Colon CancerPhase 2NCT07808151
Neoadjuvant Pembrolizumab and Porustobart in Resectable pMMR/MSS Colon Cancer
A Phase 2 study testing Pembrolizumab and Porustobart in people with Colon Cancer, run by Solstice Oncology, Inc. at 30 sites in 6 countries.
Trial summary
The goal of this clinical trial is to learn if giving two medicines together, porustobart and pembrolizumab, before surgery can treat a common type of colon cancer called microsatellite stable (MSS) colon cancer in adults. This type of cancer can be removed with surgery and has not spread to other parts of the body. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Colon Cancer
- What is being tested?
- Pembrolizumab and Porustobart
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 30 sitesin 6 countries
- Study dates
- 30 Sep 2026to 30 Sep 2029
- Phase
- Phase 2
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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- ≥18 years of age at consent
- Adenocarcinoma of the colon (rectosigmoid considered non-rectal); pMMR/MSS status
- Any T3 or T4, N any, M0; disease amenable to surgical resection
- ECOG Performance Status 0-1
- Adequate tumor tissue sample with associated pathology report
- Adequate hematologic, hepatic, and renal function
- Reproductive status/contraception requirements per protocol
Who cannot join
- Investigational agent within 3 weeks of first dose
- Imminent or urgent need for surgery
- Prior treatment with ICIs targeting CTLA-4, PD-1, or PD-L1
- Systemic corticosteroid/immunosuppressive therapy within 1 week of first dose (exceptions apply)
- History of severe hypersensitivity to a fully human mAb; interstitial lung disease; pneumonitis requiring corticosteroids
- Active or history of autoimmune disease requiring systemic treatment within 2 years
- Major surgery within 4 weeks of first dose; active infection requiring treatment
Trial locations and contacts
30 sites in 6 countries. Contact the study team or a site near you to ask about taking part.
30 sites in 6 countries
United States11 sites, 11 recruiting
- Not yet recruiting
Investigator Site
Baltimore, Maryland, 21287
- Not yet recruiting
Investigator Site
Boston, Massachusetts, 02114
- Not yet recruiting
Investigator Site
Chicago, Illinois, 60637
- Not yet recruiting
Investigator Site
Cleveland, Ohio, 44106
- Not yet recruiting
Investigator Site
Los Angeles, California, 90033
- Not yet recruiting
Investigator Site
Nashville, Tennessee, 37232
- Not yet recruiting
Investigator Site
New York, New York, 10016
- Not yet recruiting
Investigator Site
New York, New York, 10021
- Not yet recruiting
Investigator Site
New York, New York, 10027
- Recruiting
Investigator Site
Seattle, Washington, 98109
- Not yet recruiting
Investigator Site
Tampa, Florida, 33612
Belgium7 sites, 7 recruiting
- Not yet recruiting
Investigator Site
Anderlecht
- Not yet recruiting
Investigator Site
Bonheiden
- Not yet recruiting
Investigator Site
Ghent
- Not yet recruiting
Investigator Site
Leuven
- Not yet recruiting
Investigator Site
Liège
- Not yet recruiting
Investigator Site
Ostend
- Not yet recruiting
Investigator Site
Woluwe-Saint-Lambert
United Kingdom5 sites, 5 recruiting
- Not yet recruiting
Investigator Site
Aberdeen
- Not yet recruiting
Investigator Site
Cardiff
- Not yet recruiting
Investigator Site
Glasgow
- Not yet recruiting
Investigator Site
Leeds
- Not yet recruiting
Investigator Site
London
Italy3 sites, 3 recruiting
- Not yet recruiting
Investigator Site
Milan
- Not yet recruiting
Investigator Site
Naples
- Not yet recruiting
Investigator Site
Pisa
Spain3 sites, 3 recruiting
- Not yet recruiting
Investigator Site
Barcelona
- Not yet recruiting
Investigator Site
L'Hospitalet de Llobregat
- Not yet recruiting
Investigator Site
Madrid
Netherlands1 site, 1 recruiting
- Not yet recruiting
Investigator Site
Amsterdam
About this study
Official title: A Phase 2, Open-Label, Multicenter, Randomized Trial Evaluating the Efficacy and Safety of Different Schedules of Neoadjuvant Pembrolizumab and Porustobart in Patients With Resectable pMMR/MSS Colon Cancer
The goal of this clinical trial is to learn if giving two medicines together, porustobart and pembrolizumab, before surgery can treat a common type of colon cancer called microsatellite stable (MSS) colon cancer in adults. This type of cancer can be removed with surgery and has not spread to other parts of the body. Both medicines work by helping the immune system fight cancer.
The main questions this study wants to answer:
Read more
How well do the medicines destroy the cancer before surgery? What side effects do participants have when taking the medicines?
Researchers will compare two groups to see which treatment schedule works better and is safer. Both groups get pembrolizumab. One group gets one dose of porustobart (Day 1 only), and the other group gets two doses (Day 1 and Day 22).
Participants will:
Complete certain tests and procedures to make sure they are eligible Get the medicines through a vein on Day 1 and Day 22 then have surgery 6-9 weeks after starting treatment Return for checkups and tests every 6 months for up to 3 years after surgery
- Conditions
- Colon Cancer
- Being tested
- Pembrolizumab, Porustobart
- Keywords
- neoadjuvant therapy, Immune checkpoint inhibitor, CTLA-4, PD-1, Porustobart, HBM4003, Pembrolizumab, Major pathologic response, pMMR/MSS colon cancer, Resectable colon cancer, Fc-enhanced CTLA-4, Microsatellite Stable (MSS) Colon Cancer, Proficient Mismatch Repair (pMMR) Colon Cancer
- Medical subject headings
- Colonic Neoplasms, Diabetes Mellitus, Insulin-Dependent, 12, Spinocerebellar Degenerations
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PembrolizumabDrug
Also called Keytruda
Administered to: Dose Schedule 1 - Porustobart + Pembrolizumab, Dose Schedule 2 - Porustobart + Pembrolizumab
PorustobartDrug
Also called HBM4003
Administered to: Dose Schedule 1 - Porustobart + Pembrolizumab, Dose Schedule 2 - Porustobart + Pembrolizumab
| Study group | Role | What they receive |
|---|---|---|
| Dose Schedule 1 - Porustobart + Pembrolizumab | Experimental | Pembrolizumab IV every 3 weeks x 2 doses (Day 1, Day 22) plus porustobart x 1 dose (Day 1 only) Receives: Drug: Pembrolizumab; Drug: Porustobart |
| Dose Schedule 2 - Porustobart + Pembrolizumab | Experimental | Pembrolizumab IV every 3 weeks x 2 doses (Day 1, Day 22) plus porustobart every 3 weeks x 2 doses (Day 1, Day 22) Receives: Drug: Pembrolizumab; Drug: Porustobart |
What is being measured
The primary outcome is the main question the study is designed to answer.
Major Pathologic Response (MPR) rate by Blinded Independent Pathologic Review (BIPR)
MPR is defined as the proportion of patients with ≤10% residual tumor volume in the primary tumor and lymph nodes, as evaluated by BIPR, per treatment arm
Measured: Assessed from surgical resection specimen (surgery occurs Day 42-Day 63, i.e., approximately Week 6-Week 9 after first dose)
Secondary outcomes (2)
Pathologic Complete Response (pCR) rate
Measured: Assessed from surgical resection specimen (Week 6-9)
Incidence of treatment-related adverse events (AEs), serious adverse events (SAEs), and immune-related AEs
Measured: From informed consent through 60 days after last dose (or initiation of new anti-cancer treatment, whichever occurs first)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Sep 2026
- Study start30 Sep 2026 (estimated)
- Primary completion30 Sep 2029 (estimated)
- Study completion30 Sep 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Colon CancerStudies of the same condition, open and under way.
- 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 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Solstice Oncology, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07808151
- Sponsor's protocol ID
- SOL1-201
- Other IDs
- 2026-527233-58-00
- Status last verified
- Oct 2026
- First submitted
- 3 Sep 2026
- Last updated
- 22 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No