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RecruitingHuman Pharmacology (Phase I)- Bioequivalence StudyInterventional

A Study to Learn How Different Injector Pens Affect the Study Medicine Called Genotropin® (somatropin) Delivery and Taken Up Into the Blood in Healthy Adults

Growth hormone is naturally made by the body, but some people need replacement treatment using medicines such as Genotropin (somatropin). This medicine is usually injected under the skin using a handheld injector pen. This early-stage study is testing different types of injection pens in healthy adult volunteers. The main goal is to find out whether the body absorbs the medicine in the exact same way, no matter which pen device delivers the injection. This is known as a bioequivalence study. Participants will receive injections of Genotropin using different pens and will have regular blood tests to measure hormone levels over time. Because this study is in healthy volunteers, it does not aim to treat a medical condition in participants. Instead, it helps ensure that future patients who need growth hormone can rely on their pens to deliver safe and accurate doses.

At a glance

Status
Recruiting
Phase
Human Pharmacology (Phase I)- Bioequivalence Study
Sponsor
Pfizer Inc.
Enrolment target
26
Start
25 Mar 2026

What is this study about?

Genotropin contains somatropin, a man-made version of the natural growth hormone produced by the body. Doctors prescribe it to children and adults whose bodies do not produce enough growth hormone on their own. Most people who use Genotropin take it at home using a specialised injector pen, which works much like an insulin pen used for diabetes.

Over time, device designers update and improve these injector pens to make them easier to grip, dial, and inject. However, even small changes to a device can alter how the medicine enters the tissue under the skin and how quickly it reaches the bloodstream. This study is designed to compare different injector pens to ensure they all deliver the medicine equally well.

To measure this accurately, researchers are carrying out the trial in healthy adult volunteers. Testing in healthy volunteers allows doctors to see how the device performs on its own, without other health conditions or daily medications clouding the results.

The findings from this trial will help confirm that new or updated injector pens are just as safe and reliable as the current ones. This gives doctors and patients peace of mind that their treatment will work consistently, no matter which approved pen they are prescribed.

Key takeaways

  • Tests how different injector pen devices deliver the medicine Genotropin.
  • Open to healthy adult volunteers aged 18 and over.
  • Aims to confirm that all tested pens deliver the medicine into the blood equally well.
  • Involves visits to a research clinic, injections, and regular blood tests.
  • Offers no direct health benefit to volunteers, but helps improve medicine devices for future patients.

Who may be eligible?

This study is open to healthy adults aged 18 and older. Both men and women can apply. Because researchers want to see how the body absorbs the medicine under standard, normal conditions, volunteers must be in good general health.

You are unlikely to be eligible if you have an existing hormone problem, a history of cancer, or serious long-term conditions affecting your heart, liver, or kidneys. You must also not have any known allergies to somatropin or the ingredients used in the injection liquid.

Women who are pregnant, planning a pregnancy, or breastfeeding will not be able to join. Before anyone is accepted onto the study, the research team will carry out health checks, including blood tests and a physical exam, to confirm it is safe for them to take part.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

  1. I am aged 18 or older.
  2. I consider myself to be in good general health.
  3. I do not have a known allergy to somatropin or similar medicines.
  4. I am not currently pregnant or breastfeeding.
  5. I am comfortable having injections under the skin and routine blood tests.
  6. I have time available to attend clinic visits or short stays as required.
Answer every question to see your result.

What does participation involve?

If you decide to take part, you will first visit the clinic for a screening appointment to check your medical history, carry out blood tests, and confirm you are eligible. Once enrolled, you will receive doses of Genotropin given as injections under the skin using the different study pens on set days. Because the doctors need to track how the medicine enters and leaves your bloodstream, you will need to spend time at the research unit so staff can take scheduled blood samples over several hours following each dose. The study team will monitor your blood pressure, heart rate, and overall wellbeing throughout. The entire study typically lasts a few weeks, divided into dosing periods with rest days in between, followed by a final health check.

Potential risks and benefits

Because you are joining this study as a healthy volunteer, you will not receive any direct medical benefit from taking part, though your involvement helps ensure treatments are safe for future patients. Somatropin can cause temporary side effects, such as mild swelling, redness, or stinging where the needle goes in, as well as headaches, fluid retention, or muscle stiffness. Having frequent blood samples taken may also cause brief discomfort or mild bruising. The medical team will watch you closely throughout the trial to keep you safe. Joining is completely your choice, and you have the right to withdraw at any time without giving a reason.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.
  • —
    Unverified
    Belgium

Common questions

Why is this study using healthy volunteers instead of patients?

Healthy volunteers allow researchers to measure how the medicine behaves naturally in the body without the influence of other illnesses or ongoing treatments.

What is Genotropin used for in normal medical practice?

It is a prescription medicine used to replace missing growth hormone in children and adults with growth hormone deficiency.

Are study volunteers paid for their time?

Phase 1 trials involving healthy volunteers usually offer payment to cover your travel expenses and compensate you for your time and inconvenience. The study team can give you full details.

How is the study medicine given?

It is given as a small injection under the skin, usually in the tummy or thigh, using the injector pens being tested.

Can I leave the study if I change my mind?

Yes. Taking part is completely voluntary. You can leave the study at any point, and your decision will always be respected.

How to find out more

Always speak to your GP or specialist before deciding to take part in a study.

Interested in taking part?

Register your interest

Share your details and the research team for "A Study to Learn How Different Injector Pens Affect the Stud…" will contact you if you may be eligible. Always speak to your GP before agreeing to take part.

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