A Phase 3 interventional study of Aspirin and Placebo in Colon Cancer, sponsored by Swiss Group for Clinical Cancer Research. Terminated at 60 sites in 4 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-05-16.
Sponsored by Swiss Group for Clinical Cancer Research · Phase 3, Interventional, and Treatment
Following complete resection of their primary tumor, potentially eligible stage II or stage III colon cancer patients will undergo central PIK3CA testing. Patients with somatic mutations will be 2:1 randomized to daily aspirin 100 mg versus placebo for a a maximum of 3 years or until disease recurrence, patient death or withdrawal of consent, whichever occurs first. Patients will be followed up for at least 3 years from the date of surgery.
The intake of aspirin or placebo is independent of adjuvant chemotherapy, and does not impact on the indication to give (or not to give) adjuvant chemotherapy.
Colorectal cancer is the third most common malignancy for both women and men and is responsible for almost 10% of all cancer death. Despite complete removal of the tumor and use of adjuvant chemotherapy, up to 25% of patients with stage II colon cancer and up to 50% of patients with stage III disease will suffer from recurrences, which is associated with poor prognosis.
Several retrospective observations have documented a favorable effect of long-term intake of oral aspirin for the prevention of colorectal cancer in different clinical situations. Regular intake of aspirin after the diagnosis of colorectal cancer may also be associated with a lower risk of colorectal cancer-specific and overall mortality. Two recent publications in prestigious medical journals provided retrospective evidence that patients with PIK3CA-mutated colon cancer may derive a very substantial benefit from daily oral aspirin. Both analyses showed a roughly 85% reduction of the risk for tumor relapse compared to patients who did not take aspirin. However, a potential selection bias in these retrospective analyses cannot be excluded with certainty. These extremely interesting and intriguing findings must be confirmed in a randomized controlled trial to potentially change clinical practice.
The trial objective is to demonstrate a statistically significant and clinically relevant disease-free survival benefit in stage II and III PIK3CA mutated colon cancer patients taking daily adjuvant aspirin for 3 years.
Patients with resected colon cancer stage II or stage III bearing somatic mutations in exon 9 or 20 of PIK3CA will be 2:1 randomized to daily adjuvant aspirin 100 mg versus placebo for a maximum of 3 years or until disease recurrence, patient death or withdrawal of consent, whichever occurs first. Patients will be followed up for at least 3 years from the date of surgery. The intake of aspirin or placebo is independent of adjuvant chemotherapy, and does not impact on the indication to give (or not to give) adjuvant chemotherapy.
2,457 studies on the registry are indexed under Colonic Neoplasms; 458 are open to participants now.
This study's enrollment of 1,040 is above the median of 75 across 1,711 interventional studies indexed under Colonic Neoplasms.
Browse Colonic Neoplasms studies →Swiss Group for Clinical Cancer Research is the lead sponsor of 106 studies on the registry; none are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adjuvant and neoadjuvant
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Asprin 100 mg daily for maximum 3 years standard chemo if indicated
Drug: Aspirin
Placebo daily for maximum 3 years standard chemo if indicated
Drug: Placebo
Aspirin 100 mg daily
Also known as: acetylsalicylic acid
Placebo
Disease-free Survival (DFS)
The primary endpoint of this trial is DFS, defined as time from surgery until one of the following events, whichever comes first: * recurrence * second cancer * death due to any reason Patients not experiencing an event will be censored at the date of the last available tumor assessment.
Time frame: up to 7 years
Time to Recurrence (TTR)
TTR was calculated from surgery until recurrence or death due to colon cancer. Patients not experiencing an event or patients who died due to other reasons before experiencing an event were censored at the date of the last available tumor assessment.
Time frame: up to 7 years
Overall Survival (OS)
OS was calculated from surgery until death from any cause. Patients not experiencing an event were censored at the last date they were known to be alive.
Time frame: up to 7 years
Cancer-specific Survival (CSS)
CSS was calculated from surgery until death due to colon cancer, whether due to the original tumor or to a second primary same cancer. Patients who died due to other reasons were censored at the time of death. All other patients were censored at the last date they were known to be alive.
Time frame: up to 7 years
Adverse Events (AEs)
Time frame: During treatment (median 22.1 months)
| Milestone | Aspirin 100 mg | Placebo |
|---|---|---|
| Started | 75 | 38 |
| Completed | 74 | 38 |
| Not completed | 1 | 0 |
| Withdrew: Withdrawal by subject | 1 | 0 |
| Milestone | Aspirin 100 mg | Placebo |
|---|---|---|
| Started | 74 | 38 |
| Completed | 63 | 29 |
| Not completed | 11 | 9 |
| Withdrew: Death | 5 | 4 |
| Withdrew: Lost to follow-up | 6 | 5 |
The primary endpoint of this trial is DFS, defined as time from surgery until one of the following events, whichever comes first: * recurrence * second cancer * death due to any reason Patients not experiencing an event will be censored at the date of the last available tumor assessment.
| years | Aspirin 100 mg | Placebo |
|---|---|---|
| Disease-free Survival (DFS) | NA (6.19 to NA) | NA (5.77 to NA) |
TTR was calculated from surgery until recurrence or death due to colon cancer. Patients not experiencing an event or patients who died due to other reasons before experiencing an event were censored at the date of the last available tumor assessment.
| years | Aspirin 100 mg | Placebo |
|---|---|---|
| Time to Recurrence (TTR) | NA (NA to NA) | NA (5.77 to NA) |
OS was calculated from surgery until death from any cause. Patients not experiencing an event were censored at the last date they were known to be alive.
| years | Aspirin 100 mg | Placebo |
|---|---|---|
| Overall Survival (OS) | NA (NA to NA) | NA (5.77 to NA) |
CSS was calculated from surgery until death due to colon cancer, whether due to the original tumor or to a second primary same cancer. Patients who died due to other reasons were censored at the time of death. All other patients were censored at the last date they were known to be alive.
| years | Aspirin 100 mg | Placebo |
|---|---|---|
| Cancer-specific Survival (CSS) | NA (NA to NA) | NA (NA to NA) |
| Participants | Aspirin 100 mg | Placebo |
|---|---|---|
| Anemia | 0 | 1 |
| Colonic hemorrhage | 0 | 1 |
| Cranial fracture with intra cranial hemorrhage | 0 | 1 |
| Dizziness | 1 | 0 |
Collected over Deaths were assessed for up to 7 years. Adverse Events were assessed for an median of 22.1 months. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Aspirin 100 mg | 5/74 (6.8%) | 1/74 (1.4%) | 0/74 (0%) |
| Placebo | 4/38 (10.5%) | 3/38 (7.9%) | 0/38 (0%) |
| Event | Aspirin 100 mg | Placebo |
|---|---|---|
| Colonic hemorrhageGastrointestinal disorders | 0/74 | 1/38 |
| Gastrointestinal hemorrhageGastrointestinal disorders | 0/74 | 1/38 |
| Cranial fracture with intracranial hemorrhageInjury, poisoning and procedural complications | 0/74 | 1/38 |
| Intraductal proliferative breast lesionNeoplasms benign, malignant and unspecified (incl cysts and polyps) | 1/74 | 0/38 |
Full analysis set (FAS): The FAS is defined as all randomized patients who received at least one dose of aspirin/placebo excluding patients with major eligibility violations as defined in the statistical analysis plan (SAP). Following the intention-to-treat principle, patients in this population were analyzed according to the treatment they were randomized to.
| Age, Categorical(Participants) | Aspirin 100 mg | Placebo | Total |
|---|---|---|---|
| <=18 years | 0 | 0 | 0 |
| Between 18 and 65 years | 31 | 19 | 50 |
| >=65 years | 43 | 19 | 62 |
| Age, Continuous(years) | Aspirin 100 mg | Placebo | Total |
|---|---|---|---|
| Median | 68 (29 to 79) | 65 (44 to 89) | 66 (29 to 89) |
| Sex: Female, Male(Participants) | Aspirin 100 mg | Placebo | Total |
|---|---|---|---|
| Female | 30 | 18 | 48 |
| Male | 44 | 20 | 64 |
| Race/Ethnicity, Customized(Participants) | Aspirin 100 mg | Placebo | Total |
|---|---|---|---|
| Ethnicity — African | 2 | 0 | 2 |
| Ethnicity — Asian | 3 | 0 | 3 |
| Ethnicity — Caucasian | 67 | 38 | 105 |
| Ethnicity — Hispanic | 1 | 0 | 1 |
| Ethnicity — Other | 1 | 0 | 1 |
| Region of Enrollment(participants) | Aspirin 100 mg | Placebo | Total |
|---|---|---|---|
| Belgium | 4 | 1 | 5 |
| Hungary | 1 | 1 | 2 |
| Switzerland | 44 | 25 | 69 |
| Germany | 25 | 11 | 36 |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Ran from Jun 2016 to primary completion in Sep 2023, 87 months.
Results were first posted in May 2025, 1 year 8 months after primary completion.
How these figures are worked out, and which studies are left out of them.
This study is terminated, as verified in May 2025. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Aspirin
Swiss Group for Clinical Cancer Research →