Background: Meningoencephalitis of unknown origin (MUO) represents a group of immune-mediated inflammatory diseases of the Central Nervous System. While corticosteroids alone (first-line) or add-on to cytarabine, cyclosporine or leflunomide alone or in combination (second-line) are commonly utilized for therapy, a subset of patients remains refractory, highlighting the need for additional therapeutic options. Hypothesis/
Objectives: To evaluate tolerability and effectiveness of temozolomide add-on in dogs affected by MUO irresponsive to first- and second-line treatments. Animals: Dogs with clinical, imaging and microbiological findings consistent with MUO showing persistent or progressive disease despite first- and second-line therapy.
Methods: In this observational single institution study, temozolomide was administered add-on 20 mg/mtq for 10 consecutive days then gradually tapered to maintenance weekly dose. Clinical, laboratory and imaging follow-up imaging findings were graded, according to CTCAE criteria.
Results: In a population of 154 patients with MUO, 35.0% were treated with corticosteroid alone, 40.3% responded to second-line treatment. Thirty-eight (24.7%) unresponsive dogs received add-on temozolomide, 81.5% of them (31/38) showed partial or completed response, with a mean treatment duration time of 19 months (s.d. 7 months), mean survival time 66 months (s.d. 13 months) with no adverse effects >G2. Conclusions and Clinical Importance: Temozolomide add-on is well tolerated and could be effective in dogs affected by MUO unresponsive to first- and second-line treatments.
Learning Objectives:
Upon completion, partecipants will be able to define further therapy for meningoenceophalitis
Upon completion, partecipants will be able to conduct a stratification of therapeutic options in the course of meningoencephalitis
