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Phase 3 Randomized Trial of Once‑Monthly PF‑08653944 to Reduce Breathing Events in Adults with Obstructive Sleep Apnea and Overweight/Obesity Using a PAP Machine

Investigational
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What is this trial about?

A plain-language summary of the goals, design and what participants do

The study focuses on adults who have Obstructive Sleep Apnea—a condition where breathing stops or becomes very shallow during sleep—and who are also classified as Overweight or Obesity. All participants are already using a positive airway pressure therapy machine that helps keep the airway open while they sleep. The investigational medicine, called berobenatide, is given as a once‑monthly injection under the skin, while a matching placebo is used for comparison.

The purpose of the trial is to determine whether berobenatide can lower the number of breathing interruptions measured by the apnea–hypopnea index compared with placebo. Participants are randomly assigned to receive either the drug or the placebo, and neither the participants nor the study staff know which treatment is given. Over about a year, participants attend regular visits where their breathing events, body weight, blood markers of inflammation, blood pressure, sleepiness, and quality‑of‑life scores are recorded to assess both safety and effectiveness of the medication.

The research process

The trial runs in 8 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Enrollment Confirmation

    After joining the study, you receive a confirmation that you are enrolled and a schedule for the initial assessments.

    Baseline measurements are taken, including a sleep study to determine the Apnea–Hypopnea Index (AHI), body weight, blood pressure, and blood samples for laboratory tests.

  2. Step 2

    Randomization

    You are randomly assigned to receive either berobenatide or a matching placebo. The assignment is double‑blind, meaning neither you nor the study staff know which product you receive.

  3. Step 3

    First Injection

    A study nurse administers a subcutaneous injection (an injection under the skin) of the assigned product at the clinic.

    The injection is given once and marks the start of the monthly dosing schedule.

  4. Step 4

    Monthly Injections

    You receive a subcutaneous injection of the study medication once every month for a total of 12 months.

    Each injection is performed at the clinic according to the study protocol. The exact amount of the medication is determined by the study and is the same for every dose.

  5. Step 5

    Continued Use of Positive Airway Pressure (PAP)

    You continue to use your prescribed breathing machine (positive airway pressure therapy) each night as you have done before the study.

    The study does not change the settings or usage instructions for your PAP device.

  6. Step 6

    Scheduled Clinic Visits

    You attend clinic visits at several time points, for example at weeks 4, 12, 24, 36, and 52.

    During each visit, the study team measures your Apnea–Hypopnea Index (AHI), body weight, blood pressure, and collects blood samples to check markers such as high‑sensitivity C‑reactive protein (hs‑CRP).

    You also complete questionnaires that assess sleep quality, daytime sleepiness, and overall quality of life.

  7. Step 7

    Final Assessment

    At week 52, a comprehensive evaluation is performed.

    The primary outcome is the change in Apnea–Hypopnea Index (AHI) from the start of the study. Secondary outcomes include changes in body weight, hs‑CRP, blood pressure, sleep‑related questionnaires, and a quality‑of‑life score.

    All measurements are taken in the same way as at baseline to allow comparison.

  8. Step 8

    Study Completion

    After the final visit, the study medication is discontinued.

    Your data are retained for analysis, and you are no longer required to receive monthly injections.

Who can join the trial?

5 criteria

  • Adults aged 18 years or older – you must be at least 18 years old.
  • Body mass index (BMI) ≥ 27 kg/m² – BMI is a number that compares your weight to your height; a value of 27 or higher means you are overweight or obese.
  • Previously diagnosed with moderate to severe obstructive sleep apnea – you must have been told by a doctor that you have a breathing problem during sleep that is moderate or severe.
  • Ongoing positive airway pressure (PAP) therapy expected to continue – you need to be using a PAP machine, which helps keep your airway open while you sleep, and you must plan to keep using it during the study.
  • Both men and women are eligible to take part.

Who cannot join the trial?

11 criteria

  • Having lost or gained more than 5% of your body weight in the 90 days before the screening visit.
  • Being diagnosed with any form of diabetes (except gestational diabetes that has completely resolved).
  • Having a past episode of acute (sudden) or chronic (long‑term) pancreatitis, which is inflammation of the pancreas.
  • Having a personal or family history of medullary thyroid carcinoma (MTC) – a type of thyroid cancer – or multiple endocrine neoplasia type 2 (MEN 2), a genetic condition that can cause tumors in several glands.
  • Having had previous airway surgery that could affect the breathing passages.
  • Having any sleep condition other than obstructive sleep apnea, such as non‑obstructive sleep apnea syndromes.
  • Having a hypoventilation disorder, which means your breathing may be too shallow or slow.
  • Using sleep‑apnea treatments that are not CPAP or BiPAP (called non‑PAP treatments).
  • Having serious respiratory (lung), neuromuscular (nerve‑muscle), or craniofacial (facial bone) diseases that could affect breathing.
  • Having severe insomnia, meaning you have great difficulty falling or staying asleep.
  • Having any other clinically important sleep disorder that could interfere with the study’s breathing measurements.
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Investigated drugs

berobenatide is an experimental medicine being tested to help adults with obstructive sleep apnea who are overweight or obese. It is given as a once‑monthly injection under the skin. In the study, participants keep using their regular breathing‑support device, and the drug is being evaluated to see if it can further lower the number of breathing interruptions that occur during sleep. Positive airway pressure therapy (often called CPAP or a similar device) is a standard treatment for obstructive sleep apnea. It provides a steady flow of air through a mask to keep the airway open while the person sleeps. In this trial, all participants use this therapy, and the experimental drug is added to see if it gives extra benefit.

What is already known about the treatment

PF-08653944 - This medication is given as a sterile solution for subcutaneous injection, usually using a small needle under the skin. It is an investigational peptide drug that is still being studied and has not yet been approved for general medical use. The main purpose of the trial is to see if it can help adults who are overweight or obese and have obstructive sleep apnea by reducing the number of breathing interruptions during sleep. It works by binding to specific receptors in the body that influence breathing patterns and appetite, placing it in the class of synthetic peptide agents.

Investigated diseases

  • Obstructive sleep apnea

    A condition in which the upper airway collapses repeatedly during sleep, causing pauses in breathing and drops in blood oxygen. Each pause often triggers a brief awakening that restores airflow. The number of pauses can increase over months or years, especially if weight or age rise. Repeated events lead to fragmented sleep and increasing daytime sleepiness. The disorder tends to become chronic without intervention.

  • Overweight or obesity

    A state of excess body fat measured by body‑mass index that is above normal limits. Fat accumulation builds up slowly over time, often starting in early adulthood. As more fat is stored, the condition can progress to higher BMI categories. The increase in body weight can intensify strain on joints and internal organs. Without changes in diet or activity, the excess weight typically continues to rise.

Trial detailsLast updated 11 Nov 2026
Age18+ yearsPhasePhase IIITrial ID2026-526327-22-00Protocol codeC6491020Estimated enrolment228 patientsSponsorPfizer Inc.

sourced from the EU Clinical Trials Register and site verification

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