Transcript Ruth E. Stevens, PhD, MBA

Phase 1
Bioavailability(BA)/Bioequivalence(BE)
& Fed Studies
Ruth E. Stevens, PhD, MBA
Chief Scientific Officer, Executive Vice President
Camargo Pharmaceutical Services
ACPU: October 19, 2010
Approved Product Labeling
Drug Substance
Indication
Safety
Clinical
Pharmacology
DDI
Pharmacokinetics
(BA/BE/FED)
Reproductive
2
Pharmacokinetics
PHARMACOKINETICS:
What the body does to the drug (Absorption,
Distribution, Metabolism and Excretion (ADME)).
PHARMACODYNAMICS:
What the drug does to the body (Therapeutic
Effects, Side Effects).
Therapeutics
Pharmacokinetics
Dose
Pharmacodynamics
Concentration
Effect
Bioavailability
For the purpose of this subsection:
AUC
Cmax
(A) The term “bioavailability” means the rate and
extent to which the active ingredient or
therapeutic ingredient is absorbed from a drug
and becomes available at the site of drug action.
Note: AUC = AUC0-t and AUC0-inf
Reference: Food, Drug and Cosmetic Act Section 505(j)(7) Bioequivalence
Comparative Bioavailability Study
(Rate and Extent of Absorption)
Y axis-Linear Scale
Y axis-Log Scale
A = Test; 1x/day
B = Reference; 3x/day
Bioequivalence:
Cmax
AUC
(B) A drug shall be considered to be bioequivalent to a listed drug if:
(i) the rate and extent of absorption of the drug do not shown a
significant difference from the rate and extent of absorption of the
listed drug when administered at the same molar dose of the
therapeutic ingredient under similar experimental conditions in either a
single dose or multiple doses; or
(ii) the extent of absorption of the drug does not show a significant
difference from the extent of absorption of the listed drug when
administered at the same molar dose of the therapeutic ingredient
under similar experimental conditions in either a single dose or multiple
doses and the difference from the listed drug in the rate of absorption
of the drug in intentional, is reflected in its proposed labeling, is not
essential to the attainment of effective body drug concentrations on
chronic use, and is considered medically insignificant for the drug.
AUC
Note: AUC = AUC0-t and AUC0-inf
Reference: Food, Drug and Cosmetic Act Section 505(j)(7) Bioequivalence
Bioequivalent Products Concentration – Time Profiles
Rate & Extent = “SAME”
Y axis-Linear Scale
Y axis-Log Scale
Area Under-the-Curve (AUC)
Biological Matrix
Concentration (ng/mL)
“Extent of Absorption”
LOQ = Limit of Quantitation or
LQC = Last Quantifiable Concentration
LOQ
Time (hrs)
**Area Under-the-Curve (AUC0-t)
“Extent of Absorption”
Biological Matrix
Concentration (ng/mL)
** = Pivotal Bioequivalence PK Parameter
AUC 0-t or AUC0-last: Area under the plasma
concentration-time curve from time zero to the last
measurable time point.
t
Time (hrs)
**Area Under-the-Curve (AUC0-inf)
Biological Matrix
Concentration (ng/mL)
** = Pivotal Bioequivalence PK Parameter
“Extent of Absorption”
AUC 0-inf or AUC∞: Area under the plasma
concentration-time curve
from time zero to time infinity.
12
Time (hrs)
24
**Maximum Observed Concentration, Cmax
“Rate”
Biological Matrix
Concentration (ng/mL)
Value read off Y-axis

Cmax
** = Pivotal Bioequivalence PK Parameter
12
Time (hrs)
24
Biological Matrix
Concentration (ng/mL)
Time to Maximum Concentration, Tmax
Tmax
Value read off X-axis
“Rate”
12
Time (hrs)
24
Terminal Elimination Rate Constant z
(lambda, lambda z or Kel)
Biological Matrix
Concentration (ng/mL)
Rate & Extent of Absorption
z or Kel: slope
≥4 timepoints
12
Time (hrs)
24
Biological Matrix
Concentration (ng/mL)
Drug Elimination Half-Life, (t½)
z = terminal slope
Ln(2) = natural log of 2
t1/2 = ln(2)/z = 0.693
z
≥4 points on terminal slope to calculate z
12
Time (hrs)
24
Major Elements of Study Designs
[BA, BE, Fed]
(Example: Immediate-Release Products)
1. Subject Selection
•
•
•
Number of subjects: typically 24-36
Major objective: minimize intersubject variation conducted in healthy
subjects, 18-50 years old, ± 10% (range 10%-20%) of ideal body weight.
Populations traditionally excluded
•
•
•
•
Elderly: stress, blood loss, chronic disease and polypharmacy, PK effects
of altered organ function
Patients: stress, blood loss, concurrent medications, special diets, PK
effects of disease states
Some Exceptions to When Patients are Enrolled Instead of Healthy
Subjects: studies with pharmacodynamic or clinical end points, cytotoxic
drugs
Females are no longer excluded
Major Elements of Study Designs Fed State
(Example: Immediate-Release Products)
2. Meal – Office of Generic Drugs [Egg McMuffin]
Thirty minutes before dosing, subjects are served a high-fat content meal consisting of:
• One fried egg
• One slice of American cheese
• One slice of Canadian bacon
• One buttered English muffin
• One serving of hash brown potatoes
• 180mL of orange juice
• 240mL of whole milk
Grams
No. of Calories
Percent of Total
Calories
Protein
33
132
15.4%
Fat
55
280
35.3%
Carbohydrate
58
232
27%
10.000
1.000
0.100
A
B
0.010
0.001
0
5
10
15
20
Time (hr)
25
30
35
40
Major Elements of Study Designs
[BA, BE, Fed]
(Example: Immediate-Release Products)
3. Exclusion Criteria
Major organ, systemic, or mental disease, hypersensitivity to drug product or
class recent participation in investigational drug studies, recent blood donation,
recent exposure to enzyme-inducing or inhibiting agents abnormal diets or
recent significant weight loss.
4. Restrictions
No Rx medications within two weeks or OTC products within two days of study
start.
No alcohol for 48 hours prior to dosing and during sampling no xanthinecontaining products for 48 hours prior to dosing and during sampling.
No strenuous exercise or immobilization (except during sleeping times); normal
activity for four hours post-dose.
5. Informed Consent, IRB approval
6. Additional subjects enrolled to replace dropouts
Major Elements of Study Designs
[BA, BE, Fed]
(Example: Immediate-Release Products)
7. Design
•
•
•
Overnight fast of at least 10 hours, fasting continued for four hours post
dose, then standardized meals.
Dose administered with 240 mL of water; fluids restricted within ± 1
hour of dosing.
Two-way crossover:
Period 1
Period 2
Sequence 1
Treatment 1
Treatment 2
Sequence 2
Treatment 2
Treatment 1
Subject randomization
Washout period between treatments (7-10 drug half-lives)
Potencies of test and reference products within ± 5%.
Statistical Designs
Crossover Studies:
Subject receives each of the formulations one at a time in different time
periods. Designed to eliminate individual differences.
2 x 2 Crossover Designs
Subjects
R
A
N
D
O
M
I
Z
A
T
I
O
N
Period
Sequence 1
I
Reference
Sequence 2
Test
II
W
A
S
H
O
U
T
Test
Reference
Statistical Designs:
Crossover Study
(Subject Acts as Own Control)
1
Test
Estimated
Intra-subject
Variability
Intra-subject Variability (Estimated):
variability within a subject
Period I
Reference
Period II
Major Elements of Study Designs
[BA, BE, Fed]
(Immediate-Release Products Example, Fasting Study)
8. Sampling (plasma, serum, whole blood)
•
•
•
Sufficient sampling during absorption phase to define
adequately to ascending portion of the curve; avoid first
nonzero concentration as the Cmax.
Intensive sampling around the time of the expected
Cmax.
Sampling duration of at least 3 to 6 drug half-lives (NDA) or
7-10 drug half-lives (ANDA) or longest half-life of any
analyte.
Major Elements of Study Designs
[BA, BE, Fed]
(Immediate-Release Products Example, Fasting Study)
9. Pharmacokinetic Parameters
•
Area Under the Curve (AUC)
AUC0-t: Time of the last quantifiable concentration
Calculated by the trapezoidal rule
AUC0-inf: Extrapolated to infinity
= AUC0-t + Ct/Kel
•
Peak concentration (Cmax) and time to Cmax (Tmax) are obtained directly
from the observed data
•
Terminal elimination rate constant (Kel, λz) and half-life, t1/2 = ln(2)/Kel.
Pharmacokinetic Analysis
BA/BE & FED
1. Plasma/Serum and/or Whole Blood
a. Drug level at sampling times
b. Pharmacokinetic parameters
*AUC0-t
Last quantifiable concentration
*AUC0-inf
Infinity
*Cmax
Peak concentration
Tmax
Time to peak concentration
Kel
Terminal elimination rate constant
t1/2
Elimination half-life
CL/F
Clearance
Vd
Volume of Distribution
2. Urine
a. Drug level at sampling intervals (Ae)
b. Pharmacokinetic parameters
Cumulative excretion (*Ae0-t)
Maximum excretion rate (*Rmax)
Time to maximum excretion rate (Tmax)
* = Pivotal Bioequivalence PK Parameter
Statistical Requirements:
Bioequivalence
 Two one-sided tests procedure (also
called the 90% confidence interval
approach)
– The July 1, 1992 Statistical Procedures
Guidance requires 90% confidence interval
limits from 80% to 125% based upon log
transformed AUC0-t, AUC0-inf and Cmax data.
– Result must be between Lower Bound 80%
and Upper Bound 125% {Ln 80 – 125}.
BE Confidence Intervals
• For Bioequivalence, the 90% confidence interval of F’
must fall between 0.80 and 1.25.
1.25
1.25
1.25
1.25
1.00
1.00
1.00
BE
SD
X
1.00
BE
SD
0.80
0.80
BE = Bioequivalent
X
BE
SD
X
0.80
X
BE
SD
0.80
SD = Statistically Different
Statistical Designs - BE
Subject-By-Formulation Interaction
• A statistical term, meaning that the difference
between the subject-specific means for the test
product and the reference product is not the same for
all subjects in the population.
• The possibility of subject-by-formulation interaction is
one of the main concerns in the discussions of
“bioequivalence”.
Side-by-Side Spaghetti Plots:
FASTED
Treatment=A
Treatment=B
1000.00
100.00
100.00
10.00
10.00
1.00
1.00
0.10
0.10
0.01
0.01
0
5
10
15
20
25
30
Time (hr)
Test Product (n=108)
35
40
0
5
10
15
20
25
30
Time (hr)
Reference Product (n=108)
35
40
Phase 1: BA/BE (and/or FED)
Concentration – Time Profiles
6
Y axis-Linear Scale
5
4
3
A
B
2
1
0
0
5
10
15
20
25
30
35
40
Time (hr)
10.000
Y axis-Log Scale
1.000
0.100
A
B
0.010
0.001
0
5
10
15
20
Time (hr)
25
30
35
40
Bioequivalence (BE)
Excellent Concentration –
Time Profile
Subject=78
3.5
3.0
2.5
2.0
A
1.5
B
1.0
0.5
0.0
0
5
10
15
20
Time (hr)
25
30
35
40
Subject by Formulation
Interaction?
Subject=17
10
8
6
Subject=18
A
4
35
B
30
2
25
0
0
5
10
15
20
Time (hr)
25
30
35
40
20
A
15
B
10
5
0
0
2
4
6
8
Time (hr)
A=Test B=Reference
10
12
14
16
Cmax Plot: Text to Reference
Ratio: Cmax (Test)/Cmax (Reference) = 0.98
Pharmacokinetics
PHARMACOKINETICS:
What the body does to the drug (Absorption,
Distribution, Metabolism and Excretion (ADME)).
PHARMACODYNAMICS:
What the drug does to the body (Therapeutic
Effects, Side Effects).
Therapeutics
Pharmacokinetics
Dose
Pharmacodynamics
Concentration
Effect
Conclusion: What is in your
Drug Product Labeling?
Drug Substance
Indication
Clinical
Pharmacology
Pharmacokinetics
Safety
DDI
(BA/BE/FED)
Reproductive
34
Thank You
ACPU Committee
Dr. Charles Pierce
Dr. Punkaj Desai
Dr. William Sietsema