FDA approves Linzess for treatment off irritable bowel syndrome and constipation
According to the National Institutes of Health, an estimated 15.3 million Americans are affected by irritable bowel syndrome (IBS); furthermore, .an estimated 63 million people are affected by chronic constipation. On August 30, the Food and Drug Administration (FDA) announced that it had approved Linzess (linaclotide) to treat chronic idiopathic constipation and to treat irritable bowel syndrome with constipation (IBS-C) in adults.
Chronic idiopathic constipation is a diagnosis given to individuals who experience persistent constipation and do not respond to standard treatment. IBS-C is a subtype characterized mainly by abdominal pain and by hard or lumpy stools at least 25% of the time and loose or watery stools less than 25%.
Linzess is a capsule taken once daily on an empty stomach, at least 30 minutes before the first meal of the day. Linzess reportedly helps relieve constipation by helping bowel movements occur more often. In IBS-C, it may also reduce abdominal pain.
“No one medication works for all patients suffering from these gastrointestinal disorders,” noted Victoria Kusiak, MD, deputy director of the Office of Drug Evaluation III in the FDA’s Center for Drug Evaluation and Research. She added, “With the availability of new therapies, patients and their doctors can select the most appropriate treatment for their condition.”
Two double-blind studies were conducted to establish the safety and effectiveness of Linzess for the management of IBS-C. A double-blind study is one in which both the participants and administrators are unaware of whether the participant is receiving the drug or a placebo. A total of 1,604 patients were randomly assigned to take 290 micrograms (mcgs) of Linzess or a placebo for at least 12 weeks. The researchers found that Linzess was more effective in reducing the amount of abdominal pain and increasing the number of complete spontaneous bowel movements compared with the placebo. The safety and effectiveness of Linzess for the management of chronic idiopathic constipation also were established in two, double-blind studies. A total of 1,272 patients were randomly assigned to take Linzess at doses of 145 mcg or 290 mcg or a placebo for 12 weeks. The investigators found that the subjects taking Linzess experienced more complete spontaneous bowel movements than those taking the placebo. The 290 mcg dose is not approved for chronic constipation because studies indicated it was no more effective than the 145 mcg dose.
The most common side effect reported in during the clinical studies was diarrhea. Linzess is approved with a Boxed Warning to alert patients and healthcare professionals that the drug should not be used in patients 17 years of age and younger. The medication is co-marketed by Ironwood Pharmaceuticals Inc. (Cambridge, Massachusetts) and Forest Pharmaceuticals Inc. (St. Louis, Missouri).
IBS is a disorder of the lower intestinal tract. It involves a combination of abdominal pain and constipation, diarrhea, or an alternating pattern of these problems. Emotional stress often makes the symptoms worse. It is not the same as inflammatory bowel disease (IBD), which includes Crohn’s disease and ulcerative colitis.
It is not clear why individuals develop IBS; however, in some instances, it occurs after an intestinal infection. This is called postinfectious IBS. There may also be other triggers. IBS can occur at any age; however, it often begins in adolescence or early adulthood. It is more common in women. The condition is the most common intestinal complaint for which patients are referred to a gastroenterologist.
Symptoms range from mild to severe. Most individuals have mild symptoms. IBS symptoms may be worse in patients who also have stress or mood disorders, such as anxiety and depression. However, it is important to understand that these conditions do not cause IBS. Symptoms may include:
- Abdominal distention
- Abdominal fullness, gas, bloating
- Abdominal pain that: comes and goes; is reduced or goes away after a bowel movement; and occurs after meals
- Chronic and frequent constipation, usually accompanied by pain
- Chronic and frequent diarrhea, usually accompanied by pain
- Emotional distress
- Loss of appetite
Usually, a physician can diagnose IBS with few or no tests. Tests usually reveal no problems. Some experts recommend a lactose-free diet for two weeks to evaluate for possible lactase deficiency. Some patients may need an endoscopy, especially if symptoms begin later in life. Younger patients with persistent diarrhea may need this test to look for inflammatory bowel diseases that can cause similar symptoms, such as Crohn's disease or ulcerative colitis. One may need additional tests if they have blood in their stool, weight loss, signs of anemia, or have recently traveled. Patients over age 50 should be screened for colon cancer.