Advancing bowel preparation: DWJ1609 represents a patient-centered evolution in colonoscopy preparation

Abstract

Bowel preparation quality remains a central determinant of colonoscopy success, yet patient intolerance to existing regimens continues to limit adherence to colorectal cancer screening. In a recent phase III randomized controlled trial, DWJ1609, a novel oral sulfate tablet (OST) formulation, was designed to improve the patient experience without compromising cleansing efficacy. By reducing sulfate content by approximately 75% and incorporating sodium picosulfate to maintain laxative effectiveness, DWJ1609 achieved a 96.97% successful cleansing rate, meeting noninferiority criteria compared with conventional OSTs. More importantly, the formulation demonstrated a markedly improved tolerability profile, with nearly half the rate of adverse drug reactions and substantial reductions in nausea and headache—symptoms that frequently deter patients from undergoing colonoscopy. These findings highlight a meaningful shift toward patient-centered bowel preparation, addressing a longstanding barrier to screening participation. While the study population was younger and healthier than typical screening cohorts, and further validation in high-risk groups is needed, the results suggest that DWJ1609 may offer a more acceptable and safer alternative for many patients. As colorectal cancer screening expands to younger populations, innovations that enhance preparation tolerability will play an increasingly important role in improving screening uptake and outcomes.

Key Words: Bowel preparation; Colonoscopy; Oral sulfate tablets; DWJ1609; Colorectal cancer screening; Sodium picosulfate; Bowel cleansing efficacy

Core Tip: DWJ1609 is a next generation bowel preparation tablet that reduces sulfate content by 75% while maintaining excellent cleansing efficacy. In a phase III randomized trial, it significantly improved tolerability—particularly nausea and headache—without compromising safety. This patient-centered formulation may enhance adherence to colorectal cancer screening and represents a meaningful evolution in bowel preparation strategies.

INTRODUCTION

The quality of bowel preparation remains a critical determinant of colonoscopy effectiveness, directly influencing adenoma detection rates, procedure completion, and ultimately, colorectal cancer prevention outcomes[1,2]. In their rigorously designed phase III randomized controlled trial, Park et al[3] present compelling evidence for DWJ1609, a novel oral sulfate tablet (OST) formulation that addresses longstanding challenges in bowel preparation: Balancing cleansing efficacy with patient tolerability. This multicenter study demonstrates that intelligent pharmaceutical innovation—specifically reducing sulfate content by approximately 75% while incorporating sodium picosulfate—can maintain clinical effectiveness while substantially improving the patient experience. To our knowledge, the trial by Park et al[3] represents the first published phase III randomized controlled trial evaluating DWJ1609. The absence of additional independent studies is an inherent limitation of this early-stage evidence base, and the findings should be interpreted accordingly until confirmatory data from independent centers and broader patient populations become available.

THE PERSISTENT CHALLENGE OF BOWEL PREPARATION TOLERABILITY

Despite decades of refinement, bowel preparation remains the most commonly cited deterrent to colonoscopy screening compliance[4-9]. Traditional polyethylene glycol (PEG) solutions, while effective and safe, require consumption of large fluid volumes that many patients find intolerable[10-12]. Sodium picosulfate with magnesium citrate (SPMC) offered improved palatability but raised safety concerns, including reports of severe esophageal and gastric mucosal injuries when incompletely dissolved powder contacted the gastrointestinal mucosa[13-15]. Furthermore, electrolyte disturbances, including hyponatremia and hypermagnesemia, and associated complications, such as syncope, have been documented with SPMC formulations[16-20].

OSTs represented a considerable advancement, combining effective osmotic cleansing with simethicone to reduce intraluminal bubbles, thereby enhancing mucosal visualization[21-23]. However, the requirement of 28 tablets administered across two dosing sessions, combined with substantial salt load, created tolerability challenges manifesting as nausea, abdominal discomfort, and in some cases, acute gastropathy[24]. The innovative formulation tested by Park et al[3] directly addresses these limitations through rational pharmaceutical design.

METHODOLOGICAL RIGOR AND NON-INFERIORITY DESIGN

The study by Park et al[3] had methodological strengths that merit recognition. The investigators employed a prospective, randomized, single-blinded (investigator), multicenter design with independent central reading of colonoscopy videos by three gastroenterology specialists, substantially reducing assessment bias. The choice of the Harefield Cleansing Scale (HCS) as the primary efficacy endpoint was appropriate, as this validated instrument has demonstrated reliability in research and clinical practice settings[25,26]. The non-inferiority margin of -15% was conservatively selected on the basis of precedent from previous bowel preparation studies[21,27,28], and the sample size calculation appropriately powered the study to detect clinically meaningful differences.

Critically, the study utilized a split-dosing regimen, which has become the standard of care on the basis of evidence demonstrating superior cleansing efficacy and improved patient tolerance compared with day-before dosing[29-33]. The inclusion of morning-only colonoscopy procedures standardized an important variable affecting bowel preparation quality.

EFFICACY OUTCOMES: NON-INFERIORITY ESTABLISHED

The primary efficacy analysis demonstrated that DWJ1609 achieved successful bowel cleansing (HCS grade A or B) in 96.97% of participants, compared with 100% in the conventional OST group, with the lower bound of the 95% confidence interval (-8.60%) exceeding the predetermined non-inferiority margin of -15%. This finding conclusively establishes non-inferiority and provides reassurance that the reduced tablet burden and modified formulation do not compromise cleansing effectiveness.

The three cases of inadequate bowel preparation in the DWJ1609 group warrant examination. All of these cases occurred in male patients with higher body mass indices (25.2-27.7 kg/m²), and two of the three had significant comorbidities, including diabetes mellitus, which is an established risk factor for suboptimal bowel preparation[34-37]. Importantly, all three cases demonstrated 100% compliance with the medication regimen, suggesting that patient-related factors rather than formulation inadequacy contributed to these outcomes. The overall success rate of 96.97% substantially exceeds the ≥ 85% threshold recommended by the United States Multi-Society Task Force on Colorectal Cancer[38], affirming clinical acceptability.

The statistically significant difference in transverse colon HCS scores (2.9 vs 3.1, P = 0.001) between groups, while numerically small and likely reflecting interobserver variation rather than clinically meaningful differences, highlights the value of independent central reading in reducing bias. Both scores remained within the "clear liquid" range, indicating excellent cleansing quality.

SAFETY AND TOLERABILITY: THE DIFFERENTIATING ADVANTAGE

The most clinically important finding of this study lies in the substantial improvement in the tolerability profile. The incidence of adverse drug reactions in the DWJ1609 group was nearly half that of the conventional OST group (18.10% vs 33.02%, P = 0.013). Particularly noteworthy were the reductions in nausea (7.62% vs 21.70%, P = 0.004) and headache (0.95% vs 8.49%, P = 0.019)—symptoms that frequently compromise patient compliance and willingness to undergo repeat screening.

The mechanism underlying these improvements likely relates to the reduced osmotic load. By decreasing sulfate content by approximately 75% while maintaining efficacy through sodium picosulfate’s stimulant laxative effect, DWJ1609 reduces the osmotic gradient that drives fluid shifts contributing to nausea and electrolyte-related symptoms, including headache[39-41]. The absence of electrolyte abnormalities in the DWJ1609 group, compared with a single case of hyponatremia in the OST group, further indicates the safety benefit of reduced salt load.

The finding that participants in the DWJ1609 group experienced significantly less difficulty with consumption (mean score 1.9 vs 2.2, P = 0.040), with 35.35% rating preparation as “very easy” compared with 22.77% in the control group, carries important clinical implications. Patient-reported tolerability directly influences compliance with screening recommendations, and improved acceptability may translate into higher participation rates in colorectal cancer screening programs—a public health outcome of considerable importance[42-46].

CLINICAL CONTEXT AND COMPARATIVE POSITIONING

How does DWJ1609 compare with other contemporary bowel preparation options? Low-volume (2 L) PEG with ascorbic acid formulations have gained favor due to reduced fluid volume requirements while maintaining efficacy comparable to 4 L PEG preparations[47-51]. SPMC liquid formulations have addressed safety concerns associated with powder forms while preserving the low-volume advantage[52-55]. DWJ1609 offers a distinct value proposition: Tablet-based administration (reducing the burden from 28 to 20 tablets), simethicone inclusion for bubble reduction, and substantially improved tolerability while achieving excellent cleansing efficacy.

The incorporation of sodium picosulfate deserves particular emphasis. This stimulant laxative acts on colonic mucosa to enhance peristalsis and fluid secretion, complementing the osmotic effect of sulfate salts. This dual mechanism permits reduction in osmotic agent load while preserving efficacy—a pharmacologically elegant solution to the tolerability challenge[56,57].

It is important to contextualise DWJ1609 within the landscape of existing innovations rather than overstate its novelty. DWJ1609 represents an incremental but clinically meaningful advancement rather than a paradigm shift. Unlike low-volume PEG-ascorbic acid formulations, which reduced fluid burden, or SPMC preparations, which improved palatability, DWJ1609’s specific contribution lies in reducing the sulfate osmotic load by approximately 75% within a tablet-based platform while incorporating sodium picosulfate as a complementary stimulant laxative mechanism—an approach that has not been previously evaluated in a phase III randomized controlled trial. This distinguishes it from prior tablet-based formulations such as PBK-1701TC, which did not incorporate this dual-mechanism strategy.

A comparative overview of currently available bowel preparation agents, including their efficacy, tolerability profiles, and notable safety considerations, is presented in Table 1.

Table 1 Comparative overview of contemporary bowel preparation agents.

Preparation agent	Volume	Efficacy (%)	Nausea (%)	Headache (%)	Key safety issue	Tolerability	Ref.
4 L PEG	4 L split	85-95	20-40	5-10	Excellent safety	Moderate	Rivas et al[10], 2014
2 L PEG + ascorbic	2 L split	90-97	15-25	3-5	Renal caution	Good	Rivas et al[10], 2014 and Bisschops et al[47], 2019
SPMC powder	2 sachets + 2-3 L	85-92	10-20	2-5	Mucosal injury, electrolytes	Moderate-good	Seo et al[13], 2015; Dillon and Laher[16], 2009; and van Lieshout et al[52], 2017
SPMC liquid	2 bottles + 1-2 L	88-94	8-15	2-4	Electrolyte monitoring	Good	Hassan et al[42], 2013 and Hoy et al[56], 2009
Conventional OST	28 tablets +2.55 L	92-98	22-34	8-12	Gastropathy, high salt	Moderate	Yang et al[21], 2020; Yoon et al[24], 2024; and Moulin and Ponchon[39], 2018
DWJ1609	20 tablets + 2.55 L	96.97	7.6	0.95	No electrolyte issues, 75% less salt	Good-very good	Park et al[3], 2026
1 L NER1006	1 L + 1 L water	90-95	12-20	3-6	Well-tolerated	Good-very good	Bisschops et al[47], 2019

This table presents data derived from independent studies with differing designs, patient populations, outcome definitions, and follow-up periods. All comparisons between agents are indirect and should be interpreted with caution. No head-to-head randomized trial data are available for all agents listed. These data are intended to provide contextual orientation rather than definitive comparative efficacy or safety conclusions. PEG: Polyethylene glycol; SPMC: Sodium picosulfate with magnesium citrate; OST: Oral sulfate tablet.

LIMITATIONS AND FUTURE DIRECTIONS

The authors appropriately acknowledge important limitations. The study population (mean age 43.3 years) was younger and healthier than typical colorectal cancer screening cohorts, potentially underestimating both the challenge of adequate preparation and the incidence of adverse effects in older, multimorbid populations. Bowel preparation is notably more difficult in elderly patients, those with diabetes, chronic constipation, opioid use, and chronic kidney disease[58,59]. Validation studies in these high-risk populations are essential before universal adoption can be recommended.

The absence of acute gastropathy assessment represents a missed opportunity, given reports of this complication with current OST formulations[24]. Prospective evaluation using upper endoscopy in a subset of participants could have provided valuable safety data. Additionally, while morning-only colonoscopy was standardized, variations in sedation practices across centers, though comparable between groups, introduce potential confounding. The single-blinded design, where blinding was limited to the central video readers rather than the performing endoscopists, introduces the possibility of performance bias in real-world settings. Central reading of colonoscopy videos, while reducing interobserver variability in a trial context, may not fully replicate the dynamic, real-time assessment performed during routine clinical endoscopy. External validity is therefore an important consideration, and prospective evaluation under standard clinical conditions—without centralized video adjudication—would further substantiate the generalizability of these findings.

Whether DWJ1609 is appropriate for use in symptomatic patients with suspected colorectal pathology, those undergoing pre-surgical bowel preparation, or individuals with conditions predisposing to bowel obstruction has not been evaluated and cannot be extrapolated from the current data. These represent distinct clinical scenarios requiring dedicated investigation. Future research should prioritize several areas: (1) Head-to-head comparison with low-volume PEG-ascorbic acid preparations to definitively establish comparative effectiveness; (2) Adequately powered studies in elderly and multimorbid populations; (3) Cost-effectiveness analysis incorporating medication costs, adverse event management, and repeat procedure rates due to inadequate preparation; (4) Systematic gastropathy assessment using validated scoring systems; and (5) Evaluation of environmental impact, as bowel preparation agents contribute significantly to healthcare-related plastic waste.

CONCLUSION

Park et al[3] have demonstrated that DWJ1609 represents a meaningful advancement in bowel preparation technology. By achieving non-inferior cleansing efficacy while substantially improving tolerability and safety through reduced salt load and incorporation of sodium picosulfate, this formulation addresses a key barrier to colonoscopy acceptance. The 43% reduction in adverse drug reactions, particularly the approximately 65% reduction in nausea, carries significant clinical and public health implications. As colorectal cancer screening recommendations expand to include younger populations beginning at age 45[60], and as healthcare systems globally work to improve screening participation rates, patient-centered innovations that enhance the tolerability of preparation regimens assume increasing importance. DWJ1609 exemplifies how rational pharmaceutical design—reducing component burdens while incorporating complementary mechanisms—can achieve the dual goals of clinical effectiveness and improved patient experience. While validation in higher-risk and older populations remains essential before broad adoption can be recommended, the current evidence supports DWJ1609 as a promising and clinically viable alternative—particularly for patients who have previously experienced intolerance to conventional preparations. This study advances the field toward the ultimate goal: Effective colorectal cancer screening that patients willingly undergo and complete—the foundation of cancer prevention.