Treating Alpelisib-Induced Hyperinsulinemia in Patients with Advanced Breast Cancer - A Real-Life Experience

PIK3CA activating mutations are found in 40% of advanced breast cancer and are associated with worse prognosis. PI3K blockage is associated with insulin resistance, leading to hyperglycemia and hyperinsulinemia. Alpelisib is the first PI3K inhibitor used in cancer treatment. Laboratory evidence indicated that alpelisib-induced hyperinsulinemia offsets the drug's efficacy, but insulin levels were not tested in the clinical trials that evaluated alpelisib for breast cancer. Hyperglycemia could also interfere with anti-tumor effects of PI3K inhibitors by inducing Immune tolerance and altered mitochondrial metabolism. We have monitored insulin levels in 4 breast cancer patients with concomitant metabolic syndrome treated with alpelisib, and pre-treated patients with baseline increased insulin levels with pioglitazone, a potent insulin sensitizer, to target both hyperinsulinemia and hyperglycemia, and we report the treatment course of these patients. All patients achieved glycemic control and were able to maintain alpelisib dose intensity. Duration of response to alpelisib was longer than anticipated in this treatment setting. Insulin dynamics confirmed the efficacy of pioglitazone as a specific on-target hypoglycemic and hypo-insulinemic agent in the unique setting of PI3K blockade. Our experience suggests that targeting hyperinsulinemia in patients with is safe and feasible and results in good metabolic and oncologic outcomes.

Abstract 110: Anesthetic Preconditioning and Mitochondrial Slo K + Channel Activity Require Slo2.1

Introduction: Volatile anesthetic preconditioning (APC) protects the heart from ischemia-reperfusion (IR) injury. APC elicits evolutionarily-conserved protective signaling pathways that converge at the mitochondrial level, where the Slo family of K + channels is thought to mediate protection through an unknown mechanism. Recent work in C. elegans has focused attention on the Slo2 gene product as a transducer of APC effects on hypoxic survival. In mammals, Slo2 has diverged into two paralogs, Slo 2.1 (KCNT2; Slick) and Slo2.2 (KCNT1; Slack). These genes code for Na + -activated K + channels and are highly expressed in brain, but their function in cardiomyocytes and/or mitochondria is unknown.

Methods: The contribution of Slo channels to cardiac physiology was characterized using knockout mice, including Slo1 and two novel Slo2.x alleles. APC was assessed through ex-vivo cardiac IR injury. Isolated mitochondrial K + channel activity was assessed using a Tl + flux assay, and by patch-clamp of cardiac mitoplasts. Electron microscopy was used to assess mitochondrial morphology in primary cardiomyocytes and Seahorse extracellular flux analysis used to assess bioenergetics.

Results: The Slo2.x ( double KO ) and the Slo2.1 single KO mice could not be protected from cardiac IR injury by APC. Physiologic approaches demonstrated that Slo2.1 is present in mitochondria and Slo2.1 -dependent mitochondrial K + transport can be triggered directly by volatile anesthetics. Cardiomyocytes from Slo2.x dKO mice exhibited profound metabolic remodeling and electron microscopy revealed that Slo2.1 knockouts had enlarged circular mitochondria. In contrast, Slo1 KO mice responded normally to APC and exhibited wild type mitochondrial physiology.

Conclusion: Slo2.1 activation protects against cardiac IR, and is required for APC. Slo2.1 also contributes to mitochondrial metabolic homeostasis. As a molecular target for APC, identification of Slo2.1 may facilitate development of targeted therapeutic molecules that can protect the heart and minimize the side effects of volatile anesthetics.

Impact of DNA testing for early-onset familial Alzheimer disease and frontotemporal dementia

BACKGROUND

DNA testing of persons at risk for hereditary, degenerative neurologic diseases is relatively new. Only anecdotal reports of such testing in familial Alzheimer disease (FAD) exist, and little is know about the personal and social impact of such testing.

METHODS

In a descriptive, observational study, individuals at 50% risk for autosomal dominant, early-onset FAD or frontotemporal dementia with parkinsonism linked to chromosome 17 underwent DNA testing for the genetic mutations previously identified in affected family members. Individuals were followed up for (1/2) to 3 years and were interviewed regarding attitudes toward the testing process and the impact of the results.

RESULTS

Twenty-one (8.4%) of 251 persons at risk for FAD or frontotemporal dementia requested genetic testing. The most common reasons for requesting testing were concern about early symptoms of dementia, financial or family planning, and relief from anxiety. Twelve individuals had positive DNA test results, and 6 of these had early symptoms of dementia; 8 had negative results; and 1 has not yet received results. Of 14 asymptomatic individuals completing testing, 13 believed the testing was beneficial. Two persons reported moderate anxiety and 1 reported moderate depression. As expected, persons with negative test results had happier experiences overall, but even they had to deal with ongoing anxiety and depression. Thus far, there have been no psychiatric hospitalizations, suicide attempts, or denials of insurance.

CONCLUSIONS

Genetic testing in early-onset FAD and frontotemporal dementia can be completed successfully. Most individuals demonstrate effective coping skills and find the testing to be beneficial, but long-term effects remain unknown.

Inconsistencies in genetic counseling and screening for consanguineous couples and their offspring: the need for practice guidelines

PURPOSE

To determine current practices of genetic counseling and screening for consanguineous couples, their pregnancies and children, and to compare these practices to recommendations in the literature.

METHODS

A questionnaire was mailed to 1,582 board certified genetic counselors and medical geneticists in the United States.

RESULTS

The return rate was 20% (n = 309). There was wide variation in the risk figures quoted to consanguineous couples to have offspring with birth defects and mental retardation (1% to 75% for incest between first-degree relatives, and 0.25% to 20% for first cousin unions). Suggested screening practices differed for consanguineous unions before conception, during pregnancy, following birth, and for children placed for adoption. Most respondents recommended screening based on ethnicity, yet disagreed as to which genetic disorders to include.

CONCLUSIONS

To standardize genetic services, guidelines for screening the offspring of consanguineous unions are needed. A consensus should be reached as to the empirical risks for genetic disorders, birth defects, and mental retardation that may impair the offspring of consanguineous unions, with definition as to what these disorders are, and if the data applies to global populations. Guidelines should consider costs, the sensitivity and specificity of DNA and biochemical testing, and current practices of prenatal and newborn screening. Consideration should be given to screening based on ethnicity, particularly in populations where consanguineous unions are common, while remaining sensitive to cultural belief systems. Recommendations for screening healthy children from consanguineous unions to be placed for adoption pose ethical challenges.