Trial results for a Phase 4 study (NCT03505008) investigating adalimumab with methotrexate for rheumatoid arthritis were posted on ClinicalTrials.gov on 2025-03-06. The study compared two methotrexate dosing strategies as add-on therapy to adalimumab and found a risk difference of 0.0 between the groups for a key outcome.
Background
This study aimed to evaluate the optimal dosage of methotrexate (MTX) as an add-on therapy to adalimumab in participants with rheumatoid arthritis who had not achieved remission by MTX monotherapy.
Trial design
The study (NCT03505008) was a Phase 4, completed trial that enrolled 300 participants across Japan, South Korea, and Taiwan. The trial investigated adalimumab in combination with methotrexate for participants with rheumatoid arthritis. Participants were divided into two groups: an ADA/MTX-Maximum Tolerated Dose Group and an ADA/MTX-Reduced Dose Group, to compare the efficacy of different methotrexate dosages as add-on therapy.
Key results
The trial results compared outcomes between the ADA/MTX-Maximum Tolerated Dose Group and the ADA/MTX-Reduced Dose Group at Week 48.
- For the Simple Disease Activity Index (SDAI) Remission Rate at Week 48 in mFAS, 25 Participants were in remission in the Maximum Tolerated Dose Group, compared to 27 Participants in the Reduced Dose Group.
- For the Simple Disease Activity Index (SDAI) Remission Rate at Week 48 in PPS, 23 Participants were in remission in the Maximum Tolerated Dose Group, compared to 27 Participants in the Reduced Dose Group.
- The American College of Rheumatology (ACR) 20 Response Rate at Week 48 showed 47 Participants in both the Maximum Tolerated Dose Group and the Reduced Dose Group.
- For the ACR 50 Response Rate at Week 48, 36 Participants were in the Maximum Tolerated Dose Group, compared to 38 Participants in the Reduced Dose Group.
- The ACR 70 Response Rate at Week 48 showed 22 Participants in the Maximum Tolerated Dose Group, compared to 26 Participants in the Reduced Dose Group.
- Regarding the Health Assessment Questionnaire - Disability Index ≤0.5 at Week 48, 40 Participants in the Maximum Tolerated Dose Group achieved this, compared to 41 Participants in the Reduced Dose Group.
A key analysis indicated a Risk Difference (RD) of 0.0 between the groups, with a 90.0% confidence interval, suggesting no significant difference in the measured outcome between the two dosing strategies.
What this means
The findings from this Phase 4 study suggest that there is no significant difference in key efficacy outcomes, such as SDAI remission rates and ACR response rates, between a maximum tolerated dose and a reduced dose of methotrexate when used as an add-on therapy to adalimumab for patients with rheumatoid arthritis who have not achieved remission with MTX monotherapy. This outcome, particularly the 0.0 risk difference, could imply that a reduced methotrexate dose may offer comparable efficacy to a maximum tolerated dose in this patient population, potentially allowing for strategies to minimize methotrexate-related side effects without compromising treatment effectiveness.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT03505008, titled "Evaluation of the Optimal MTX Dose as an Add-on Therapy to Adalimumab for RA Patients in Japan, South Korea and Taiwan," were posted on 2025-03-06 on clinicaltrials.gov.