TREMFYA - Overview of the AFFINITY Clinical Trial

SUMMARY

• The company cannot recommend any practices, procedures, or usage that deviate from the approved labeling.
• AFFINITY was a phase 2a, multicenter, randomized, double-blind, active-controlled, proof-of-concept study designed to evaluate the efficacy and safety of subcutaneous (SC) TREMFYA and SC golimumab combination treatment vs SC TREMFYA monotherapy in adult patients with active psoriatic arthritis (PsA) and an inadequate response to 1 or 2 tumor necrosis factor inhibitors (TNFis).¹
  • At week 24 (primary endpoint), 29% vs 22% of patients in the TREMFYA and golimumab group vs the TREMFYA group, respectively, achieved minimal disease activity (MDA) response (odds ratio [OR], 90% confidence interval [CI], 1.4 [0.6, 3.3]); P=0.557).
  • Through week 24, adverse reactions (AEs) and infection rates were reported as follows:
    • AEs occurred in 66% (39/59) and 56% (18/32) of patients in the TREMFYA and golimumab group and the TREMFYA group, respectively.
    • Infection rates were reported at 32% (19/59) and 38% (12/32) of patients in the TREMFYA and golimumab group and the TREMFYA group, respectively.
  • During the week 24 to week 36 safety follow-up, no deaths, serious AEs, serious infections, tuberculosis, or opportunistic infections occurred.
    • There were 3 additional patients in the TREMFYA and golimumab combination group who reported AEs. There was also, one additional case of infection in the TREMFYA monotherapy group during this timeframe.

CLINICAL DATA

Scher et al (2026)¹ reported week 24 results from the AFFINITY study. The study was a phase 2a, multicenter, randomized, double-blind, active-controlled, proof-of-concept study designed to evaluate the efficacy and safety of SC TREMFYA and SC golimumab as a combination treatment vs SC TREMFYA monotherapy in adult patients with active PsA and inadequate response to 1 or 2 TNFis.

Study Design/Methods

• Key inclusion criteria are as follows:
  • Adult patients (18 to 65 years of age) with a diagnosis of PsA for ≥6 months prior to the first study intervention and met the ClASsification Criteria for Psoriatic ARthritis (CASPAR) at screening.
  • Presence of active PsA (≥3 swollen joint counts and ≥3 tender joint counts).
  • Presence of active plaque psoriasis (PsO) (≥1 psoriatic plaque of ≥2 centimeters diameter or nail changes consistent with PsO).
  • Inadequate response to TNFi therapy, defined as the presence of active PsA despite treatment with either 1 or 2 TNFi(s) and the following:
    • Lack of benefit in response to ≥12 weeks of etanercept, adalimumab, or certolizumab pegol therapy (or their biosimilars) or ≥14 weeks of infliximab or any biosimilar therapy.
    • The last dose of TNFi therapy must have been administered >5 half-lives before starting study treatment.
  • Presence of ≥1 of the PsA subsets (distal interphalangeal joint involvement, polyarticular arthritis with absence of rheumatoid nodules, asymmetric peripheral arthritis, or spondylitis with peripheral arthritis).
  • Presence of C-reactive protein (CRP) ≥0.3 mg/dL at baseline as an initial inclusion requirement with a protocol amendment to allow up to 10% of patients with CRP <0.1 mg/dL due to enrollment challenges from the impact of the Ukraine/Russia crisis.
• Key exclusion criteria include prior exposure to either TREMFYA or golimumab, administration of >2 prior TNFis (or biosimilars), or administration of any biologic treatments other than a TNFi.
• The total duration of the study was 42 weeks and included a screening phase (up to 6 weeks), double-blind phase from weeks 0 to 24, and a safety follow-up phase from week 24 to week 36.
• Eligible patients were randomized into 2 groups (group 1: SC TREMFYA and SC golimumab; and group 2: SC TREMFYA and SC placebo), See Figure: Overview of Study Design.

• All P-values, except for week 24 MDA response (primary endpoint), are nominal. These endpoints were not adjusted for multiple comparisons. Therefore, these P-values displayed are nominal, and statistical significance has not been established.
• The efficacy and safety outcomes to be evaluated in this trial are summarized in Table: Efficacy and Safety Outcomes

Results

Baseline Characteristics

• A total of 91 patients were included in the study; 92% (54/59) of patients receiving TREMFYA and golimumab combination treatment and 88% (28/32) of patients receiving TREMFYA completed the study through week 24.
• For baseline characteristics, see Table: Selected Baseline Demographics and Characteristics.

Efficacy

• For the primary endpoint at week 24, 29% of patients in the TREMFYA and golimumab group vs 22% of patients in the TREMFYA group achieved MDA response (OR [90% CI], 1.4 [0.6, 3.3]; P=0.557).
• At week 16 (secondary endpoint), 32% of patients in the TREMFYA and golimumab group vs 12% of patients in the TREMFYA group achieved MDA response (P=0.056; Nominal P value. This endpoint was not adjusted for multiple comparisons. Therefore, the P-value displayed is nominal, and statistical significance has not been established).
• Selected secondary endpoints at week 24 are described in Table: Summary of Selected Secondary Endpoints at Week 24.

Safety

• For a summary of AEs in the AFFINITY study through week 24, see Table: Summary of AEs through Week 24.

• From week 24 to the week 36 safety follow-up, no deaths, serious adverse events (SAEs), serious infections, tuberculosis, or opportunistic infections occurred.
  • There were 3 additional patients in the TREMFYA and golimumab combination group who reported AEs. There was also one additional case of infection in the TREMFYA monotherapy group during this timeframe.

Literature Search

A literature search of MEDLINE^®, Embase^®, BIOSIS Previews^®, DERWENT^® (and other resources, including internal/external databases) was conducted on 17 June 2026.