In 2023, anti-inflammatory drugs comprised 27.9% of specialty plan spend across RxBenefits’ Book of Business, totaling more than $447 million. However, that figure dropped to 21.8% in 2024, due in large part to the launch of Humira biosimilars, which began reshaping the competitive landscape.

With Stelara biosimilars entering the market and formulary positioning in flux, anti-inflammatory spend may continue to shift, but remains a critical cost driver. Strategic formulary optimization and independent utilization management will be key to unlocking the potential savings these biosimilars offer.

2. Dermatology (psoriasis, atopic dermatitis, alopecia areata)

Dermatology overtook anti-inflammatory as the largest specialty drug class by spend in 2024, rising to 27% of total specialty plan spend – up from 24.1% in 2023. This increase was driven by newer biologics, expanding indications, and steady demand for chronic skin condition treatments.

With at least three new psoriasis treatments in Phase III trials and formulary dynamics evolving quickly, benefits advisors need to monitor whether new therapies displace – or layer on top of – existing high-cost medications. Without active formulary and clinical oversight, spend may continue to climb.

3. Oncology (targeted therapies and supportive care)

While biosimilars have helped reduce costs for supportive care drugs such as denosumab, the growth in high-cost targeted therapies and novel oncology treatments continues to outpace savings. Many new agents are tailored to small patient populations, but carry significant price tags.

Benefits advisors will need to help plan sponsors assess whether increased biosimilar use can meaningfully offset the growing budget impact of personalized cancer treatments. Expect oncology to remain a top driver of specialty spend for the foreseeable future.

4. Neurology and CNS (migraine, multiple sclerosis, narcolepsy)

Non-specialty neurologic medications – especially migraine therapies and narcolepsy agents – are gaining traction. However, cost concerns persist, and pharmacy benefits managers (PBMs) are evolving their classification strategies, with some agents being reclassified as specialty drugs.

Advisors should ensure their clients are keeping a close eye on classification and formulary changes that could shift member out-of-pocket responsibilities and plan liability. Utilization oversight and access balance will continue to be essential in CNS conditions.

5. GLP-1 Therapies (type 2 diabetes, weight management, and beyond)

As most advisors know, the rising popularity and utilization of GLP-1 receptor agonists has been one of the most impactful areas on client costs. Already highly popular in treating type 2 diabetes and obesity-related weight loss, they are no longer confined to those categories alone.

They are rapidly becoming central to treatment protocols across multiple disease states:

• Wegovy (semaglutide) has been approved to reduce the risk of major adverse cardiovascular events (MACE) – including death, heart attack, or stroke – in adults with cardiovascular disease and overweight or obesity.
• Zepbound (tirzepatide) received FDA approval in December 2024 for the treatment of moderate-to-severe obstructive sleep apnea (OSA) in adults with obesity.

Advisors must help plan sponsors prepare for broader PBM coverage mandates, escalating demand, and cost containment challenges. Clinical criteria, coverage policy design, and sourcing strategies will all play a role in managing this high-impact drug class.

Next steps

As therapeutic innovation accelerates and biosimilar availability expands, benefits advisors need to stay proactive and help their clients leverage formulary design, clinical oversight, and transparent analytics to ensure their pharmacy plan design aligns with their unique cost control and member health priorities.