A Phase 1/2 interventional study of Arginine-Restricted Diet and CAPOX Chemotherapy in Rectal Cancer Patients, sponsored by Xuelei Ma MD. Not yet recruiting. Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-11-03.
Sponsored by Xuelei Ma MD · Phase 1/2, Interventional, and Treatment
This is a Phase Ib/II clinical trial designed to evaluate the safety, tolerability, and preliminary efficacy of an arginine-restricted diet combined with standard neoadjuvant chemoradiotherapy in patients with locally advanced middle/high rectal cancer.
Background: Standard neoadjuvant chemoradiotherapy is the standard treatment for locally advanced rectal cancer to shrink tumors before surgery. However, the rate of complete tumor disappearance (pathological complete response) with standard treatment remains relatively low (around 10-20%). Arginine is an amino acid that supports tumor growth and immune escape. Preclinical studies and our previous Phase I trial (NCT07038044) suggest that restricting arginine in the diet can alter tumor metabolism and enhance the body's anti-tumor immune response.
Study Design: The study consists of two phases. Phase Ib is a single-arm safety run-in, where 6 patients will receive the arginine-restricted diet plus standard chemoradiotherapy.
Phase II is a randomized, open-label, controlled phase. Approximately 120 patients will be randomly assigned in a 1:1 ratio to either the experimental group or the control group. Neither the patient nor the doctor can choose the group.
Interventions:
Standard Treatment: All participants will receive standard CAPOX chemotherapy (oxaliplatin and capecitabine) and long-course radiotherapy.
Arginine-Restricted Diet: Patients in the experimental group will consume a specially formulated, nutritionally complete, arginine-restricted nutritional powder combined with specific low-arginine foods for 7-8 weeks during the radiotherapy period, replacing their normal diet. Patients in the control group will maintain a normal diet.
Objectives: The primary objective is to evaluate whether this dietary intervention can improve the complete response rate (including pathological complete response [pCR] and clinical complete response [cCR]) compared to standard treatment alone. Secondary objectives include assessing safety (adverse events), surgical outcomes (R0 resection rate), survival outcomes (event-free survival, progression-free survival, overall survival), and changes in nutritional and immune status.
2,400 studies on the registry are indexed under Rectal Neoplasms; 587 are open to participants now.
This study's planned enrollment of 126 is above the median of 65 across 1,751 interventional studies indexed under Rectal Neoplasms.
Browse Rectal Neoplasms studies →Xuelei Ma MD is the lead sponsor of 4 studies on the registry; 4 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.
(ANC) ≥ 1.5 × 10\^9/L;
count ≥ 100 × 10\^9/L;
≥ 9 g/dL;
Serum albumin ≥ 3.0 g/dL;
Total ≤ 1.5 × ;
and ALT ≤ 2.5 × ULN;
≥ 50 mL/min or serum creatinine ≤ 1.5 × ULN;
≤ 1.5 × ULN, PT and APTT ≤ 1.5 × ULN;
Urine protein \< 2+ (if ≥ 2+, 24-hour urine protein must be \< 2.0 g);
Normal myocardial enzyme profile.
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.
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.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
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.
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).
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.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
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.
Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.
Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.
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.
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
The US National Cancer Institute’s scale of how severe an adverse event is — any unwanted medical event during a study, such as a symptom, an illness or an abnormal test result, whether or not a treatment caused it. Whether it did is judged separately.
“Side effects of earlier treatment resolved to grade 1 or less” means they have settled to mild or gone.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
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.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
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.
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.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Absolute neutrophil count (ANC)
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (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.
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.
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.
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.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
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.
INR, PT and aPTT (clotting tests)
Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.
Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.
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.
Reproductive potential
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask 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.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CTCAE grade
The US National Cancer Institute’s scale of how severe an adverse event is — any unwanted medical event during a study, such as a symptom, an illness or an abnormal test result, whether or not a treatment caused it. Whether it did is judged separately.
“Side effects of earlier treatment resolved to grade 1 or less” means they have settled to mild or gone.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
TIA (transient ischaemic attack)
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
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.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients (including Phase Ib and Phase II) receive standard neoadjuvant chemoradiotherapy (CAPOX regimen + long-course radiotherapy) combined with a 7-8 week arginine-restricted diet. The diet replaces normal food with a specially formulated arginine-free nutritional powder and specific low-arginine foods.
Dietary Supplement: Arginine-Restricted Diet · Drug: CAPOX Chemotherapy · Radiation: Long-Course Radiotherapy
Patients (Phase II only) receive standard neoadjuvant chemoradiotherapy (CAPOX regimen + long-course radiotherapy) while maintaining a normal diet without arginine restriction.
Drug: CAPOX Chemotherapy · Radiation: Long-Course Radiotherapy
Participants receive a specially formulated arginine-free nutritional powder combined with specific low-arginine foods. This diet replaces the patient's normal food intake for 7-8 weeks during the radiotherapy period. Energy and protein targets are maintained at 30 kcal/kg/day and 1.5 g/kg/day, respectively.
Drug pages: Capecitabine · Oxaliplatin
Standard neoadjuvant chemotherapy using the CAPOX regimen (Oxaliplatin plus Capecitabine) for a total of 6 cycles, administered every 3 weeks. Capecitabine is also taken orally concurrently during the radiotherapy period.
Patients receive long-course neoadjuvant radiotherapy administered between Cycle 1 and Cycle 2 of CAPOX chemotherapy. The total dose is 45.0-50.4 Gy delivered in 25-28 fractions, concurrent with oral capecitabine.
Rate of Complete Response (pCR and cCR)
Time frame: At the time of radical surgery (for pCR) or after the completion of all neoadjuvant therapy and before surgery (for cCR), approximately 24 to 26 weeks after the initiation of neoadjuvant treatment.
No study locations are listed for this record.
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Oct 2026; primary completion for Oct 2026, 0 months later.
Of 37 phase 1/2 interventional studies under Rectal Neoplasms, half reached primary completion within 75 months of starting (the median), counting those still running; a quarter within 36 and three quarters within 106. This study's planned 0 months is below that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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Xuelei Ma MD