P08.75 Update of valganciclovir add-on therapy in glioblastoma. Effect in new ly diagnosed and in recurrent patients

Abstract

Background: Since the overall survival of patients with glioblastoma is still very limited with current combined therapy of surgery and radiochemotherapy, we have studied the potential effect of adding valganciclovir early after diagnosis, or at relapse. Our earlier retrospective results on 50 patients have shown significant prolonged survival; the median survival increased to 24 months and the 2 years survival was 62%. Method This is an updated retrospective analysis of glioblastoma patients treated at a single institution. Valganciclovir tablets 450mg 2x2 were given during the initial 3 weeks as induction therapy, followed by maintenance 1 x 2 continuously, until disease progression and/or late palliative situation. Ten patients receiving valganciclovir during shorter period are not included: early progression (3), hematologic toxicity grade III (1), non compliance (4) patient stopped intake early (2). Results Seventy-six patients with newly diagnosed glioblastoma and positive immunohistology for CMV antigens in the tumor. Valganciclovir was adminstered for 6 months (which was the duration of the first phase II exploratory study: VIGAS) or longer. The follow-up is at least 1 year. The median 2-year survival is 80 %. The median estimate overall survival is 5 years (9-72 months, n=56), the patients with shorter survival had partial resection. Twenty patients are alive, and the median survival is > 20 months, the longest survival so far is > 81/2 years. In twenty-five patients with recurrence, valganciclovir was added to salvage therapy (3 underwent reoperation before starting valganciclovir), relapse treatment was heterogeneous (second line chemotherapy-CCNU in general, a few received re-irradiation up to 34 Gy and 3 radiosurgery). The median survival after recurrence was 10 months (1-24 months, n=25). Conclusion The addition of valganciclovir prolonged survival in newly diagnosed glioblastoma patients. There was no additional toxicity when valganciclovir was combined to chemotherapy. The effect in recurrent patients is more limited, because patients were treated late. Earlier therapy at recurrence in patients with good function may have better effect. Larger randomized trials of anti CMV therapy are planned.