14. CLINICAL STUDIES

14.1 Acute and Chronic Hyperammonemia due to NAGS Deficiency

The efficacy of CARBAGLU in the treatment of acute and chronic hyperammonemia due to NAGS deficiency was evaluated in a retrospective case series of 23 NAGS deficiency patients treated with CARBAGLU over a median duration of 7.9 years (range 0.6 to 20.8 years). For acute treatment, patients received CARBAGLU at 100 mg/kg/day to 250 mg/kg/day orally administered in 2 to 4 divided doses. For maintenance treatment, the dosage was reduced over time based on plasma ammonia level and clinical response.

The baseline characteristics of the patient population are shown in Table 5.

Table 5: Baseline Characteristics of 23 NAGS Deficiency Patients Treated with CARBAGLU
		Patients N=23
Sex	Male	14 (61%)
Sex	Female	9 (39%)
Age at initiation of CARBAGLU therapy (years)	Mean (SD)	2 (4)
Age at initiation of CARBAGLU therapy (years)	Min-Max	0-13
Age groups at initiation of CARBAGLU therapy	<30 days	9 (39%)
	>30 days - 11 months	9 (39%)
	≥1 - 13 years	5 (22%)
NAGS gene mutations by DNA testing	Homozygous	14 (61%)
	Heterozygous	4 (17%)
	Not available	5 (22%)
Patients current treatment status	On-going	18 (78%)
	Discontinued	5 (22%)

The clinical and biochemical data in the 23-patient case series were retrospectively collected, unblinded and uncontrolled and preclude formal statistical testing. Short-term efficacy was evaluated using mean and median change in plasma ammonia levels from baseline to days 1 to 3. Persistence of the effect was evaluated using long-term mean and median change in plasma ammonia level. Of the 23 NAGS deficiency patients in the case series, 13 patients had documented plasma ammonia levels prior to CARBAGLU treatment and after long-term treatment with CARBAGLU and were evaluable. Table 5 summarizes the plasma ammonia levels at baseline, days 1 to 3 post-CARBAGLU treatment, and long-term CARBAGLU treatment (mean 8 years) in the 13 evaluable patients.

All 13 patients had increased plasma ammonia levels at baseline (mean 271 micromol/L; normal range: 5 to 50 micromol/L). By day 3 and with long-term treatment, normal plasma ammonia levels were attained (Table 6).

Table 6: Plasma Ammonia Levels in NAGS Deficiency Patients at Baseline and After Treatment with CARBAGLU
Timepoint	Patients (N = 13)	Ammonia level (micromol/L)
Baseline (prior to first dose of CARBAGLU)	N	13
	Mean (SD)	271 (359)
	Median	157
	Range	72-1428
	Missing Data	0
Day 1	N	10
	Mean (SD)	181 (358)
	Median	65
	Range	25-1190
	Missing Data	3
Day 2	N	8
	Mean (SD)	69 (78)
	Median	44
	Range	11-255
	Missing Data	5
Day 3	N	5
	Mean (SD)	27 (11)
	Median	25
	Range	12-42
	Missing Data	8
Long-term treatment (mean duration 8 years; median duration 6 years; range 1-16 years based on last available value while on CARBAGLU treatment)	N	13
	Mean (SD)	23 (7)
	Median	24
	Range	9-34
	Missing Data	0

The mean plasma ammonia level at baseline and the decline that is observed after treatment with CARBAGLU in 13 evaluable patients with NAGS deficiency is illustrated in Figure 1.

Figure 1: Mean Plasma Ammonia in 13 Evaluable NAGS Deficiency Patients at Baseline and After Treatment with CARBAGLU

ammonia response chart

14.2 Acute Hyperammonemia due to PA and MMA

A randomized, double-blind, placebo-controlled, multicenter clinical trial evaluated the efficacy of CARBAGLU in the treatment of hyperammonemia in patients with PA and MMA (NCT01599286).

Eligible hyperammonemic episodes, defined as an admission to the hospital with a plasma ammonia level ≥ 70 micromol/L, were randomized 1:1 to receive either CARBAGLU or placebo for 7 days or until hospital discharge, whichever occurred earlier. All patients received standard of care, including a combination of protein restriction, intravenous glucose, insulin, and/or L-carnitine; the use of alternative pathway medications (e.g., sodium benzoate and medications with phenylacetate as an active metabolite) was prohibited. CARBAGLU was dosed orally at 150 mg/kg/day for patients ≤ 15 kg or 3.3 g/m2/day for patients > 15 kg and was divided into 2 equal doses administered 12 hours apart by NG tube, G-tube, or oral syringe. Plasma ammonia testing was performed at pre-randomization and at post-dosing intervals of every 6 -12 hours for the first 48 hours and every day thereafter if the ammonia level was ≥ 50 micromol/L.

The efficacy evaluation was based on 90 hyperammonemic episodes (42 treated with CARBAGLU and 48 with placebo) in 24 patients (12 male and 12 female) with PA (n = 15) or MMA (n = 9). The median patient age was 8 years (range 4 days to 29 years). The primary endpoint was the time from the first dose of drug to the earlier of plasma ammonia level ≤ 50 micromol/L (normal range) or hospital discharge. The median time to reach the primary endpoint was 1.5 days in the CARBAGLU group compared to 2.0 days in the placebo group, a difference of 0.5 days (95% confidence interval: -1.2, 0.1), driven by an effect on plasma ammonia normalization. Throughout the first three days of treatment, a higher proportion of CARBAGLU-treated episodes reached the primary endpoint compared to placebo-treated episodes (Figure 2).

Figure 2: Episodes Reaching the Earlier of Plasma Ammonia Level ≤ 50 micromol/L or Hospital Discharge in Patients with PA or MMA Treated with CARBAGLU or Placebo for up to 7 days