Open-label Extension to Study ZS-004 [Phase 3 Multicenter, Multi-phase, Multi-dose, Prospective, Randomized, Double-blind, Placebo-controlled Maintenance Study of Safety Efficacy of ZS (Sodium Zirconium Cycolsilicate) in Hyperkalemia.]

Subjects who completed the Double-blind Randomized Maintenance Phase (DBRMP) Study Day 29
visit in ZS-004 (NCT 02088073) and have an i-STAT potassium value that is 3.5 to 6.2 mmol/l
inclusive or who discontinued during ZS-004 due to hypo- or hyperkalemia in the DBRMP and
have a mean i-STAT potassium value from two consecutive measurements at 0 and 60 minutes on
Acute Phase Day 1/Maintenance Phase Day 1 that is 3.5 to 6.2 mmol/l inclusive may have the
option to participate in ZS-004E (NCT 021070920). Subjects who discontinued from study ZS-004
due to any other reasons (e.g. adverse events, poor compliance, investigator decision) will
not be entered into study ZS-004E. All subjects who continue into the extension study must
begin dosing within two (2) days after the last dose of investigational product in ZS-004.