Phase II clinical trial of KCHO-1 for Alzheimer's disease: study protocol for a multicenter, randomized, double-blind, multi-dose, placebo trial

Abstract

Background

Alzheimer’s disease (AD) is the most common degenerative brain disorder leading to dementia, characterized by a slow onset and gradual progression. Early symptoms typically include difficulties in recalling recent events, which later extend to impairments in various cognitive functions such as language, judgment, and problem-solving, ultimately resulting in the complete loss of independent daily functioning. KCHO-1, a herbal extract with demonstrated anti-inflammatory and neuroprotective properties, has shown promise in mitigating the effects of neurodegenerative disorders. This study aims to develop a protocol for determining the optimal dosage of KCHO-1 in treating AD, providing a foundation for its potential therapeutic application.

Methods

This is a phase II, multi-center, 3-arm randomized controlled study. Sixty patients with AD will be randomly assigned to one of three groups. Each group will receive a standard treatment with 1.6 g of KCHO-1, 2.4 g of KCHO-1, or a placebo. The primary outcome is ADAS-K-cog. Secondary outcomes include results of K-MMSE, K-IADL, NPI-Q, CDR, GDS, KQOL-AD, R-MBPC, and S-GDpS. The frequencies of severe adverse events as well as overall adverse occurrences are listed and documented. The trial protocol has been approved by the Institutional Review Board of the Wonkwang University Hospital Gwangju Korean Medical Center and Wonkwang University Hospital (WKIRB 2021/14–19 and WKUH IRB 2023–10-005–012, respectively). The Ministry of Food and Drug Safety (MFDS) approved the drug as an investigational new drug (30731).

Discussion

The purpose of this study is to establish the ideal KCHO-1 dosage. Additionally, it seeks to validate KCHO-1’s safety and effectiveness in reducing functional deterioration in AD patients.

Trial registration

Korean National Clinical Trial Registry CRIS; KCT0008433. Registered on 12 May 2023.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-026-09572-z.

Background

Alzheimer’s disease (AD) is the most prevalent form of dementia, characterized by histopathological features such as brain atrophy, senile plaques, neurofibrillary tangles, neuronal granular vacuole degeneration, and Hirano bodies in the cerebral cortex and hippocampus. It is believed that β-amyloid (Aβ) accumulation and oxidative stress in the early pathological stages contribute to disease progression [1–6].

The cerebral cortex of 3-month-old 3xTg-AD mice and the peripheral blood mononuclear cells (PBMCs) of individuals with mild cognitive impairment exhibit decreased expression levels of antioxidant proteins SOD1 and HO-1, which are associated with oxidative stress in the early stages of AD [6, 7]. Current pharmacological treatments, including cholinesterase inhibitors and NMDA receptor antagonists, primarily target symptom management by modulating neurotransmitter activity, while psychotropic drugs such as antidepressants and sedatives are used to address behavioral and psychological symptoms. Despite the implementation of non-pharmacological interventions such as cognitive and occupational therapies, no treatment currently addresses the underlying pathology of AD.

Currently, the only approved pharmacological treatments for AD are anti-dementia drugs, including Tacrine (Cognex), Donepezil (Aricept), Galantamine (Razadyne, Reminyl, Nivalin), Rivastigmine (Exelon), and Memantine (Namenda). These drugs are marketed globally and provide symptomatic relief by improving cognitive function. However, most are synthetically derived, and concerns remain regarding their long-term safety, potential side effects, and toxicity profiles, which have not been fully elucidated. Additionally, these treatments face limitations in terms of efficacy, particularly in addressing the progressive nature of AD.

Given the limitations of current anti-dementia medications, including their side effects, limited efficacy, and inability to address the underlying causes of AD, there is an urgent need for the development of novel treatments that offer improved safety profiles, greater efficacy, and potential disease-modifying properties. In particular, the development of herbal preparations with low toxicity, potent cholinergic system enhancement, and neuroprotective properties could significantly address the shortcomings of existing therapies. Such treatments should aim to improve cognitive functions, including learning and memory, over long-term use without the associated adverse effects. In response to this need, our research team has developed KCHO-1, derived from natural products, after several years of research. Preliminary findings suggest that KCHO-1 demonstrates potent anti-dementia effects, offering a promising therapeutic approach for the treatment of AD.

In studies investigating the mechanism of action of KCHO-1, also known as Mecasin, a herbal extract from modified jakyakgamchobuja-tang, it has been demonstrated that KCHO-1 can upregulate the gene expression of HO-1, a key regulator of oxidative stress in hippocampal memory cells. Additionally, KCHO-1 has shown neuroprotective effects, including the inhibition of reactive oxygen species (ROS) production, the prolongation of neuronal survival, and the improvement of symptoms associated with degenerative brain diseases. Notably, KCHO-1’s antioxidant effects are mediated through the Nrf2-HO-1 axis, where it suppresses ROS production in hippocampal memory cells (HT22 cells). Furthermore, its anti-inflammatory action in BV2 microglia cells suggests an ability to modulate immune cell activity within the brain, which has been identified as a critical therapeutic mechanism in AD through multiple studies [8–15], and it is potential to target diverse neurodegenerative conditions through its antioxidative and anti-inflammatory effects with HO-1 expression [16].

The primary aim of this study is to determine the optimal dosage of KCHO-1 and to establish a protocol for investigating its potential to slow functional decline in patients with mild-to-moderate AD. This is a phase II, randomized, multi-center, blinded, three-arm parallel study. Additionally, this research seeks to evaluate the safety profile of KCHO-1, addressing any concerns regarding its long-term use in this patient population.

Methods/design

Primary objective

This clinical trial aims to determine the optimal dosage of KCHO-1 for individuals with mild to moderate AD, with the data collected being used to inform the design of a future confirmatory therapeutic trial. Participants will be administered two distinct doses of KCHO-1, and the efficacy and safety of each treatment will be evaluated. After 24 weeks of KCHO-1 administration, changes in cognitive function will be assessed using the Korean version of the Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-K-cog). The efficacy will be compared among three groups: a KCHO-1 low-dose group, a KCHO-1 high-dose group, and a placebo group. The ADAS-K-cog assessments will be performed by a clinical psychologist or a trained resident specializing in dementia neuropsychological testing, under the supervision of a dementia-related specialist.

Secondary objectives

The efficacy of KCHO-1 will be evaluated by comparing changes across multiple clinical and functional assessments, including the Korea-Mini Mental State Examination (K-MMSE), Korean Instrumental Activities of Daily Living (K-IADL), Neuropsychiatric Inventory Questionnaire (NPI-Q), Clinical Dementia Rating (CDR), Global Deterioration Scale (GDS), Korean Quality of Life-Alzheimer’s Disease (KQOL-AD), Revised-Memory and Behavior Problem Checklist (R-MBPC), and Short form Geriatric Depression Scale (S-GDpS). These assessments will be used to compare outcomes in the low-dose KCHO-1 group, the high-dose KCHO-1 group, and the placebo group.

Safety assessment

Safety will be evaluated through assessment of adverse events, cardiopulmonary examinations, vital signs, physical examinations, and clinical laboratory tests, including hematology (WBC, RBC, hemoglobin, hematocrit, MCV, MCH, MCHC, platelets, neutrophils, lymphocytes, monocytes, eosinophils, basophils, aPTT, and PT); blood chemistry (total cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, total bilirubin, direct bilirubin, total protein, albumin, BUN, creatinine, AST, ALT, ALP, GGT, and glucose); electrolyte tests (Na, K, Cl, and Ca); urinalysis including urine HCG; routine urinalysis (specific gravity, pH, leukocytes, nitrite, protein, glucose, ketone, urobilinogen, bilirubin, and erythrocytes); and microscopic examination (urine RBC, urine WBC, epithelial cells, crystals, and casts); thyroid function tests (T3, T4, and TSH); and other blood tests (fibrinogen, homocysteine, lipoprotein(a), VDRL, vitamin B12, folate, anti-HIV, and HbA1c).

Design and setting

This study is designed as a parallel, randomized, double-blind, placebo-controlled, multi-dose clinical trial. After receiving a detailed explanation of the study procedures, participants will sign an informed consent form and be assigned a subject identification code. Participant selection will follow predefined inclusion and exclusion criteria. Eligible participants will be randomized into three groups: KCHO-1 high-dose, KCHO-1 low-dose, and placebo. This double-blind trial will ensure that neither participants nor investigators know the treatment assignments. Each subject will visit their assigned institution at 4-week intervals and participate in the study for a total duration of 24 weeks. On day 183, participants will return for a final visit, where they will be monitored for adverse events, and the presence or absence of adverse events will be recorded. Figure 1 illustrates the trial’s flow diagram. The optimal dosage and therapeutic efficacy of KCHO-1 will be evaluated by comparing two doses (1.6 g and 2.4 g). Table 1 outlines the detailed study procedure timetable. The trial will be conducted at multiple institutions, including Wonkwang University Hospital Gwangju Korean Medical Center and Wonkwang University Hospital in South Korea, both of which specialize in the diagnosis and treatment of Alzheimer’s disease. Patients will be recruited from the outpatient clinics of neurology and geriatrics departments within these hospitals. Eligibility for inclusion in the study will be determined based on the predefined criteria outlined below.

Fig. 1.

Flow diagram of this study

Table 1.

Schedule of study procedures

	Screening	Treatment period						Closing	Early terminatio/Unscheduled visit	F/U
Visit	Visit 1 −7~ 1D	Visit 2 D1	Visit 3 D29	Visit 4 D57	Visit 5 D85	Visit 6 D113	Visit 7 D141	Visit 8 D169		Visit 9 D183 follow up
			4 weeks	8 weeks	12 weeks	16 weeks	20 weeks	24 weeks		26 weeks
Informed consent form	●
Assignment of screening number	●
Demographic investigation1)	●
Medical history and medication history investigation2)	●
Questionnaires
K-MMSE	●							●
Hachinski Ischemic Scale	●
CDR	●							●
ADAS-K-cog		●						●
K-IADL		●						●
NPI-Q		●						●
KQOL-AD		●						●
R-MBPC		●						●
GDS		●						●
S-GDpS		●						●
Physical examination3)	●	●	●	●	●	●	●	●	●	●
Vital sign	●		●	●	●	●	●	●	●	●
Cardiopulmonary test4)	●							●	●	●
Brain MRI	●							●
Clinical laboratory test5)	●		●	●	●	●	●	●	●	●
BMI (height, weight)	●		●	●	●	●	●	●	●	●
Confirmation of changes in medication administration		●	●	●	●	●	●	●	●	●
Inclusion/Exclusion criteria	●	●
Randomization		●
Medication prescription and administration		●	●	●	●	●	●
Confirmation of compliance			●	●	●	●	●	●	●
Confirmation of Adverse Events			●	●	●	●	●	●	●	●
Investigation of blinding maintenance (blind test)			●	●	●	●	●	●

*A window period of ± 5 days from the scheduled visit date after Visit 3 is allowed

1) Sex, date of birth, age, level of education, etc. is investigated

2) If there is no diagnosis history of Alzheimer’s disease during the screening visit with a diagnosis of Alzheimer’s disease suspected, the diagnosis of Alzheimer’s disease is confirmed by a specialist among investigators of this study or a specialist at a tertiary hospital near the institution

3) Perform a physical examination based on the subject’s clinical condition for the cardiovascular system, lung and respiratory system, gastrointestinal/liver and biliary system, metabolism/endocrine system, kidney/urinary system, reproductive system, musculoskeletal system, skin and connective tissue, nervous system, mental system, and other body organs

4) Perform an electrocardiogram (ECG) and X-ray radiography

5) a) Hematological examination: WBC, RBC, hemoglobin, hematocrit, MCV, MCH, MCHC, platelets, neutrophil, lymphocyte, monocyte, eosinophil, basophil, aPTT, PT,

b) Blood biochemical examination: total cholesterol, triglyceride, LDL cholesterol, HDL cholesterol, total bilirubin, D-bilirubin, total protein, albumin, BUN, creatinine, AST, ALT, ALP, GGT, glucose,

c) Electrolyte test: Na, K, Cl, CA,

d) Urine examination: urine HCG, U/A routine [SG, pH, WBC (leukocyte), nitrite, protein, glucose, ketone, urobilinogen, bilirubin, RBC (erythrocyte)], microscopy (U.RBC, U.WBC, U.Epi.cell, U.crysatl, U.Cast,

e) Thyroid gland function test: T3, T4, TSH,

f) Other blood tests: fibrinogen, homocysteine, lipoprotein (A), VDRL vitamin B12, folate, anti-HIV, and HbA1c

Participants

Inclusion criteria

Inclusion criteria (all of the following criteria must be met):

1. Male and female patients aged 55 to under 80 years who have been diagnosed with AD by a specialist based on the DSM-5 and NINCDS-ADRDA criteria.

   • 1.1. Patients presenting with mild to moderate cognitive impairment, with a K-MMSE (Korea-Mini Mental State Examination) score ranging from 10 to 25 and a Clinical Dementia Rating (CDR) score between 0.5 and 2 at the screening visit.
   • 1.2. Patients must have a score of 4 or lower on the Hachinski Ischemic Scale at the screening visit.

2. Patients who have maintained a stable dose of Acetylcholinesterase Inhibitors (AChEI) for a minimum of 3 months prior to the screening visit.

3. Patients who can be accompanied by a guardian when visiting an institution during the clinical trial process and whose guardian can help to proceed with the clinical trial.

4. A subject and his or her legal representative voluntarily have agreed in writing to the informed consent form.

Exclusion criteria

1. Patients with a history of malignancy within the past 5 years at the screening visit.

2. Dementia due to causes other than Alzheimer’s type (i.e., Patients with degenerative brain diseases such as vascular dementia, Parkinson’s disease, Huntington’s disease, frontotemporal dementia, and Creutzfeld-Jakob disease).

3. Patients with systemic conditions that can cause dementia, such as hypothyroidism, vitamin B12 or folate deficiency, niacin deficiency, hyperkalemia, neurosyphilis, or human immunodeficiency virus (HIV) infection.

4. Patients with a history of major psychiatric disorders diagnosed according to DSM-5 criteria, including schizophrenia, delusional disorder, depression, bipolar disorder, alcohol, or substance use disorders.

5. Patients with a history of neurological disorders, such as epilepsy, localized brain injury, or head trauma.

6. Patients with clinically significant structural CNS diseases identified by brain MRI (or CT) scan results, such as major cerebrovascular disease (cortical infarction diameter > 10 mm), previous major hemorrhage (> 1 cm³), cerebral vascular malformation, cortical hemosiderosis, intracranial aneurysms, intracranial tumors, or changes suggestive of normal pressure hydrocephalus.

7. Patients currently taking psychotropic medications or hormone therapy.

8. Patients with uncontrolled gastrointestinal, endocrine, or cardiovascular diseases despite dietary or medical treatment.

9. Patients with a severely unstable medical condition, based on the investigator’s judgment and supported by clinical laboratory tests, electrocardiogram (ECG), chest X-ray, and vital signs.

10. Patients with diabetes that are uncontrolled by hypoglycemic agents (fasting blood glucose > 126 mg/dL after at least 8 h of fasting, or > 200 mg/dL 2 h after an oral glucose tolerance test, or hemoglobin A1c > 6.5%, and concurrent detection of glucose in urine) or insulin-dependent diabetes mellitus.

11. Patients with hypertension, defined as systolic blood pressure > 165 mmHg or diastolic blood pressure > 96 mmHg.

12. Patients with AST (GOT) or ALT (GPT) levels above the upper limit of normal (however, in cases of abnormal values, participation in the trial may be allowed if the investigator determines that the abnormality is not clinically significant).

13. Patients with chronic renal failure or serum creatinine levels exceeding the upper limit of normal (however, in cases of abnormal values, participation in the trial may be allowed if the investigator determines that the abnormality is not clinically significant).

14. Patients who, from the time of enrollment through the entire trial period and for up to 12 weeks after the final administration of the investigational drug, do not agree to use medically approved methods of contraception, or those planning sperm donation, pregnancy, or currently pregnant or breastfeeding. (Medically approved contraceptive methods include at least 6 months of continuous use of oral contraceptives, injectable or implantable contraceptives, or intrauterine devices).

15. Patients who participated in another clinical trial within 3 months prior to the start of the study.

16. Patients with hypersensitivity or allergies to the investigational drug or related substances.

17. Patients with diseases or digestive disorders that may affect drug absorption, or those who have undergone related surgeries.

18. Patients who, in the investigator’s judgment, are deemed unsuitable for participation in this clinical trial.

19. Patients with family members, relatives, or friends who are participating in this study.

Participant recruitment

The present study aims to recruit a total of 60 participants. All participants will provide written informed consent prior to their enrollment in the study. Recruitment will be conducted through advertisement flyers and online platforms.

Criteria for discontinuing allocated interventions

The criteria for discontinuing a participant’s allocated intervention are as follows: (1) Withdrawal of consent by the participant or their legal representative. (2) Inability to continue medication due to adverse events or abnormal laboratory findings. (3) A medication compliance rate of less than 80% during the treatment period. (4) Discovery of a violation of inclusion/exclusion criteria during the trial. (5) The need for unavoidable use of combination medications. (6) Inability to follow up with the participant. (7) Investigator’s judgment that continuing the trial is not feasible for the participant. Reasons for discontinuation or dropout will be systematically recorded in the case report form and reported in the study results.

Strategies to improve adherence to interventions

Adherence to the intervention will be monitored through pill counts and medication diaries collected at each 4-week visit over the 24-week study period. Participants and caregivers will receive detailed instructions on twice-daily medication intake at the start of the study, with reinforcement during follow-up visits. Study coordinators will assess adherence, address any concerns, and provide additional guidance as needed. Reminder calls or messages will be sent periodically to enhance compliance. Any missed doses will be documented, and deviations will be minimized through regular participant engagement.

Relevant concomitant care permitted or prohibited during the trial

The use of any medication other than the assigned study drug is generally prohibited. However, the following medications are permitted under specific conditions:

1. AChEIs: must remain at a stable dose for at least 3 months prior to screening and throughout the study.

2. Aspirin (≤ 325 mg/day): allowed for cardioprotection.

3. Antidepressants, antipsychotics, anxiolytics, vitamin E, and ginkgo extract: permitted only if the dosage remains unchanged for 3 months before screening.

4. Medications for pre-existing conditions (e.g., diabetes, hyperlipidemia, pain management): allowed if the regimen remains stable and does not interfere with the study drug.

Provisions for post-trial care

The sponsor has secured insurance in compliance with Korean regulatory requirements for clinical trials. This insurance covers any potential harm to participants, including injury or death, resulting from study-related activities. Coverage extends to adverse events that occur during the trial or within a defined period following study completion, as stipulated by national guidelines. Participants will also receive appropriate medical care and follow-up in the event of any trial-related complications.

Sample size

The primary purpose of this trial is to determine the optimal dosage of KCHO-1 and to evaluate its efficacy and safety. Taking into account an anticipated dropout rate of 25%, a total of 20 participants will be assigned to each of the three groups.

Basis for calculating the number of subjects

This clinical trial is an exploratory trial designed to evaluate the efficacy and safety of KCHO-1. Unlike confirmatory trials, where the primary goal is to statistically confirm the efficacy or safety of a drug, the objective of exploratory trials is to investigate the characteristics of the investigational product using descriptive methods. The findings from this trial will be used as foundational data for designing future confirmatory trials, including determining the optimal dosage and calculating the appropriate sample size with sufficient statistical power for efficacy evaluation. In this trial, we aim to explore the clinical efficacy and safety of KCHO-1. Considering the minimum statistical requirements, research funding, and other conditions, a total of 60 participants will be enrolled: 20 participants in the low-dose KCHO-1 group, 20 participants in the high-dose KCHO-1 group, and 20 participants in the placebo group.

Randomization, allocation concealment, and blinding

Overview

A placebo, identical in color, shape, weight, scent, and taste to the investigational drug, will be used throughout the trial to maintain blinding. The contract research organization (CRO) will independently perform randomization and, based on the assigned codes, will package and provide the investigational drugs (Drug 1 and Drug 2) to the trial sites according to the allocation groups. The trial staff will assign a code number to each participant who passes the screening and begins the baseline phase, following the method described in “(2) Randomization and stratification method with blinding,” and will distribute the corresponding investigational drug. Neither the investigator nor the participants will know to which group they have been assigned until the trial has concluded. After the trial is completed, the blinding will be lifted for data analysis.

Randomization and stratification method with blinding

A 6-block randomization method will be used to assign participants to the low-dose group (A), high-dose group (C), or placebo group (D) in a 1:1:1 ratio at each trial site. The randomization manager at the contract research organization (CRO) will create a block randomization table, with six blocks, stratified by site and gender. Random block sequences will be selected from the 720 possible combinations (e.g., ACDACD, ACDADC, ADCACD, CADCAD, CADCDA), and the random numbers generated by the SAS® system’s randomization program will be sequentially applied from participant number 1 onward. To maintain blinding during the trial, only a minimal number of sponsor personnel, who are not directly involved with the clinical sites, will have access to the randomization table before the trial concludes. The investigator may use emergency codes, which will only be unblinded if necessary to determine a participant’s group allocation for further treatment. The investigator must make every effort to contact the sponsor before unblinding a participant’s treatment group. In the event that a participant’s group allocation is unblinded, the monitor must be notified by phone immediately. If blinding is compromised for an investigator, trial staff, or the participant, the participant may be withdrawn from the trial. However, if ethical reasons require the participant to continue, the investigator must obtain special approval from the sponsor to proceed with treatment.

Intervention

1. KCHO-1

   KCHO-1 is composed of 30% ethanol extracts from nine medicinal herbs, including Curcuma longa, Salvia miltiorrhiza, Gastrodia elata, Chaenomeles sinensis, Polygala tenuifolia, Paeonia lactiflora, Glycyrrhiza uralensis, Atractylodes lancea, and processed Aconitum carmichaelii. KCHO-1 will be manufactured by Hanpoong Pharm and Foods Co. (Chonju, South Korea) in accordance with certified Good Manufacturing Practices (GMP) standards approved by the Ministry of Food and Drug Safety and will be produced as a rectangular, maroon, film-coated tablet. Single-dose toxicity tests have identified a no-observed-adverse-effect level (NOAEL) exceeding 5000 mg/kg/day, while animal studies have demonstrated efficacy at doses ranging from 250 to 500 mg/kg/day [15]. Based on this range, the calculated effective dose for a 60-kg adult is between 15 and 30 g/day, with safe doses reaching up to 120 g/day. For this trial, the safe dose has been calculated as follows: 5000 mg/kg × (6/37) × (1/10) × 60 kg = 4.8625 g and the effective dose as: 250–500 mg/kg × (3/37) × 60 kg = 1.216–2.432 g. Dosages for the study groups were determined by selecting a safe dose of 1.6 g for the low-dose group and a safe and effective dose of 2.4 g for the high-dose group (6/37: rat-to-human conversion based on rat NOAEL; 3/37: mouse-to-human conversion based on mouse effective dose; 1/10: safety factor applied to NOAEL).

2. Placebo

   The placebo will be a rectangular, maroon, film-coated tablet manufactured by the same pharmaceutical company responsible for producing KCHO-1. The placebo tablet will be composed of inert pharmaceutical ingredients, including microcrystalline cellulose, corn starch, light anhydrous silicic acid, carboxymethylcellulose calcium, caramel color, magnesium stearate, a coating substance (hypromellose 2910, polyethylene glycol 6000), and color additives (black iron oxide, red iron oxide).

3. Administration method

   KCHO-1 and placebo are taken orally with water within 30 min after breakfast and dinner daily according to the following dosages:

   1. KCHO-1 low-dose group: KCHO-1 1.6 g (4 tablets) + placebo (2 tablets).
   2. KCHO-1 high-dose group: KCHO-1 2.4 g (6 tablets).
   3. Placebo group: Placebo (6 tablets).

Outcomes

Primary outcome

1. Score by ADAS-K-cog assessment scale

   It is a tool for evaluating a patient’s condition by a doctor, oriental medical doctor, or clinical psychologist. It is evaluated as the sum of scores. ADAS-K-cog is a cognitive function test tool developed to evaluate various cognitive abilities, including <language function>, <memory>, <understanding>, <time>, <orientation to place>, and <voluntary language ability>[17]. Its score ranges from 0 to 70, with a higher score meaning a greater functional disorder.

Secondary outcomes

1. K-IADL (Korean instrumental activities of daily living)

   Instrumental activities of daily living (IADL) tend to decline early in cases of AD, and family members may notice this decline before cognitive impairment is detected in neuropsychological tests, making it a sensitive tool for diagnosing early dementia. In this clinical trial, we will use the Korean version of the IADL (K-IADL), which was developed by selecting 11 items deemed suitable for elderly individuals in Korea by the Dementia Research Association. This assessment is administered in the form of a questionnaire, where a caregiver evaluates the patient’s performance over the past 4 weeks [18].

2. NPI-Q (Neuropsychiatric Inventory Questionnaire)

   The Neuropsychiatric inventory (NPI) has the disadvantage of requiring an examiner and taking a considerable amount of time to administer. To address this, the Neuropsychiatric Inventory Questionnaire (NPI-Q), a simplified version of the NPI, was developed to allow caregivers of dementia patients to complete the assessment independently. In this clinical trial, both the NPI and NPI-Q will be utilized, as the difference in results between the two tools is less than 2%. The NPI-Q will be used in its standardized adapted form to ensure consistency in assessment.

3. CDR (clinical dementia rating)

   As a tool for assessing the severity of dementia, the clinical dementia rating (CDR) is the most widely used scale globally. The CDR assesses individual domains and provides an overall score, graded from 0 to 3 points. However, an “expanded version” of the scale with scores ranging from 0 to 5 points has been developed, further subdividing the severe dementia category into CDR-3, CDR-4, and CDR-5. In Korea, standardization studies have been conducted by translating the expanded CDR into Korean [19, 20].

4. KQOL–AD (Korean Quality of Life–Alzheimer’s Disease)

   The Quality of Life Scale for Alzheimer’s Disease (QOL-AD) is a dementia-specific tool with high reliability and validity for both mild and moderate Alzheimer’s patients. It is widely used not only for Alzheimer’s patients but also for those with dementia and mild cognitive impairment, as it effectively reflects behavioral and psychological symptoms. Among dementia-specific quality of life scales, it is the most commonly used in research. In this study, we will use the Korean version of the QOL-AD (KQOL-AD), which has been validated for Korean populations, to assess the quality of life in patients with mild cognitive impairment before and after taking herbal medicine [21–23].

5. R-MBPC (Revised-Memory and Behavior Problem Checklist)

   Dementia patients typically exhibit a wide range of complex behavioral problems associated with the disease. The Revised Memory and Behavior Problems Checklist (R-MBPC) is a questionnaire designed to assess the frequency of behavioral issues in dementia patients, while also measuring the caregiver’s response to these behaviors.

6. Global Deterioration Scale (GDS)

   The Global Deterioration Scale (GDS) is a tool used to assess the severity of dementia by describing the cognitive impairment at each stage with specific examples. The scale allows for relatively quick evaluations by referencing these examples, and it is particularly useful for finely classifying early cognitive impairments. In 2002, the validity of the Korean version of the GDS was verified [24].

7. K-MMSE (Mini-Mental state Examination)

   The Mini-Mental State Examination (MMSE) is one of the most widely used screening tools [25]. It is advantageous for repeated measurements over the course of an illness due to its minimal learning effect, allowing for the monitoring of cognitive changes over time [25]. In Korea, it is the most commonly used cognitive screening test, with its reliability and validity well-established for diagnosing moderate and severe AD [26]. Two widely used versions in Korea are the K-MMSE and the MMSE-K, which were adapted through independent standardization processes to suit the Korean population [27, 28]. The overall MMSE score is used to classify results in epidemiological studies: scores of 24 to 30 indicate no cognitive impairment, 18 to 23 indicate mild cognitive impairment, and 0 to 17 indicate clear cognitive impairment.

8. S-GDpS (Short form Geriatric Depression Scale)

   The Short form Geriatric Depression Scale (S-GDpS) is a tool designed to assess depression symptoms in older adults. Cho et al. developed a condensed version with 15 questions to create the Korean version of the GDS (Geriatric Depression Scale). A score of five or higher indicates a suspicion of depression [29, 30].

9. Investigation of blind maintenance

   This will be conducted to assess the appropriateness of blinding and the reliability of the treatment.

Evaluation criteria and evaluation method

The primary objective of this study is to evaluate the efficacy of the investigational drug compared with the control drug, while also evaluating the difference in efficacy between the low-dose and high-dose groups. If a statistically significant difference is observed between the groups (p < 0.05), the magnitude and pattern of the difference will be described in relation to overall clinical outcomes. In addition, this study aims to obtain preliminary information on treatment effects and safety, and to explore response trends across dose groups. In the event that no statistically significant difference is observed between the groups, the dosage group required for Phase III clinical trials will be determined by reviewing clinical results, including efficacy patterns and safety profiles such as the incidence of adverse events.

Data collection and management

Plans for assessment and collection of outcomes

Outcome assessments will be conducted at baseline and at 4-week intervals throughout the 24-week study period, with a final follow-up on Day 183 for adverse event monitoring. The primary outcome measure is ADAS-K-cog, while secondary outcomes include K-MMSE, K-IADL, NPI-Q, CDR, GDS, KQOL-AD, R-MBPC, and S-GDpS. Laboratory tests, including hematological, biochemical, and urinalysis parameters, will be performed at designated visits. To ensure data quality, study assessors will undergo standardized training, and duplicate measurements will be taken when necessary. All outcome data will be recorded in electronic case report forms (eCRFs), which will be securely stored and managed by the study sponsor.

Plans to promote participant retention and complete follow-up

To minimize participant dropout and ensure complete follow-up, scheduled reminder calls and messages will be sent before each visit. Participants and caregivers will receive continuous engagement and counseling on the importance of adherence. For participants who discontinue or deviate from the protocol, available outcome data will still be collected, and a final follow-up assessment will be conducted to evaluate safety and efficacy outcomes.

Data management

Clinical trial data will be managed using CRScube’s electronic database system, ensuring compliance with Korean regulatory standards. Data entry will follow a structured Field Edit Description (FED) system, including data type, size, range, and validity checks to maintain consistency.

Key data management practices include the following:

1. Double data entry for critical variables.

2. Manual and automated validation to detect discrepancies.

3. Restricted access to authorized personnel only.

4. Audit trails for any modifications.

5. Database lock and closure following data verification and cleaning.

6. All study data will be securely archived for 10 years after trial completion.

Confidentiality

Research data will be stored using a unique study identification code assigned to each participant. The identification code list will be maintained separately and will only be accessible to the principal investigator and designated research staff during the study. After trial completion, the list will be securely archived in compliance with research guidelines. No personally identifiable information will be included in any publications.

Plans for collection, laboratory evaluation, and storage of biological specimens

Blood and urine samples will be collected at designated visits for safety and efficacy assessments. Laboratory tests will include hematological, biochemical, electrolyte, and urine analyses, along with thyroid function and other relevant biomarker evaluations. Samples will be processed immediately and stored under controlled temperature conditions before analysis. All biological samples will be disposed of in accordance with Korean bioethics regulations.

Statistical analysis

Primary efficacy outcome analysis method

The primary efficacy outcome is the change in ADAS-K-cog scores over 24 weeks. Depending on whether the assumption of normality is satisfied, a one-way ANOVA or Kruskal–Wallis test will be conducted to evaluate if there are statistically significant differences in the change in ADAS-K-cog scores between the three groups. If a significant result is found, post-hoc comparisons between the placebo group and the two KCHO-1 dosage groups will be conducted using Dunnett’s test for the one-way ANOVA. For the Kruskal–Wallis test, the Wilcoxon rank sum test will be used for post-hoc comparisons between the placebo group and each KCHO-1 dosage group. If the Wilcoxon rank sum test is applied, the Bonferroni correction will be used to adjust for multiple comparisons, setting the significance level at 0.025. Since this clinical trial is a multi-dose study aimed at identifying the optimal dosage, statistical tests and trend analyses will be conducted after the trial’s conclusion to determine the safest and most effective dosage group between the two KCHO-1 dosage groups for further trials.

Secondary efficacy outcome variables and additional analysis methods

The secondary efficacy outcomes are the changes in K-MMSE, K-IADL, NPI-Q, CDR, GDS, KQOL-AD, R-MBPC, and S-GDpS scores over 24 weeks. Each variable will be analyzed using either one-way ANOVA or the Kruskal–Wallis test, depending on whether the normality assumption is met, to determine statistically significant differences between the groups. If significant differences are found, post-hoc comparisons between the placebo group and the two KCHO-1 dosage groups will be performed using Dunnett’s test for one-way ANOVA. For the Kruskal–Wallis test, post-hoc comparisons between the placebo group and each KCHO-1 dosage group will be carried out using the Wilcoxon rank sum test, with Bonferroni correction applied to adjust for multiple comparisons, setting the significance level at 0.025. Within-group comparisons for each variable will be conducted using the paired t-test.

Methods in analysis to handle protocol non-adherence and missing data

For the Full Analysis Set (FAS), missing values in efficacy outcome variables will be handled using the Last Observation (Post-baseline) Carried Forward (LOCF) method. If a participant discontinues the trial before completion or if missing data occur at any time point, the most recent post-baseline value, including the baseline measurement, will be carried forward and used for analysis. For the Per Protocol Set (PPS), as well as for laboratory assessments and other safety variables, missing data will not be imputed, and analyses will be conducted using only the available observed data. When adjustment for baseline values is required, analysis of covariance (ANCOVA) will be used to compare treatment groups while controlling for baseline measurements. Parametric analyses will be used as the primary analytical approach when their assumptions are reasonably satisfied. Nonparametric methods (e.g., Kruskal–Wallis test or Wilcoxon rank-sum test) will be applied as supportive or sensitivity analyses when marked deviations from distributional assumptions are observed, rather than as the main analytical strategy.

Analysis methods for safety variables

For cardiopulmonary tests, vital signs, and clinical pathology data, appropriate statistical methods will be applied based on the characteristics of each variable to analyze pre- and post-treatment within-group comparisons. The frequency, incidence rate, detailed timing of occurrence, severity, and causal relationship with the investigational drug for adverse events will be presented, and graphs will be used to report the data when necessary. Statistical analysis will be conducted using methods such as ANOVA, t-test, chi-square test, or Fisher’s exact test, depending on the characteristics of the variables.

Oversight and monitoring

Composition of the coordinating center and trial steering committee

The trial is managed by a designated research team, which includes the following:

1. Principal investigator (PI): Responsible for the overall supervision of the study and medical decision-making for participants.

2. Study coordinator: Oversees trial registration, ensures protocol adherence, coordinates study visits, and manages safety reporting.

3. Clinical research associate (CRA): Conducts site monitoring visits and ensures compliance with Good Clinical Practice (GCP) and regulatory guidelines.

4. Data manager: Manages electronic data capture, quality control, and compliance with data management protocols.

Adverse event reporting and harms

All adverse events (AEs) reported by participants or observed by investigators will be recorded in the eCRF, including the date of onset, duration, severity, outcome, and relationship to the investigational product. An adverse event is defined as any undesirable and unintended sign, symptom, or disease occurring after administration of the study drug, regardless of its causal relationship. An adverse drug reaction refers to an adverse event for which a causal relationship with the study drug cannot be excluded. All adverse events occurring after initiation of the study will be recorded irrespective of causality. Investigators will assess each event and document any changes in frequency or severity during the study period. Serious adverse events (SAEs), including events that are life-threatening, require hospitalization or prolongation of hospitalization, result in significant disability, or lead to death, will be reported to the IRB and the sponsor within the required regulatory timeframe. Participants experiencing SAEs will be followed until the event resolves or stabilizes. Safety evaluation will be conducted throughout the study through regular clinical assessments, including evaluation of vital signs, physical and cardiopulmonary examinations, and review of laboratory findings. Cardiovascular-related adverse events will be specifically evaluated by measuring blood pressure and pulse rate and by performing electrocardiogram examinations before and after administration of the investigational product according to the study schedule. Any clinically significant abnormalities identified during safety evaluation will be documented, assessed for clinical relevance, and managed with appropriate medical actions, including dose adjustment, temporary interruption, or discontinuation of the investigational product when necessary.

Stopping guidelines

The trial may be discontinued prematurely in accordance with predefined stopping guidelines based on safety, ethical, and regulatory considerations. Trial continuation will be reviewed by the sponsor if significant information related to the quality, efficacy, or safety of the investigational product becomes available, if substantial protocol modifications are required that cannot be implemented at the trial sites, or if the IRB determines that the trial cannot be ethically or appropriately continued. In addition, early termination may be decided in cases of serious or persistent violations of the study protocol or applicable regulatory requirements. When early termination or suspension is decided, the sponsor will promptly notify the principal investigators, and the investigators will inform the IRB and trial participants in a timely manner and ensure appropriate follow-up procedures.

Frequency and plans for auditing trial conduct

Trial monitoring will be conducted by a contracted clinical research organization (CRO; NeoNutra Co., Ltd.) through regular on-site visits and remote communications, including telephone-based monitoring, in accordance with Good Clinical Practice and applicable regulatory requirements. The timing and frequency of on-site monitoring visits will be determined in consultation with the principal investigator, taking into account trial progress and site-specific needs. During monitoring visits, source documents, investigational product accountability, and data records will be reviewed to ensure data accuracy, completeness, and protocol compliance. Identified issues will be discussed with investigators and addressed promptly. In addition to monitoring visits, overall trial conduct will be reviewed on a regular basis through routine sponsor–CRO communications throughout the trial period, and as this study involves a low-risk intervention, a Data Monitoring Committee was not considered; safety oversight is ensured through CRO monitoring, adverse event reporting, and IRB oversight.

Plans for communicating important protocol amendments to relevant parties

Any important modifications to the protocol will be reviewed by the sponsor and submitted to the IRB for approval prior to implementation. Following approval, the principal investigator will notify participating study centers, and revised protocol documents will be distributed to investigators for inclusion in the Investigator Site File. Investigators and relevant study staff will be informed of amendments through official communications. Participants will be notified if protocol changes affect their participation. Any deviations from the approved protocol will be fully documented using protocol deviation or breach report forms. Relevant protocol amendments will also be updated in the clinical trial registry in accordance with applicable requirements.

Dissemination plans

The trial results will be disseminated through peer-reviewed journal publications, conference presentations, and regulatory reporting. Summary findings may be provided to participants upon request. Data will be managed and stored using CRScube’s electronic database system, ensuring compliance with Korean regulatory guidelines. However, individual participant-level data (IPD) and statistical code will not be publicly shared due to confidentiality regulations. Data access may be granted upon reasonable request, subject to approval by the IRB.

Discussion

The efficacy evaluation for this clinical trial will include all participants who meet the inclusion criteria, have taken at least one dose of the investigational drug, and have attended at least one post-treatment visit with primary efficacy assessment results available. These participants, comprising the FAS, will be analyzed across the KCHO-1 1.6 g group, KCHO-1 2.4 g group, and the placebo group. There have been no previous randomized controlled trials investigating the effects of KCHO-1 on AD. This planned clinical trial aims to determine the optimal dosage of KCHO-1 and evaluate whether KCHO-1 treatment is effective and safe for patients with AD. A limitation of this study is that the diagnosis of AD is based on clinical criteria (DSM-5 and NINCDS-ADRDA) without confirmatory biomarker-based assessments using neuroimaging, PET, or cerebrospinal fluid analyses. Therefore, diagnostic heterogeneity and possible misclassification cannot be completely excluded and should be considered when interpreting the trial findings.

Trial status

Trial recruitment started in May 2023. It will close in May 2026 (protocol version 4.1, dated July 23, 2024). At the time of this manuscript’s submission, the trial was in the recruiting phase.

Abbreviations

Aβ

β-Amyloid

AD

Alzheimer’s disease

ADAS-K-cog

Korean version of Alzheimer’s disease assessment scale-cognitive subscale

Ach

Acetylcholine

AChEI

Acetylcholinesterase inhibitors

CDR

Clinical dementia rating

CRO

Contract research organization

GDS

Global Deterioration Scale

HIV

Human immunodeficiency virus

HO-1

HemeOxygenase-1

K-IADL

Korean Instrumental Activities of Daily Living

K-MMSE

Korea-Mini Mental State Examination

KQOL-AD

Korean Quality of Life-Alzheimer’s Disease

LS

Least squares

MFDS

Ministry of Food and Drug Safety

NE

Not estimable

NMDA

N-methyl-D-aspartate

NPH

Normal pressure hydrocephalus

NPI

Neuropsychiatric Inventory

NPI-Q

Neuropsychiatric Inventory Questionnaire

PBMC

Peripheral blood mononuclear cells

R-MBPC

Revised-Memory and Behavior Problem Checklist

S-GDpS

Short form Geriatric Depression Scale

Authors’ contributions

C.H.K., D.K., S.H.Y., H.W.K., D.H., S.K. conceptualized and designed the study. S.K. were responsible for funding acquisition. J.S., T.S.J., H.S.J. contributed to the acquisition of data. J.S., T.S.J., H.S.J. analyzed the data and wrote the first draft, supervised by S.K. The authors read and approved the final manuscript.

Funding

This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (HI21C2525).

Data availability

All data generated or analyzed during this study is included in this published article.

Declarations

Ethics approval and consent to participate

The trial protocol has been approved by the IRB of Wonkwang University Hospital Gwangju Korean Medical Center and Wonkwang University Hospital (WKIRB 2021/14–19 and WKUH IRB 2023–10-005–012, respectively). The study is registered with the national clinical trial registry, the Clinical Research Information Service (CRIS), which is a primary registry of the World Health Organization International Clinical Trials Registry Platform (KCT0008433). Investigational New Drug (IND) status (30731) was granted by the Ministry of Food and Drug Safety (MFDS). Any protocol modifications will be submitted for approval by the IRBs and the MFDS before implementation. Written informed consent was obtained from all participants prior to their involvement in the study.

Consent for publication

Not applicable.

This manuscript does not contain individual personal data from patients.

Competing interests

The authors declare that they have no competing interests.