Olaparib First-Line Maintenance Monotherapy in BRCA-Mutated Epithelial Ovarian Cancer: Descriptive Analysis of the First French Real-World Data Study.

BACKGROUND: Olaparib, a poly(ADP-ribose) polymerase inhibitor, was approved by the European Commission in June 2019, following the results of the SOLO-1/GOG 3004 trial as maintenance monotherapy in adult patients with BRCA-mutated epithelial ovarian cancer. OBJECTIVE: This study aimed to provide a descriptive analysis of the first real-world data from patients with BRCA-mutated ovarian cancer who received olaparib as first-line maintenance monotherapy in the French cohort Temporary Authorisation for Use (Autorisation Temporaire d'Utilisation de cohorte, ATUc) programme from 11 March, 2019 to 16 January, 2020. METHODS: Eligible patients were aged 18 years and over with confirmed epithelial ovarian, primary peritoneal or Fallopian tube cancer and a deleterious or suspected deleterious germline or somatic BRCA 1/2 mutation. Patients were in complete or partial clinical response at the end of first-line platinum-based chemotherapy. Olaparib maintenance therapy was initiated within 8 weeks of the patients' last dose of chemotherapy. Real-world data were collected through treatment access request forms completed by physicians. Clinical and safety data were collected monthly until the end of the ATUc programme. RESULTS: A total of 107 centres in metropolitan France and the French Overseas Departments and Territories requested the inclusion for 238 patients, of whom 194 received maintenance olaparib. In total, 87.6% of the primary tumour locations were ovary, the most common histology was high-grade serous (93.0%) and the most common International Federation of Gynaecology and Obstetrics (Fédération Internationale de Gynécologie et d'Obstétrique) stage was IIIC (56.8%). BRCA testing was performed in routine practice, prior to inclusion into the ATUc programme. All patients had a BRCA mutation: 52.5% had a somatic mutation, 38.4% had a germinal mutation and 9.1% had germinal and somatic mutations. Twenty-four (12%) patients experienced serious adverse drug reactions at the last safety follow-up (17 February, 2020). The most common were anaemia (12 [6%] patients), neutropenia (3 [2%] patients) and thrombocytopenia (3 [2%] patients). CONCLUSIONS: The rapid enrolment into the ATUc programme highlighted the strong unmet need for patients with ovarian cancer and a BRCA mutation in first-line maintenance treatment. Olaparib was well tolerated and no new safety signals were observed in this real-world patient population.

Inhibition of xanthine oxidase reduces hyperglycemia-induced oxidative stress and improves mitochondrial alterations in skeletal muscle of diabetic mice.

Reactive oxygen species (ROS) have been widely implicated in the pathogenesis of diabetes and more recently in mitochondrial alterations in skeletal muscle of diabetic mice. However, so far the exact sources of ROS in skeletal muscle have remained elusive. Aiming at better understanding the causes of mitochondrial alterations in diabetic muscle, we designed this study to characterize the sites of ROS production in skeletal muscle of streptozotocin (STZ)-induced diabetic mice. Hyperglycemic STZ mice showed increased markers of systemic and muscular oxidative stress, as evidenced by increased circulating H(2)O(2) and muscle carbonylated protein levels. Interestingly, insulin treatment reduced hyperglycemia and improved systemic and muscular oxidative stress in STZ mice. We demonstrated that increased oxidative stress in muscle of STZ mice is associated with an increase of xanthine oxidase (XO) expression and activity and is mediated by an induction of H(2)O(2) production by both mitochondria and XO. Finally, treatment of STZ mice, as well as high-fat and high-sucrose diet-fed mice, with oxypurinol reduced markers of systemic and muscular oxidative stress and prevented structural and functional mitochondrial alterations, confirming the in vivo relevance of XO in ROS production in diabetic mice. These data indicate that mitochondria and XO are the major sources of hyperglycemia-induced ROS production in skeletal muscle and that the inhibition of XO reduces oxidative stress and improves mitochondrial alterations in diabetic muscle.

Mitochondrial dysfunction results from oxidative stress in the skeletal muscle of diet-induced insulin-resistant mice.

Mitochondrial dysfunction in skeletal muscle has been implicated in the development of type 2 diabetes. However, whether these changes are a cause or a consequence of insulin resistance is not clear. We investigated the structure and function of muscle mitochondria during the development of insulin resistance and progression to diabetes in mice fed a high-fat, high-sucrose diet. Although 1 month of high-fat, high-sucrose diet feeding was sufficient to induce glucose intolerance, mice showed no evidence of mitochondrial dysfunction at this stage. However, an extended diet intervention induced a diabetic state in which we observed altered mitochondrial biogenesis, structure, and function in muscle tissue. We assessed the role of oxidative stress in the development of these mitochondrial abnormalities and found that diet-induced diabetic mice had an increase in ROS production in skeletal muscle. In addition, ROS production was associated with mitochondrial alterations in the muscle of hyperglycemic streptozotocin-treated mice, and normalization of glycemia or antioxidant treatment decreased muscle ROS production and restored mitochondrial integrity. Glucose- or lipid-induced ROS production resulted in mitochondrial alterations in muscle cells in vitro, and these effects were blocked by antioxidant treatment. These data suggest that mitochondrial alterations do not precede the onset of insulin resistance and result from increased ROS production in muscle in diet-induced diabetic mice.