Primary or Delayed Repair for Complete Atrioventricular Septal Defect, Tetralogy of Fallot, and Ventricular Septal Defect: Relationship to Country Economic Status

OBJECTIVE

Primary repair in the first six months of life is routine for tetralogy of Fallot, complete atrioventricular septal defect, and ventricular septal defect in high-income countries. The objective of this analysis was to understand the utilization and outcomes of palliative and reparative procedures in high versus middle-income countries.

METHODS

The World Database of Pediatric and Congenital Heart Surgery identified patients who underwent surgery for: tetralogy of Fallot, complete atrioventricular septal defect, and ventricular septal defect. Patients were categorized as undergoing primary repair, repair after prior palliation, or palliation only. Country economic status was categorized as lower middle, upper middle, and high, defined by the World Bank. Multiple logistic regression models were utilized to identify independent predictors of hospital mortality.

RESULTS

Economic categories included high (n = 571, 5.3%), upper middle (n = 5,342, 50%), and lower middle (n = 4,793, 49.7%). The proportion of patients and median age with primary repair were: tetralogy of Fallot, 88.6%, 17.7 months; complete atrioventricular septal defect, 83.4%, 7.7 months; and ventricular septal defect, 97.1%, ten months. Age at repair was younger in high income countries (P < .0001). Overall mortality after repair was lowest in high income countries. Risk factors for hospital mortality included prematurity, genetic syndromes, and urgent or emergent operations (all P < .05).

CONCLUSIONS

Primary repair was selected in >90% of patients, but definitive repair was delayed in lower and upper middle income countries compared with high-income countries. Repair after prior palliation versus primary repair was not a risk factor for hospital mortality. Initial palliation continues to have a small but important role in the management of these three specific congenital heart defects.

Abstract P1-10-08: Development of a first-in-class oral selective ERα covalent antagonist (SERCA) for the treatment of ERαWT and ERαMUT breast cancer

Mutations in estrogen receptor alpha (ERα) are detected in up to 30% of breast cancer patients who have relapsed during endocrine therapy. ERα mutations functionally confer resistance to existing classes of endocrine therapies, likely through gaining constitutive activity. The fact that current ER-directed therapies are only partially effective in the ERα mutant setting, and that a significant proportion of resistant breast cancer metastases continue to remain dependent on ERα signaling for growth/survival, highlights the critical need to develop the next generation of ERα antagonists that can overcome aberrant ERα activity. Using structure-based drug design approaches we have identified a novel class of ERα antagonist referred to as Selective ERα Covalent Antagonist (SERCA) that inactivate both wild-type and mutant ERα by targeting a unique cysteine residue that is not conserved among other steroid hormone receptors. Biophysical, biochemical and cellular analyses confirm the covalent mechanism of action, specific binding to ER and selective inhibition of ERα-dependent transcription of SERCAs. H3B-6545 is a highly selective SERCA that potently antagonizes wild-type and mutant ERα in biochemical and cell based assays demonstrating increased potency over standard of care and other experimental agents. In vivo, H3B-6545 shows superior efficacy to fulvestrant in the MCF-7 xenograft model with once daily oral dosing, achieving maximal antitumor activity at doses &gt;10x below the maximum tolerated dose in mice. In addition, H3B-6545 shows superior antitumor activity to both tamoxifen and fulvestrant in patient derived xenograft models of breast cancer carrying estrogen receptor mutations. In summary, H3B-6545 is a first-in-class, orally available and selective ER covalent antagonist with a compelling pre-clinical profile that is being developed for the treatment of ERα positive breast cancer.

Citation Format: Korpal M, Puyang X, Furman C, Zheng GZ, Banka D, Wu J, Zhang Z, Thomas M, Mackenzie C, Yao H, Rimkunas V, Kumar P, Caleb B, Karr C, Subramanian V, Irwin S, Larsen N, Vaillancourt F, Nguyen T-V, Davis A, Chan B, Hao MH, O'Shea M, Prajapati S, Agoulnik S, Kuznetsov G, Kumar N, Yu Y, Lai G, Hart A, Eckley S, Fekkes P, Bowser T, Joshi JJ, Selvaraj A, Wardell S, Norris J, Smith S, Reynolds D, Mitchell L, Wang J, Yu L, Kim A, Rioux N, Sahmoud T, Warmuth M, Smith PG, Zhu P. Development of a first-in-class oral selective ERα covalent antagonist (SERCA) for the treatment of ERαWT and ERαMUT breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-10-08.