Bowel Preps

The Current and Future Outlook

Colorectal cancer is the third most prevalent cancer in the United States. According to the American Cancer Society, there will be approximately 104,950 new cases of colon cancer and 40,340 new cases of rectal cancer in 2005. Together, they will cause about 56,290 deaths.

Of course, screening for colon cancer through colonoscopy remains a vitally important component in identifying and successfully treating the disease. Despite the efforts of many, screening rates among those who could benefit the most remain low. One study contends that improving these rates depends on a number of factors, including altering existing attitudes among potential patients, and changing physicians’ behaviors, insurance coverage, and the surveillance and reminder systems necessary to support screening programs.¹

In another study, researchers set out to determine exactly which elements of the colonoscopy process deterred patients from getting the procedure.² In this case, questionnaires on barriers to screening colonoscopy were sent to 300 patients, 150 of whom had never been screened and 150 of whom had previously undergone screening. Questions were also posed on respondents’ knowledge and awareness of colon cancer risk, treatment efficacy, and effectiveness of screening. Results showed that significant deterrents included volume of bowel preparation, lack of referral from primary care physician, fear of discomfort during the procedure and embarrassment. Interestingly, the previously screened and never screened groups expressed very similar objections to the process. Of these, not wanting to take the bowel prep ranked as the No. 1 deterrent. Respondents were also asked to identify possible methods of improving the experience. Answers to this query, in order of ranking, included:

• Being sedated in order to avoid discomfort during the procedure
• Being able to take the bowel prep in tablet form dissolved in six glasses of water
• Coverage of the procedure by insurance company
• Being able to choose endoscopist’s gender

Given the fact the bowel preps are often seen as a significant factor in how patients perceive their screening colonoscopy experience, clinicians must make informed and educated choices in selecting the most appropriate prep.

Erwin Sahagun, marketing manager for Schwarz Pharma, notes that differences in products require careful evaluation. “What we want to ensure is that the colon is going to be clean,” he says. “The first factor is, will it do the job? With our product, the first bowel movement should occur approximately one hour after the start of administration. Ingestion of TriLyte™ with flavor packs solution prior to gastrointestinal examination produces satisfactory preparation in over 95 percent of patients.

“Time required for preparation is another issue,” Sahagun continues. “With our product, complete bowel evacuation can occur within four hours.” Jeff Arcara, vice president of commercial development at InKine Pharmaceutical Company Inc. cites cleansing efficacy, tolerability and incidence of vomiting as important factors that should be considered in evaluating the choices in the bowel prep market.

“When selecting a bowel prep, it’s important to choose one that will maximize the potential for patient compliance,” says Allyson Mortati, global product manager for E-Z-EM Inc. “E-Z-EM’s NutraPrep allows patients to eat the day before the exam, instead of requiring compliance to a difficult regimen of clear liquids.”

“NutraPrep provides three complete meals plus beverages and snacks,” Mortati continues. “This represents a significant improvement over clear liquid diets that patients are generally limited to for the day prior to a procedure. In addition, E-Z-EM’s LoSo Prep is a pleasanttasting bowel preparation consisting of magnesium citrate, bisacodyl tablets, and bisacodyl suppository; it also has a low liquid volume.

“Patients typically report that the bowel prep was the most difficult part of a colon procedure,” Mortati explains. “By allowing the patient to eat on the day of bowel preparation, and providing a more palatable bowel preparation, NutraPrep and LoSo Prep help to maximize the patient’s positive experience, while providing superior bowel cleansing.”

In a study seeking to evaluate the adequacy and acceptance of the bowel cleansing preps for colonoscopies in children, NutraPrep was evaluated against phospho-soda prep and was found to be effective, safe and well-tolerated.³ In this case, 65 patients were randomly selected to receive one of these two bowel preps. NutraPrep was found to result in superior cleansing and a decreased amount of retained stool when compared to the phospho-soda prep and clear liquid diet.

Additionally, patients who took the phospho-soda prep were more likely to become hungry during the preparation process as compared to those who took NutraPrep. Neither regimen significantly differed in terms of adequacy of colon visualization, tolerance of the prep, side effects or compliance.

Increasing patient compliance is a constant concern, and finding ways to do so is always a priority. “In addition, we offer a choice of five flavor packs,” says Sahagun. “By giving them a choice, there is a greater chance for a clear, successful colonoscopy. We continue to educate nurses and schedulers about bowel preparation so that they can make the right choice for their patients.”

“First and foremost, clinicians want a clean prep — they want something that’s going to work,” says Lynne Gagne, product manager for Braintree Laboratories. “Second, they’re going to want something that patients will take — that is easiest for the patient to take. Also, when they’re thinking about what they’re going to give the patient, they have to think about safety. The four-liter and two-liter HalfLytely® products are safe for cardiac and renal patients, whereas you have to watch out with some of the phospho-soda preps. There are contraindications there.

“The original lavage was four liters — almost a gallon,” Gagne continues. “Volume was always the biggest complaint. So we took away two liters and added four bisacodyl tablets.” Gagne concedes that patients would ultimately prefer to take a single pill with a glass of water, but she says the decrease in volume can be a significant factor in increasing compliance.

In a 2003 study, 200 patients undergoing colonoscopy were randomized to receive HalfLytely’s reduced-volume regimen or the standard four-liter method.⁴ Results showed no difference in the efficacy of colon cleansing between the two, and found that the reduced-volume prep resulted in a significant reduction of side effects, including less fullness, nausea, vomiting and overall discomfort.

At Braintree, taste is also a consideration for new products. “We released HalfLytely in October 2004,” Gagne says. “We just got approved for an extension of that product, which is HalfLytely with flavor pack. We’ll be offering cherry, orange and lemon-lime, all in one kit, so patients can choose their flavor. We’ll probably be launching that in June of 2005.”

Arcara notes that his company is also gearing up for a new product release. “InKine is developing a next-generation sodium phosphate bowel purgative that is more effective in cleansing, is smaller, easier to swallow and requires lower dosing (and therefore has less impact on electrolytes),” says Arcara.

These new INKP-102 tablets are designed to be smaller in size and easier to swallow than InKine’s Visicol® tablets, and contain no microcrystalline cellulose (MCC). INKP-102 was reported to have yielded positive phase 3 study results in February 2005 in a randomized, investigator-blinded, noninferiority study. The study included 706 adults who underwent colonoscopy and were prepped using either 32 or 40 tablets of INKP- 102, or the existing Visicol tablets. The dosing regimen of the new product was said to be less complicated, more convenient, and shorter in terms of duration.

In evaluating the efficacy of the new product, it was found, in both doses, to be significantly superior or comparable to the company’s current product. In terms of retained material in the colon, both doses of INKP-102 required the use of less irrigation fluid during the colonoscopy than Visicol, an indicator of improved cleansing action.

In a press release, Leonard S. Jacob, MD, PhD, chairman and CEO of InKine, lauds the results of the study and the new product’s potential. “This study confirms InKine’s belief that delivery of a MCC-free sodium phosphate tablet regimen administered at a lower dose with less liquid volume would result in improved efficacy and safety compared to currently marketed Visicol tablets,” he says. “We have conducted several studies to date which have demonstrated that Visicol is the patient-preferred purgative. The data from this study indicates that INKP-102 represents an improvement over Visicol in key aspects of efficacy, safety and patient preference. We believe that if approved by FDA, INKP-102 could significantly expand InKine’s share of the market for colon cleansing products and could emerge as the physician preferred purgative.”

Measures of patient acceptance and preference were also positive for the new product. In a questionnaire given just before the colonoscopy, patients indicated a more favorable impression of the new product as compared to Visicol. Patients found the reduced dose of INKP-102 easier to take than Visicol, and were more likely to take it for future colonoscopies.

In an ideal world, colon cleansing would be convenient, safe, effective and comfortable for all patients. Although the current bowel prep market may not be able to offer perfection, it is still incumbent upon clinicians in the endoscopy suite to size up the current options and decide what makes the most sense for the best possible combination of clinical efficacy and patient satisfaction.

Works Cited

1. Winawer S, et al. Colorectal Cancer Screening and Surveillance: Clinical Guidelines and Rationale — Update Based on New Evidence. Gastroenterology. 2003 Feb;124(2):544-60.

2. Harewood, GC, et al. A Prospective, Controlled Assessment of Factors Influencing Acceptance of Screening Colonoscopy. Am J Gastroenterol. 2002 Dec;97(12):3186-94.

3. El-Baba MF, et al. A Prospective Study to Assess the Efficacy of Bowel Preparation in Pediatric Patients With the Use of a Bowel Cleansing Preparation and a Nutritional Food Package Compared With Oral Sodium Phosphate. Journal of Pediatric Gastroenterology and Nutrition 2003; 37:329.

4. DiPalma, JA, et al. Comparison of Reduced Volume Versus Four Liters Sulfate-Free Electrolyte Lavage Solutions for Colonoscopy Colon Cleansing. Am J Gastroenterol. 2003 Oct;98(10):2187-91.

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