Inflammatory Bowel Disease
Inflammatory Bowel Disease (IBD) is a chronic autoimmune disease, which is the name of a group of disorders in which the intestines (small and large intestines or bowels) become inflamed (red and swollen). This inflammation causes symptoms such as severe or chronic pain in the abdomen, diarrhea that may be bloody, weight loss, loss of appetite, bleeding from the rectum, joint pain, fever and skin problems. Symptoms can range from mild to severe. Also, symptoms can come and go, sometimes going away for months or even years at a time. When people with IBD start to have symptoms again, they are said to be having a relapse or flare-up. When they are not having symptoms, the disease is said to have gone into remission.
The most common forms of IBD are Ulcerative Colitis (UC) and Crohn’s disease (Crohn’s). The main difference between the two diseases is the parts of the digestive tract they affect. There are about 1.1 million Americans living with IBD.
In both Crohn’s and UC, the mucosal inflammation generates large amounts of proinflammatory cytokines such as IFNyand TNFa, which is why drugs blocking these cytokines have been shown to be effective in controlling symptoms.
Crohn's disease can affect any area of the gastrointestinal tract, but most commonly affects the lower part of the small intestine, the ileum, and the first part of the large intestine and has the characteristic of relapsing inflammatory processes. Inflammation may be patchy and segmental, and typically transmural (all layers of the intestinal wall). The swelling and scar tissue can thicken the intestinal wall, which narrows the passageway for food that is being digested. The area of the intestine that has narrowed is called a stricture. Also, deep ulcers (holes) may turn into tunnels, called fistulas, which connect different parts of the intestine. They may also connect to nearby organs, such as the bladder or vagina, or connect to the skin. When serious damage has been made to the intestine, there may be no other option but to surgically remove large portions of the intestine. About 65 to 75 % of people with Crohn's disease need surgery at some point in their lives. Surgery can relieve symptoms and correct problems like strictures, fistulae, or bleeding in the intestine. Surgery can help relieve Crohn's disease symptoms. But, since Crohn's disease occurs in patches, surgery cannot cure the disease. If a part of the small or large intestine is removed, the inflammation may then affect the part next to the section that was removed. When the large intestine has to be removed, an external pouch is required to collect the waste.
While the disease can present itself at any age in a patient, initial incidence is often in the teens and twenties, with another peak incidence in the fifties to seventies. There is evidence of a genetic link to Crohn's disease, putting individuals with siblings afflicted with the disease at higher risk. It is thought to have an environmental component as evidenced by a higher incidence in western industrialized nations compared to other parts of the world. This particular distribution also points to the hygiene hypothesis playing an important role. Males and females are equally affected, while smokers are two times more likely to develop Crohn's disease than nonsmokers. There is no known pharmacological or surgical cure for Crohn’s disease; treatment options are limited to the control of symptoms, maintenance of remission, and prevention of relapse.
Since the etiology of the disease is not completely understood, curative therapies have not yet been developed. Current therapeutic options in the management of patients are symptomatic only. Therapeutic approaches concentrate on suppression of acute flare-ups combined with induction and maintenance of remission to prevent further recurrences. Standard therapy for the symptomatic treatment of Crohn’s disease may include sulfasalazine, mesalazine, systemic and topical glucocorticoids, immunosuppressants like azathioprine or 6-mercaptopurine, and in severe cases also treatment with anti-TNF-alpha therapy, methotrexate, or cyclosporine as monotherapy or in combination with other agents.
Ulcerative colitis affects the top layer of the large intestine. The disease causes swelling and tiny open sores, or ulcers, to form on the surface of the lining of the large intestine. The ulcers can bleed and produce pus. In severe cases of ulcerative colitis, ulcers may weaken the intestinal wall so much that a hole develops and causes the contents of the large intestine, including bacteria, to spill into the abdominal (belly) cavity or leak into the blood. This causes a serious infection and requires emergency surgery.
Inflammation in the colon also causes the colon to empty frequently, causing diarrhea. When the inflammation occurs in the rectum and lower part of the colon it is called ulcerative proctitis. If the entire colon is affected it is called pancolitis. If only the left side of the colon is affected it is called limited or distal colitis.
Ulcerative colitis can occur in people of any age, but it usually starts between the ages of 15 and 30, and less frequently between 50 and 70 years of age. It affects men and women equally and appears to run in families, with reports of up to 20 percent of people with ulcerative colitis having a family member or relative with ulcerative colitis or Crohn's disease.
The medical therapies available to Crohn’s patients are also applicable to patients with ulcerative colitis, and about 25 to 40 percent of people with ulcerative colitis need surgery at some point in their lives. Surgery that removes the entire large intestine can completely cure ulcerative colitis.
IBD Population & Market Potential
According to a 2012 Decision Resources report, in the U.S., the prevalence of Crohn's in 2011 was 498,000 patients and UC was 582,000 patients. Prevalence rates for these and all autoimmune disorders are expected to continue to rise in the next several years.