MRI and Dose Selection in a Phase II Trial of Baricitinib with Conventional Synthetic Disease-modifying Antirheumatic Drugs in Rheumatoid Arthritis

Novel quantitative digital image analysis methodology for assessment of inflammatory changes in MRI data in a post-hoc analysis of data acquired from a phase IIb study of baricitinib in patients with active rheumatoid arthritis

PURPOSE

To evaluate a novel quantitative methodology to assess inflammatory changes in magnetic resonance imaging (MRI) data from patients with rheumatoid arthritis (RA) and the impact of image quality on imaging outcomes compared to the RA Magnetic Resonance Imaging Score (RAMRIS).

METHODS

Three-dimensional, T1-weighted, fat-suppressed MRI sequences of the hand/wrist before and after intravenous Gadolinium contrast from patients with RA in a placebo-controlled clinical trial (NCT01185353) were re-evaluated post hoc. The methodology was integrated into proprietary software (DYNAMIKA®) and assessed inflammation through pixelated measurements of the contrast-enhancing (inflammatory) volume. A semi-automatic approach outlined contrast-enhancing synovial tissue in the wrist and second to fifth metacarpophalangeal joints with a rough region of interest (ROI); quantitative imaging biomarkers were generated by means of quantitative total volume of inflammation and quantitative degree of inflammation relative to the signal in a 1 cm in diameter ROI in the center of the thenar or lumbrical muscle for internal reference. The time from Gadolinium injection to finalization of the post-contrast images was calculated from the images' Digital Imaging and Communications in Medicine header. An experienced reader graded image quality as poor, acceptable, or good.

RESULTS

Results from this quantitative methodology, especially when excluding images with poor quality scores (14-32%), provided a more pronounced and monotonically increasing dose-response than the original RAMRIS results on synovitis and osteitis.

CONCLUSIONS

This computer-aided quantitative scoring method provided continuous measures of inflammatory changes relative to muscle and may be more sensitive and interpretable concerning dose/response separation between RA treatment groups.

Baricitinib inhibits structural joint damage progression in patients with rheumatoid arthritis-a comprehensive review

Baricitinib is an oral selective inhibitor of Janus kinase (JAK)1 and JAK2 that has proved effective and well tolerated in the treatment of rheumatoid arthritis (RA) in an extensive programme of clinical studies of patients with moderate-to-severe disease. In a phase 2b dose-ranging study of baricitinib in combination with traditional disease-modifying antirheumatic drugs (DMARDs) in RA patients, magnetic resonance imaging showed that baricitinib 2 mg or 4 mg once daily provided dose-dependent suppression of synovitis, osteitis, erosion and cartilage loss at weeks 12 and 24 versus placebo. These findings correlated with clinical outcomes and were confirmed in three phase 3 studies (RA-BEGIN, RA-BEAM and RA-BUILD) using X-rays to assess structural joint damage. In patients naïve to DMARDs (RA-BEGIN study), baricitinib 4 mg once daily as monotherapy or combined with methotrexate produced smaller mean changes in structural joint damage than methotrexate monotherapy at week 24. Differences versus methotrexate were statistically significant for combined therapy. In patients responding inadequately to methotrexate (RA-BEAM study), baricitinib 4 mg plus background methotrexate significantly inhibited structural joint damage at week 24 versus placebo, and the results were comparable to those observed with adalimumab plus background methotrexate. In patients responding inadequately to conventional synthetic DMARDs (csDMARDs; RA-BUILD study), baricitinib 4 mg again significantly inhibited radiographic progression compared with placebo at week 24. Benefits were also observed with baricitinib 2 mg once daily, but the effects of baricitinib 4 mg were more robust. The positive effects of baricitinib 4 mg on radiographic progression continued over 1 and 2 years in the long-term extension study RA-BEYOND, with similar effects to adalimumab and significantly greater effects than placebo. Findings from the phase 3 studies of patients with RA were supported by preclinical studies, which showed that baricitinib has an osteoprotective effect, increasing mineralisation in bone-forming cells. In conclusion, baricitinib 4 mg once daily inhibits radiographic joint damage progression in patients with moderate-to-severe RA who are naïve to DMARDs or respond inadequately to csDMARDs, including methotrexate, and the beneficial effects are similar to those observed with adalimumab.

Tyrosine kinase inhibitors for the treatment of rheumatoid arthritis: phase I to Ⅱ clinical trials

Introduction: Rheumatoid arthritis (RA) is a chronic, refractory disorder caused by autoimmunity in the synovial joints. Disease-modifying anti-rheumatic drugs (DMARDs) and biologicals offer remission in only two-thirds of RA patients within 3 months, hence new therapeutic approaches are necessary. Tyrosine kinase inhibitors (TKIs) are newly developed small molecule drugs which have demonstrated encouraging results in this disease.Areas covered: The key findings from phase I and II clinical trials that have investigated the use of novel TKIs in the treatment of RA are discussed. We examined the literature published between January 2014 to January 2019 using electronic databases including PubMed, Web of Science, Medline, Embase, and Google Scholar. Additional information about phase I and II trials on the ClinicalTrial.gov website up to January 2019 was also retrieved.Expert opinion: JAK inhibitors are promising drugs with sound efficacy and acceptable safety and may be beneficial to patients who do not respond to DMARDs and biologicals. The response rates among RA patients to TKIs are diverse; genetic and environmental factors may be involved in the varying responses which are closely related to the pathogenesis of RA. Future studies may reveal the underlying mechanisms of resistance and non-response.