Not yet recruitingPHASE2INTERVENTIONAL

Neoadjuvant Pembrolizumab and Porustobart in Resectable pMMR/MSS Colon Cancer

This research study is looking at two medicines called Pembrolizumab and Porustobart for a common type of colon cancer. This specific type of colon cancer (called microsatellite stable, or MSS) can be removed by surgery and has not spread to other parts of the body. The medicines are given before surgery to see if they can help your body's immune system fight the cancer more effectively. Researchers want to find out how well these medicines shrink or destroy the cancer before an operation, and what side effects people might experience. They will compare two different ways of giving the medicines to see which is best and safest. Participants will receive the medicines through a drip before surgery, then have regular check-ups for up to three years.

At a glance

Status

Not yet recruiting

Phase

PHASE2

Sponsor

Solstice Oncology, Inc.

Enrolment target

100

Start

30 Sep 2026

Estimated completion

30 Sep 2029

Colon Cancer Microsatellite Stable (MSS) Colon Cancer Proficient Mismatch Repair (pMMR) Colon Cancer

What is this study about?

This study is about a common type of bowel cancer (colon cancer) that doctors can usually remove with an operation. This particular type of cancer is called 'microsatellite stable' (MSS) and hasn't spread to other parts of the body. We want to see if giving two medicines, Pembrolizumab and Porustobart, before surgery can help your own body's defence system, called the immune system, to fight the cancer. Both medicines are designed to 'wake up' the immune system so it can better recognise and attack cancer cells.

The main aim is to understand how well these medicines work at shrinking or destroying the cancer before you have your operation. We also want to learn about any side effects people might have while taking them. This information will help doctors decide if this combination of medicines could be a good treatment option in the future for people with this type of colon cancer.

Researchers are comparing two different treatment plans. Everyone in the study will receive Pembrolizumab. One group will get Porustobart just once (on Day 1), and the other group will get it twice (on Day 1 and Day 22). By comparing these two groups, doctors hope to find the most effective and safest way to give these medicines.

Key takeaways

This study explores a new way to treat colon cancer before surgery.
It uses two medicines to boost your body's immune system against cancer.
The cancer must be removable by surgery and not spread.
You'll get medicines via a drip, have surgery, then follow-up check-ups.
The study aims to understand how well the medicines work and their side effects.
Participation is voluntary, and you can withdraw anytime.

Who may be eligible?

To join this study, you must be at least 18 years old and have colon cancer that can be removed by surgery and has not spread. Your cancer must also be of a specific type called 'pMMR/MSS'. Doctors will check your medical records and perform tests to make sure your general health is good enough to take part, including checking your blood, liver, and kidney function.

There are also some reasons why you might not be able to join. For example, if you’ve recently taken part in another experimental drug study, or if you need surgery very urgently. You also can't have had certain types of immunotherapy medicines before, or have certain long-term illnesses like serious autoimmune diseases (where your immune system attacks your own body) that needed strong treatment recently.

Your study doctor will discuss all the requirements with you to see if this study is a good fit for your situation.

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.

Are you 18 years old or older?
Do you have colon cancer that can be removed by surgery and hasn't spread?
Has your doctor confirmed your cancer is 'pMMR/MSS' type?
Are you generally healthy enough for treatment, with good organ function?
Have you *not* had certain other immune-boosting cancer treatments before?
Do you *not* have certain serious health conditions like active autoimmune disease?

Answer every question to see your result.

What does participation involve?

If you decide to join this study, you will first have several tests and checks to make sure you are suitable. Once confirmed, you will receive the study medicines, Pembrolizumab and Porustobart, through a drip into your vein. This will happen on Day 1 and Day 22 of your treatment plan.

Around 6 to 9 weeks after your first dose of medication, you will have your planned surgery to remove the cancer. After your surgery, you will need to come back for regular check-ups and tests. These follow-up appointments will happen every six months and will continue for up to three years. This is to monitor your health and see how you are doing in the long term.

Potential risks and benefits

Taking part in any medical study carries potential benefits and risks. You might benefit from a new treatment that could help your immune system fight your cancer more effectively before surgery. However, like all medicines, Pembrolizumab and Porustobart can cause side effects. These can vary from mild to more serious, and your study team will explain them to you in detail. It’s important to remember that participating in a clinical trial is always voluntary, and you are free to withdraw from the study at any time, for any reason, without it affecting your usual medical care.

Locations (30)

Investigator Site
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Los Angeles, United States
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Tampa, United States
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Chicago, United States
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Baltimore, United States
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Boston, United States
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New York, United States
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New York, United States
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New York, United States
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Cleveland, United States
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Nashville, United States
Investigator Site
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Seattle, United States
Investigator Site
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Anderlecht, Belgium

Common questions

What type of cancer is this study for?

This study is for a common type of bowel (colon) cancer that can be removed by surgery and has not spread, specifically called 'microsatellite stable' (MSS) colon cancer.

What are Pembrolizumab and Porustobart?

They are medicines that help your body's immune system recognise and fight cancer cells. They are given through a drip before surgery.

How long will I be in the study?

You'll receive medicines over a few weeks before surgery, then have check-ups every six months for up to three years after your operation.

Will I still have surgery?

Yes, all participants in this study will still have surgery to remove their colon cancer after receiving the study medicines.

Can I leave the study if I change my mind?

Yes, you can leave the study at any time and for any reason, and it will not affect your future medical care.

How to find out more

Medical Monitor

sol1-201@solsticeoncology.com 617-982-2331 Official trial record

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