Blood, 15 July 2002, Vol. 100, No. 2, pp. 728-730
BRIEF REPORT
Effects of pegylated recombinant human megakaryocyte growth and
development factor in patients with idiopathic
thrombocytopenic purpura
Shosaku Nomura,
Kazuo Dan,
Tomomitsu Hotta,
Kingo Fujimura, and
Yasuo Ikeda
From the First Department of Internal Medicine, Kansai
Medical University, Osaka, Japan; the Division of Hematology,
Department of Internal Medicine, Nippon Medical School; the Department
of Hematology and Rheumatology, Tokai University School of Medicine,
Kanagawa, Japan; and the Department of Clinical Pharmaceutical Science,
Graduate School of Medicine, Hiroshima University, Hiroshima, Japan;
and the Division of Hematology, Department of Internal Medicine, Keio
University School of Medicine, Tokyo, Japan.
 |
Abstract |
We conducted a phase 1-2 clinical trial to evaluate the effect of
pegylated recombinant human megakaryocyte growth and development factor
(PEG-rHuMGDF) in patients with chronic idiopathic thrombocytopenic purpura (ITP) refractory to standard therapy who had platelet counts
below 30 × 109/L. Four patients received PEG-rHuMGDF
(0.5 µg/kg of body weight per day) by daily intravenous injection for
up to 7 days. Administration of PEG-rHuMGDF increased platelet
counts in 3 patients. A striking thrombocytosis occurred in 2 patients, whose platelet counts were elevated to more than
700 × 109/L a week after the last administration of
PEG-rHuMGDF and returned to baseline levels within 4 to 6 weeks. Before
the platelet peak, the percentage of reticulated platelets increased
transiently in 3 patients tested, including one patient who had no
response. Bleeding episodes decreased after the start of
PEG-rHuMGDF therapy. These results suggest that PEG-rHuMGDF might have
a clinical benefit in ameliorating thrombocytopenia associated with ITP.
(Blood. 2002;100:728-730)
© 2002 by The American Society of Hematology.
| |
Introduction |
Idiopathic thrombocytopenic purpura (ITP) is
characterized by thrombocytopenia, increased levels of
platelet-associated immunoglobulin, and normal to increased numbers of
megakaryocytes.1,2 The mechanisms of thrombocytopenia and
production of antiplatelet antibodies have been investigated
extensively. In addition to markedly shortened platelet survival,
impaired platelet production is also responsible for thrombocytopenia
in ITP.3 Various therapeutic strategies are used for
treatment of patients with ITP, including corticosteroids, danazol,
immunosuppressive agents, and splenectomy.4 High-dose
intravenous immunoglobulin causes a transient increase in platelet
counts in most patients with ITP.5 Because of the heterogeneity of the disease, however, approximately 20% of cases are
refractory to these treatments. A thrombopoietic cytokine is a
candidate for a new medical treatment in some situations. In a recent
pilot trial in patients with refractory ITP, however, recombinant human
interleukin 11 was not effective.6
Thrombopoietin (TPO) is the primary physiologic regulator of platelet
production.7-10 Initial clinical trials indicated that pegylated recombinant human megakaryocyte growth and development factor
(PEG-rHuMGDF), a nonglycosylated, truncated form of human TPO modified
with polyethylene glycol, potently stimulates platelet production
before chemotherapy in patients with cancer.11 Studies in
healthy human volunteers showed that in addition to increasing platelet
production, PEG-rHuMGDF increases the number and ploidy of marrow
megakaryocytes without influencing platelet function and
viability.12 PEG-rHuMGDF was also used in healthy platelet donors to increase platelet counts and, consequently, platelet yield
from apheresis. A median of 3-fold more apheresis platelets were
obtained after administration of PEG-rHuMGDF.13 However, a
small but significant proportion of subjects in these studies had
development of neutralizing antibodies to endogenous TPO that resulted
in thrombocytopenia.14 Further clinical studies have been
performed to assess the therapeutic effect of PEG-rHuMGDF on platelet
recovery in patients with cancer receiving myelosuppressive chemotherapy15,16 as well as in patients with severe
thrombocytopenia associated with aplastic anemia and myelodysplastic
syndrome.17
In patients with cancer who have received myelosuppressive
chemotherapy, serum TPO levels increased during the period of
thrombocytopenia and then decreased as counts of circulating platelets
increased. In patients with ITP, however, serum TPO levels were normal
or only slightly elevated in spite of a marked
thrombocytopenia.18 These findings, along with the
observation of normal or increased numbers of megakaryocytes in the
bone marrow, suggest that exogenously administered PEG-rHuMGDF might
further stimulate megakaryocytopoiesis and correct thrombocytopenia in
patients with ITP. We here describe the first clinical trial of
PEG-rHuMGDF in patients with chronic ITP refractory to corticosteroid
therapy, splenectomy, or both.
| |
Study design |
Patients with chronic ITP refractory to corticosteroid therapy,
splenectomy, or both and baseline platelet counts below
30 × 109/L during the 3 months before registration were
eligible for this study. Patients also met the following criteria: more
than 18 but under 70 years of age and an Eastern Cooperative Oncologic Group performance status of 0, 1, or 2. Exclusion criteria included serious bleeding, thrombocytopenia associated with systemic lupus erythematosus, infection with human immunodeficiency virus,
splenomegaly, cyclic thrombocytopenia, and previous history of vascular
disease or thromboembolism, or marked heart, lung, liver, or renal
impairment. All patients gave written informed consent to participation
before treatment. The study was approved by the ethics committees of the participating hospitals.
The study was designed as an open-labeled, cohort-sequential,
dose-escalation phase 1-2 clinical trial using doses ranging from 0.5 to 10.0 µg/kg of body weight per day of PEG-rHuMGDF (KRN9000; Kirin
Brewery Company, Tokyo, Japan). Patients received daily intravenous
administration of PEG-rHuMGDF for up to 7 days until platelet counts
exceeded 100 × 109/L.
Complete blood counts and mean platelet volume (MPV) were measured
before treatment, 3 times weekly during the first 2 weeks, and once at
3, 4, 5 and 7 weeks after the start of PEG-rHuMGDF administration.
Reticulated platelets were assayed by using auramine O, a fluorescent
dye, at one selected site (Keio University), as described
previously.19 Serum was collected for assay of antibodies20 against PEG-rHuMGDF and nonpegylated rHuMGDF
before treatment and at 2 weeks, 4 weeks, 3 months, and 6 months after the final injection of PEG-rHuMGDF. Patients were closely monitored for
adverse effects throughout the study.
| |
Results and discussion |
Four patients (Table 1) were given
PEG-rHuMGDF at a dose of 0.5 µg/kg per day for up to 7 days. This
dose was the lowest effective dose in healthy volunteers receiving a
single intravenous injection (J. Azuma et al, unpublished results,
1996). The 7-day treatment with PEG-rHuMGDF was completed in
patients 1 and 3. However, patient 2 received only a single injection
and patient 4 received PEG-rHuMGDF for 6 days (Figure
1).
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| Figure 1.
Changes in platelet counts and the percentage of
reticulated platelets in patients with ITP treated with PEG-rHuMGDF.
Platelet counts ( ) and reticulated platelets ( ) were measured in
patients who received daily intravenous injections of PEG-rHuMGDF (0.5 µg/kg per day [ ]) for up to 7 days. Patients 1 and 3 were given
PEG-rHuMGDF for 7 days. Patient 2 received only a single injection
because hypertension, vomiting, headache, and cold sweating developed
within 2.5 hours after the injection and her systolic blood pressure
rose to 208 mmHg (from 150 mmHg before injection). Computed tomography
(CT) and magnetic resonance imaging of the brain (MRI) showed no
abnormalities. Blood pressure was controlled with nifedipine by 9 days
after administration. Patient 4 received PEG-rHuMGDF for 6 days. On the
night of day 6, his vision became dim while reading a book and numbness
of the fingers developed. His blood pressure was 160/90 mmHg. CT on day
6 revealed no abnormalities. Repeated CT on day 10 and MRI showed no
evidence of hemorrhage or infarction.
|
|
As shown in Figure 1, patients 2, 3, and 4 had a response to
PEG-rHuMGDF therapy. In patients 3 and 4, daily administration of
PEG-rHuMGDF dramatically increased platelet counts, which reached a
maximum level of 747 × 109/L on day 15 in patient 3 and
of 821 × 109/L on day 14 in patient 4. Such a delayed
platelet response likely reflects the mechanism of action of
PEG-rHuMGDF, which stimulates megakaryocyte progenitor cells rather
than mature megakaryocytes.21 Even in patient 2, who
received only one dose of PEG-rHuMGDF, platelet counts increased up to
103 × 109/L on day 10. Patient 1, however, had no
platelet response to PEG-rHuMGDF. Although Harker22
previously observed increased megakaryocytopoiesis and platelet
turnover in patients with ITP, which might have predicted an
ineffective response to PEG-rHuMGDF in our patient 1, a substantial
increase in platelet counts was clearly observed in 3 of our 4 patients, thereby suggesting a potent stimulation of thrombopoiesis by
exogenously administered PEG-rHuMGDF. In all 3 patients who had
a response to PEG-rHuMGDF, MPV decreased as platelet counts increased,
a finding similar to that in other clinical studies of PEG-rHuMGDF
(data not shown).12,23 In contrast to its potent activity
with respect to platelet production, PEG-rHuMGDF had a minimal effect
on red and white blood cells (data not shown).
Before the start of PEG-rHuMGDF therapy, Patients 1, 2, and 4 had
bleeding episodes (ecchymoses and petechiae; Table 1). These decreased
after administration of PEG-rHuMGDF, even in patient 1, whose platelet
counts remained low.
In addition to the striking rise in platelet counts, there was a
significant increase in the percentage of reticulated platelets in all
patients except patient 2, in whom measurement of this variable was not
performed (Figure 1). In patients 3 and 4, the increase in reticulated
platelets reached the peak value on day 3 and day 6, respectively,
preceding the platelet peak by 8 to 12 days. Even in patient 1, who had
no platelet response, the percentage of reticulated platelets increased
transiently and peaked on day 10, which might have been related to the
decrease of bleeding episodes. The data on the reticulated
platelets indicate that PEG-rHuMGDF therapy increased production of new
platelets in these patients.
It was reported previously that neutralizing antibodies with consequent
thrombocytopenia developed in approximately 4% of healthy
volunteers who received more than one dose of
PEG-rHuMGDF.14 In the current study,
however, no antibodies were detected in serum from any patient 6 months
after the start of treatment.
Although data from only 4 patients are available, our current results
strongly suggest that PEG-rHuMGDF may be clinically useful in patients
with chronic ITP. PEG-rHuMGDF therapy might be effective in
ameliorating thrombocytopenia and improving bleeding symptoms in some
patients with chronic ITP refractory to standard therapy. For example,
administration of PEG-rHuMGDF could be used to increase platelet counts
transiently before elective surgery, such as splenectomy, in patients
with ITP. The current dose-escalation study was discontinued at a dose
of 0.5µg/kg per day because the lowest dose of PEG-rHuMGDF used for 7 successive days caused an excessive increase in platelet counts in 2 of
the 4 patients. Further studies must be conducted to determine the
optimal dose and schedule of PEG-rHuMGDF administration in patients
with chronic ITP.
| |
Acknowledgments |
We thank Drs Kiyoaki Watanabe and Yohko Kawai for measurement of
reticulated platelets.
| |
Footnotes |
Submitted October 22, 2001; accepted March 14, 2002.
Supported by research grants from Kirin Brewery Company Ltd, Tokyo, Japan.
The publication costs of this
article were defrayed in part by
page charge payment. Therefore,
and solely to indicate this fact,
this article is hereby marked
"advertisement"
in accordance with 18 U.S.C.
section 1734.
Reprints: Yasuo Ikeda, Division of Hematology, Department of
Internal Medicine, Keio University School of Medicine, 35 Shinanomachi,
Shinjuku-ku, Tokyo 160-8582, Japan; e-mail: yikeda{at}sc.itc.keio.ac.jp.
| |
References |
1.
Karpatkin S.
Autoimmune thrombocytopenic purpura.
Blood.
1980;56:329-343[Abstract/Free Full Text].
2.
McMillan R.
Chronic idiopathic thrombocytopenic purpura.
N Engl J Med.
1981;304:1135-1147[Medline]
[Order article via Infotrieve].
3.
Ballem PJ, Segal GM, Stratton JR, Gernsheimer T, Adamson JW, Slichter SJ.
Mechanisms of thrombocytopenia in chronic autoimmune thrombocytopenic purpura.
J Clin Invest.
1987;80:33-40[Medline]
[Order article via Infotrieve].
4.
Berchtold P, McMillan R.
Therapy of chronic idiopathic thrombocytopenic purpura in adults.
Blood.
1989;74:2309-2317[Abstract/Free Full Text].
5.
Imbach P, Barandun S, d'Apuzzo V, et al.
High-dose intravenous gammaglobulin for idiopathic thrombocytopenic purpura in childhood.
Lancet.
1981;1:1228-1231[Medline]
[Order article via Infotrieve].
6.
Bussel JB, Mukherjee R, Stone AJ.
A pilot study of rhuIL-11 treatment of refractory ITP.
Am J Hematol.
2001;66:172-177[CrossRef][Medline]
[Order article via Infotrieve].
7.
de Sauvage FJ, Hass PE, Spencer SD, et al.
Stimulation of megakaryocytopoiesis and thrombopoiesis by the c-Mpl ligand.
Nature.
1994;369:533-538[CrossRef][Medline]
[Order article via Infotrieve].
8.
Kaushansky K, Lok S, Holly RD, et al.
Promotion of megakaryocyte progenitor expansion and differentiation by the c-Mpl ligand thrombopoietin.
Nature.
1994;369:568-571[CrossRef][Medline]
[Order article via Infotrieve].
9.
Kato T, Ogami K, Shimada Y, et al.
Purification and characterization of thrombopoietin.
J Biochem.
1995;118:229-236[Abstract/Free Full Text].
10.
Kuter DJ, Beeler DL, Rosenberg RD.
The purification of megapoietin: a physiological regulator of megakaryocyte growth and platelet production.
Proc Natl Acad Sci U S A.
1994;91:11104-11108[Abstract/Free Full Text].
11.
Basser RL, Rasko JEJ, Clarke K, et al.
Thrombopoietic effects of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) in patients with advanced cancer.
Lancet.
1996;348:1279-1281[CrossRef][Medline]
[Order article via Infotrieve].
12.
Harker LA, Roskos LK, Marzec UM, et al.
Effects of megakaryocyte growth and development factor on platelet production, platelet life span, and platelet function in healthy human volunteers.
Blood.
2000;95:2514-2522[Abstract/Free Full Text].
13.
Kuter DJ, Goodnough LT, Romo J, et al.
Thrombopoietin therapy increases platelet yields in healthy platelet donors.
Blood.
2001;98:1339-1345[Abstract/Free Full Text].
14.
Li J, Yang C, Xia Y, et al.
Thrombocytopenia caused by the development of antibodies to thrombopoietin.
Blood.
2001;98:3241-3248[Abstract/Free Full Text].
15.
Fanucchi M, Glaspy J, Crawford J, et al.
Effects of polyethylene glycol-conjugated recombinant human megakaryocyte growth and development factor on platelet counts after chemotherapy for lung cancer.
N Engl J Med.
1997;336:404-409[Abstract/Free Full Text].
16.
Basser RL, Rasko JEJ, Clarke K, et al.
Randomized, blinded, placebo-controlled phase I trial of pegylated recombinant human megakaryocyte growth and development factor with filgrastim after dose-intensive chemotherapy in patients with advanced cancer.
Blood.
1997;89:3118-3128[Abstract/Free Full Text].
17.
Komatsu N, Okamoto T, Yoshida T, et al.
Pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) increased platelet counts (PLT) in patients (pts) with aplastic anemia (AA) and myelodysplastic syndrome (MDS) [abstract].
Blood.
2000;96:296a.
18.
Kosugi S, Kurata Y, Tomiyama Y, et al.
Circulating thrombopoietin level in chronic immune thrombocytopenic purpura.
Br J Haematol.
1996;93:704-706[CrossRef][Medline]
[Order article via Infotrieve].
19.
Watanabe K, Takeuchi K, Kawai Y, Ikeda Y, Kubota F, Nakamoto H.
Automated measurement of reticulated platelets in estimating thrombopoiesis.
Eur J Haematol.
1995;54:163-171[Medline]
[Order article via Infotrieve].
20.
Shiozaki H, Miyawaki S, Kuwaki T, Hagiwara T, Kato T, Miyazaki H.
Autoantibodies neutralizing thrombopoietin in a patient with amegakaryocytic thrombocytopenic purpura [letter].
Blood.
2000;95:2187-2188[Free Full Text].
21.
Horie K, Miyazaki H, Hagiwara T, et al.
Action of thrombopoietin at the megakaryocyte progenitor level is critical for the subsequent proplatelet production.
Exp Hematol.
1997;25:169-176[Medline]
[Order article via Infotrieve].
22.
Harker LA.
Thrombokinetics in idiopathic thrombocytopenic purpura.
Br J Haematol.
1970;19:95-104[Medline]
[Order article via Infotrieve].
23.
O'Malley CJ, Rasko JEJ, Basser RL, et al.
Administration of pegylated recombinant human megakaryocyte growth and development factor to humans stimulates the production of functional platelets that show no evidence of in vivo activation.
Blood.
1996;88:3288-3298[Abstract/Free Full Text].
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Abstract
Introduction
