ALLIANCE IMAGENT GI APPROVED AS FIRST ORAL MAGNETIC RESONANCE IMAGING AGENT IN U.S.; PERFLUBRON IS INDICATED FOR DELINEATION OF BOWEL FROM ADJACENT ORGANS

Alliance Pharmaceutical's Imagent GI (perflubron), the first oral contrast agent for magnetic resonance imaging to be commercially available in the U.S., was approved by FDA on Aug. 13. Approved draft labeling states that Imagent GI is indicated for "oral use with MR imaging to enhance delineation of the bowel. ...to distinguish it from adjacent organs and areas of suspected pathology." FDA designated the imaging agent a "1P" product (a new molecular entity given priority review by the agency). Imagent GI's approval comes 38 months after Alliance's June 1990 NDA (20-091) submission. Imagent GI was recommended for approval by FDA's Medical Imaging Drugs Advisory Committee in May 1992 ("The Pink Sheet" May 25, 1992, T&G-9). The committee's decision came after it debated whether to recommend Imagent GI because the product lacked a disease-specific indication. At the time, the group recommended a revised general indication that the contrast agent "reduces signal from the bowel and assists.... in the detection of abnormalities in the abdomen." Draft approved labeling notes that clinical studies were conducted in 162 subjects "including 30 normal volunteers." Of the 132 patients with "suspected pelvic and abdominal abnormalities who were referred for MR imaging," 73 were women ranging in age from 20-84 years, labeling notes. The age range for the 59 men involved in the clinicals was 21-85 years. The normal volunteers were divided evenly between women and men. Labeling states that "improvement in bowel delineation was demonstrated in 92% to 94% of the subjects for all MR pulsing sequences studied." Improvement in the "ability to visualize the left lobe of the liver, mesenteric fat, urinary bladder, uterine myometrium, and pathologic tissue ranged from 62% to 89%," labeling states. "For regions of the pancreas and right lobe of the liver, improvement ranged from 12% to 42%." Alliance will sponsor a Phase IV study to provide additional information on the clinical utility of Imagent GI in specific diseases, FDA's approval letter notes. The contrast agent is contraindicated for "patients who have known or suspected complete bowel obstruction and/or perforation of the bowel." Studies were not performed in patients with those conditions. The agent, which is administered orally immediately prior to MRI, is a "clear, colorless liquid, that is not miscible with water...and exhibits no osmotic properties," labeling notes. A total of 273 patients received Imagent GI during the clinical trials. Draft labeling states that "53% reported at least one adverse reaction, while 30% experienced an oily or bad taste; 15.8% nausea and/or vomiting and 14.3% diarrhea." Labeling notes that of the "subjects who experienced nausea and/or vomiting, 94% received [Lilly's] glucagon, an antiperistaltic agent known to cause nausea and vomiting." Additionally, labeling states that "of the 127 subjects who received larger doses in the pivotal trials, there was a 25% incidence of diarrhea." Labeling contains a breakdown of adverse reactions by gender, with the incidence of "nausea and/or vomiting listed at 23% for women and 8% among men and diarrhea listed at 19% in women and 9% among men." Alliance explained that Imagent GI is "an inert substance that does not interact with any other substance" and that there is no actual diarrhea but "a diarrhea-like sensation" in the bowel. The recommended dosage of Imagent GI is 9 mL/kg based on the usual 600 mL total dose administered in the clinical trials. Labeling advises that the "dose should not exceed 1,000 mL." Additionally, labeling notes that the contrast agent has a "rapid transit time" and it recommends that "imaging for the upper abdominal region be initiated within 15 minutes after dosing." For the pelvic region, "imaging should begin 15-60 minutes after dosing," labeling states. Imagent GI should be available in three to four weeks pending FDA clearance of the company's promotional materials, San Diego- based Alliance Pharmaceutical said Aug. 17. The contrast agent will be distributed through Picker Healthcare Products, an Ohio- based radiological firm specializing in radiological film, chemicals and accessories. The price of Imagent GI to hospitals will be an estimated $150-$200 per treatment, Alliance reported. The company estimate is based on body weight for an average-sized adult. Imagent GI is the first drug product approved for Alliance Pharmaceutical. The firm reported a net loss of $19 mil. for the nine months extended March 31 on revenues of $580,000. The San Diego firm has three other Imagent contrast agents in clinical trials; Imagent LN for the enhancement of lymph node images on computed tomography (CT); Imagent BP, a blood pool imaging agent for CT, and Imagent US, a perfluoro-chemical-based intravenous contrast agent for use with ultrasound to image blood flow within organs.