At 11, Payton Herres received a donated heart after years of health problems caused by Ebstein’s anomaly. Fifteen years later, she faced a fight to access everolimus, the anti-rejection medicine she had relied on since 2013. After her insurer stopped covering the drug and its cost rose sharply, Herres turned to social media. Her story went viral and reached Mark Cuban, whose pharmacy began supplying the medicine at a lower cost.