Phase II study of sunitinib in men with advanced prostate cancer.
BACKGROUND
This study explored the efficacy and tolerability of sunitinib, an inhibitor of tyrosine kinase receptors, in men with castration-resistant prostate cancer (CRPC).


METHODS
Men with no prior chemotherapy (group A) and men with docetaxel (Taxotere)-resistant prostate cancer (group B) were treated with sunitinib. The primary end point was confirmed 50% prostate-specific antigen (PSA) decline. Secondary end points included objective response rate and safety. Serum-soluble biomarkers were measured.


RESULTS
Seventeen men were enrolled in each group. One confirmed PSA response was observed in each group, and an additional eight men and seven men had stable PSA at week 12 in groups A and B, respectively. Improvements in imaging were observed in the absence of post-treatment PSA declines. Common adverse effects included fatigue, nausea, diarrhea, myelosuppression and transaminase elevation. Significant changes following sunitinib treatment were observed in serum-soluble biomarkers including soluble vascular endothelial growth factor receptor-2, platelet-derived growth factor aa, placental growth factor and leptin.


CONCLUSIONS
Sunitinib monotherapy resulted in few confirmed 50% post-treatment declines in PSA in men with CRPC. Serum markers of angiogenesis confirmed on-target effects of sunitinib. Assessments of radiographic disease status were often discordant with changes in PSA, indicating that alternate end points are important in future trials.
Dror Michaelson
M
M
Division of Hematology/Oncology, Massachusetts General Hospital, Boston, MA 02114, USA. dmichaelson1@partners.org
Regan
M M
MM
Oh
W K
WK
Kaufman
D S
DS
Olivier
K
K
Michaelson
S Z
SZ
Spicer
B
B
Gurski
C
C
Kantoff
P W
PW
Smith
M R
MR
D000230:Adenocarcinoma / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy*; D000368:Aged; D000369:Aged, 80 and over; D020533:Angiogenesis Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D042501:Angiogenic Proteins / Q000097:blood; D000972:Antineoplastic Agents, Phytogenic / Q000627:therapeutic use; D000077143:Docetaxel; D019008:Drug Resistance, Neoplasm; D006801:Humans; D007211:Indoles / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy*; D047428:Protein Kinase Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D011758:Pyrroles / Q000009:adverse effects / Q000627:therapeutic use*; D011859:Radiography; D000077210:Sunitinib; D043823:Taxoids / Q000627:therapeutic use; D013997:Time Factors; D016896:Treatment Outcome
D020533:Angiogenesis Inhibitors; D042501:Angiogenic Proteins; D000972:Antineoplastic Agents, Phytogenic; D007211:Indoles; D047428:Protein Kinase Inhibitors; D011758:Pyrroles; D043823:Taxoids; D000077143:Docetaxel; D017430:Prostate-Specific Antigen; D000077210:Sunitinib