BACKGROUND: In malignant glioma (MG) patients undergoing radiation therapy (RT) with concomitant temozolomide, chemoradiation-induced nausea and vomiting (cRINV) degrades quality of life (QoL) and reduces treatment adherence, which thereby potentially compromises cancer control. METHODS: We conducted a 6-week phase II single-arm trial of PAL, a second-generation 5-HT3RA antiemetic, for cRINV prevention in MG patients receiving radiation therapy (RT; 54-60 Gy) and concomitant daily temozolomide (TMZ; 75 mg/m(2)/dX42d). Each week before radiation, patients received single-dose palonosetron (PAL) 0.25 mg IV (total = 6 doses). With safety/tolerability as the primary endpoint, the study was designed to differentiate between toxicity rates of 25 % (unacceptable) and 10 % (acceptable) toxicity rates. Secondary endpoints included the percentage of patients achieving cRINV complete response (CR: no emesis or rescue antiemetic) and QoL. Patients reported adverse effects in Common Toxicity Criteria for Adverse Events diaries; recorded vomiting, nausea, and rescue medication use in diaries (which were used to assess cRINV-CR); and reported QoL 4 days/week using the Modified Functional Living Index-Emesis (M-FLIE) and Osoba nausea and vomiting/retching modules. RESULTS: We enrolled 38 patients (mean age 59 years, 55 % female, 95 % white, 68 % used oral corticosteroids, 76 % reported low alcohol use). Four patients (10.5 %) experienced unacceptable treatment-related toxicity, defined as any grade 3, 4, or 5 non-hematologic toxicity. M-FLIE and Osoba scores showed no evidence of treatment impact on QoL. Overall, cRINV-CR rates for 6 weeks ranged from 67-79 %. CONCLUSION: Single-dose weekly PAL is a safe and tolerable antiemetic for cRINV prevention in MG patients receiving standard RT and concomitant TMZ.