Biological Medications for Hidradenitis Suppurativa

What Are Biological Medications?

Biological medications are a fairly new class of medications used for a broad range of both skin diseases and internal diseases. They work by suppressing the immune system and the body’s inflammatory response. Hidradenitis suppurativa is an inflammatory condition with recurrent, painful, and draining lesions in the armpits, under the breasts, in the groin, and around the buttocks.^[1] There are several biological agents that physicians may use for moderate to severe hidradenitis suppurativa treatment, including adalimumab, infliximab, ustekinumab, and anakinra.^[2] Currently, only adalimumab is approved by the United States Food and Drug Administration (FDA) for the treatment of hidradenitis suppurativa. The other medications may be used off-label. 

Typically, hidradenitis suppurativa is treated with topical medications, injectable steroids, and antibiotics, although in severe cases physicians have used surgery. However, physicians may turn to biological medications in severe or refractory cases of hidradenitis suppurativa.^[2] 

*Brand names in parentheses

How Do Biological Medications Work for Hidradenitis Suppurativa?

Biological agents work by targeting and inhibiting specific components of the immune system in order to suppress the body’s inflammatory response. Theoretically, agents that target only specific components will be more effective with fewer side effects. The biological medications typically target signaling molecules involved in the immune response, as well as various receptors for these molecules. For hidradenitis suppurativa, the biological medications used (adalimumab and infliximab) are tumor necrosis factor-alpha (TNF-alpha) inhibitors.^[4] Tumor necrosis factor-alpha is a signaling molecule that allows immune cells to communicate with each other; it also promotes an inflammatory response. 

An emerging biological medication with success in treating hidradenitis suppurativa is ustekinumab, which is an interleukin-12/23 inhibitor.^[5] Interleukins are inflammatory signals that are involved in the activation and communication of immune cells called T cells. Another medication called anakinra has only been used in a few published clinical trials and works by blocking the interleukin-1 receptor.^[6] Interleukin receptors allow circulating interleukins to communicate with cells and create the inflammatory effects of interleukins.

It is not clear how biologicals improve hidradenitis suppurativa. Although they have not been shown to cure the disease, they can significantly improve symptoms, quality of life, and physician clinical grading.^[1]

What Conditions Do Biological Treatments Treat? 

The only biological agent that is FDA-approved to treat hidradenitis suppurativa is adalimumab. Below are the FDA-approved skin and non-skin uses of various biological agents:

Skin Diseases

• Adalimumab: moderate to severe hidradenitis suppurativa, plaque psoriasis
• Infliximab: plaque psoriasis
• Ustekinumab: plaque psoriasis
• Anakinra: none

Non-Skin Diseases

• Adalimumab: ankylosing spondylitis, Crohn’s disease, juvenile idiopathic arthritis, psoriatic arthritis, rheumatoid arthritis, ulcerative colitis, uveitis
• Infliximab: ankylosing spondylitis, Crohn’s disease, psoriatic arthritis, rheumatoid arthritis, ulcerative colitis
• Ustekinumab: Crohn’s disease, psoriatic arthritis
• Anakinra: neonatal-onset multisystem inflammatory disease, rheumatoid arthritis

How Are Biologicals Given? 

Some biological agents can be self-injected by the patient, while others require infusion through an IV (see table above). Unlike many other medications used to treat symptoms of hidradenitis suppurativa, biological medications are not given daily and therefore may be more convenient.  

The recommended FDA-approved dosing of adalimumab for hidradenitis suppurativa is an initial 160 mg subcutaneous injection, then an 80 mg injection on day 15, followed by 40 mg injections once per week starting on day 29.

What Are Common Risks and Side Effects of Biologicals?

There are several risks associated with using biological medications due to their nature of suppressing the immune system. The table below lists risks of each of the biological medication classes used for hidradenitis suppurativa.^[7]

• People receiving biological medication simultaneously with other immunosuppressive medications, such as steroids or methotrexate, are at increased risk for serious infections. Before starting therapy, all patients should be screened for latent tuberculosis infection.
• There is an increased incidence of associated risks in elderly, pediatric, and surgery patient populations receiving biological medications.
• Live vaccines should not be given when being treated with biological medications.
• People receiving biological medications are at risk for skin cancer and internal malignancies. All patients on biological therapy should be closely monitored by their health care provider(s).