Everolimus Alleviates Obstructive Hydrocephalus due to Subependymal Giant Cell Astrocytomas.

BACKGROUND: Subependymal giant cell astrocytomas (SEGAs) are low-grade tumors affecting up to 20% of patients with tuberous sclerosis complex (TSC). Early neurosurgical resection has been the only standard treatment until few years ago when a better understanding of the molecular pathogenesis of TSC led to the use of mammalian target of rapamycin (mTOR) inhibitors. Surgical resection of SEGAs is still considered as the first line treatment in individuals with symptomatic hydrocephalus and intratumoral hemorrhage. We describe four patients with symptomatic or asymptomatic hydrocephalus who were successfully treated with the mTOR inhibitor everolimus. METHODS: We collected the clinical data of four consecutive patients presenting with symptomatic or asymptomatic hydrocephalus due to a growth of subependymal giant cell atrocytomas and who could not undergo surgery for different reasons. RESULTS: All patients experienced a clinically significant response to everolimus and an early shrinkage of the SEGA with improvement in ventricular dilatation. Everolimus was well tolerated by all individuals. CONCLUSIONS: Our clinical series demonstrate a possible expanding indication for mTOR inhibition in TSC, which can be considered in patients with asymptomatic hydrocephalus or even when the symptoms already appeared. It offers a significant therapeutic alternative to individuals that once would have undergone immediate surgery. Everolimus might also allow postponement of a neurosurgical resection, making it elective with an overall lower risk.

Differentiating the mTOR inhibitors everolimus and sirolimus in the treatment of tuberous sclerosis complex.

Tuberous sclerosis complex (TSC) is a genetic autosomal dominant disorder characterized by benign tumor-like lesions, called hamartomas, in multiple organ systems, including the brain, skin, heart, kidneys, and lung. These hamartomas cause a diverse set of clinical problems based on their location and often result in epilepsy, learning difficulties, and behavioral problems. TSC is caused by mutations within the TSC1 or TSC2 genes that inactivate the genes' tumor-suppressive function and drive hamartomatous cell growth. In normal cells, TSC1 and TSC2 integrate growth signals and nutrient inputs to downregulate signaling to mammalian target of rapamycin (mTOR), an evolutionarily conserved serine-threonine kinase that controls cell growth and cell survival. The molecular connection between TSC and mTOR led to the clinical use of allosteric mTOR inhibitors (sirolimus and everolimus) for the treatment of TSC. Everolimus is approved for subependymal giant cell astrocytomas and renal angiomyolipomas in patients with TSC. Sirolimus, though not approved for TSC, has undergone considerable investigation to treat various aspects of the disease. Everolimus and sirolimus selectively inhibit mTOR signaling with similar molecular mechanisms, but with distinct clinical profiles. This review differentiates mTOR inhibitors in TSC while describing the molecular mechanisms, pathogenic mutations, and clinical trial outcomes for managing TSC.

Complications of mammalian target of rapamycin inhibitor anticancer treatment among patients with tuberous sclerosis complex are common and occasionally life-threatening.

The aim of this study was to evaluate the most common adverse events (AEs) linked to everolimus therapy, a mammalian target of rapamycin (mTOR) inhibitor, in children and adolescents with tuberous sclerosis complex (TSC) hospitalized in one medical center. The study group included 18 patients with a diagnosis of subependymal giant cell astrocytoma or renal angiomyolipoma related to TSC. The median duration of therapy was 15 months. All clinical symptoms and laboratory abnormalities including complete blood count, fasting lipid profile, glucose level, and liver and kidney function tests were analyzed as potential AEs. The most common AEs of everolimus therapy were laboratory abnormalities (100% of patients) and infection complications (83 episodes in 15 patients). Infectious episodes of pharyngitis (67%), diarrhea (44%), stomatitis (39%), and bronchitis (39%) were the most common infections. They were mostly mild or moderate in severity (grade 1-2). In two cases, life-threatening conditions related to mTOR inhibitor treatment were encountered. The first was classified as grade 4 pleuropneumonia and Streptococcus pneumoniae sepsis, whereas the second was classified as death related to AE (grade 5) Escherichia coli sepsis. The most common laboratory abnormalities were hypercholesterolemia (13/18 patients - 72%) and hypertriglyceridemia (12/18 patients - 66%). Neutropenia (12/18 patents - 66%) and anemia (8/18 patients - 44%) were the most common hematologic toxicities. Everolimus treatment in TSC patients may lead to life-threatening outcomes, including sepsis and death. Long-lasting effects of everolimus treatment in the context of high incidences of different laboratory abnormalities found in TSC patients are another subject that should be researched further.

Everolimus for tumor recurrence after surgical resection for subependymal giant cell astrocytoma associated with tuberous sclerosis complex.

A recent phase 1/2 study demonstrated that treatment with the mammalian target of rapamycin inhibitor everolimus reduced subependymal giant cell astrocytoma volume by 30% in 75% of the patients, all of whom were poor candidates for surgical resection. Of the enrolled patients, 4 had had previous surgery to remove subependymal giant cell astrocytoma, and the outcomes for these patients were retrospectively analyzed and are presented here. All 4 experienced over 50% initial reduction in the volume of their subependymal giant cell astrocytoma after 2 to 3 years of therapy with everolimus. Although the volume of 1 patient's subependymal giant cell astrocytoma returned to baseline volume 36 months after initiating everolimus, they have remained asymptomatic with no recurrent hydrocephalus. Further surgery has been avoided in all cases to date. This course of treatment offers a new and welcome option for these difficult-to-treat patients.

Regression of subependymal giant cell astrocytoma with rapamycin in tuberous sclerosis complex.

The authors present a 21-year-old woman who has been receiving rapamycin for 5 months for bilateral subependymal giant cell astrocytomas. The patient was started at a dose of 0.2 mg/kg/day. Levels were maintained between 11 and 13 ng/mL. Magnetic resonance imaging of the brain 2(1/2) months after initiating rapamycin demonstrated a decrease in size of both astrocytomas (11 to 7.5 mm on the right and 8 to 5 mm on the left). Further studies are needed with prolonged observation to confirm these findings, determine the length of necessary treatment, and evaluate recurrence risk after discontinuation of rapamycin.