Selective CD4+ lymphopenia in melanoma patients treated with temozolomide: a toxicity with therapeutic implications.
OBJECTIVE
Standard schedule temozolomide (TMZ; daily for 5 days every 4 weeks) is often used in melanoma patients, but phase III data show that it is no more effective than standard dacarbazine. Extended TMZ dosing regimens may be superior by delivering the drug continuously at a higher dose over time. Using an extended dosing schedule, we noted a high incidence of lymphopenia and occasional opportunistic infections (OIs). Here we report our retrospective experience in the first 97 patients.


METHODS
TMZ was administered at 75 mg/m(2)/d orally for 6 weeks every 8 weeks, although nine patients were treated continuously without a break. Seventeen patients were treated with TMZ alone; 73 patients received TMZ with thalidomide; seven patients received TMZ with low-dose interferon alfa.


RESULTS
Median duration of TMZ treatment was 113 days; 29% received > or = 24 weeks of therapy. Lymphopenia was seen in 60% of patients (absolute lymphocyte count < 800/microL) with a median of 101 days to lymphopenia. TMZ did not cause significant neutropenia or thrombocytopenia. Lymphopenia was not more common in patients treated concomitantly with thalidomide. In all patients analyzed for lymphocyte subsets, lymphopenia induced by TMZ affected the CD4(+) compartment preferentially. There were two documented OIs (Pneumocystis and Aspergillus pneumonia) as well as other infections indicative of T-cell dysfunction in another 21 patients.


CONCLUSIONS
TMZ at this dose and schedule results in CD4(+) lymphopenia in a majority of patients that can result in OIs. Pneumocystis pneumonia prophylaxis should be considered for patients who develop sustained lymphopenia on TMZ.
Su
Y B
YB
Department of Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
Sohn
Sejean
S
Krown
Susan E
SE
Livingston
Philip O
PO
Wolchok
Jedd D
JD
Quinn
Carolyn
C
Williams
Linda
L
Foster
Theresa
T
Sepkowitz
Kent A
KA
Chapman
Paul B
PB
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018906:Antineoplastic Agents, Alkylating / Q000008:administration & dosage / Q000009:adverse effects*; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects*; D003606:Dacarbazine / Q000009:adverse effects* / Q000031:analogs & derivatives* / Q000276:immunology; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008231:Lymphopenia / Q000139:chemically induced*; D008297:Male; D008545:Melanoma / Q000188:drug therapy* / Q000276:immunology; D008875:Middle Aged; D015999:Multivariate Analysis; D009894:Opportunistic Infections / Q000139:chemically induced; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D000077204:Temozolomide
D018906:Antineoplastic Agents, Alkylating; D003606:Dacarbazine; D000077204:Temozolomide