Effects of multiple courses of oral gefitinib, topotecan, and cyclophosphamide in poor risk neuroblastoma

20009

Background: Gefitinib (G) has shown potent inhibitory activity on neuroblastoma (NB) cell proliferation in in vitro models. Experimental data have also reported that the addition of G to cytotoxic drugs can increase in vitro and in vivo antitumor activity in several tumor models, but if this will translate in significant clinical benefits, with respect to survival, is still unclear. We evaluated the feasibility of administering an oral regimen including G combined with topotecan (TPT) and cyclophosphamide (CPA) in heavily pretreated pts with relapsed/resistant metastatic NB. Methods: Patients received oral CPA (50 mg/m2/day) followed by TPT (0.8 mg/m2/day) plus G (at the fixed dose of 250 mg/day) for 14 consecutive days in an outpatient setting. Courses were repeated every 28 days until progression, and response was evaluated every second course. Expression of EGFR mRNA in primary tumors was assessed by real-time RT-PCR. Results: Six pts (1M/5F), median age 5.4 years (range 4.1–8.2), were enrolled between October 2004 and October 2006. All pts were relapsed after high-dose chemotherapy and hemopoietic rescue with PBSCs. At the time of inclusion, 3 pts were in PR after 8 courses of second-line therapy, whilst 2 pts had achieved SD after 1 and 8 courses of second-line therapy, resp; 1 pt had PD right after PBSC rescue. Significant levels of EGFR mRNA were detected in 4/6 tumors. A median of 7.5 courses (range 1–24) per pt were administered. In 4 pts, the dose of TPT and CPA was reduced by 25% after the first course. After a median follow-up of 12 months (range 1–26), 1 pt is DOD at 15 months since the inclusion and 5 pts are alive, 1 in VGPR (26+ months) and 5 with SD (26+, 1+, 4+, 9+ and 18+ months). Median PFS is 7.5 months (range 1–26). Neutropenia grade 4 was observed in 4/6 pts; rash grade 2 in 2 pts, and hepatic (LFT increase) grade 3 toxicity in 1. Conclusions: The regimen was feasible and well tolerated in this series of heavily pretreated pts. PFS is encouraging, but deserves further evaluation and longer follow-up. Additional molecular studies are ongoing aimed at identifying the subset of NB pts most likely to benefit from the synergy between G and cytotoxic drugs observed in preclinical models.

No significant financial relationships to disclose.