Participants will be enrolled from the ongoing GFB-887 multiple ascending dose trial. Participants will be transitioned to a 200 mg QD dose level regardless of the dose received in the previous study although the data review team (DRT) and Medical Monitor may elect to decrease or increase the dose to minimize adverse events or improve clinical efficacy. The DRT may also elect to change dosing levels due to emerging data on GFB-887. Participants will take GFB-887 once daily at home. A phone visit will be conducted at Week 4 and at Week 8 to assess safety and tolerability. Participants will return to the clinic for follow up visits at Weeks 12, 24, 36, 48, and every 24 weeks thereafter through approximately 3 years from the time of the participant's first dose to evaluate long-term safety and durability of response (for up to approximately 13 scheduled in-clinic visits).
This is an open-label Phase 2 study evaluating the long term safety and tolerability of GFB-887 in patients with focal segmental glomerulosclerosis (FSGS), and treatment-resistant minimal change disease (TR-MCD)