Brand of the Year: Enbrel
Enbrel, containing etanercept, is a breakthrough product approved for the treatment of chronic inflammatory diseases such as rheumatoid arthritis, juvenile rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and psoriasis. Enbrel continues to maintain a leading position in the dermatology and rheumatology biologic marketplaces, ranking No. 1 in worldwide sales among biotechnology products used in rheumatology and dermatology.
Enbrel is the first FDA-approved drug to treat moderate-to-severe plaque psoriasis and psoriatic arthritis. Psoriasis is a chronic, painful condition that causes the skin to overgrow and develop thick scaly patches, which in severe cases can virtually cover a person's entire body. Almost 7 million Americans suffer from psoriasis.
Psoriatic arthritis is a chronic, often destructive disease characterized by joint inflammation and erosion, and is associated with psoriatic skin lesions. The progressive joint pain and swelling, which is often coupled with painful, scaly, red skin lesions, can disrupt a person's ability to perform activities of daily life that most people take for granted such as getting dressed, eating, or walking. About 1 million people suffer from psoriatic arthritis in the United States.
Enbrel has been used by more than 376,000 patients worldwide. Patients can self-administer an Enbrel injection. The drug was first approved and launched in the United States in 1998, and in Europe in 2000. 2005 marked the launch of Enbrel in Japan, the world's second-largest pharmaceutical market, in conjunction with Takeda Pharmaceutical Co. Enbrel was launched in Japan for the treatment of rheumatoid arthritis March 30 under a joint-promotion agreement between Wyeth KK (wyeth.jp) and Takeda (takeda.com). Rheumatoid arthritis is a systemic, chronic, and potentially disabling disorder that affects about 700,000 people in Japan.
With rheumatoid arthritis, the body's immune system attacks the lining of the joints, resulting in pain and swelling and may lead to fatigue, disability, deformity, organ damage, or premature death if not managed properly. According to analysts with Decision Resources Inc., Enbrel leads the market for biologic drugs to treat rheumatoid arthritis and psoriasis. Rheumatologists and dermatologists prefer Enbrel over all other biologic agents because the drug has been marketed for a sufficient period of time to provide assurance of the durability of its efficacy and safety.
"Prescriptions for Enbrel will increase modestly as a result of continued uptake and the impact of Medicare reform," says Cynthia Mundy, Ph.D., analyst, Decision Resources (dresources.com). "Among rheumatologists, Enbrel already enjoys widespread use."
According to Dr. Mundy, rheumatologists are expected to move some of their patients currently treated with Centocor Inc.'s (centocor.com) Remicade to Enbrel now that Medicare reform and changes to the reimbursement landscape for self-administered drugs have taken effect.
In 2005, FDA approved an expanded indication for Enbrel to improve physical function in patients with psoriatic arthritis. Enbrel is the first drug in its class to receive this expanded indication. In addition, FDA approved an update to the Enbrel label to include new radiographic data demonstrating that Enbrel continued to inhibit the progression of joint destruction for two years among most psoriatic arthritis patients who received ongoing therapy.
Results for Enbrel were announced in November at the American College of Rheumatology Annual Scientific Meeting showing that in a long-term blinded study in patients with rheumatoid arthritis, more than three quarters of patients treated with Enbrel plus methotrexate combination therapy experienced no progression of joint damage at three years.
In the first quarter of 2006, Amgen (amgen.com) recorded Enbrel sales of $658 million, 11% more than the same period in 2005. Enbrel sales growth in the first quarter was affected by slowing market growth and increased competitive activity. Wyeth (wyeth.com) reported first-quarter Enbrel sales of $335 million, up 42%.
Enbrel is the only soluble tumor necrosis factor receptor approved to reduce signs and symptoms, induce major clinical response, improve physical function, and inhibit the progression of structural damage in patients with moderately to severely active rheumatoid arthritis. Enbrel can be used alone or in combination with methotrexate.
Enbrel is the only drug indicated to reduce the signs and symptoms, inhibit the progression of structural damage of active arthritis, and improve physical function in patients with psoriatic arthritis. The product is approved to reduce the signs and symptoms of moderately to severely active polyarticular-course juvenile rheumatoid arthritis in patients 4 years old or older who have had an inadequate response to one or more disease-modifying antirheumatic drugs. Enbrel is also the first biologic approved to reduce the signs and symptoms in patients with active ankylosing spondylitis. Enbrel is indicated for the treatment of adult patients 18 years old or older with chronic moderate-to-severe plaque psoriasis who are candidates for systemic therapy or phototherapy.
Enbrel acts by binding tumor necrosis factor, one of the dominant inflammatory cytokines or regulatory proteins that play an important role in normal immune function and the cascade of reactions involved in the inflammatory process of rheumatoid arthritis, juvenile rheumatoid arthritis, psoriasis, psoriatic arthritis, and ankylosing spondylitis. The binding of Enbrel to TNF renders the bound TNF biologically inactive, resulting in significant reduction in inflammatory activity.
Analysts with Decision Resources believe that the increasing number of immune diseases being treated with tumor necrosis factor-alpha inhibitors will enable Enbrel and Humira to dominate this market for the next 10 years. Humira contains adalimumab and is marketed by Abbott Laboratories (abbott.com). These analysts say expanding patient populations will be treated with etanercept and adalimumab for a number of diseases, including psoriasis, psoriatic arthritis, and ulcerative colitis. Due to the high price of these drugs and their increased use in treatment, the market for TNF-alpha inhibitors will grow from $7.1 billion in 2005 to almost $12 billion in 2014 in the United States, Western Europe, and Japan.
"Biologic agents targeting TNF-alpha first launched in 1998 for the treatment of rheumatoid arthritis and Crohn's disease and are now used to treat psoriasis, psoriatic arthritis, and ulcerative colitis," Dr. Mundy says. "Although physicians were initially cautious about TNF-alpha inhibitors due to safety concerns, the availability of safety data over the past several years has provided reassurance that the benefits of TNF-alpha inhibitor therapy significantly outweigh the risks."
Enbrel is in Phase II clinical development for the treatment of asthma as well as for the treatment of idiopathic pulmonary fibrosis.
According to Datamonitor Plc. analysts, Enbrel is among several novel antifibrotic agents in clinical trials that offer new hope for major advances in the treatment of idiopathic pulmonary fibrosis by inhibiting the processes that lead to end-stage fibrosis. Idiopathic pulmonary fibrosis is a progressive and lethal disease of elderly patients for which current therapy is minimally effective.
To date, very few multicenter trials have been conducted in idiopathic pulmonary fibrosis. Datamonitor analysts estimate, however, that the promising antifibrotic drugs in Phase II/III clinical trials could potentially bring relief to more than 200,000 sufferers and will create a new market estimated to be worth more than $2 billion annually.
Idiopathic pulmonary fibrosis is a disease of unknown cause that affects people 50 years old and older. A typical symptom cluster includes shortness of breath, a chronic dry hacking cough, and chest discomfort. Shortness of breath is usually the most prominent and disabling symptom, although the cough may have a greater impact on a patient's daily life in terms of decreased socialization.
The pathology of the disease is poorly understood, although current thinking suggests that the disease is a disorder of wound healing, in which progressive fibrosis gradually interferes with a persons ability to breathe. Novel antifibrotic agents in clinical trials, such as interferon-gamma 1b, pirfenidone, bosentan, and etanercept, which inhibit the process of fibrosis, may prevent the fatal outcome common in idiopathic pulmonary fibrosis patients.
There are estimated to be about 220,000 people in the United States, Europe, and Japan that are affected by idiopathic pulmonary fibrosis, with about 90,000 of these patients in the United States. These figures are comparable to the prevalence of diseases such as chronic myeloid leukemia. As a consequence of misdiagnosis and late presentation, however, the actual number of diagnosed patients is significantly lower.
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