A phase I trial of recombinant human thrombopoietin in patients with delayed platelet recovery after hematopoietic stem cell transplantation.
Delayed platelet recovery is a significant complication after both autologous and allogeneic hematopoietic stem cell transplantation (HSCT). A multicenter, phase I dose-escalation study of recombinant human thrombopoietin (rhTPO) was conducted to assess its safety and to obtain preliminary data on its efficacy in patients with persistent severe thrombocytopenia (<20,000/microL) >35 days after HSCT. Thirty-eight patients, 37 of whom were evaluable, were enrolled in the study from April 1996 through January 1997. rhTPO was administered at doses of 0.6, 1.2, and 2.4 microg/kg as a single dose (group A) or in multiple doses every 3 days for a total of 5 doses (group B). No significant adverse effects were observed. Ten patients had recovery of platelet counts during the 28-day study period; 3 of these 10 had an increase in marrow megakaryocyte content 7 days after completing treatment with rhTPO. When all baseline marrows were compared with samples after rhTPO treatment, there was no difference in marrow megakaryocyte content (P = 0.49). This study design could not answer the question of whether the recoveries of platelet counts observed in some patients were spontaneous or influenced by rhTPO treatment; nonetheless, the authors found no correlation between the dose of rhTPO and the recovery of platelet counts. Increases in serum TPO levels were dose-dependent and remained significantly elevated for up to 72 hours after treatment. To evaluate response, further studies of treatment strategies with rhTPO in patients with delayed platelet recovery are required.
Nash
R A
RA
Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA.
Kurzrock
R
R
DiPersio
J
J
Vose
J
J
Linker
C
C
Maharaj
D
D
Nademanee
A P
AP
Negrin
R
R
Nimer
S
S
Shulman
H
H
Ashby
M
M
Jones
D
D
Appelbaum
F R
FR
Champlin
R
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D000906:Antibodies / Q000276:immunology; D000918:Antibody Specificity; D004341:Drug Evaluation; D005260:Female; D006085:Graft Survival / Q000187:drug effects; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008533:Megakaryocytes / Q000473:pathology; D008875:Middle Aged; D009503:Neutropenia / Q000188:drug therapy / Q000209:etiology; D010976:Platelet Count / Q000187:drug effects; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D015996:Survival Rate; D013921:Thrombocytopenia / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D013926:Thrombopoietin / Q000008:administration & dosage* / Q000276:immunology / Q000493:pharmacokinetics; D013997:Time Factors
D000906:Antibodies; D011994:Recombinant Proteins; D013926:Thrombopoietin