The Bioequivalence Study of Two Different Formulations of Candesartan Cilexetil After a Single Oral Dose Administration Under Fasting Conditions

This single dose study was designed in accordance with EMA (the European Medicines Agency) regulatory guidelines, with the aim of characterizing the bioavailability of candesartan in the two formulations in healthy subjects. As this is a bioequivalence trial where each subject received each study treatment in a crossover fashion, a control group was not included. Within the clinical portion of the study each subject received a single oral dose of the test and the reference formulation in compliance with the generated randomization code. The primary study endpoints were the pharmacokinetic (PK) parameters Cmax and AUC0-t of candesartan.

This is a single center, randomized, 2-treatment, 2-period, 2-sequence, crossover, single dose study design, in which 40 healthy adult subjects received one of the study treatments during each study period.

The objective of this study was to determine the bioequivalence of two different formulations of candesartan after a single oral dose administration under fasting conditions.

The intra-subject variation following a single dose of candesartan cilexetil appeared to be around 28.8% for Cmax and around 24% for AUC0-t. Statistically, given that the expected Test to Reference ratio of geometric least-squares means (LSmeans) should fall within 95 and 105%, it is estimated that the lowest number of subjects to meet the 80 to 125% bioequivalence range with a statistical a priori power of at least 80% is about 36. Therefore, the inclusion of 40 subjects should be sufficient to account for the possibility of drop-outs, variations around the estimated intra-subject coefficient of variation (CV) and to conclude in favor of the hypothesis of bioequivalence with sufficient statistical power.

Subject eligibility for this study will be determined at the screening visit and eligible subjects will be admitted to the clinical research unit at least 10 hours prior to drug administration for each study period.

A subject who withdraws or is withdrawn during the pretrial evaluations but before receiving the first dose (the test or the reference product) in Period 1 will not be considered as a drop-out and will not be included in the final database. Standbys should be recruited and available to replace any subject who withdraws prior to the first drug administration. On-study drop-outs will not be replaced.

Altasciences will generate the randomization code with a computer program according to the study design, the number of subjects and the sequence of treatment administration. The random allocation of each sequence of treatment administration to each subject will be done in such a way that the study is balanced. Once generated, the randomization code will be final and will not be modified. Eligible subjects will be randomized to one of two treatment sequences. There will be two sequences in the study: AB and BA, where A = the test product, B = the reference product (see detailed description of A and B items in Section "Arms and Interventions").

For each study period, subjects will receive a single 32 mg oral dose of candesartan cilexetil (the test or the reference formulation). Study participants will be aware they will receive different formulations of the same drug, without being informed which product (Test or Reference) is being administered.The date and time of each dose will be recorded. For each subject, all scheduled postdose activities and assessments will be performed relative to the time of study drug administration.

Fasting will continue for at least 4 hours following drug administration, after which a standardized lunch will be served. A supper and a light snack will be served at appropriate times thereafter, but not before 9 hours after dosing. Water will be provided as needed until 1 hour predose. Water will be allowed beginning 1 hour after the administration of the drug.

A total of 21 blood samples will be collected (one tube of 3 mL each) in each study period for pharmacokinetic (PK) assessments.The first blood sample will be collected prior to drug administration while the others will be collected up to 48 hours after drug administration.

Given that the parent compound, candesartan cilexetil, is rapidly and completely converted to the pharmacologically active metabolite, candesartan, candesartan cilexetil cannot be reliably measured. Therefore, the analyte to be measured in the present study will be candesartan. Candesartan plasma concentrations will be measured according to a validated bioanalytical method.

Subjects are to be discharged from the clinic after the 24-hour following drug administration. However, they may be advised to stay at the clinical site for safety reasons, if judged necessary by the physician in charge. Subjects will return to the clinical site for each of the 2 remaining blood samples.

The expected terminal elimination half-life observed after a single oral 32 mg dose of candesartan cilexetil tablets under fasting conditions is 11.6 hours. To avoid any carry-over effect, a wash-out of 7 calendar days is planned between drug administrations.

The decision of which subjects will be included in the PK analysis is to be documented by the pharmacokineticist (or delegate) and approved by the sponsor before the start of the sample analysis by the bioanalytical facility. Subjects who are expected to provide evaluable PK data for both the Test and Reference products (based on viable PK samples) will be included in the PK analysis. Concentration data of the remaining subjects will be presented separately. Subjects who do not complete the sampling schedule of one or more study periods may be included in the PK and statistical analysis and bioequivalence determination for only the PK parameters that are judged not to be affected by the missing sample(s).

Statistical analysis of Tmax will be based on a non-parametric approach. Statistical analysis of all other PK parameters will be based on an ANOVA model. Two-sided 90% confidence interval of the ratio of geometric LSmeans obtained from the ln-transformed PK parameters will be calculated.

Statistical inference of candesartan will be based on a bioequivalence approach using the following standards: the ratio of geometric LSmeans with corresponding 90% confidence interval calculated from the exponential of the difference between the Test and the Reference for the ln-transformed parameters Cmax and AUC0-t should all be within the 80.00 to 125.00% bioequivalence range.

The safety population will include all subjects who received at least one dose of one of the IPs. Safety assessments will include vital signs, clinical laboratory tests and AE monitoring. Additional safety measurements may be performed at the discretion of the investigator for reasons related to subject safety.The physician in charge will be present at the clinical site for at least the first 4 hours following each drug administration and will remain available at all times throughout the study.

Total study duration: up to 38 days (including screening).

Eligibility Criteria:
Inclusion Criteria:

1. Provision of signed and dated informed consent form (ICF)
2. Stated willingness to comply with all study procedures and availability for the duration of the study
3. Healthy Caucasian adult male or female
4. If female, meets one of the following criteria:

(1) Physiological postmenopausal status, defined as the following:

a) absence of menses for at least one year prior to the first study drug administration (without an alternative medical condition); and b) Follicle stimulating hormone (FSH) levels ≥ 40 mIU/mL at screening; or (2) Surgical postmenopausal status, defined as the following:

1. bilateral oophorectomy; and
2. absence of menses for at least 90 days prior to the first study drug administration; and
3. FSH levels ≥ 40 mIU/mL at screening; or (3) Hysterectomy with FSH levels ≥ 40 mIU/mL at screening If postmenopausal and has an FSH of \< 40 mIU/mL, but meets all other criteria in (1), (2) or (3) above as well as all the other inclusion criteria, screening estradiol serum level must be equal to or below 150 pmol/L. In the case of hysterectomy, if FSH and estradiol do not meet the criteria, eligibility for study participation will be based on medical judgment.

   5. Aged at least 18 years but not older than 55 years

   6. Body mass index (BMI) within 18.5 kg/m2 to 30.0 kg/m2, inclusively

   7. Non- or ex-smoker (An ex-smoker is defined as someone who completely stopped using nicotine products for at least 180 days prior to the first study drug administration)

   8. Clinical laboratory values within the laboratory's stated normal range; if not within this range, they must be without clinical significance, as determined by an investigator

   9. Have no clinically significant diseases captured in the medical history or evidence of clinically significant findings on the physical examination (including vital signs) and/or ECG, as determined by an investigator

   Exclusion Criteria:
   1. Female who is lactating at screening
   2. Female who is pregnant according to the pregnancy test at screening or prior to the first study drug administration
   3. Seated pulse rate less than 50 Beats per Minute (bpm) at the screening visit and prior to the first study drug administration
   4. Seated blood pressure below 110/60 mmHg at the screening visit and prior to the first study drug administration
   5. History of significant hypersensitivity to candesartan or any related products (including excipients of the formulations) as well as severe hypersensitivity reactions (like angioedema) to any drugs
   6. Presence or history of significant gastrointestinal, liver or kidney disease, or any other condition (including but not limited to cholecystectomy) that is known to interfere with drug absorption, distribution, metabolism or excretion, or known to potentiate or predispose to undesired effects
   7. History of significant cardiovascular, pulmonary, hematologic, neurological, psychiatric, endocrine, immunologic or dermatologic disease
   8. Presence of clinically significant ECG abnormalities at the screening visit, as defined by medical judgment
   9. History of rare hereditary problems of galactose and/or lactose intolerance, lactase deficiency or glucose-galactose malabsorption
   10. Maintenance therapy with any drug or significant history of drug dependency or alcohol abuse (\> 3 units of alcohol per day, intake of excessive alcohol, acute or chronic)
   11. Any clinically significant illness in the 28 days prior to the first study drug administration
   12. Use of any prescription drugs (with the exception of hormone replacement therapy) in the 28 days prior to the first study drug administration, that in the opinion of an investigator would put into question the status of the participant as healthy
   13. Any history of tuberculosis
   14. Positive test result for alcohol and/or drugs of abuse at screening or prior to the first drug administration
   15. Positive screening results to HIV Ag/Ab Combo, Hepatitis B surface Antigen (HBsAG) or Hepatitis C Virus (HCV) tests
   16. Inclusion in a previous group for this clinical study
   17. Intake of candesartan in the 28 days prior to the first study drug administration
   18. Intake of an Investigational Product (IP) in the 28 days prior to the first study drug administration
   19. Donation of 50 mL or more of blood in the 28 days prior to the first study drug administration
   20. Donation of 500 mL or more of blood (Canadian Blood Services, Hema-Quebec, clinical studies, etc.) in the 56 days prior to the first study drug administration