CLINICAL PHARMACOLOGY
Mechanism Of Action
The mechanism of action of BONJESTA is unknown.
Pharmacokinetics
The pharmacokinetics of BONJESTA has been characterized in healthy non-pregnant adult women.
Absorption
In a single-dose, crossover clinical trial conducted in 48 healthy, premenopausal women under fasting
conditions, one BONJESTA (20 mg doxylamine succinate and 20 mg pyridoxine) tablet was bioequivalent to
two combination tablets of 10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride based on the
exposure (AUC) and peak concentration (Cmax) of doxylamine and baseline corrected pyridoxal 5'-phosphate.
Mean ± SD plasma (whole blood for pyridoxal) pharmacokinetic (PK) parameters are summarized in Table 2.
Table 2 - Mean ± SD Single-Dose Pharmacokinetics of BONJESTA in Healthy Premenopausal Adult
Women
|
BONJESTA
Mean±SD |
AUC0-t
(ng•h/mL) |
AUC0-inf
(ng•h/mL) |
AUC0-72
(ng•h/mL) |
Cmax
(ng/mL) |
Tmax
b
(h) |
Doxylamine |
N=48 |
1367.0 ±
356.7 |
1425.8 ±
405.1 |
- |
92.3 ±
15.7 |
4.5
(2.5-5.5) |
Pyridoxine |
N=47 |
42.3 ±
14.7 |
42.5 ±
14.7 |
- |
47.1 ±
18.7 |
0.5
(0.5-4.7) |
Pyridoxala |
N=48* |
203.7 ±
51.7 |
233.6 ±
55.9 |
- |
58.9 ±
17.0 |
3.0
(0.8-5.0) |
Pyridoxal 5'-
phosphatea |
N=48 |
- |
- |
1076.2 ±
382.2 |
30.1 ±
9.2 |
9.0
(3.0-16.0) |
* N=46 for AUC0-inf
a Baseline corrected values
b Median (range) |
In a multiple-dose, crossover clinical trial conducted in 31 healthy, premenopausal women, one BONJESTA
(20 mg doxylamine succinate and 20 mg pyridoxine) tablet given twice daily for 11 days was bioequivalent to
one combination tablet of 10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride given three times
daily (1 tablet in the morning, 1 tablet in the afternoon and 2 tablets at bedtime), based on the exposure (AUC)
and peak concentration (Cmax) of doxylamine and baseline corrected pyridoxal 5'-phosphate. Mean ± SD plasma
(whole blood for pyridoxal) PK parameters are summarized in Table 3.
Table 3 - Mean ± SD Multiple-Dose (Day 11) Pharmacokinetic Parameters of BONJESTA (given twice
daily) in Healthy Premenopausal Adult Women
|
BONJESTA
Mean±SD |
AUC0-24
(ng•h/mL) |
AUC0-12
(ng•h/mL) |
AUC0-6
(ng•h/mL) |
Cmax
(ng/mL) |
Tmax
b
(h) |
Doxylamine |
N=34 |
2879.4 ±
696.0 |
1573.2 ±
406.5 |
883.6 ±
228.5 |
173.6 ±
45.5 |
3.5
(1.0-20.0) |
Pyridoxine |
N=34 |
80.0 ±
22.7 |
46.3 ±
15.4 |
45.3 ±
16.3 |
48.2 ±
23.7 |
1.5
(0.3-16.5) |
Pyridoxala |
N=34 |
1511.3 ±
300.0 |
848.1 ±
183.6 |
647.2 ±
149.6 |
189.6 ±
48.3 |
3.0
(2.0-15.0) |
Pyridoxal 5'-
phosphatea |
N=34 |
1742.3 ±
554.3 |
831.7 ±
274.5 |
426.2 ±
144.0 |
85.9 ±
26.2 |
15.0
(2.0-24.0) |
a Baseline corrected values
b Median (range) |
Food Effect
In a single-dose, crossover clinical trial conducted in 23 healthy, premenopausal women, the administration of a
high fat, high calorie meal delayed the absorption of doxylamine, pyridoxine, and pyridoxine metabolites. This
delay is associated with lower peak concentrations of doxylamine, pyridoxine, and pyridoxal. The extent of
absorption for pyridoxine was decreased.
The effect of food on the peak concentration and the extent of absorption of the pyridoxine component is more
complex because the pyridoxine metabolites such as pyridoxal, pyridoxamine, pyridoxal 5'-phosphate, and
pyridoxamine 5'-phosphate also contribute to the biological activity. Food significantly reduces the
bioavailability of pyridoxine, lowering its Cmax and AUC by approximately 67% and 37%, respectively,
compared to fasting conditions. Similarly, food significantly reduces pyridoxal Cmax by approximately 46%
compared to fasting conditions. In contrast, food did not affect pyridoxal 5'-phosphate Cmax and AUC.
Table 4 - Mean ± SD Pharmacokinetic Parameters of Doxylamine and Pyridoxine Metabolites Following a
Single Dose Administration of BONJESTA Under Fed and Fasted Conditions in Healthy Premenopausal
Adult Women
|
BONJESTA
N=23 |
AUC0-t
(ng•h/mL) |
AUC0-inf
(ng•h/mL) |
Cmax
(ng/mL) |
Tmax
b,c
(h) |
T1/2el
(h) |
Doxylamine
Mean±SD |
Fasted |
1273.7 ±
276.2 |
1321.9 ±
315.5 |
85.9±
10.6 |
3.5
(2.5-5.5) |
11.9 ±
2.2 |
Fed |
1242.8 ±
254.0 |
1281.4 ±
282.9 |
64.5 ±
15.2 |
6.5
(2.0 -
24.0) |
12.7 ±
2.60 |
Pyridoxine
Mean±SD |
Fasted |
34.7 ±
10.6 |
35.1 ±
8.5 |
38.9 ±
19.3 |
0.8
(0.3-4.3) |
0.4 ±
0.2 |
Fed |
22.8 ±
9.9 |
27.0 ±
10.1 |
12.7 ±
5.7 |
8.0
(1.0 -
21.0) |
1.2 ±
2.4 |
Pyridoxala
Mean±SD |
Fasted |
209.4 ±
30.0 |
244.0 ±
32.5 |
62.0 ±
17.8 |
2.3
(0.8-5.0) |
8.0 ±
1.7 |
Fed |
204.2 ±
25.7 |
249.2 ±
43.0 |
33.1 ±
6.1 |
6.0
(1.0-21.0) |
12.5 ±
7.6 |
Pyridoxal
5'-
phosphatea
Mean±SD |
Fasted |
1021.7 ±
318.5 |
- |
27.4 ±
7.7 |
5.0
(3.0-71.8) |
- |
Fed |
1064.6 ±
386.9 |
- |
30.2 ±
10.0 |
16.0
(6.0-22.0) |
- |
a Baseline corrected values
b Profile of Subject 20 was excluded
c Median (range) |
Distribution
Pyridoxine is highly protein bound, primarily to albumin. Its main active metabolite, pyridoxal 5'-phosphate
(PLP) accounts for at least 60% of circulating vitamin B6 concentrations.
Metabolism
Doxylamine is biotransformed in the liver by N-dealkylation to its principle metabolites N-desmethyldoxylamine
and N, N-didesmethyldoxylamine.
Pyridoxine is a prodrug primarily metabolized in the liver.
Excretion
The principle metabolites of doxylamine, N-desmethyl-doxylamine and N, N-didesmethyldoxylamine, are
excreted by the kidney.
The terminal elimination half-life of doxylamine and pyridoxine are 11.9 hours and 0.4 hours, respectively (see
Table 5).
Table 5 - Terminal Elimination Half-Life (T1/2el) for BONJESTA Administered as a Single Dose under
Fasting Conditions in Healthy Premenopausal Adult Women (N=23)
|
BONJESTA
T 1/2el (h) |
Doxylamine |
11.9 ± 2.2 |
Pyridoxine |
0.4 ± 0.2a |
Pyridoxal |
8.0 ± 1.7b |
a N=12
b Baseline corrected value |
Use In Specific Populations
Race
No pharmacokinetic studies have been conducted related to race.
Hepatic Impairment
No pharmacokinetic studies have been conducted in hepatic impaired patients.
Renal Impairment
No pharmacokinetic studies have been conducted in renal impaired patients.
Clinical Studies
There have been no efficacy and safety trials conducted with BONJESTA.
A double-blind, randomized, multi-center, placebo-controlled study was conducted to support the safety and
efficacy of 10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride tablets (a different formulation
and dosage strength than BONJESTA) in the treatment of nausea and vomiting of pregnancy. Adult women 18
years of age or older and 7 to 14 weeks gestation (median 9 weeks of gestation) with nausea and vomiting of
pregnancy were randomized to 14 days of 10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride
tablets or placebo. Two tablets of 10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride were
administered at bedtime on Day 1. If symptoms of nausea and vomiting persisted into the afternoon hours of
Day 2, the woman was directed to take her usual dose of two tablets at bedtime that night and, beginning on
Day 3, to take one tablet in the morning and two tablets at bedtime. Based upon assessment of remaining
symptoms at her clinic visit on Day 4 (± 1 day), the woman may have been directed to take an additional tablet
mid-afternoon. A maximum of four tablets (one in the morning, one in the mid-afternoon and two at bedtime)
were taken daily.
Over the treatment period, 19% of 10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride tablettreated
women remained on 2 tablets daily, 21% received 3 tablets daily, and 60% received 4 tablets daily.
The primary efficacy endpoint was the change from baseline at Day 15 in the Pregnancy Unique-Quantification
of Emesis (PUQE) score. The PUQE score incorporates the number of daily vomiting episodes, number of daily
heaves, and length of daily nausea in hours, for an overall score of symptoms rated from 3 (no symptoms) to 15
(most severe).
At baseline, the mean PUQE score was 9.0 in the 10 mg doxylamine succinate and 10 mg pyridoxine
hydrochloride tablets arm and 8.8 in the placebo arm. There was a 0.7 (95% confidence interval 0.2 to 1.2 with
p-value 0.006) mean decrease (improvement in nausea and vomiting symptoms) from baseline in PUQE score
at Day 15 with 10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride tablets compared to placebo
(see Table 6).
Table 6 - Change from Baseline in the Primary Endpoint, Pregnancy Unique-Quantification of Emesis
(PUQE) Score at Day 15. (Intent-to-Treat Population with Last-Observation Carried Forward)
PUQE Score* |
Combination 10 mg
Doxylamine Succinate
and 10 mg
Pyridoxine Hydrochloride
Tablets
N=131 |
Placebo
N=125 |
Treatment Difference
[95% Confidence Interval] |
Baseline |
9.0 ± 2.1 |
8.8 ± 2.1 |
|
Change from baseline at Day 15 |
-4.8 ± 2.7 |
-3.9 ± 2.6 |
-0.7 [-1.2, -0.2] |
*The Pregnancy-Unique Quantification of Emesis and Nausea (PUQE) score incorporated the number of daily vomiting episodes,
number of daily heaves, and length of daily nausea in hours, for an overall score of symptoms rated from 3 (no symptoms) to 15 (most
severe). Baseline was defined as the PUQE score completed at the enrollment visit. |