Macdougall_edit.qxp 7/2/08 10:09 am Page 30
developed fatal hepatic necrosis that was temporally related to the EPO as a result of gene therapy is a potentially attractive area of research.
introduction of this compound.
Although investigations regarding causality There are a number of delivery systems that have been investigated for
are ongoing, the US Food and Drug Administration (FDA) has temporarily this purpose, including the injection of naked DNA,
suspended any further clinical trials with the HIF stabilisers. transfection,
use of artificial human chromosomes
of autologous or allogeneic cells manipulated ex vivo.
As with all gene
GATA Inhibition therapy, there are many hurdles to overcome before this strategy could
The GATA family is made up of six transcription factors – GATA 1–6. be used in humans. Not only would there need to be assurance regarding
GATA-2 inhibits EPO gene transcription by binding to the GATA sequence the absence of oncogenicity, but it would also be imperative to show that
on the EPO promoter, thereby leading to downregulation of EPO tight control of the activity of the transferred gene can be achieved. This
messenger RNA (mRNA) expression and subsequent EPO synthesis.
may be possible and one experiment in animals has shown that linking
Therefore, GATA-2 acts as a negative regulatory molecule of EPO gene the transgene to a hypoxia-responsive DNA element may establish
expression. Disrupting this negative signal is a potential future strategy in anoxygen-dependent feedback regulation of the transgene, similar to
producing an antianaemic agent. Several molecules are under that of the endogenous EPO gene.
investigation, including K-11706, which has been shown to enhance EPO
production both in vitro and in vivo.
New targets and strategies for stimulating erythropoiesis and treating
Haemopoietic Cell Phosphatase Inhibition anaemia have been developed in line with elucidation of the molecular
Another strategy with potential for enhancing erythropoiesis is targeting mechanisms controlling RC production. Following the introduction of
haemopoietic cell phosphatase (HCP, SHP-1).
This protein tyrosine recombinant human EPO, attempts were made to modify the molecule and
phosphatase is located in the cytoplasm of haemopoietic cells and causes produce longer-acting erythropoietic agents, such as darbepoetin alfa and
dephosphorylation of janus kinase (JAK-2), acting as a negative regulator CERA. Other modifications to the EPO molecule, such as the production of
of EPO intracellular signal transduction. The potential importance of this fusion proteins, are being explored, as is the potential for EPO gene therapy.
molecule in mediating responsiveness to EPO therapy was studied in The concept that smaller molecules such as peptides or even non-peptides
CD34+ cells derived from haemodialysis patients responding poorly to may be able to bind to and activate the EPO receptor is also being explored,
As with the GATA inhibitors, HCP inhibitors have not yet been and the first such molecule (Hematide) is already in phase III of its clinical
tested in humans and it is not clear whether they will have a role in the development programme. Other strategies attempting to create orally active
management of CKD anaemia. However, they could potentially be used agents, such as inhibition of prolyl hydroxylase, GATA or haemopoietic cell
as adjuvant therapy to enhance the response to other ESAs, or even to phosphatase, remain in the laboratory, but may yet translate into future
enhance the patient’s own endogenous EPO. therapeutic agents for the management of CKD anaemia. ■
Erythropoietin Gene Therapy Disclosure
With increasing concern that high doses of erythropoietic products may Iain C Macdougall has received consulting fees, lecture fees and grant
be harmful, the ability to generate lower but more continuous levels of support from Amgen, Ortho Biotech, Roche, Shire and Affymax.
1. Macdougall IC, Roberts DE, Coles GA, Williams JD, Clinical of three recombinant human GM-CSF-EPO hybrid proteins in 22. Wiecek A, et al., Pharmacological stabilisation of HIF increases
pharmacokinetics of epoetin (recombinant human cynomolgus monkeys, Mol Biotechnol, 1998;10:115–22. haemoglobin concentration in anaemic patients with chronic
erythropoietin), Clin Pharmacokinet, 1991;20:99–113. 13. Way JC, Lauder S, Brunkhorst B, et al., Improvement of Fc- kidney disease, Nephrol Dial Transplant, 2005;20(Suppl. 5):v195.
2. Lin FK, Suggs S, et al., Cloning and expression of the human erythropoietin structure and pharmacokinetics by modification 23. Astellas Pharma Inc, Adverse Event of FG-2216 for the
erythropoietin gene, Proc Natl Acad Sci U S A, 1985;7580–84. at a disulfide bond, Protein Eng Des Sel, 2005;18:111–18. Treatment of Anaemia, www.astellas.com, 2007.
3. Egrie JC, et al., The role of carbohydrate on the biological 14. Bugelski P, Nesspor BT, et al., Pharmacokinetics and 24. Imagawa S, Yamamoto M, Miura Y, Negative regulation of the
activity of erythropoietin, Glycoconjugate J, 1993;10:263. pharmacodynamics of CTNO528, a novel erythropoiesis receptor erythropoietin gene expression by the GATA transcription
4. Sikole A, Spasovski G, Zafirov D, Polenakovic M, Epoetin agonist in normal and anaemic rats, Blood, 2005;106:146b. factors, Blood, 1997;89:1430–39.
omega for treatment of anaemia in maintenance haemodialysis 15. Dumont JA, Bitonti AJ, et al., Delivery of an erythropoietin-Fc fusion 25. Nakano Y, et al., Oral administration of K-11706 inhibits GATA
patients, Clin Nephrol, 2002;57:237–45. protein by inhalation in humans through an immunoglobulin binding activity, enhances hypoxia-inducible factor 1 binding
5. Martin KJ, on behalf of the Epoetin Delta 3001 Study Group: transport pathway, J Aerosol Med, 2005;18:294–303. activity, and restores indicators in an in vivo mouse model of
Epoetin delta in the management of renal anaemia: results of a 16. Wrighton NC, et al., Small peptides as potent mimetics of the anaemia of chronic disease, Blood, 2005;104:4300–4307.
six-month study, Nephrol Dial Transplant, 2007;22:3052–4. protein hormone erythropoietin, Science, 1996;273:458–64. 26. Barbone FP, et al., New epoetin molecules and novel therapeutic
6. Schellekens H, Biosimilar epoetins, Clin J Am Soc Nephrol, 17. Fan Q, Leuther KK, Holmes CP, et al., Pre-clinical evaluation of approaches, Nephrol Dial Transplant, 1999;14(Suppl. 2):80–84.
2008; in press. Hematide, a novel erythropoiesis stimulating agent, for the 27. Akagi S, Ichikawa H, et al., The critical role of SRC homology
7. The Court Service – Court of Appeal – Civil Judgement: In TKT’s treatment of anaemia, Exp Hematol, 2006;34:1303–11. domain 2-containing tyrosine phosphatase-1 in recombinant
technology, those cells were designated as R223 cells. Neutral 18. Woodburn KW, Leuther K, Fan Q, et al., Renal excretion is the human erythropoietin hyporesponsive anaemia in chronic
Citation Number, EWCA Civ, www.hmcourts-service.gov.uk/ primary route of elimination for the erythropoiesis-stimulating haemodialysis patients, J Am Soc Nephrol, 2004;15:3215–24.
judgmentsfiles/j1329/Kirin_v_Hoechst.htm, 2002;1096. agent Hematide as assessed by quantitative whole-body 28. Fattori E, Cappelletti M, Zampaglione I, et al., Gene electro-
8. Macdougall IC, Gray SJ, Elston O, et al., Pharmacokinetics of autoradioluminography (QWBA) in Sprague Dawley rats, ERA- transfer on an improved erythropoietin plasmid in mice and
novel erythropoiesis stimulating protein compared with epoetin EDTA Congress, 2007; abstract SaP333. non-human primates, J Gene Med, 2005;7:228–36.
alfa in dialysis patients, J Am Soc Nephrol, 1999;10:2392–5. 19. Macdougall IC, Tucker B, et al., Hematide™, a synthetic 29. Rivera VM, Gao GP, et al., Long-term pharmacologically
9. Macdougall IC: CERA (Continuous Erythropoietin Receptor peptide-based erythropoiesis stimulating agent, achieves regulated expression of erythropoietin in primates following
Activator), a new erythropoiesis-stimulating agent for the correction of anaemia and maintains haemoglobin in patients AAV-mediated gene transfer, Blood, 2005;105:1424–30.
treatment of anaemia, Curr Hematol Rep, 2005;4:436–40. with chronic kidney disease not on dialysis, American Society of 30. Kakeda M, Hiratsuka M, et al., Human artificial chromosome
10. Kochendoerfer GG, Chen SY, Mao F, et al., Design and Nephrology 11th Annual Renal Week, 2007; abstract F-FC079. (HAC) vector provides long-term therapeutic transgene expression
chemical synthesis of a homogeneous polymer-modified 20. Woodburn KW, Fan Q, Winslow S, et al., Hematide™ is in normal human primary fibroblasts, Gene Ther, 2005;12:852–6.
erythropoiesis protein, Science, 2003;299:884–7. immunologically distinct from erythropoietin and corrects 31. Lippin Y, et al., Human erythropoietin gene therapy for patients
11. Lee DE, Son W, Ha BJ, et al., The prolonged half-lives of new anaemia induced by antierythropoietin antibodies in a rat pure with chronic renal failure, Blood, 2005;106:2280–86.
erythropoietin derivatives via peptide addition, Biochem Biophys red cell aplasia model, Exp Hematol, 2007;35:1201–8. 32. Binley K, Askham Z, Iqball S, et al., Long-term reversal of
Res Commun, 2006;339:380–85. 21. Qureshi SA, Kim RM, et al., Mimicry of erythropoietin by a non- chronic anaemia using a hypoxia-regulated erythropoietin gene
12. Coscarella A, et al., Pharmacokinetic and immunogenic behaviour peptide molecule, Proc Natl Acad Sci U S A, 1999;96:12156–61. therapy, Blood, 2002;100:2406–13.
30 EUROPEAN RENAL DISEASE 2007