A phase II trial of imatinib mesylate in merkel cell carcinoma (neuroendocrine carcinoma of the skin): A Southwest Oncology Group study (S0331).
BACKGROUND
Imatinib mesylate (Gleevec) was evaluated as a treatment for Merkel cell carcinoma (MCC, neuroendocrine carcinoma of the skin) based on the identification of strong c-KIT staining of these neoplasms.


METHODS
Eligibility included patients with measurable metastatic or unresectable MCC, c-KIT (CD117) expression and a Zubrod performance status of 0 to 2. Imatinib 400 mg daily was administered orally in 28-day cycles to 23 patients.


RESULTS
Overall, imatinib was well tolerated with grade 1 or 2 nausea, diarrhea, and hematologic toxicity as the most frequent side effects. A partial response was seen in 1 patient (4%; 95% CI: 0%-22%). Median progression-free survival was 1 month (95% CI: 1-2 months). Median overall survival was 5 months (95% CI: 2-8 months). One patient achieved a partial response and another had prolonged disease stabilization while receiving treatment.


CONCLUSIONS
The majority of patients progressed rapidly within 1 to 2 cycles of treatment. The observed progression-free survival and overall survival were not adequate to conclude that this agent was active in advanced MCC, and thus the planned second stage of patient accrual was not opened.
Samlowski
Wolfram E
WE
Nevada Cancer Institute, Las Vegas, USA.
Moon
James
J
Tuthill
Ralph J
RJ
Heinrich
Michael C
MC
Balzer-Haas
Naomi S
NS
Merl
Stuart A
SA
DeConti
Ronald C
RC
Thompson
John A
JA
Witter
Merle T
MT
Flaherty
Lawrence E
LE
Sondak
Vernon K
VK
D000368:Aged; D000369:Aged, 80 and over; D001549:Benzamides; D015266:Carcinoma, Merkel Cell / Q000188:drug therapy*; D064420:Drug-Related Side Effects and Adverse Reactions; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D000068877:Imatinib Mesylate; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000009:adverse effects / Q000627:therapeutic use*; D047428:Protein Kinase Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D011743:Pyrimidines / Q000009:adverse effects / Q000627:therapeutic use*; D012878:Skin Neoplasms / Q000188:drug therapy*; D016019:Survival Analysis
D001549:Benzamides; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D000068877:Imatinib Mesylate