Phase II Trial of Palbociclib in Recurrent Retinoblastoma-Positive Anaplastic Oligodendroglioma: A Study from the Spanish Group for Research in Neuro-Oncology (GEINO).

BACKGROUND: The cell cycle checkpoint G1/S, dependent on cyclin-dependent kinase (CDK) 4 amplification/overexpression and retinoblastoma phosphorylation, is altered in most anaplastic oligodendrogliomas (AOs). OBJECTIVE: We aimed to evaluate the efficacy of palbociclib, an oral inhibitor of CDK4/6 with proven efficacy in breast cancer, in patients with AO. The primary endpoint was progression-free survival at 6 months. PATIENTS AND METHODS: We conducted a multicenter, open-label, phase II trial evaluating the efficacy and safety of palbociclib in patients with AO who progressed on radiotherapy and chemotherapy with histologically and molecularly confirmed grade 3 oligodendroglioma and conserved retinoblastoma protein (pRb) expression by immunohistochemistry. Patients were treated with palbociclib (125 mg/day) for 3/1 weeks on/off. RESULTS: Overall, 34 patients were enrolled across 10 hospitals in the Spanish Group of Neuro-Oncology (GEINO) study. The study was stopped early owing to the lack of efficacy, with 74% of evaluable patients progressing within 6 months, which was insufficient to consider palbociclib as an active drug in this population. Within the median follow-up of 12 months, the median progression-free survival was 2.8 months [95% confidence interval (CI) 2.6-3.1] and the median overall survival was 32.1 months (95% CI 5.1-59.2). There were no partial or complete responses; only 13 patients (38%) achieved stable disease as the best response. Palbociclib was well tolerated, with neutropenia (grade 3 or higher: 58.8%) and thrombocytopenia (grade 3 or higher: 14.7%) as the most common adverse events (AEs). Both AEs had no significant impact. CONCLUSION: Despite the good tolerance, palbociclib monotherapy did not show favorable efficacy against recurrent AO. TRIAL REGISTRATION: This study is registered with ClinicalTrials.gov, identifier NCT0253032 (retrospectively registered on 21 August 2015).

Persistent asymptomatic or mild symptomatic hyperCKemia due to mutations in ANO5: the mildest end of the anoctaminopathies spectrum.

BACKGROUND: The ANO5 gene encodes for anoctamin-5, a chloride channel involved in muscle cell membrane repair. Recessive mutations in ANO5 are associated with muscular diseases termed anoctaminopathies, which are characterized by proximal or distal weakness, or isolated hyperCKemia. We present the largest series of patients with asymptomatic/paucisymptomatic anoctaminopathy reported so far, highlighting their clinical and radiological characteristics. METHODS: Twenty subjects were recruited retrospectively from the Neuromuscular Disorders Units database of two national reference centers. All had a confirmed genetic diagnosis (mean age of diagnosis was 48 years) established between 2015 and 2019. Clinical and complementary data were evaluated through clinical records. RESULTS: None of the patients complained about weakness or showed abnormal muscular balance. Among paucisymptomatic patients, the main complaints or findings were generalized myalgia, exercise intolerance and calf hypertrophy, occasionally associated with calf pain. All patients showed persistent hyperCKemia, ranging from mild-moderate to severe. Muscle biopsy revealed inflammatory changes in three cases. Muscle magnetic resonance imaging revealed typical signs (preferential involvement of adductor and gastrocnemius muscles) in all but one patient. In two cases, abnormal findings were detectable only in STIR sequences (not in T1). Three patients showed radiological progression despite remaining asymptomatic. Twelve different mutations in ANO5 were detected, of which seven are novel. CONCLUSIONS: Recessive mutations in ANO5 are a frequent cause of undiagnosed asymptomatic/paucisymptomatic hyperCKemia. Patients with an apparent indolent phenotype may show muscle involvement in complementary tests (muscle biopsy and imaging), which may progress over time. Awareness of anoctaminopathy as the cause of nonspecific muscular complaints or of isolated hyperCKemia is essential to correctly diagnose affected patients.

Bethlem myopathy: a series of 16 patients and description of seven new associated mutations.

BACKGROUND: Bethlem myopathy represents the milder phenotype of collagen type VI-related myopathies. However, clinical manifestations are highly variable among patients and no phenotype-genotype correlation has been described. We aim to analyse the clinical, pathological and genetic features of a series of patients with Bethlem myopathy, and we describe seven new mutations. METHODS: A series of 16 patients with the diagnosis of Bethlem myopathy were analyzed retrospectively from their medical records for clinical, creatine kinase (CK), muscle biopsy, and muscle magnetic resonance (MRI) data. Genetic testing was performed through next-generation sequencing of custom amplicon-based targeted genes panel of myopathies. Mutations were confirmed by Sanger sequencing. RESULTS: The most frequent phenotype consisted of proximal limb weakness associated with interphalangeal and wrists contractures. However, cases with isolated contractures or isolated myopathy were found. CK levels did not correlate with severity of the disease. The most frequent mutation was the COL6A3 variant c.7447A>G, p.Lys2486Glu, with either an homozygous or compound heterozygous presentation. Five new mutations were found in COL6A1 gene and other two in COL6A3 gene, all of them with a dominant heritability pattern. From these, a new COL6A1 mutation (c.1657G>A, p.Glu553Arg) was related to an oligosymptomatic phenotype with predominating contractures in the absence of weakness and a normal muscle MRI. Finally, the most common COL6A1 mutation reported to date that leads to an Ullrich phenotype (c. 868G>A, p.Gly290Arg), has been found here as Bethlem presentation. CONCLUSIONS: Manifestations of Bethlem myopathy are quite variable, so either contractures or weakness may be lacking, and no phenotype-genotype associations can be brought.