Background: Bortezomib is a selective reversible proteasome inhibitor with proapoptotic effects. Preclinical and phase I clinical data suggest activity of bortezomib in NSCLC, either as monotherapy or in combination with chemotherapeutic agents including gemcitabine and cisplatin.
Methods: Chemotherapy-naïve patients with inoperable stage IIIB or IV NSCLC were administered bortezomib 1 mg/m(2) i.v. on days 1 and 8, and starting on day 21 (cycle 2), bortezomib (days 1 and 8) in combination with gemcitabine 1000 mg/m(2), (days 1 and 8), and cisplatin 70 mg/m(2) (day 1) in cycles of 21 days. Up to 8 cycles of combination therapy could be administered; single-agent bortezomib was continued until disease progression or unacceptable toxicity.
Results: Fifty-three patients [median age 66 years; 79.2 % male; 96.2 % stage IV; performance status (ECOG) 0/1 73.6/26.4 %; adenocarcinoma 45.3 %, squamous cell carcinoma 41.5 %] were enrolled. All patients were evaluable for toxicity and 43 for efficacy. Grade 3-4 hematologic toxicity consisted of neutropenia (22.6 %) and thrombocytopenia (17 %). Grade 2-4 non-hematologic adverse events were fever (9.4 %), fatigue (20.8 %), infection (18.9 %), and dyspnea (15.1 %). There was no >grade 2 neurotoxicity. Febrile neutropenia occurred in two (1.9 %) patients, and there were three possibly treatment-related deaths (5.4 %). In the intention-to-treat population, the objective response rate was 17 % (95 % CI 6.9-27.1 %). No difference in response rate was observed for squamous versus other histology (18.2 vs. 16.1 %, p = 0.845). The median progression-free survival was 2.5 months, the median overall survival 10.6 months and the 1-year survival rate 38.1 %.
Conclusion: The incorporation of bortezomib into the gemcitabine/cisplatin regimen, in the dose and schedule used in this study, could not improve the efficacy of the chemotherapy regimen and has not to be further investigated.
Keywords: Bortezomib; Cisplatin; Gemcitabine; Non-small cell lung cancer.