A report of three multiclinic trials evaluating arbaprostil in arthritic patients with ASA/NSAID gastric mucosal damage. The Upjohn Company Arbaprostil ASA/NSAID Gastric Mucosal Damage Treatment Study Groups.

Three randomized, placebo-controlled multiclinic trials involving arbaprostil dosages of (a) 10 micrograms; (b) 25 micrograms; and (c) 10, 25, or 50 micrograms orally for 4 wk in patients older than 18 yr with rheumatoid arthritis or osteoarthritis who had endoscopically documented nonsteroidal antiinflammatory drug-associated gastric mucosal damage were conducted in the United States. All patients continued taking the nonsteroidal antiinflammatory drugs and were reendoscoped after 4 wk of therapy. Success at that time was defined as complete resolution of all gastric mucosal damage. Six hundred fifty-eight patients were enrolled in the three trials. Significantly more patients experienced healing in the arbaprostil treatment groups in all trials compared with those who received placebo. The healing rates in the various trials were 68% and 32% (10 micrograms vs. placebo; p = 0.007); 77% and 23% (25 micrograms vs. placebo; p less than 0.001); and 52%, 46%, 35%, and 16% (50, 25, and 10 micrograms vs. placebo; p less than 0.001, less than 0.001, and 0.002, respectively). Diarrhea, mostly of a mild nature, was the only arbaprostil-associated side effect and was found with the 25- and 50-microgram dosages (33% and 59%, respectively). No exacerbation of arthritis signs or symptoms was found. Arbaprostil at doses with varying effects on gastric acid secretion (25 and 50 micrograms) was documented in these trials to be an effective and safe agent for healing gastric mucosal damage associated with aspirin or other nonsteroidal antiinflammatory drugs in patients with either rheumatoid arthritis or osteoarthritis without adversely affecting joint symptomatology.

Arbaprostil [15(R)-15-methyl prostaglandin E2] in a single nighttime dose of either 50 or 100 micrograms in acute duodenal ulcer.

To determine the efficacy of single nighttime doses of arbaprostil [15(R)-15-methyl prostaglandin E2], 50 or 100 micrograms for 4 wk, a double-blind randomized placebo-controlled multiclinic trial was undertaken. Success was defined as complete healing of the ulcer documented by endoscopy. Fifty-one of 64 patients enrolled were considered evaluable. Ulcer healing was documented in 64.3%, 85.7%, and 31.2% of the 100-micrograms arbaprostil, 50-micrograms arbaprostil, and placebo treatment groups (p value vs. placebo = 0.003 and 0.002, respectively). No difference in side effects or changes in laboratory parameters were found between the treatment groups except that diarrhea, usually mild, was found more often in the 100-micrograms arbaprostil group (60.0%) than in the 50-micrograms arbaprostil (31.8%) or placebo groups (23.5%) (p value 100 micrograms arbaprostil vs. placebo = 0.02). A single nighttime administration of arbaprostil seems to be a safe and efficacious agent for the treatment of acute duodenal ulcer.

A multiclinic trial evaluating arbaprostil [15(R)-15-methyl prostaglandin E2] as a therapeutic agent for gastric ulcer.

A randomized, double-blind, placebo-controlled, multiclinic trial evaluated arbaprostil [15(R)-15 methyl prostaglandin E2] for the treatment of acute gastric ulcer, achieving an overall enrollment of 124 patients (of which 113 were considered evaluable). This 6-wk trial used an arbaprostil dose of 10 micrograms q.i.d., which has little gastric acid antisecretory activity. Endoscopies were performed after 21 and 42 days of treatment, at which times the arbaprostil and placebo healing rates, respectively, were 6/59 (10.2%) and 4/53 (7.6%) on day 21 and 25/59 (42.4%) and 16/50 (32.0%) on day 42. No significant differences between the treatment groups were found for pain relief, antacid consumption, and mucosal healing. This trial documents that a 10-micrograms dose of arbaprostil (which may be considered cytoprotective because of its small effect on gastric acid secretion), although safe and associated with no side effects, is not efficacious in healing acute gastric ulcers.

Failure of a cytoprotective dose of Arbacet to heal acute gastric ulcers.

Twenty outpatients with an endoscopic diagnosis of gastric ulcer were evaluated for 6 wk in a randomized, double-blind trial comparing 15(R)-15-methyl prostaglandin E2 (Arbacet) (10 micrograms, 0.5 h before each meal and at bedtime) with placebo. Endoscopy was performed at 3 wk and 6 wk during the study period. Five of nine patients (56%) taking Arbacet and seven of 11 patients (64%) in the placebo group had complete healing of their gastric ulcer. Healing occurred in four patients from the Arbacet group and three patients in the placebo group at 3 wk. A cytoprotective dose of Arbacet (40 micrograms daily) is not significantly better than placebo in healing gastric ulcers.

Damage and protection of the human gastric mucosa. A multiparameter assessment.

Studies in animals and humans have indicated that endogenous prostaglandins as well as synthetic prostaglandin analogues can prevent gastric mucosal damage induced by various agents. Methods were developed to assess induced damage and the effects of potentially protective agents (synthetic prostaglandin analogues and the histamine [H2]-receptor antagonist cimetidine) on the human gastric mucosa by measuring ion fluxes and transmucosal potential difference, as well as by observations with gastrointestinal endoscopy. Commonly ingested agents, such as aspirin, 1,300 mg, and 20 percent ethanol increased hydrogen ion and sodium ion fluxes, decreased potential difference, and caused gross mucosal damage, as observed by endoscopy. Conversely, acetaminophen, 2,600 mg, and 10 percent ethanol did not have any significant effects. Hyperosmolar solutions (1,800 and 3,600 mOsm/kg) also produced acute damage. Sodium taurocholate (10 mmol/liter) when instilled into the stomach, either at pH 1.1 or 7.0, produced both functional and structural damage. When given as a single dose, neither 15(R)15-methyl PGE2 nor the synthetic PGE1 analogue, misoprostol, prevented mucosal damage induced by aspirin and taurocholate (pH 1.1), respectively. Cimetidine, 400 mg orally, however, did reduce aspirin-induced mucosal damage, and this effect was independent of gastric acid inhibition.

The effect of 15(R)-15-methyl prostaglandin E2 (Arbacet) on the healing of aspirin or nonsteroidal antiinflammatory drug-induced gastric mucosal lesions: an endoscopic study.

Twenty-nine outpatients chronically ingesting daily aspirin or nonsteroidal antiinflammatory drugs for rheumatological disease, who had endoscopically proven gastric mucosal lesions worse than erythema, were evaluated for 4 wk in a randomized, double-blind trial comparing 15(R)-15-methyl prostaglandin E2 (Arbacet) (10 micrograms, 0.5 h before each meal and at bedtime) with placebo. Patients continued their usual daily dose of antiarthritic medication throughout the study period, and an endoscopy was performed on the final day to assess healing. Five of 14 patients (36%) taking Arbacet and two of 15 patients (13%) in the placebo group had complete healing of their gastric lesions after 4 wk. Arbacet at a daily dose of 40 micrograms is not significantly better than placebo in healing gastric lesions caused by aspirin or nonsteroidal antiinflammatory drugs, if antiinflammatory therapy is continued.

Cytoprotective doses of arbacet with minimal antisecretory properties are not effective in duodenal ulcer healing.

The efficacy of arbacet (a synthetic analog of prostaglandin E2) in definite cytoprotective but minimal antisecretory dose was evaluated in the treatment of duodenal ulcer. One hundred five patients with endoscopically proven duodenal ulcer were randomized in a double-blind manner to receive four times daily either arbacet 25 micrograms or placebo. Ulcer healing was assessed endoscopically after two and four weeks of treatment. The mean age, sex distribution, and tobacco and alcohol consumption were similar in the two treatment groups. The ulcers of 16 patients in both the placebo and the arbacet-treated group healed after 14 days of treatment. At the end of the study, healing of the ulcer was observed in 69.2% of the arbacet-treated patients and in 60.4% of patients in the placebo treated group. (Difference was not statistically significant). We conclude that cytoprotective doses of arbacet with minimal antisecretory properties are not effective in duodenal ulcer healing.

Failure of a cytoprotective dose of arbaprostil to heal acute duodenal ulcers. Results of a multiclinic trial.

Previous therapeutic trials with prostaglandins have shown them to be effective in healing duodenal ulcers when used at doses that are highly effective suppressors of gastric acid secretion. We undertook this trial to determine if a cytoprotective dose of arbaprostil (10 micrograms q.i.d. for 4 wk) would also be efficacious in this disease state. Eighty-two patients between the ages of 19 and 72 yr with endoscopically documented duodenal ulcers were entered into this randomized double-blind placebo-controlled trial. The patients were monitored with biweekly endoscopies and laboratory examinations, weekly interviews during the period when drug was administered, and a follow-up interview plus laboratory examinations 1 wk after drug administration was completed. No statistically significant differences between the arbaprostil and placebo treatment groups were found for ulcer healing rates, pain relief, antacid consumption, side effects, or laboratory examinations. It is presumed that this prostaglandin may not have sufficient duodenal cytoprotective capacity to effectively heal duodenal ulcers, or that some suppression of gastric acid secretion may be required to achieve significant clinical efficacy.

The influence of 15(R)-15 methyl PGE2, methyl ester, on Nd:YAG laser-induced gastric ulcers.

The effect of 15(R)-15 methyl PGE2 on the evolution of gastric ulcers induced by endoscopic Nd:YAG laser photocoagulation was studied. By continuous application of 50 to 70 watt power for 4 sec at a distance of 15 mm from the gastric mucosa, reproducible ulcers can be induced. The effect of the drug in nonantisecretory doses (10 micrograms/kg) on the acute ulcer formation and on the healing rate was evaluated in mongrel dogs by light microscopy. Local administration or oral pretreatment did not influence the size or depth of acute ulcers (7.4 mm in diameter) as compared to a control series (7.2 mm). Pretreatment for several days, however, had a marked beneficial effect on the healing rate of the ulcers (1.71 mm after 7 days compared to 2.76 mm for the control series). From these data it may be concluded that 15(R)-15 methyl PGE2 has a beneficial effect on ulcer healing, even in nonantisecretory doses.

Prevention of acute aspirin-induced gastric mucosal injury by 15-R-15 methyl prostaglandin E2: an endoscopic study.

The deleterious effects of aspirin on gastric mucosa have been well documented in experimental and clinical studies. Prostaglandins offer a potential method by which this injury may be prevented. In these studies, we developed a single-dose endoscopic assay system of aspirin-induced gastric mucosal injury in normal volunteers. With this system, 27 of 30 volunteers (90%) demonstrated severe mucosal injury after ingestion of aspirin. Subsequently, we evaluated whether pretreatment with 15-R-15 methyl prostaglandin E2 prevented severe injury after ingestion of aspirin. Following an initial dose-response study, a double-blind crossover trial was performed using pretreatment with placebo or with 10-micrograms doses of 15-R-15 methyl prostaglandin E2 for 24 h before treatment with aspirin. The results of this trial indicate that prostaglandin pretreatment significantly prevented the occurrence of endoscopically visible severe gastric mucosal injury after single-dose aspirin administration.

Prostanoids cytoprotection for maintaining remission in ulcerative colitis. Failure of 15(R), 15-methylprostaglandin E2.

To establish whether the cytoprotective properties of prostanoids can be used for maintaining remission in ulcerative colitis, 24 patients with ulcerative colitis in remission were randomly assigned to receive either 15(R), 15-methyl-PGE2 (200 micrograms/day) or to continue with sulfasalazine (2.0 g/day) for up to 28 weeks. All patients included were symptom free and sigmoidoscopy and rectal biopsy performed upon entering the trial did not reveal any signs of disease activity. Of the 12 patients who discontinued sulfasalazine and were allocated to receive 15(R), 15-methyl-PGE2, five flared up within the first four weeks and three others had to stop the trial because of severe diarrhea. Because of the high incidence of side effects and flare-up, the other four patients were instructed to stop the trial. In contrast, only two of the 12 sulfasalazine-treated patients flared-up and the other 10 concluded the 28 weeks of the trial symptom free. These results indicate that 15(R), 15-methyl-PGE2 cannot be used to control and support remission in ulcerative colitis patients.

Effect of 15(R)-15-methyl prostaglandin E2 (arbaprostil) on the healing of duodenal ulcer: a double-blind multicenter study.

A multicenter study was conducted on 173 patients with active, endoscopically proven duodenal ulcers (158 men, 15 women). They were randomly assigned, in a double-blind manner, to two groups: those receiving placebo capsules (91 patients) and those receiving capsules containing 100 microgram of 15(R)-15-methyl prostaglandin E2 (arbaprostil) (82 patients). Each drug was ingested four times a day (1 h before meals and at bedtime) for 28 days. Endoscopy was performed on days 0, 14, and 28 after the trial began. At each examination, the ulcer size was measured and whether the ulcer had healed was recorded. Arbaprostil increased the incidence of ulcer healing to approximately the same degree as reported in most extensive studies with cimetidine. At 14 days, three times as many patients were totally healed in the arbaprostil-treated as in the placebo-treated group (37% vs. 12%, p less than 0.001). At 28 days, 67% of patients receiving arbaprostil were healed compared with 39% in the group receiving placebo (p less than 0.001). Similarly, the ulcer size, measured endoscopically, was much smaller after arbaprostil administration than in the group receiving placebo after both 14 and 28 days (p less than 0.001). Side effects attributable to treatment consisted primarily of loose stools and diarrhea (34%). Smoking retarded healing in the placebo-treated group (p less than 0.05), but did not significantly retard healing in patients treated with arbaprostil. We conclude that arbaprostil markedly accelerates the healing rate of active duodenal ulcers. This effect may be due to inhibition of acid secretion as well as gastric cytoprotection.

Treatment of hemorrhagic gastritis with 15(R)-15 methyl prostaglandin E2: report of a case.

A 19-yr-old male developed severe hemorrhagic gastritis following three abdominal operations. Treatment with intravenous cimetidine and hourly antacids to maintain his gastric pH above 5 failed to affect gastrointestinal bleeding. Also, peripheral venous vasopressin, propantheline bromide, and glucagon were without effect. Total gastrectomy was considered to control his bleeding. However, since a number of prostaglandin analogs prevent gastric lesions produced by many noxious agents (e.g., aspirin, alcohol, strong acid or alkali, etc.) in animals and humans, the patient was treated with 50 micrograms of 15(R)-15 methyl prostaglandin E2 intragastrically every 6 h for 10 days. To epimerize the 15(R) form to the more active 15(S) form, 50-100 ml of 50-mN HCl was placed into the patient's stomach immediately before each dose. Bleeding ceased within 24 h of the onset of 15(R)-15 methyl prostaglandin E2 therapy and did not recur. The prompt response to 15(R)-15 methyl prostaglandin E2 in combination with hourly antacids in this patient with persistent and severe hemorrhagic gastritis suggests a therapeutic effect and the need for a prospective double-blind clinical trial.