A phase I safety, pharmacological, and biological study of the farnesyl protein transferase inhibitor, lonafarnib (SCH 663366), in combination with cisplatin and gemcitabine in patients with advanced solid tumors.
OBJECTIVE
This phase I study was conducted to evaluate the safety, tolerability, pharmacological properties and biological activity of the combination of the lonafarnib, a farnesylproteintransferase (FTPase) inhibitor, with gemcitabine and cisplatin in patients with advanced solid malignancies.


METHODS
This was a single institution study to determine the maximal tolerated dose (MTD) of escalating lonafarnib (75-125 mg po BID) with gemcitabine (750-1,000 mg/m(2) on days 1, 8, 15) and fixed cisplatin (75 mg/m(2) day 1) every 28 days. Due to dose-limiting toxicities (DLTs) of neutropenia and thrombocytopenia in initial patients, these patients were considered "heavily pre-treated" and the protocol was amended to limit prior therapy and re-escalate lonafarnib in "less heavily pre-treated patients" on 28-day and 21-day schedules. Cycle 1 and 2 pharmacokinetics (PK), and farnesylation of the HDJ2 chaperone protein and FPTase activity were analyzed.


RESULTS
Twenty-two patients received 53 courses of therapy. Nausea, vomiting, and fatigue were frequent in all patients. Severe toxicities were observed in 91% of patients: neutropenia (41%), nausea (36%), thrombocytopenia (32%), anemia (23%) and vomiting (23%). Nine patients withdrew from the study due to toxicity. DLTs of neutropenia, febrile neutropenia, thrombocytopenia, and fatigue limited dose-escalation on the 28-day schedule. The MTD was established as lonafarnib 75 mg BID, gemcitabine 750 mg/m(2) days 1, 8, 15, and cisplatin 75 mg/m(2) in heavily pre-treated patients. The MTD in the less heavily pre-treated patients could not be established on the 28-day schedule as DLTs were observed at the lowest dose level, and dose escalation was not completed on the 21-day schedule due to early study termination by the Sponsor. No PK interactions were observed. FTPase inhibition was not observed at the MTD, however HDJ-2 gel shift was observed in one patient at the 100 mg BID lonafarnib dose. Anti-cancer activity was observed: four patients had stable disease lasting >2 cycles, one subject had a complete response, and another had a partial response, both with metastatic breast cancer.


CONCLUSIONS
Lonafarnib 75 mg BID, gemcitabine 750 mg/m(2) days 1, 8, 15, and cisplatin 75 mg/m(2) day 1 on a 28-day schedule was established as the MTD. Lonafarnib did not demonstrate FTPase inhibition at these doses. Despite the observed efficacy, substantial toxicity and questionable contribution of anti-tumor activity of lonafarnib to gemcitabine and cisplatin limits further exploration of this combination.
Chow
Laura Q M
LQ
University of Colorado Cancer Center, Aurora, CO, USA.
Eckhardt
S Gail
SG
O'Bryant
Cindy L
CL
Schultz
Mary Kay
MK
Morrow
Mark
M
Grolnic
Stacy
S
Basche
Michele
M
Gore
Lia
L
D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D002945:Cisplatin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D051231:Farnesyltranstransferase / Q000037:antagonists & inhibitors* / Q000097:blood; D005221:Fatigue / Q000139:chemically induced / Q000503:physiopathology; D005260:Female; D050956:HSP40 Heat-Shock Proteins / Q000097:blood; D006801:Humans; D008297:Male; D020714:Maximum Tolerated Dose; D008875:Middle Aged; D009325:Nausea / Q000139:chemically induced / Q000503:physiopathology; D010880:Piperidines / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D011725:Pyridines / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D016896:Treatment Outcome; D014839:Vomiting / Q000139:chemically induced / Q000503:physiopathology; D000093542:Gemcitabine; D003986:Dibenzocycloheptenes
D002945:Cisplatin; D003841:Deoxycytidine; D051231:Farnesyltranstransferase; D050956:HSP40 Heat-Shock Proteins; D010880:Piperidines; D011725:Pyridines; D000093542:Gemcitabine; C107481:DNAJA1 protein, human; C115354:lonafarnib; D003986:Dibenzocycloheptenes