Everolimus long-term safety and efficacy in subependymal giant cell astrocytoma

Abstract

Objective: To report long-term efficacy and safety data for everolimus for the treatment of subependymal giant cell astrocytoma (SEGA) in patients with tuberous sclerosis complex (TSC).

Methods: This was an open-label extension phase of a prospective, phase 1-2 trial (NCT00411619) in patients ≥3 years of age with SEGA associated with TSC. Patients received oral everolimus starting at 3 mg/m2 per day and subsequently titrated, subject to tolerability, to attain whole blood trough concentrations of 5-15 ng/mL. Change in SEGA volume, seizures, and safety assessments were the main outcome measures.

Results: Of 28 patients enrolled, 25 were still under treatment at the time of analysis. Median dose was 5.3 mg/m2/day and median treatment duration was 34.2 months (range 4.7-47.1). At all time points (18, 24, 30, and 36 months), primary SEGA volume was reduced by ≥30% from baseline (treatment response) in 65%-79% of patients. All patients reported ≥1 adverse event (AE), mostly grade 1/2 in severity, consistent with that previously reported, and none led to everolimus discontinuation. The most commonly reported drug-related AEs were upper respiratory infections (85.7%), stomatitis (85.7%), sinusitis (46.4%), and otitis media (35.7%). No drug-related grade 4 or 5 events occurred.

Conclusion: Everolimus therapy is safe and effective for longer term (median exposure 34.2 months) treatment of patients with TSC with SEGA.

Classification of evidence: This study provides Class III evidence that everolimus, titrated to trough serum levels of 5-15 ng/mL, was effective in reducing tumor size in patients with SEGA secondary to TSC for a median of 34 months.

Figure 1. CONSORT diagram of patient disposition throughout the trial

Figure 2. Effect of everolimus on primary subependymal giant cell astrocytoma volume over time

Figure 3. Effect of everolimus on subependymal giant cell astrocytoma volume over time

(A) Patient A: Note resolution of hydrocephalus and progressive decrease in bilateral subependymal giant cell astrocytoma (SEGA); subependymal nodule at left ventricular trigone appears to increase at 30 months, but this is artifactual due to slice variation. (B) Patient B: Infiltrating SEGA status after 2 failed resections and proton beam irradiation; note progressive reduction in enhancement and tumor size. (C) Patient C: SEGA volume at baseline and after everolimus for 4 years; patient's trough serum levels ranged from 1 to 3 ng/mL. (D) Patient D: SEGA volume at baseline and after everolimus for 4 years, although lesion approximates baseline volume note reduction in contrast enhancement.