A Bristol Myers Squibb drug that was first in its class to hit a certain immunological target now has positive data from two pivotal tests in psoriatic arthritis that could support expanding use of the product to this inflammatory autoimmune condition.

Expanding approval of the drug, Sotkytu, to include psoriatic arthritis would grow revenue for a product that so far has fallen short of the blockbuster expectations that followed its 2022 approval in plaque psoriasis. Meanwhile, competition is heating up as competitors make headway with their own drug candidates for the target, an enzyme called TYK2.

Psoriatic arthritis is an autoimmune disease that leads to painful swelling in joints and ligaments as well as skin lesions. First-line treatment includes disease-modifying antirheumatic drugs, both small molecules and biologics. For those whose disease does not respond to these therapies, a class of drugs called Janus kinase (JAK) inhibitors offer another treatment option. BMS' Sotyktu could bring patients another option, and a potentially earlier one that also has a better safety profile.

BMS said Monday that its TYK2 inhibitor met the main goal of two Phase 3 tests in active psoriatic arthritis, one that enrolled patients where were not previously treated with a disease-modifying antirheumatic drug and the other with patients who previously received TNF-alpha inhibitors, drugs from an older class of biologic medicines whose approved uses include treating psoriatic arthritis.

Without releasing specific figures for the pair of 16-week studies, BMS said a significantly greater proportion of those treated with its drug achieved a 20% improvement or greater according to a composite measure of the signs and symptoms of the chronic autoimmune disorder. Also, the once daily pill met a key secondary goal measuring disease activity at week 16.

TYK2, which is closely related to JAK proteins, is involved in signaling pathways associated with inflammation. Hitting TYK2 while avoiding JAKs is intended to be safer. The risks of hitting JAK proteins include cardiovascular and cancer complications. These risks are now flagged in a black box warning for the entire JAK inhibitor drug class. The FDA approved JAK-blocking drugs for psoriatic arthritis are Pfizer's Xeljanz and AbbVie's Rinvoq.

JAK inhibitors were not used as a comparator in BMS's placebo-controlled psoriatic arthritis tests, named POETYK PsA-1 and POETYK PsA-2. On measures of safety, BMS said the latest results are consistent with Sotyktu's established safety profile from earlier clinical trials. In the pivotal study that led to the drug's approval as a treatment for moderate-to-severe plaque psoriasis, the most common adverse event was upper respiratory tract infection. The company said it will work with clinical trial investigators to present detailed study results at upcoming medical conferences.

"These POETYK PsA-1 and POETYK PsA-2 findings demonstrate that oral Sotyktu has the potential to be the first TYK2 inhibitor for people living with psoriatic arthritis and reinforce the established efficacy and safety profile of Sotyktu, Roland Chen, BMS's senior vice president and head, immunology, cardiovascular and neuroscience development, said in a prepared statement. "We are encouraged by the positive data across both Phase 3 trials and look forward to discussing the results with health authorities."

With the latest data in psoriatic arthritis, BMS is trying to fend off competition. Takeda Pharmaceutical's zasocitinib (formerly known as TAK-279), acquired in a $4 billion deal, has reached Phase 3 testing in psoriasis and mid-stage clinical development in psoriatic arthritis, Crohn's disease, and ulcerative colitis. Startup Sudo Biosciences, which emerged from stealth in 2022, is developing TYK2 inhibitors for neuroinflammatory disorders.

BMS reported Sotyktu accounted for $163 million in revenue for the first nine months of 2024, a 52.3% increase compared to the same period in 2023. In addition to the psoriatic arthritis research, the drug has reached late-stage clinical development in Sjogren's syndrome and systemic lupus erythematosus.