Combined biodifferentiating and antiangiogenic oral metronomic therapy is feasible and effective in relapsed solid tumors in children: Single-center pilot study

Background: To outline an outpatient-based treatment for children with relapsed solid tumors, who already have been extensively pretreated, we defined a 4-drug protocol named COMBAT (combined oral maintenance biodifferentiating and antiangiogenic therapy). Using this protocol, we performed a pilot study to determine its feasibility in children with relapsed and/or high-risk pediatric solid tumors. Patients and Methods: 22 children received the COMBAT protocol. Treatment consisted of daily celecoxib administration along with daily 13-cis-retinoic acid (2 weeks on / 2 weeks off) and cycles of metronomic temozolomide (go mg/m(2) for 42 days) and low-dose etoposide (21 days). The treatment was scheduled for a period of 1 year. Results: 9 of the 14 patients assessable for response demonstrated evidence of treatment benefit manifested as prolonged disease stabilization or response. The protocol medication was well tolerated with very good compliance. Only minimal side effects where observed which responded to dose modification or local therapy. Conclusions: The COMBAT regimen is well tolerated by patients with intensive prior therapy including myeloablative regimens. Favorable responses observed in this cohort of patients support the further exploration of this and/or similar strategies in the treatment of pediatric solid tumors.