Alzheimer DiseasePhase 1NCT07897708
A Study to Learn How Different Amounts of the Study Medicine Called PF-08161842 Are Tolerated and Act in the Body in Healthy and Older Adults
A Phase 1 study testing PF-08161842 in people with Alzheimer Disease, run by Pfizer.
Trial summary
The purpose of this clinical study is to learn about the safety and effects of the study medicine (called PF-08161842) and how it is processed by the body. This is the first time PF-08161842 will be given to people. Read more about this study
- Who is it for?
- Ages 18 to 85 yearsHealthy volunteers can take part
- Conditions the study is for
- Alzheimer Disease
- What is being tested?
- PF-08161842
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 98 participants
- Where
- No sites listed yet
- Study dates
- 17 Nov 2026to 14 Dec 2027
- Phase
- Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 85 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Healthy adults, ages 18 to 64 years and healthy older adults, ages 65 to 85 years.
- Body mass index (BMI) of 16-32 kg/m2; and a total body weight >50kg (110 lb.).
Who cannot join
- Evidence or history of clinically significant medical conditions.
- Participation in studies of other investigational products (drug or vaccine) at any time during their participation in this study.
- A positive urine drug test.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: A PHASE 1, RANDOMIZED, DOUBLE-BLIND, SPONSOR-OPEN, PLACEBO CONTROLLED, DOSE ESCALATING STUDY TO EVALUATE THE SAFETY, TOLERABILITY, PHARMACOKINETICS, AND PHARMACODYNAMICS OF SINGLE AND MULTIPLE ORAL DOSES OF PF-08161842 IN HEALTHY AND OLDER PARTICIPANTS
The purpose of this clinical study is to learn about the safety and effects of the study medicine (called PF-08161842) and how it is processed by the body. This is the first time PF-08161842 will be given to people.
This study is seeking healthy adults:
Read more
- 18 to 64 years of age or 65 to 85 years of age
- Who are in generally good health
- Who meet study conditions for body weight and body mass index (BMI)
Participants will receive either PF-08161842 tablets or matching placebo tablets. Placebo tablets do not contain active medicine. In some study groups, participants will receive a single dose of study medicine. In other study groups, they will receive the study medicine for 14 days. The tablets will be taken by mouth at the study clinic.
We will compare the experiences of people receiving the study medicine with those of people who do not. This will help researchers determine if PF-08161842 is safe and how it affects the body.
Participants will stay at the study clinic for several days so the study team can closely monitor their health. The study will include physical examinations, checks of blood pressure, heart rate, temperature, and breathing. It will also include blood and urine samples and heart tracing tests (ECGs). Researchers will assess how the body processes the study medicine. Some participants will also have lumbar punctures (spinal taps) to collect small samples of fluid from around the brain and spinal cord. The study team will monitor participants for any reactions throughout the study.
For people receiving a single dose, the study will last for about 9 weeks. For those receiving multiple doses the study will last for about 11 weeks. This includes screening, study visits, clinic stay, and follow-up contact after the last dose.
- Conditions
- Alzheimer Disease
- Being tested
- PF-08161842, Placebo for PF-08161842
- Keywords
- Healthy Participants
- Medical subject headings
- Alzheimer Disease
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PF-08161842Drug
Oral tablet (Parts A and B).
Placebo for PF-08161842Drug
Matching placebo tablet (Parts A and B).
| Study group | Role | What they receive |
|---|---|---|
| Part A: Cohorts 1-6 and 7 (optional) | Experimental | Participants will receive PF-08161842 or matching placebo as a single dose on Day 1. Receives: Drug: PF-08161842; Drug: Placebo for PF-08161842 |
| Part B: Cohort 8-12 and 13 (Optional) | Experimental | Participants will receive doses of PF-08161842 or matching placebo from Day 1 through Day 14. Receives: Drug: PF-08161842; Drug: Placebo for PF-08161842 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants With Treatment Emergent Adverse Events (TEAEs)
Measured: From first dose through approximately 28 to 35 days after the last dose
Number of Participants With Serious Adverse Events (SAEs)
Measured: From first dose through approximately 28 to 35 days after the last dose
Number of Participants With Clinically Significant Laboratory Abnormalities
Measured: From first dose through approximately 28 to 35 days after the last dose
Number of Participants With Clinically Significant Vital Signs Abnormalities
Measured: From first dose through approximately 28 to 35 days after the last dose
Number of Participants With Clinically Significant Electrocardiogram (ECG) Findings
Measured: From first dose through approximately 28 to 35 days after the last dose
Number of Participants With Clinically Significant Columbia-Suicidality Severity Rating Scale (C-SSRS)
Measured: From first dose through approximately 28 to 35 days after the last dose
Secondary outcomes (7)
Area Under the Concentration-time Curve From Time Zero to the Time of the Last Quantifiable Concentration (AUClast)
Measured: Part A only: Up to Day 5
Area Under the Curve From Time Zero to end of Dosing Interval (AUCtau)
Measured: Part B only: Up to Day 17
Maximum Observed Plasma Concentration (Cmax)
Measured: Part A: Up to Day 5 Part B: Up to Day 17
Time to Reach Maximum Observed Plasma Concentration (Tmax)
Measured: Part A: Up to Day 5 Part B: Up to Day 17
Area Under the Curve From Time Zero to Extrapolated Infinite Time (AUCinf) if data permit
Measured: Part A only: Up to Day 5
Plasma Decay Half-life (t1/2) if data permit
Measured: Part A only: Up to Day 5
Cerebrospinal Fluid (CSF) Concentration of PF-08161842
Measured: Part A: At day 2 post dose Part B: At day 15 post dose
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Oct 2026
- Study start17 Nov 2026 (estimated)
- Primary completion17 Mar 2027 (estimated)
- Study completion14 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Alzheimer DiseaseStudies of the same condition, open and under way.
- More trials run by PfizerThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 98 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07897708
- Sponsor's protocol ID
- C6621001
- Status last verified
- Oct 2026
- First submitted
- 20 Oct 2026
- Last updated
- 27 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.
Study at a glance
From the registry record, last updated by the sponsor on 27 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A PHASE 1, RANDOMIZED, DOUBLE-BLIND, SPONSOR-OPEN, PLACEBO CONTROLLED, DOSE ESCALATING STUDY TO EVALUATE THE SAFETY, TOLERABILITY, PHARMACOKINETICS, AND PHARMACODYNAMICS OF SINGLE AND MULTIPLE ORAL DOSES OF PF-08161842 IN HEALTHY AND OLDER PARTICIPANTS
- ClinicalTrials.gov ID
- NCT07897708
- Acronym / sponsor ID
- C6621001
- Conditions
- Alzheimer Disease
- Keywords
- Healthy Participants
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 98 participants (estimated)
- Lead sponsor
- PfizerIndustry (pharma, biotech, devices)
- Study start
- 17 Nov 2026 (estimated)
- Primary completion
- 17 Mar 2027 (estimated)
- Study completion
- 14 Dec 2027 (estimated)
- First posted
- 27 Oct 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this clinical study is to learn about the safety and effects of the study medicine (called PF-08161842) and how it is processed by the body. This is the first time PF-08161842 will be given to people.
This study is seeking healthy adults:
- 18 to 64 years of age or 65 to 85 years of age
- Who are in generally good health
- Who meet study conditions for body weight and body mass index (BMI)
Participants will receive either PF-08161842 tablets or matching placebo tablets. Placebo tablets do not contain active medicine. In some study groups, participants will receive a single dose of study medicine. In other study groups, they will receive the study medicine for 14 days. The tablets will be taken by mouth at the study clinic.
We will compare the experiences of people receiving the study medicine with those of people who do not. This will help researchers determine if PF-08161842 is safe and how it affects the body.
Participants will stay at the study clinic for several days so the study team can closely monitor their health. The study will include physical examinations, checks of blood pressure, heart rate, temperature, and breathing. It will also include blood and urine samples and heart tracing tests (ECGs). Researchers will assess how the body processes the study medicine. Some participants will also have lumbar punctures (spinal taps) to collect small samples of fluid from around the brain and spinal cord. The study team will monitor participants for any reactions throughout the study.
For people receiving a single dose, the study will last for about 9 weeks. For those receiving multiple doses the study will last for about 11 weeks. This includes screening, study visits, clinic stay, and follow-up contact after the last dose.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Part A: Cohorts 1-6 and 7 (optional) | Experimental | Drug: PF-08161842, Drug: Placebo for PF-08161842Participants will receive PF-08161842 or matching placebo as a single dose on Day 1. |
| Part B: Cohort 8-12 and 13 (Optional) | Experimental | Drug: PF-08161842, Drug: Placebo for PF-08161842Participants will receive doses of PF-08161842 or matching placebo from Day 1 through Day 14. |
Who may qualify
- Ages
- 18 to 85 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Healthy adults, ages 18 to 64 years and healthy older adults, ages 65 to 85 years.
- Body mass index (BMI) of 16-32 kg/m2; and a total body weight >50kg (110 lb.).
Key exclusion criteria (3 listed)
- Evidence or history of clinically significant medical conditions.
- Participation in studies of other investigational products (drug or vaccine) at any time during their participation in this study.
- A positive urine drug test.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| PF-08161842Oral tablet (Parts A and B). | Drug | Part A: Cohorts 1-6 and 7 (optional), Part B: Cohort 8-12 and 13 (Optional) |
| Placebo for PF-08161842Matching placebo tablet (Parts A and B). | Drug | Part A: Cohorts 1-6 and 7 (optional), Part B: Cohort 8-12 and 13 (Optional) |
Primary outcome
Number of Participants With Treatment Emergent Adverse Events (TEAEs)
Time frame: From first dose through approximately 28 to 35 days after the last dose
Number of Participants With Serious Adverse Events (SAEs)
Time frame: From first dose through approximately 28 to 35 days after the last dose
Number of Participants With Clinically Significant Laboratory Abnormalities
Time frame: From first dose through approximately 28 to 35 days after the last dose
Number of Participants With Clinically Significant Vital Signs Abnormalities
Time frame: From first dose through approximately 28 to 35 days after the last dose
Number of Participants With Clinically Significant Electrocardiogram (ECG) Findings
Time frame: From first dose through approximately 28 to 35 days after the last dose
Number of Participants With Clinically Significant Columbia-Suicidality Severity Rating Scale (C-SSRS)
Time frame: From first dose through approximately 28 to 35 days after the last dose
7 secondary outcomes
Area Under the Concentration-time Curve From Time Zero to the Time of the Last Quantifiable Concentration (AUClast)
Time frame: Part A only: Up to Day 5
Area Under the Curve From Time Zero to end of Dosing Interval (AUCtau)
Time frame: Part B only: Up to Day 17
Maximum Observed Plasma Concentration (Cmax)
Time frame: Part A: Up to Day 5 Part B: Up to Day 17
Time to Reach Maximum Observed Plasma Concentration (Tmax)
Time frame: Part A: Up to Day 5 Part B: Up to Day 17
Area Under the Curve From Time Zero to Extrapolated Infinite Time (AUCinf) if data permit
Time frame: Part A only: Up to Day 5
Plasma Decay Half-life (t1/2) if data permit
Time frame: Part A only: Up to Day 5
Cerebrospinal Fluid (CSF) Concentration of PF-08161842
Time frame: Part A: At day 2 post dose Part B: At day 15 post dose
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Oct 2026.
- To obtain contact information for a study center near you, click here.Link provided by the sponsor.
- Individual participant dataSharing planned: No. Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Pfizer CT.gov Call Center study director
Pfizer
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing PF-08161842 in people with Alzheimer Disease, run by Pfizer.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 27 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Pfizer CT.gov Call Center (1-800-718-1021, ClinicalTrials.gov_Inquiries@pfizer.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Participants With Treatment Emergent Adverse Events (TEAEs) (time frame: From first dose through approximately 28 to 35 days after the last dose). The study lists 6 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Oct 2026.