Oral melphalan at diagnosis hampers adequate collection of peripheral blood progenitor cells in multiple myeloma.
OBJECTIVE
Since optimal collection of peripheral blood progenitor cells (PBPC) remains crucial for high-dose therapy in patients with multiple myeloma (MM) in relapse phase or refractory to chemotherapy, we evaluated several variables that may influence mobilization.


METHODS
Eighty-nine patients who underwent a standard mobilization procedure with cyclophosphamide (3 g/m2) and growth factors entered the study. A composite collection totalling at least 2x106 CD34+/kg was defined as a sufficient yield: 59 patients achieved an adequate collection. A reliable factor to predict adequate yields was prior therapy: an adequate collection was obtained in 92% of patients treated with conventional non-alkylating therapy (VAD-based regimens), in 56% treated with oral melphalan and in 23% who had received intravenous melphalan.


RESULTS
The three groups were similar for most clinical features. After adjustment for several potential confounders, the probability of an adequate PBPC collection remained higher in the group treated with non-alkylating agents, with an odds ratio (OR) of 6.14 (95% confidence interval, CI=1.34, 28.13) and lower in those treated with intravenous melphalan (OR=0.08; CI=0.01-0.61), when compared to the group treated with oral melphalan. Among the other prognostic factors (stage, percentage of bone marrow plasma cells, b2-microglobulin, labeling index, isotype, monoclonal component, Bence-Jones proteinuria) evaluated at diagnosis, there was no clear association with progenitor cell yield.


CONCLUSIONS
In conclusion, patients who are potential candidates for high-dose therapy with PBPC support should not receive conventional alkylating therapy, even orally. Alternatively, progenitor cells should be collected early in the course of MM.
Boccadoro
Mario
M
Divisione di Ematologia dell'Università di Torino, Azienda Ospedaliera S. Giovanni Battista, via Genova 3, 10126 Turin, Italy. mario.boccadoro@unito.it
Palumbo
Antonio
A
Bringhen
Sara
S
Merletti
Franco
F
Ciccone
Giovannino
G
Richiardi
Lorenzo
L
Rus
Cecilia
C
Bertola
Alessandra
A
Giaccone
Luisa
L
Omedè
Paola
P
Musto
Pellegrino
P
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D018906:Antineoplastic Agents, Alkylating / Q000008:administration & dosage / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000627:therapeutic use; D001772:Blood Cell Count; D003131:Combined Modality Therapy; D000075202:Contraindications; D003520:Cyclophosphamide / Q000494:pharmacology; D003907:Dexamethasone / Q000008:administration & dosage; D004317:Doxorubicin / Q000008:administration & dosage; D005260:Female; D019650:Hematopoietic Stem Cell Mobilization / Q000379:methods; D006412:Hematopoietic Stem Cells / Q000187:drug effects*; D006801:Humans; D008297:Male; D008558:Melphalan / Q000008:administration & dosage / Q000494:pharmacology*; D008875:Middle Aged; D009101:Multiple Myeloma / Q000097:blood / Q000188:drug therapy* / Q000628:therapy; D016017:Odds Ratio; D012189:Retrospective Studies; D016879:Salvage Therapy; D033581:Stem Cell Transplantation; D014750:Vincristine / Q000008:administration & dosage
D018906:Antineoplastic Agents, Alkylating; D014750:Vincristine; D003907:Dexamethasone; D004317:Doxorubicin; D003520:Cyclophosphamide; D008558:Melphalan