Phase I trial of bortezomib in combination with docetaxel in patients with advanced solid tumors.
OBJECTIVE
Bortezomib (PS-341), a first-in-class proteasome inhibitor, is metabolized by deboronation involving cytochrome P4503A (CYP3A), which also metabolizes docetaxel. Preclinical studies have shown synergy between bortezomib and taxanes. We conducted a phase I study combining bortezomib and docetaxel in refractory solid tumor patients.


METHODS
Patients received escalating doses of weekly docetaxel (days 1 and 8) and twice weekly bortezomib (days 2, 5, 9, and 12) in 3-week cycles. Two subjects were enrolled at each dose level, with cohort expansion to six for dose-limiting toxicity (DLT). Dose levels 1, 2, and 3 consisted of docetaxel/bortezomib 25/0.8, 25/1.0, and 30/1.0 mg/m(2), respectively. CYP3A activity and docetaxel pharmacokinetic studies were conducted, and proteasome inhibition was assessed.


RESULTS
Fourteen patients received a total of 34 cycles of treatment. Dose level 2 was expanded for DLT that occurred in two of six patients consisting of febrile neutropenia in one patient and grade 3 thrombocytopenia in one patient. One patient received two cycles at dose level 3 with dose reduction to dose level 2, where grade 3 thrombocytopenia occurred at cycle 3. Both episodes of grade 3 thrombocytopenia were transient (<7 days). Dose level 1 was then expanded to six patients where no DLTs occurred. CYP3A activity and docetaxel clearance did not change between weeks 1 and 5.


CONCLUSIONS
The maximum tolerated dose was docetaxel 25 mg/m(2) (days 1 and 8) with bortezomib 0.8 mg/m(2) (days 2, 5, 9, and 12) given every 21 days. Bortezomib treatment did not alter CYP3A activity and docetaxel clearance.
Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland 21231, USA. wmesser1@jhmi.edu
Wells A
WA
Messersmith
Sharyn D
SD
Baker
Lance
L
Lassiter
Rana A
RA
Sullivan
Kimberly
K
Dinh
Virna I
VI
Almuete
John J
JJ
Wright
Ross C
RC
Donehower
Michael A
MA
Carducci
Deborah K
DK
Armstrong
D000328:Adult; D000368:Aged; D000740:Anemia / Q000139:chemically induced; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use*; D019540:Area Under Curve; D001897:Boronic Acids / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D000069286:Bortezomib; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D000077143:Docetaxel; D004305:Dose-Response Relationship, Drug; D005221:Fatigue / Q000139:chemically induced; D005260:Female; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D061988:Proteasome Inhibitors; D011719:Pyrazines / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D043823:Taxoids / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics; D016896:Treatment Outcome
D001897:Boronic Acids; D061988:Proteasome Inhibitors; D011719:Pyrazines; D043823:Taxoids; D000077143:Docetaxel; D000069286:Bortezomib; D003577:Cytochrome P-450 Enzyme System; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; D046988:Proteasome Endopeptidase Complex