Immunology programs

Izokibep

Clinical efficacy in multiple autoimmune diseases

Izokibep is being developed as a best-in-class treatment for several autoimmune diseases that are driven by the protein IL-17. Izokibep has a unique ability to reach the affected tissues, where it binds IL-17A selectively and with high affinity – 10 to 100 times stronger than the current leading IL-17 inhibiting antibody drugs.

The development program for izokibep has generated compelling efficacy and safety data, and izokibep has already been studied in more than 1,000 patients, in some for as long as three years. Positive Phase 3 studies in hidradenitis suppurativa (HS) and psoriatic arthritis (PsA) demonstrate levels of clinical response comparable with next generation approaches to IL-17 inhibition. They further show that targeting IL-17A alone with greater potency can achieve the same or better clinical responses than agents targeting IL-17 subunits more broadly, without their associated safety liabilities. The results support a clear path to approval for izokibep.

Izokibep in hidradenitis suppurativa

HS is a chronic inflammatory disease that affects hair follicles in skin areas with a high concentration of sweat glands. The disease produces recurrent painful varicose ulcers, mainly in the armpits, groin, and the area around the anus. The treatment consists mainly of analgesics, antibiotics, and, in severe cases,
surgery and/or biologics.

Izokibep has demonstrated best-in-class efficacy and safety results in a Phase 3 clinical study in patients with moderate to severe HS. The study was a global, double-blind, placebo-controlled, trial comprising 258 patients. The study achieved its primary endpoint of HiSCR75 at 12 weeks versus placebo, as well as the key secondary endpoints of HiSCR90 and HiSCR100. Data from week 16 and week 32 further demonstrated deepening of responses with izokibep over time. No new safety signals were identified, and the favorable safety profile demonstrated in previous trials was confirmed.

Izokibep in psoriatic arthritis

PsA occurs in patients with psoriasis whose condition develops to include inflammation of the joints. Such patients are currently treated with NSAIDs or immunosuppressive drugs and more severe cases with biologics and JAK inhibitors.

Izokibep has achieved compelling results in a Phase 2b/3 clinical study in patients with moderate to severe PsA. The study was a global, double-blind, placebo-controlled, trial comprising 351 patients. The primary endpoint of ACR50 at 16 weeks versus placebo was met with high statistical significance. Robust clinical responses were also achieved for ACR70, PASI100, as well as the composite endpoints ACR50/PASI100 and Minimal Disease Activity. Week 52 data showed continued improvement over time. Izokibep was well-tolerated with a favorable safety profile.

Izokibep in axial spondyloarthritis

Axial spondyloarthritis (axSpA) is an autoimmune disease that affects the spine, as well as joints in other parts of the body causing severe pain and reduced mobility. Izokibep has clear potential to be efficacious in axSpA given the strong results in PsA, which is a closely related disease.

Izokibep in psoriasis

Psoriasis is an autoimmune disease characterized by thickened, reddened, and clearly defined patches in the skin.

Izokibep has been evaluated in a double-blind, placebo-controlled Phase 2 study in 108 patients diagnosed with moderate to severe psoriasis. The treatment results indicated a competitive efficacy and safety profile for izokibep, which was confirmed with 3-year extension data. The study was published in the British Journal of Dermatology (BJD) in September 20231.

RLYB116

Affibody’s licensee Rallybio, a US-based biotech company, is developing the drug candidate RLYB116 which acts by inhibiting the activation of complement factor 5 (C5) in the complement cascade, which is part of the immune system. When erroneously triggered, the complement system may give rise to severe
diseases, such as immune platelet transfusion refractoriness (PTR), refractory antiphospholipid syndrome (APS), paroxysmal nocturnal hemoglobinuria (PNH) and generalized myasthenia gravis (gMG).

Rallybio has presented positive results from a Phase 1 single ascending dose (SAD) study and from a Phase 1 multiple ascending dose (MAD) study in healthy subjects. The results showed that a single 100 mg subcutaneous dose of RLYB116 induced a more than 99% reduction in free C5 and that a 100 mg
once-a-week dose obtained a sustained reduction in free C5 and was observed to be generally well tolerated.

In February 2026, Rallybio announced positive results from a confirmatory pharmacokinetic/pharmacodynamic (PK/PD) clinical Phase 1 study demonstrating that a 300 mg once-a-week dose of subcutaneously administered RLYB116 achieved complete and sustained inhibition of terminal complement and was well tolerated.

ABY-062

Unlike antibody drugs, which must be given as an injection or infusion, Affibody^® molecules can be developed for inhalation. This offers major advantages in the treatment of lung diseases. Affibody is developing the drug candidate ABY-062, which inhibits the protein TSLP – a key factor in the inflammatory process that causes and exacerbates asthma and chronic obstructive pulmonary disease (COPD). Preclinical data show that inhaled ABY-062 is absorbed into the respiratory tract at concentrations that are expected to be clinically efficacious. The drug candidate is currently in preclinical development ready for FiH studies. 

Collaboration with Chiesi to address respiratory diseases

Affibody and the multinational pharma company Chiesi have a collaboration to discover and develop novel Affibody^® molecules as innovative treatments for respiratory diseases.