Preventive Approach to Congenital Heart Block With Hydroxychloroquine

Detailed Summary

Women with antibodies to proteins called SSA/Ro and or SSB/La face a 2% chance of having a child with a life threatening heart condition regardless of whether they have very active lupus, are in remission, or have only vague symptoms. This heart problem is referred to as congenital heart block (the most serious being third degree complete block) and represents damage thought to be caused by these autoantibodies. The heart beats abnormally slowly and almost all children require permanent pacemakers before the age of 20. Importantly, women who have had one child with heart block have a ten-fold higher risk of having another child with the same heart condition. Unfortunately, even close monitoring by special techniques during pregnancy does not reverse complete heart block once it is observed. Thus, treatments aimed at prevention are critical. This study will evaluate for the first time whether hydroxychloroquine, a drug used by many patients with SLE, prevents the development of this heart condition. Data from laboratory experiments suggests that this drug, which crosses the placenta, may decrease the inflammation initiated by the passage of anti-Ro antibodies to the fetus. The study uses a Simon's 2-Stage design, and plans to enroll 19 patients in Stage 1 and 35 patients in Stage 2 if Stage 1 is successful. Patients can already be on hydroxychloroquine or will be started as soon as pregnancy is confirmed. The hope is that fewer than 3 cases of heart block will occur in Stage 1, and fewer than 6 cases will occur out of all 54 patients if Stage 2 is reached. The results of this study are expected to become an integral part of the counseling of women with anti-Ro/La antibodies who are considering pregnancy.

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