sirolimus and Glioma--Subependymal

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.

Topics: Animals; Antibiotics, Antineoplastic; Antineoplastic Agents; Brain Neoplasms; Clinical Trials as Topic; Everolimus; Female; Glioma, Subependymal; Humans; Male; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome; Tuberous Sclerosis; Tuberous Sclerosis Complex 1 Protein; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins

Tuberous sclerosis complex is an autosomal dominant disease, with variable expressivity and multisystemic involvement, which is characterised by the growth of benign tumours called hamartomas. The organs that are most commonly affected are the brain, skin, kidneys, eyes, heart and lungs. Of all the children with this disease, 85% present neurological manifestations that, due to their severity, are the main cause of morbidity and mortality. The most significant neurological manifestations are epilepsy, autism spectrum disorders and mental retardation. It has been shown that in tuberous sclerosis complex the genes TSC1 and TSC2 alter the mTOR enzyme cascade, which sets off inhibition of this pathway. The possibility of resorting to treatments applied at the origin, thus inhibiting this pathway, is currently being evaluated.

Topics: Anticonvulsants; Astrocytoma; Autistic Disorder; Brain Diseases; Brain Neoplasms; Drug Design; Epilepsy; Everolimus; Glioma, Subependymal; Hamartoma; Humans; Intellectual Disability; Learning Disabilities; Molecular Targeted Therapy; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis; Tuberous Sclerosis Complex 1 Protein; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins

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.

Topics: Adult; Antineoplastic Agents; Chemotherapy, Adjuvant; Child; Combined Modality Therapy; Everolimus; Female; Follow-Up Studies; Glioma, Subependymal; Humans; Image Enhancement; Image Interpretation, Computer-Assisted; Magnetic Resonance Imaging; Male; Neoplasm Recurrence, Local; Neoplasm, Residual; Sirolimus; Tuberous Sclerosis; Tumor Burden; Young Adult

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.

Topics: Adolescent; Adult; Angiomyolipoma; Antineoplastic Agents; Child; Child, Preschool; Everolimus; Glioma, Subependymal; Humans; Infant; Male; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis; Young Adult

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.

Topics: Antibiotics, Antineoplastic; Brain; Brain Neoplasms; Dose-Response Relationship, Drug; Female; Glioma, Subependymal; Humans; Magnetic Resonance Imaging; Sirolimus; Treatment Outcome; Tuberous Sclerosis; Young Adult