1. 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

2. Approved Product Labeling
Drug Substance
Indication
Safety
Clinical Pharmacology
DDI
Pharmacokinetics
(BA/BE/FED)
Reproductive

3. Pharmacokinetics Therapeutics Concentration Pharmacokinetics Dose
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
Concentration
Pharmacokinetics
Dose
Effect
Pharmacodynamics

4. Bioavailability Cmax AUC For the purpose of this subsection:
(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.
AUC
Note: AUC = AUC0-t and AUC0-inf
Reference: Food, Drug and Cosmetic Act Section 505(j)(7) Bioequivalence

5. Comparative Bioavailability Study (Rate and Extent of Absorption)
Y axis-Linear Scale
Y axis-Log Scale
A = Test; 1x/day
B = Reference; 3x/day

6. Bioequivalence: Cmax AUC AUC
(B) A drug shall be considered to be bioequivalent to a listed drug if:
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
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

7. Bioequivalent Products - Concentration – Time Profiles Rate & Extent = “SAME”
Y axis-Linear Scale
Y axis-Log Scale

8. “Extent of Absorption”
Area Under-the-Curve (AUC)
“Extent of Absorption”
LOQ = Limit of Quantitation or
LQC = Last Quantifiable Concentration
Concentration (ng/mL)
Biological Matrix
LOQ
Time (hrs)

9. **Area Under-the-Curve (AUC0-t) “Extent of Absorption”
** = 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.
Concentration (ng/mL)
Biological Matrix t
Time (hrs)

10. **Area Under-the-Curve (AUC0-inf)
** = Pivotal Bioequivalence PK Parameter
“Extent of Absorption”
Concentration (ng/mL)
Biological Matrix
AUC 0-inf or AUC∞: Area under the plasma
concentration-time curve
from time zero to time infinity. 12 24
Time (hrs)

11. **Maximum Observed Concentration, Cmax “Rate”
Value read off Y-axis 
Concentration (ng/mL)
Biological Matrix
Cmax
** = Pivotal Bioequivalence PK Parameter 12 24
Time (hrs)

12. Time to Maximum Concentration, Tmax
Concentration (ng/mL)
Biological Matrix
Tmax
Value read off X-axis
“Rate” 12 24
Time (hrs)

13. Terminal Elimination Rate Constant z (lambda, lambda z or Kel)
Rate & Extent of Absorption
z or Kel: slope
≥4 timepoints
Concentration (ng/mL)
Biological Matrix 12 24
Time (hrs)

14. Drug Elimination Half-Life, (t½)
z = terminal slope
Ln(2) = natural log of 2
Concentration (ng/mL)
Biological Matrix
t1/2 = ln(2)/z = 0.693 z
≥4 points on terminal slope to calculate z 12 24
Time (hrs)

15. Major Elements of Study Designs [BA, BE, Fed] (Example: Immediate-Release Products)
Subject Selection
Number of subjects: typically 24-36
Major objective: minimize intersubject variation conducted in healthy subjects, 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

16. 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%

18. 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 xanthine-containing 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

19. Major Elements of Study Designs [BA, BE, Fed] (Example: Immediate-Release Products)
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:
Subject randomization
Washout period between treatments (7-10 drug half-lives)
Potencies of test and reference products within ± 5%.
Period 1
Period 2
Sequence 1
Treatment 1
Treatment 2
Sequence 2

20. Statistical Designs Reference Test Test Reference
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 R A N D O M I Z T
Period
Subjects
Sequence 1 I II W A S H O U T
Reference
Test
Sequence 2
Test
Reference

21. Statistical Designs: Crossover Study (Subject Acts as Own Control)1
Test
Period I
Estimated
Intra-subject
Variability
Reference
Period II
Intra-subject Variability (Estimated):
variability within a subject

22. 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.

23. 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.

24. Pharmacokinetic Analysis BA/BE & FED
Plasma/Serum and/or Whole Blood
Drug level at sampling times
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
Urine
Drug level at sampling intervals (Ae)
Pharmacokinetic parameters Cumulative excretion (*Ae0-t) Maximum excretion rate (*Rmax) Time to maximum excretion rate (Tmax)
The following information on urine potassium concentration data should be recorded for each subject:
Amount excreted in each collection interval (Ae)
Cumulative urinary excretion from 0 to 24 hours (Ae0-24h)
Cumulative urinary excretion from 0 to 48 hours (Ae0-48h)
Maximal rate of urinary excretion (Rmax)
Time of maximal urinary excretion (Tmax)
Excretion rate in each collection interval (R)
Midpoint of each collection interval (t)
All data should be calculated using baseline-adjusted and nonbaseline-adjusted data. Statistical analysis (p=0.05) should be done by ANOVA for baseline-adjusted parameters, and the 90 percent confidence intervals should be generated for natural log-transformed cumulative urinary excretion from 0 to 24 hours (Ae0-24h) and maximal rate of urinary excretion data (Rmax). The two one-sided tests procedure can be used to determine 90 percent confidence intervals.
V. IN VITRO TESTING
* = Pivotal Bioequivalence PK Parameter

25. 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}.

26. BE Confidence Intervals
For Bioequivalence, the 90% confidence interval of F’ must fall between 0.80 and 1.25.
0.80
1.00
1.25 BE SD X
BE = Bioequivalent SD = Statistically Different

27. 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”.

28. Side-by-Side Spaghetti Plots: FASTED
Test Product (n=108)
Reference Product (n=108)

29. Phase 1: BA/BE (and/or FED) Concentration – Time Profiles
Y axis-Linear Scale
Y axis-Log Scale

30. Bioequivalence (BE) Excellent Concentration – Time Profile

31. Subject by Formulation Interaction?
A=Test B=Reference

32. Cmax Plot: Text to Reference
OK for the 22nd – not the 23rd
Ratio: Cmax (Test)/Cmax (Reference) = 0.98

33. Pharmacokinetics Therapeutics Concentration Pharmacokinetics Dose
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
Concentration
Pharmacokinetics
Dose
Effect
Pharmacodynamics

34. Conclusion: What is in your Drug Product Labeling?
Drug Substance
Indication
Clinical Pharmacology
Safety
DDI
Pharmacokinetics
(BA/BE/FED)
Reproductive

35. Thank You ACPU Committee Dr. Charles Pierce Dr. Punkaj Desai Dr
Thank You ACPU Committee Dr. Charles Pierce Dr. Punkaj Desai Dr. William Sietsema