For patients suffering the misery of severe hidradenitis suppurativa, the new biological agents can prove “life-changing”.
But their benefit does come with strings attached, says dermatologist Associate Professor Saxon Smith from the Dermatology and Skin Cancer Centre in NSW.
The inclusion of adalimumab on the PBS for the treatment of hidradenitis suppurativa, believed to be the first of many biologics and biosimilars to be listed on the PBS for the same indication represents a major advance in the management of a condition which has been a challenge to treat in the past.
“If you want a horrendous condition that is painful, weeping, socially debilitating and just horrible to have, this is probably your number one guy,” Professor Smith said.
Characterised by nodules and abscesses in areas such as the armpits and groin, these patients often “bounce around for years” being told they just have recurrent boils.
However, the disease is inflammatory rather than infective, and as it progresses, the affected areas become weepy, smelly and painful, severely impacting patients’ quality of life. True prevalence in Australia is unknown, but the condition is thought to affect about 2% of the adult population, representing a huge unmet need, and it is at least twice as common in women as in men.
Consensus guidelines on management are currently being drafted but it is well established that lifestyle factors, specifically losing weight and quitting smoking are critical.
Antibiotic therapy is the next treatment of choice and to be eligible for biologic therapy patients need to have trialled (and failed) two oral antibiotics for at least three months each.
Other treatments include spironolactone, metformin, the OCP and finasteride, but the effectiveness of these has been limited.
Up until recently, the next available option was only really surgery, which is reserved for very severe cases and usually involves extensive excision and marsupialisation of the nodules and abscesses. It is still an option, but the newer biologic therapy will hopefully mean fewer people will progress to needing it.
Prior to commencing biologic therapy, patients need a full work up. As the biologic suppresses the immune system, they need to be certain that they are fully vaccinated against measles, mumps, rubella, hepatitis A and B and any other disease they might be likely to encounter that requires a live vaccine as these are contraindicated with the biologics, especially the TNFa inhibitors. They also have to be tested for latent TB (with Quantiferon Gold Tb) and if geographically appropriate, strongyloides.
As patients with chronic inflammatory skin conditions such as hidradenitis suppurativa are known to be at increased risk of cardiovascular disease – metabolic screening is also recommended.
Once treatment is commenced, patients need to be monitored for a wide range of possible adverse events from neutropenia to urticaria. It is not uncommon for patients to report more frequent episodes of sinusitis or rhinitis, and candidiasis both oral and genital is another common consequence, though this usually responds well to topical treatment.
But even with all the hoops and restrictions, the biologics are changing the face of treatment in the world of dermatology, particularly in the world of chronic disease and GPs are going to be managing more and more patients on these new agents, Professor Smith advised.
From the presentation, Working with the New Biologics for Skin Disease, by Associate Professor Saxon Smith at the GP Hot Topics evening seminar in Sydney in March 2018