Background Combining bevacizumab (BEV) 10 mg/kg with irinotecan (IRI) 125 mg/m² every 14 days represents a treatment option in recurrent gliobastoma multiforme (GBM) based on a phase II trial. When IRI is administered concurrently with enzyme inducing antiepileptic drugs (EIAEDs), the dosage must be increased to 340 mg/m² to compensate for enhanced cytochrome CY3A4/5 enzyme activity.

Purpose To assess the activity and safety of BEV plus IRI for recurrent GBM in clinical practice in our hospital.

Material and methods We performed a retrospective chart review of patients with recurrent GBM treated with BEV and IRI. Variables collected were: sex, age, performance status (PS), use of EIAEDs, doses of IRI (habitual or high doses), necessity for dose reduction and cause, median number of cycles, cause of ending treatment (toxicity, progression or exitus), response rate (RECIST criteria) and progression free survival (PFS). We analysed if the use of high doses of IRI was related to severe adverse events (AE).

Results From January 2000 to October 2015, 74 patients, 45 (61%) male/29 (40%) female, were included. They were, on average, 55 years old (SD 11.7). 22 patients (30%) had PS ≥2 at the start of the treatment and 52 (70%) at the end. 60 patients (81%) were taking any antiepileptic drug, but just 14 (19%) of them were taking EIAEDs. High doses of IRI were administered to 11 (15%) patients. From the total number of patients, 17 (23%) needed a dose reduction due to: haematological disorders (40%), diarrhoea (35%) and asthenia (25%). Only 2 (2%) of these patients were receiving high doses of IRI. Median number of cycles was nine (range 1–82). 11 patients (15%) continued on treatment at the end of the study. Cause for ending treatment were: toxicity 18 (24%), progression 29 (39%) and exitus 16 (22%). Response rate was 39% (32% PR; 7% CR); SD 22%. Median PFS was 7.73 months (95% CI 5.66 to 9.80).

Conclusion The combination of bevacizumab and irinotecan is effective against recurrent GBM. The results we obtained were consistent with historical trials (median PFS 6 months) with mild toxicity. We did not find any relation between high doses of irinotecan and AE.

No conflict of interest.