Travere Therapeutics Inc.’s stock TVTX tumbled 35% Tuesday, after the company said data from a two-year study of a kidney drug failed to show a statistically significant improvement. The company said the Phase 3 trial of Sparsentan as a treatment for focal segmental glomerulosclerosis, or FSGS, did not meet the primary efficacy eGFR slope endpoint over 108 weeks of treatment. The eGFR slope is used to measure renal function. FSGS is a disease that causes scarring of the kidneys and is a common cause of acquired glomerular disease leading to end stage kidney disease. It’s estimated to affect more than 40,000 patients…