Abbott announced that the US Food and Drug Administration (FDA) approved an expanded indication for Humira (adalimumab) that includes inhibiting structural joint damage and improving physical function in patients with psoriatic arthritis (PsA). The expanded indication is in addition to the psoriatic arthritis approval granted in October 2005.
Humira is also approved in the US for use in moderate to severe rheumatoid arthritis (RA) and active ankylosing spondylitis (AS).
PsA is a chronic disease that combines symptoms of arthritis, including joint pain and inflammation, and those of psoriatic skin disease, such as painful, raised red lesions covered by silvery white scales. Approximately one million men and women suffer from PsA in the US and, when left untreated, the disease can be potentially disabling. Early recognition, diagnosis and treatment of PsA can relieve pain and inflammation and possibly help inhibit extensive joint involvement and damage in later stages of the disease.
"Psoriatic arthritis can be debilitating for many people, hindering everyday activities. For these people, and others, the new indication for Humira is welcome news to our community," said Gail Zimmerman, president and CEO of the National Psoriasis Foundation.
The expanded indication is based on results from an extension of the Adalimumab Effectiveness in Psoriatic Arthritis Trial (ADEPT), the largest randomized, placebo-controlled biologic trial in PsA. ADEPT was a phase III, controlled study in 313 patients with moderate to severe PsA, who had an inadequate response to NSAID (non-steroidal anti-inflammatory drug) therapy. Patients were randomized to receive either Humira 40 mg every other week or placebo. At week 24, 285 patients elected to enrol in a 24-week open-label extension.
Patients taking Humira experienced significantly less joint damage than patients taking placebo. Joint damage was assessed with X-rays taken at baseline and weeks 24 and 48, using the modified total Sharp score (mTSS), a measure of joint damage progression. A smaller change in mTSS reflects less progression of joint damage, with a positive score indicating worse radiographic damage. At week 24, the co-primary endpoint (the average change in joint damage, as measured by a mean change in mTSS) was 10 times greater in the placebo arm than in the Humira arm (0.9 and -0.1, respectively). More than three times as many patients on placebo (29 per cent) experienced joint damage compared to patients taking Humira (9 per cent) at week 24. Results in the Humira group were maintained through 48 weeks, the mean change in mTSS compared to baseline was -0.2 at 48 weeks.
Patients taking Humira showed significant improvement in physical function as assessed by the Health Assessment Questionnaire Disability Index (HAQ) score and the short form-36 Health Status Survey (SF-36). HAQ scores assess a patient's ability to perform daily activities such as getting dressed, walking and climbing stairs. Statistically significant improvements in HAQ were achieved by patients in the Humira group compared to placebo at week 24. Patients taking Humira also showed statistically significant improvement compared to placebo in the SF-36 physical component score. The SF-36 is a broad questionnaire that examines the physical and mental impact on patients. Improvements in physical function were maintained through week 84.
The October 2005 FDA approval of Humira for active arthritis in psoriatic arthritis was based on two studies including ADEPT 24-week results measuring joint symptoms with American College of Rheumatology (ACR) scores and skin disease symptoms with the Psoriasis Area Severity Index (PASI). Patients' arthritic symptoms responded to Humira, with nearly 60 per cent of patients achieving ACR20 through week 24. An ACR20 score indicates a 20 per cent or greater improvement in tender and swollen joint counts and several other clinical measures. The primary endpoint was ACR20 at week 12 in the Adept trial.
Adept also studied the ability of Humira to improve the psoriatic skin symptoms associated with PsA. Sixty-nine patients in the Humira group had skin lesions on greater than 3 per cent of their body skin surface at the onset of the trial. (The palm of an adult hand represents approximately 1 per cent.) Of these patients, approximately three out of five achieved 75 per cent improvement, and more than two out of five achieved 90 per cent improvement at 24 weeks (called PASI 75 or 90 responses, respectively in the study).
Joint results were maintained for patients in the Humira group through week 48. Patients in the placebo group achieved similar results after receiving Humira from week 24 through week 48. Skin results were also maintained in the Humira group through week 48, when nearly three out of five patients achieved PASI 75 skin clearance and nearly one out of two patients achieved PASI 90 skin clearance response at week 48. Patients in the placebo group achieved similar results after receiving Humira in the 24-week, open-label extension.
"Psoriatic arthritis is a multifaceted disease in which patients can experience joint and skin symptoms that may lead to disability and decreased quality of life," said Eugene Sun, M.D., vice president, global pharmaceutical clinical development, Abbott. "Humira effectively treats multiple aspects of the disease, making it a promising comprehensive treatment for these patients."
Psoriatic arthritis combines skin symptoms, such as dry, scaly skin and painful patches of red, raised skin known as plaques, with arthritis symptoms including joint pain and inflammation. Common symptoms of psoriatic arthritis include varying degrees of skin involvement along with stiffness, pain, swelling and tenderness of the joints that can lead to a reduced range of motion and potential severe joint destruction.
Left untreated, psoriatic arthritis can be a progressively disabling disease. The arthritic manifestations often include debilitating disease of the hands and feet, as seen in rheumatoid arthritis, as well as painful inflammation of the tendon insertions (the part of the tendon that attaches to the bone) and arthritis of the spine. Psoriatic arthritis is often found in patients who suffer from psoriasis, a chronic skin disease that affects nearly 3 per cent of the world's population. It is estimated that up to 30 per cent of people with psoriasis also develop psoriatic arthritis.
Like RA, psoriatic arthritis is an autoimmune disorder in which a human protein, tumour necrosis factor-alpha (TNF-alpha), has been suggested to play a role in disease development. Humira, which is a fully human monoclonal antibody that resembles antibodies normally found in the body, works by specifically blocking TNF-alpha.
Serious infections, sepsis, tuberculosis (TB) and rare cases of opportunistic infections, including fatalities, have been reported with the use of TNF-blocking agents, including Humira. Many of these serious infections have occurred in patients also taking other immunosuppressive agents that in addition to their underlying disease could predispose them to infections. Treatment with Humira should not be initiated in patients with active infections. TNF-blocking agents, including Humira, have been associated with reactivation of hepatitis B (HBV) in patients who are chronic carriers of this virus. Some cases have been fatal. Patients at risk for HBV infections should be evaluated for prior evidence of HBV infections before initiating Humira. The combination of Humira and anakinra is not recommended.
TNF-blocking agents, including Humira, have been associated in rare cases with demyelinating disease and severe allergic reactions. Infrequent reports of serious blood disorders have been reported with TNF-blocking agents. More cases of malignancies have been observed among patients receiving TNF blockers, including Humira, compared to control patients in clinical trials. These malignancies, other than lymphoma and non-melanoma skin cancer, were similar in type and number to what would be expected in the general population. There was an approximately four fold higher rate of lymphoma in combined controlled and uncontrolled open-label portions of Humira clinical trials. The potential role of TNF-blocking therapy in the development of malignancies is not known.
In Humira clinical trials for ankylosing spondylitis and psoriatic arthritis, the safety profile for patients treated with Humira was similar to the safety profile seen in patients with rheumatoid arthritis.
Humira is the only fully human monoclonal antibody approved for the treatment of rheumatoid arthritis (RA), psoriatic arthritis (PsA), and ankylosing spondylitis (AS) in the U.S. and Europe. Humira resembles antibodies normally found in the body. It works by blocking tumour necrosis factor alpha (TNF-a), a protein that plays a central role in the inflammatory responses of autoimmune diseases. To date, Humira has been approved in 67 countries and more than 160,000 people worldwide are currently being treated with Humira. Clinical trials are currently under way evaluating the potential of Humira in other autoimmune diseases.
In the US, Humira is approved by the FDA for reducing signs and symptoms, inducing major clinical response, inhibiting the progression of joint structural damage, and improving physical function in adult patients with moderately to severely active RA. Humira is indicated for reducing the signs and symptoms of active arthritis, inhibiting the progression of structural damage and improving physical function in patients with psoriatic arthritis. Humira can be used alone or in combination with methotrexate or other disease-modifying anti-rheumatic drugs (DMARDs). Humira was also approved on July 28, 2006 for reducing signs and symptoms in patients with active AS.