG, Latham T, Hokororo A, Beyanga M, Howard TA, Kamugisha E, McElhinney KE, Tebuka E, Ware RE. Surveillance for sickle cell disease, United Republic of Tanzania. Bull World Health Organ 2020; 98:859-868. [PMID: 33293746 PMCID: PMC7716099 DOI: 10.2471/blt.20.253583] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 08/17/2020] [Accepted: 08/28/2020] [Indexed: 11/27/2022] Open
Abstract
Objective To determine the regional- and district-level newborn prevalence of sickle cell trait and disease, and the prevalence of haemoglobin variants and genetic modifiers of sickle cell disease, in the nine regions of north-western United Republic of Tanzania. Methods We repurposed dried blood spot samples from children (aged 0–24 months) born to mothers living with human immunodeficiency virus (HIV), collected as part of the HIV Early Infant Diagnosis programme, for sickle cell diagnosis. We performed isoelectric focusing to determine whether samples had normal haemoglobin, sickle cell trait, sickle cell disease or a rare haemoglobin variant. We shipped samples diagnosed as disease or variant to Cincinnati Children’s Hospital in the United States of America for deoxyribonucleic-acid-based analyses to determine the prevalence of α-thalassaemia, glucose-6-phosphate dehydrogenase (G6PD) deficiency or fetal haemoglobin genetic modifiers. Findings We analysed a total of 17 200 specimens during February 2017–May 2018. We observed a prevalence of sickle cell trait and disease of 20.3% (3492/17 200) and 1.2% (210/17 200), respectively. District-level trait varied from 8.6% (5/58) to 28.1% (77/274). Among confirmed sickle cell disease specimens, we noted 42.7% (61/143) had 1-gene deletion and 14.7% (21/143) had 2-gene deletion α-thalassaemia trait. We documented G6PD A– deficiency in 19.2% (14/73) of males. Conclusion Our calculated prevalence is twice as high as previously reported and reinforces the need for enhanced sickle cell diagnostic services. Our district-level data will inform public health policy, allowing screening and disease-modifying hydroxyurea therapy to be focused on high-prevalence areas, until universal newborn screening is available.
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Affiliation(s)
- Emmanuela E Ambrose
- Department of Paediatrics and Child Health, Catholic University of Health and Allied Sciences, Mwanza, United Republic of Tanzania
| | - Luke R Smart
- Division of Hematology, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati Children's Hospital, 3333 Burnet Avenue, MLC 7015 Cincinnati, Ohio 45229, United States of America
| | - Mwesige Charles
- Department of Laboratory Services, Bugando Medical Centre, Mwanza, United Republic of Tanzania
| | - Arielle G Hernandez
- Division of Hematology, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati Children's Hospital, 3333 Burnet Avenue, MLC 7015 Cincinnati, Ohio 45229, United States of America
| | - Teresa Latham
- Division of Hematology, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati Children's Hospital, 3333 Burnet Avenue, MLC 7015 Cincinnati, Ohio 45229, United States of America
| | - Adolfine Hokororo
- Department of Paediatrics and Child Health, Catholic University of Health and Allied Sciences, Mwanza, United Republic of Tanzania
| | - Medard Beyanga
- Department of Laboratory Services, Bugando Medical Centre, Mwanza, United Republic of Tanzania
| | - Thad A Howard
- Division of Hematology, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati Children's Hospital, 3333 Burnet Avenue, MLC 7015 Cincinnati, Ohio 45229, United States of America
| | - Erasmus Kamugisha
- Department of Biochemistry and Molecular Biology, Catholic University of Health and Allied Sciences, Mwanza, United Republic of Tanzania
| | - Kathryn E McElhinney
- Division of Hematology, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati Children's Hospital, 3333 Burnet Avenue, MLC 7015 Cincinnati, Ohio 45229, United States of America
| | - Erius Tebuka
- Department of Pathology, Catholic University of Health and Allied Sciences, Mwanza, United Republic of Tanzania
| | - Russell E Ware
- Division of Hematology, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati Children's Hospital, 3333 Burnet Avenue, MLC 7015 Cincinnati, Ohio 45229, United States of America
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Kiyaga C, Hernandez AG, Ssewanyana I, Schaefer BA, McElhinney KE, Ndeezi G, Howard TA, Ndugwa CM, Ware RE, Aceng JR. Sickle cell screening in Uganda: High burden, human immunodeficiency virus comorbidity, and genetic modifiers. Pediatr Blood Cancer 2019; 66:e27807. [PMID: 31094093 DOI: 10.1002/pbc.27807] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/03/2019] [Accepted: 04/23/2019] [Indexed: 12/26/2022]
Abstract
BACKGROUND The Uganda Sickle Surveillance Study provided evidence for a large sickle burden among HIV-exposed infants in Uganda. To date, however, no large scale screening program has been developed for Central or East Africa. METHODS A 3-year targeted sickle cell screening project in Uganda was designed by the Ministry of Health to (1) determine sickle cell trait and disease prevalence within high-burden districts, (2) document the prevalence among HIV-exposed and nonexposed children, (3) confirm previously suggested HIV comorbidity, and (4) estimate the co-inheritance of known genetic modifiers of sickle cell disease. RESULTS A total of 163 334 dried blood spot samples collected between April 2015 and March 2018 were analyzed, including 112 352 samples within the HIV Early Infant Diagnosis program. A high burden with >1% sickle cell disease was found within targeted East Central and Mid-Northern districts, in both HIV-exposed and nonexposed children. Based on crude birth-rate data, 236 905 sickle cell trait births and 16 695 sickle cell disease births will occur annually in Uganda. Compared to sickle cell disease without HIV, the odds ratio of having sickle cell disease plus HIV was 0.50 (95% confidence interval = 0.40-0.64, P < .0001). Alpha-thalassemia trait and G6PD deficiency were common with sickle cell disease, but with different geospatial distribution. CONCLUSIONS High sickle cell burden and potential HIV comorbidity are confirmed in Uganda. Genetic modifiers are common and likely influence laboratory and clinical phenotypes. These prospective data document that targeted sickle cell screening is feasible and effective in Uganda, and support development of district-level comprehensive care programs.
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Affiliation(s)
- Charles Kiyaga
- Central Public Health Laboratories, Ministry of Health, Kampala, Uganda
| | - Arielle G Hernandez
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Global Health Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Isaac Ssewanyana
- Central Public Health Laboratories, Ministry of Health, Kampala, Uganda
| | - Beverly A Schaefer
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Kathryn E McElhinney
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Grace Ndeezi
- Department of Paediatrics and Child Health, Makerere University College of Health Sciences, Kampala, Uganda
| | - Thad A Howard
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Christopher M Ndugwa
- Department of Paediatrics and Child Health, Makerere University College of Health Sciences, Kampala, Uganda
| | - Russell E Ware
- Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Global Health Center, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
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Adams GN, Rosenfeldt L, Frederick M, Miller W, Waltz D, Kombrinck K, McElhinney KE, Flick MJ, Monia BP, Revenko AS, Palumbo JS. Colon Cancer Growth and Dissemination Relies upon Thrombin, Stromal PAR-1, and Fibrinogen. Cancer Res 2015; 75:4235-43. [PMID: 26238780 DOI: 10.1158/0008-5472.can-15-0964] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 07/01/2015] [Indexed: 12/13/2022]
Abstract
Thrombin-mediated proteolysis is a major determinant of metastasis, but is not universally important for primary tumor growth. Here, we report that colorectal adenocarcinoma represents one important exception whereby thrombin-mediated functions support both primary tumor growth and metastasis. In contrast with studies of multiple nongastrointestinal cancers, we found that the growth of primary tumors formed by murine and human colon cancer cells was reduced in mice by genetic or pharmacologic reduction of circulating prothrombin. Reduced prothrombin expression was associated with lower mitotic indices and invasion of surrounding tissue. Mechanistic investigations revealed that thrombin-driven colonic adenocarcinoma growth relied upon at least two targets of thrombin-mediated proteolysis, protease-activated receptor-1 (PAR-1) expressed by stromal cells and the extracellular matrix protein, fibrinogen. Colonic adenocarcinoma growth was reduced in PAR-1-deficient mice, implicating stromal cell-associated PAR-1 as one thrombin target important for tumor outgrowth. Furthermore, tumor growth was dramatically impeded in fibrinogen-deficient mice, offering the first direct evidence of a critical functional role for fibrinogen in malignant tumor growth. Tumors harvested from fibrinogen-deficient mice displayed a relative reduction in cell proliferative indices, as well as increased tumor necrosis and decreased tumor vascular density. Collectively, our findings established a functional role for thrombin and its targets PAR-1 and fibrinogen in the pathogenesis of colonic adenocarcinoma, supporting tumor growth as well as local invasion and metastasis.
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Affiliation(s)
- Gregory N Adams
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Leah Rosenfeldt
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Malinda Frederick
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Whitney Miller
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Dusty Waltz
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Keith Kombrinck
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Kathryn E McElhinney
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Matthew J Flick
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Brett P Monia
- Department of Antisense Drug Discovery, ISIS Pharmaceuticals, Inc., Carlsbad, California
| | - Alexey S Revenko
- Department of Antisense Drug Discovery, ISIS Pharmaceuticals, Inc., Carlsbad, California
| | - Joseph S Palumbo
- Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
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