Dive Brief:
- CSL Behring announced March 16 that the Food and Drug Administration approved Hizentra for the treatment of chronic inflammatory demyelinating polyneuropathy (CIDP), a rare autoimmune condition characterized by progressive muscle weakness in the legs and arms as well as peripheral numbness and weakness.
- While there are 45 clinical trials that are in various stages for the treatment of CIDP, the injectable option was largely shown to be effective and well-tolerated. CSL is banking on the dosing advantage of subcutaneous administration — all of the other options in this class are administered through intravenous infusion.
- "It is possible for patients and caregivers to self-administer subcutaneous treatments, so Hizentra offers patients and their doctors the flexibility and freedom to control their treatment during a time, at a place, and on a schedule that is convenient for them," said CSL spokesperson Jennifer Purdue to BioPharma Dive. "Self-administration alleviates some of the burden associated with infusions that are required with other treatments, like scheduling time at a hospital or infusion center."
Dive Insight:
Closely related to Guillain-Barré syndrome (GBS), CIDP is a chronic and progressive illness typically treated with corticosteroids, plasmapheresis or intravenous immunoglobulin (IVIg) therapy.
While CIDP is rare, affecting only one to eight in 100,000 people according to patient advocacy group GBS/CIDP Foundation International, it is often misdiagnosed. Symptoms are similar to those experienced by patients with myasthenia gravis, multiple sclerosis, GBS and spinal cord disease. If left untreated, 30% of people with CIDP progress to full wheelchair dependence, according to the patient group.
The precise mechanism of action in CIDP is not fully known, but IVIg-based treatments improve neuromuscular disability and impairment and can also be used as a maintenance therapy to prevent relapse.
Hizentra is already approved in the EU under the name Privigen, and in the U.S. as a treatment of primary immunodeficiency and immune thrombocytopenic purpura. The approval to treat CIDP was granted through an sBLA and based on the results from the the PRIMA and PATH studies.
In the PRIMA study, all eligible patients received a Privigen induction dose (2 g/kg bw), followed by up to seven infusions of 1 g/kg bw at three-week intervals. The primary efficacy endpoint was the responder rate at completion. The INCAT disability scale was chosen as the primary outcome, and paralysis score was assigned by way of an adapted MRC sum score. The researchers also measured grip strength of participants.
The PATH study looked specifically at treatment with subcutaneous immunoglobulin versus placebo. Enrolling 172 patients with CIDP, it is considered the largest trial of CIDP to date and the first to study two administrations of immunoglobulins and two doses.
Both subcutaneous doses of Hizentra were found to be effective and well tolerated, with five patients experiencing serious adverse events. Fifty-five percent of patients across both subcutaneous infusion groups in the PATH study experienced an adverse reaction to treatment.
Six patients withdrew consent because of issues with subcutaneous infusions (three in the high-dose group for mild local reactions, one in the low-dose group and one in the placebo group) did not feel comfortable with the subcutaneous technique, and one in the high-dose group no longer wanted to participate because of a need to travel abroad.
Other treatments in this class include older IVIg products, such as Gamunex-C, approved in 2003. But because Hizentra is the first and only subcutaneous immunoglobulin approved for CIDP, it may offer a compelling dosing benefit that could provide it a competitive advantage.
While the convenience of self-administration may be something CSL is relying on, in the PATH study, more than half of participants (53%) who received subcutaneous immunoglobulin preferred their current treatment option over the one they injected themselves.
According to Purdue, the price per gram for Hizentra will not change as a result of this new indication. But, she added, "The dosing regimen for CIDP is different from that of PI, therefore the cost per patient will vary based on the individual’s weight-based dosage."