One Subcutaneous 2-ml Injection of Mirikizumab is Bioequivalent to Two 1-ml Subcutaneous Injections in Healthy...

Mirikizumab, an anti-interleukin-23 p19 monoclonal antibody, is approved for treating adults with moderately to severely active ulcerative colitis and Crohn's disease. For ulcerative colitis maintenance therapy, mirikizumab is administered via two 1-ml subcutaneous (SC) injections. Volume and number of SC administrations can impact injection site reactions and local pain, as well as treatment compliance. We assessed the pharmacokinetic (PK) and safety comparability of an investigational one 2-ml SC injection compared with the commercially available two 1-ml SC injections.

In this phase 1 study, USA-based healthy adults were stratified by weight and randomized (1:1) to receive citrate-free 200 mg SC mirikizumab as either two 1-ml injections (each 100 mg) or one 2-ml (200 mg) injection, delivered by an autoinjector. Participants in each arm were subrandomized by injection site location (arm, abdomen, or thigh). Blood sampling and safety assessments were conducted up to 10 weeks post dose. The primary endpoint was PK, and the secondary endpoint was safety.

A total of 244 participants received one injection and 240 received two injections (mean age 42.5 years; 51.0% female). Baseline characteristics were similar in both groups. Primary PK parameters fell within the bioequivalence range (geometric least-squares mean [GLSM] ratio 0.800-1.250). Observed GLSMs were consistent across injection site locations. Treatment-emergent adverse events were reported in 48 participants with one injection (19.7%) and 55 with two injections (22.9%); most were mild (62/74 events with one injection [83.8%] and 85/100 with two injections [85.0%]). No serious adverse events were reported in either group.

Mirikizumab 200 mg administered as one 2-ml SC injection was bioequivalent to two 1-ml injections, and most treatment-emergent adverse events were mild in both groups. In clinical practice, reducing the number of injections may improve treatment adherence.

ClinicalTrials.gov identifier NCT06475729.