Pharmacotherapeutic group: Drugs for treatment of hyperkalaemia and hyperphosphatemia,
ATC code: V03AE10
Mechanism of actionSodium zirconium cyclosilicate is a non-absorbed, non-polymer inorganic powder with a uniformmicropore structure that preferentially captures potassium in exchange for hydrogen and sodiumcations. Sodium zirconium cyclosilicate is highly selective for potassium ions, even in the presence ofother cations, such as calcium and magnesium, in vitro. Sodium zirconium cyclosilicate capturespotassium throughout the entire gastrointestinal (GI) tract and reduces the concentration of freepotassium in the GI lumen, thereby lowering serum potassium levels and increasing faecal potassiumexcretion to resolve hyperkalaemia.
Pharmacodynamic effectsSodium zirconium cyclosilicate starts reducing serum potassium concentrations as soon as 1 hour afteringestion and normokalaemia can be achieved typically within 24 to 48 hours. Sodium zirconiumcyclosilicate does not affect serum calcium or magnesium concentrations, or urinary sodium excretion.
There is a close correlation between starting serum potassium levels and effect size; patients withhigher starting serum potassium levels have greater reductions in serum potassium. There is areduction in urinary potassium excretion which is a consequence of a reduction in serum potassiumconcentration. In a study of healthy subjects given Lokelma 5 g or 10 g once daily for four days, dose-dependent reduction in serum potassium concentration and total urinary potassium excretion wereaccompanied by mean increases in faecal potassium excretion. No statistically significant changes inurinary sodium excretion were observed.
There were no studies conducted to investigate the pharmacodynamics when sodium zirconiumcyclosilicate is administered with or without food.
Sodium zirconium cyclosilicate has also been shown to bind ammonium in vitro and in vivo, therebyremoving ammonium and increasing serum bicarbonate levels. Lokelma-treated patients experiencedan increase of 1.1 mmol/L at 5 g once daily, 2.3 mmol/L at 10 g once daily and 2.6 mmol/L at 15 gonce daily in bicarbonate compared with a mean increase of 0.6 mmol/L for those receiving placebo.
In an environment where other factors affecting renin and aldosterone were not controlled, Lokelmademonstrated a dose-independent change in mean serum aldosterone levels (range: -30% to -31%)compared with the placebo group (+14%). No consistent effect on systolic and diastolic blood pressurehas been observed.
In addition, mean reductions in blood urea nitrogen (BUN) were observed in the 5 g (1.1 mg/dL) and10 g (2.0 mg/dL) three times daily groups compared with small mean increases in the placebo(0.8 mg/dL) and low dose sodium zirconium cyclosilicate (0.3 mg/dL) groups.
Clinical efficacy and safetyThe potassium-lowering effects of Lokelma have been demonstrated in three randomised,double-blind, placebo-controlled trials in patients with hyperkalaemia. All three studies tested theinitial effect of Lokelma to correct hyperkalaemia during a 48-hour period and two studies also testedmaintenance of normokalaemia effect obtained. The maintenance studies included patients withchronic kidney disease (58%), heart failure (10%), diabetes mellitus (62%) and RAAS inhibitortherapy (68%). In addition, two open-label maintenance studies tested long-term safety of Lokelma.
These five studies included 1760 patients given doses of Lokelma; 507 exposed for at least 360 days.
In addition, the efficacy and safety of Lokelma was studied in a double-blind, placebo-controlled trialof 196 chronic haemodialysis patients with hyperkalaemia, who received doses of Lokelma for8 weeks. In the studies, Lokelma reduced serum potassium and maintained normal serum potassiumlevels regardless of the underlying cause of hyperkalaemia, age, sex, race, comorbid disease orconcomitant use of RAAS inhibitors. No dietary restrictions were imposed; patients were instructed tocontinue their usual diet without any specified alterations.
Study 1
A two-phase, placebo-controlled correction and maintenance use study
A two-part, double-blind, randomised, placebo-controlled clinical trial of 753 patients (mean age of66 years, range 22 to 93 years) with hyperkalaemia (5 to ≤ 6.5 mmol/L, baseline potassium average5.3 mmol/L), and included patients with chronic kidney disease, heart failure, diabetes mellitus andthose on RAAS inhibitor therapy.
During the correction phase, patients were randomised to receive Lokelma (1.25 g, 2.5 g, 5 g or 10 g)or placebo, administered three times daily for the initial 48 hours (Table 2).
Table 2. Correction phase (Study 1): Percentage of normokalaemic subjects after 48 hours of
Lokelma
Lokelma dose (three times daily)
Placebo 1.25 g 2.5 g 5 g 10 g
N 158 154 141 157 143
Baseline serum potassium, mmol/L 5.3 5.4 5.4 5.3 5.3
Normokalaemic at 48 hours, % 48 51 68 78 86p-value vs. placebo NS < 0.001 < 0.001 < 0.001
NS: not significant
Lokelma 10 g administered three times daily lowered serum potassium by 0.7 mmol/L at 48 hours(p < 0.001 vs. placebo); statistically significant 14% potassium reduction was observed 1 hour afterthe first dose. Patients with higher starting potassium levels had a greater response to Lokelma.
Patients with pre-treatment potassium levels in excess of 5.5 mmol/L (average baseline 5.8 mmol/L)saw an average decrease of 1.1 mmol/L at 48 hours while those with starting potassium levels at orbelow 5.3 mmol/L had an average decrease of 0.6 mmol/L at the highest dose.
Patients who became normokalaemic after receiving Lokelma during the correction phase werere-randomised to receive once daily placebo or once daily Lokelma at the same dose level as they hadreceived three times daily during the correction phase (Table 3).
Table 3. Maintenance phase (12 days, Study 1): Mean number of normokalaemic days
Maintenance phase treatment (once daily)
Placebo Lokelma P-value vs.placebo
Correction phase Lokelma dose N Days n Days1.25 g three times daily 41 7.6 49 7.2 NS2.5 g three times daily 46 6.2 54 8.6 0.0085 g three times daily 68 6.0 64 9.0 0.00110 g three times daily 61 8.2 63 10.2 0.005
NS: not significant
At the end of the maintenance period, when Lokelma was no longer administered, average potassiumlevels increased to near baseline levels.
Study 2
A multi-phase, placebo-controlled maintenance study with an additional open-label phase
In the correction phase of the study, 258 patients with hyperkalaemia (baseline average 5.6, range4.1 - 7.2 mmol/L) received 10 g of Lokelma administered three times daily for 48 hours. Reductions inpotassium were observed 1 hour after the first 10 g dose of Lokelma. Median time to normokalaemiawas 2.2 hours with 66% of patients achieving normokalaemia at 24 hours and 88% at 48 hours.
Responses were larger in patients with more severe hyperkalaemia; serum potassium fell 0.8, 1.2 and1.5 mmol/L in patients with baseline serum potassium < 5.5, 5.5-5.9 and ≥ 6 mmol/L, respectively.
Patients who achieved normokalaemia (potassium levels between 3.5 and 5 mmol/L) were randomisedin a double-blind fashion to one of three doses of Lokelma [5 g (n=45), 10 g (n=51), or 15 g (n=56)] orplacebo (n=85) administered once daily for 28 days (the double-blind randomised withdrawal phase).
The proportion of subjects with average serum potassium < 5.1 mmol/L from Study Day 8 to 29(three-week period) was greater at the 5 g, 10 g and 15 g once daily doses of Lokelma (80%, 90% and94%, respectively), compared with placebo (46%). There was a mean decrease in serum potassium of0.77 mmol/L, 1.10 mmol/L, 1.19 mmol/L and 0.44 mmol/L, respectively, and the proportion ofsubjects who remained normokalaemic was 71%, 76%, 85% and 48% in the 5 g, 10 g, 15 g once dailydoses of Lokelma and placebo groups, respectively.
Maintenance phase with Lokelma titration (open-label) results: 123 patients entered the 11-monthopen-label phase. The proportion of subjects with average serum potassium < 5.1 mmol/L was 88%,the average serum potassium level was 4.66 mmol/L and the proportion of serum potassiummeasurements below 3.5 mmol/L was less than 1%; between 3.5 and 5.1 mmol/L was 77%; orbetween 3.5 and 5.5 mmol/L was 93%, irrespective of other factors that might influence the serumpotassium. Treatment was discontinued on study exit (Day 365).
Kaplan-Meier estimates of time to relapse for maintenance phase showed dose dependence in time torelapse with median time for 5 g dose ranging from 4 to 21 days depending on the baseline serumpotassium values. Serum potassium should be monitored periodically and the Lokelma dose titrated asdescribed in section 4.2 Posology and Method of Administration.
Figure 1 illustrates the mean serum potassium over the correction and maintenance phases of thestudy.
Figure 1. Correction and maintenance phases (Study 2): mean serum potassium over time with95% CI10g* Placebo 5g Titrated dose10g 15g Off treatment
Exit EOS
Correction (hour) Maintenance fixed dose (day) Maintenance titrated-dose (day)
Exit=Last Visit within 1 day of Last Dose, EOS=End of Study (7 days +/- 1 day after Last Dose)
*Given three times daily
Study 3
A study in chronic kidney disease patients with hyperkalaemia
This study was a double-blind placebo-controlled dose-escalating study in 90 patients (60 Lokelmapatients; 30 controls) with baseline eGFR between 30-60 ml/min/1.73m2 and hyperkalaemia (baselineserum potassium 5.2 mmol/L, range 4.6-6 mmol/L). Patients were randomised to receive escalatingdoses of Lokelma (0.3 g, 3 g and 10 g) or placebo, administered three times a day with meals for twoto four days. The primary endpoint was the rate of change in serum potassium from baselinethroughout the initial 2 days of treatment. The trial met the primary efficacy endpoint at the 3 g and10 g doses of Lokelma compared to placebo. Lokelma at the 10 g dose and the 3 g dose resulted inmean maximal reductions of 0.92 mmol/L and 0.43 mmol/L, respectively. Twenty-four hour urinecollections showed that Lokelma decreased urinary potassium excretion from baseline by15.8 mmol/24 h compared to placebo increase by 8.9 mmol/24 h (p < 0.001). Sodium excretion wasunchanged relative to placebo (10 g, increase by 25.4 mmol/24 h compared to placebo increase by36.9 mmol/24 h (NS)).
Study 4
A two-phase, multicenter, multi-dose, open-label safety and efficacy study
The long term (up to 12 months) effects of Lokelma were assessed in this study in 751 subjects withhyperkalaemia (baseline average 5.59 mmol/L; range 4.3-7.6 mmol/L). Comorbid conditions includedchronic kidney disease (65%), diabetes mellitus (64%), heart failure (15%) and hypertension (83%).
Use of diuretics and RAAS inhibitors was reported by 51 and 70% of subjects, respectively. Duringthe correction phase, 10 g of Lokelma was administered three times daily for at least 24 hours and upto 72 hours. Subjects who achieved normokalaemia (3.5-5.0 mmol/L, inclusive) within 72 hoursentered the maintenance phase of the study. All subjects in the maintenance phase received Lokelma ata starting dose of 5 g once daily which could be increased in increments of 5 g once daily (to amaximum of 15 g once daily) or decreased (to a minimum of 5 g once every other day) based upon thetitration regimen.
Mean Serum Potassium with 95% CI (mmol/L)
Normokalaemia was achieved in 494/748 (66%), 563/748 (75%) and 583/748 (78%) of subjects after24, 48 and 72 hours of correction phase dosing with an average reduction in serum potassium of0.81 mmol/L, 1.02 mmol/L and 1.10 mmol/L at 24 (n=748), 48 (n=104) and 72 (n=28) hours,respectively. Normokalaemia was dependent on baseline potassium concentration, with subjects withthe highest baseline serum potassium concentrations having the most prominent decrease after startingthe study drug but with the lowest proportion of subjects achieving normokalaemia. One hundred andtwenty-six patients had a baseline serum potassium ≥ 6.0 mmol/L (mean baseline potassium6.28 mmol/L). These subjects had a mean reduction of 1.37 mmol/L at the end of the correction phase.
Table 4. Correction phase (Study 4): proportion of subjects with serum potassium concentrations between3.5 and 5.0 mmol/L, inclusive, or between 3.5 and 5.5 mmol/L, inclusive, by correction phase study day -
ITT population
Lokelma 10 g three times daily (N=749)
Serum potassium 3.5 to 5.0 mmol/L, Serum potassium 3.5 to 5.5 mmol/L,
Correction Phase (CP)inclusive inclusiven/N Proportion 95% CI n/N Proportion 95% CI
CP at 24 hours 494/748 0.660 0.625, 0.694 692/748 0.925 0.904, 0.943
CP at 48 hours 563/748 0.753 0.720, 0.783 732/748 0.979 0.965, 0.988
CP at 72 hours/CP Last 583/748 0.779 0.748, 0.809 738/748 0.987 0.976, 0.994
Note: One subject had a post-dose value that was more than 1 day after last dose. Therefore, thesubject was eligible for the Correction Phase ITT Population; however, the time point was excludedfrom the analysis.
Normokalaemia was maintained while patients remained on drug and the mean serum potassiumincreased following discontinuation. Among those patients using RAAS inhibitors at baseline, 89%did not discontinue RAAS inhibitor therapy, 74% were able to maintain the same dose during themaintenance phase and among those not on RAAS inhibitors at baseline, 14% were able to initiate thistherapy. During maintenance phase, 75.6% of subjects maintained normokalaemia, despite use of
RAAS inhibitors.
Figure 2 illustrates the mean serum potassium over the correction and maintenance phases of thestudy.
Figure 2: Correction and maintenance phases in 12-month open-label study (Study 4) - meanserum potassium over time with 95% CI10g Titrated dose Off treatment
CPBL MPBL Exit EOS
Correction (hour) Maintenance (day)
CPBL=Correction Phase Baseline, MPBL=Maintenance Phase Baseline
Exit=Last Visit within 1 day of Last Dose, EOS=End of Study (7 days +/- 1 day after Last Dose)
Study 5
A randomised, double-blind, placebo-controlled study in patients on chronic haemodialysis
In this study, 196 patients (mean age 58 years, range 20 to 86 years) with end stage renal disease onstable dialysis for at least 3 months and persistent pre-dialysis hyperkalaemia were randomised toreceive Lokelma 5 g or placebo once daily on non-dialysis days. At randomization, mean serumpotassium levels were 5.8 mmol/L (range 4.2-7.3 mmol/L) in the Lokelma group and 5.9 mmol/L(range 4.2-7.3 mmol/L) in the placebo group. To achieve pre-dialysis serum potassium level between4.0-5.0 mmol/L during the dose adjustment period (initial 4 weeks), the dose could be adjusted weeklyin 5 g increments up to 15 g once daily based on pre-dialysis serum potassium measurement after the
LIDI. The dose reached at the end of the dose-adjustment period was maintained throughout thesubsequent 4-week evaluation period. At the end of the dose adjustment period, 37%, 43%, and 19%of patients were on Lokelma 5 g, 10 g and 15 g. The proportion of responders, defined as thosesubjects who maintained a pre-dialysis serum potassium between 4.0 and 5.0 mmol/L on at least 3 outof 4 dialysis treatments after LIDI and who did not receive rescue therapy during the evaluationperiod, was 41% in the Lokelma group, and 1% in the placebo group (p < 0.001) (see Figure 3).
In post-hoc analyses the number of times patients had serum potassium between 4.0 and 5.0 mmol/Lafter the LIDI during the evaluation period was higher in the Lokelma group. 24% of patients werewithin this range at all 4 visits in the Lokelma group and none in the placebo group. The post-hocanalysis showed the proportion of patients who maintained serum potassium level between 3.5 and5.5 mmol/L on at least 3 out of 4 dialysis treatments after LIDI during the evaluation period was 70%in the Lokelma group and 21% in the placebo group.
At the end of treatment, the mean post-dialysis serum potassium level was 3.6 mmol/L (range2.6-5.7 mmol/L) in Lokelma group and 3.9 mmol/L (range 2.2-7.3 mmol/L) in the placebo group.
There were no differences between Lokelma and placebo groups in interdialytic weight gain (IDWG).
IDWG was defined as pre-dialysis weight minus post-dialysis weight on the previous dialysis sessionand was measured after the LIDI.
Serum Potassium with 95% CI (mmol/L)
Figure 3: Mean pre-dialysis serum potassium levels over time in patients on chronicdialysis
Lokelma
Placebo
Screening (Day) Dose adjustment (Day) Evaluation (Day) F/U (Day)
Subjects (n)
Lokelma
Placebo
F/U- follow-up period
The displayed error bars correspond to 95% confidence intervals.n = Number of patients with non-missing potassium measurements at a particular visit.
Paediatric populationThe European Medicines Agency has deferred the obligation to submit the results of studies with
Lokelma in one or more subsets of the paediatric population in male and female children from birth toless than 18 years of age, with hyperkalaemia (see section 4.2 for information on paediatric use).