Concerns and Side Effects of Azathioprine During Adalimumab Induction and Maintenance Therapy for Japanese Patients With Crohn's Disease: A Subanalysis of a Prospective Randomised Clinical Trial [DIAMOND Study]

BACKGROUND

Combining a thiopurine with the human anti-tumour necrosis factor-α monoclonal antibody adalimumab for Crohn's disease [CD] treatment is controversial with regard to efficacy and safety. By conducting a subanalysis of a multicentre, randomised, prospective, open-label trial [the DIAMOND study, UMIN registration number 000005146], we studied the risk of discontinuation of thiopurine in combination with adalimumab.

METHODS

In the preceding DIAMOND study, we analysed the: [i] timing and reasons for dropout in the monotherapy group and combination group; [ii] risk factors for dropout in the combination group.

RESULTS

There was no significant difference in the dropout rate up to Week 52 between the monotherapy group and combination group [p = 0.325]. The main reason for study dropout was active CD in the monotherapy group, whereas it was adverse effects in the combination group [Fisher's exact test, p <0.001]. Kaplan-Meier analyses revealed significantly earlier dropout in the combination group [log-rank test, p = 0.001]. Multivariable analysis revealed low body weight to be a risk for dropout due to adverse effects in the combination group.

CONCLUSIONS

Combination of azathioprine with adalimumab resulted in dropout in the early stage of the study due to side effects of azathioprine, in comparison with late dropout due to active CD in the adalimumab monotherapy group.

Safety of Infliximab for the Eye Under Human T-Cell Leukemia Virus Type 1 Infectious Conditions in vitro

Use of biologics has been widely advocated for inflammatory diseases recently. Anti-tumor necrosis factor (TNF)-α antibody therapy is reportedly effective against ocular inflammation. However, side effects of TNF-α inhibition have been reported, particularly in the form of exacerbation of infections such as tuberculosis. Paradoxical reactions such as exacerbated inflammation are also well known. Around 20 million humans are infected with human T-cell leukemia virus type 1 (HTLV-1) globally, and this virus can cause adult T-cell leukemia, HTLV-1-associated myelopathy and HTLV-1 uveitis. As for ophthalmic concerns, it has not been identified whether anti-TNF-α antibody stimulates HTLV-1-infected cells and ocular cells to induce HTLV-1 uveitis in HTLV-1 carriers. Here we investigated the effects of anti-TNF-α antibody on ocular status under HTLV-1 infectious conditions using ocular cells and HTLV-1-infected cells in vitro. We used the ARPE-19 human retinal pigment epithelial cell line as ocular cells considered to play an important role in the blood-ocular barrier, and the MT2 HTLV-1-infected cell line. Jurkat cells were used as controls. Infliximab (IFX) was used as an anti-TNF-α antibody to achieve TNF-α inhibition. We evaluated the production of inflammatory cytokines and intercellular adhesion molecule (ICAM)-1, proliferation of ARPE-19, expression of TNF-α receptor (TNF-R) and HTLV-1 proviral DNA, and the percentage of apoptotic ARPE-19. Inflammatory cytokines such as interleukin (IL)-6, IL-8, TNF, and ICAM-1 were significantly elevated through contact between ARPE-19 and MT2. Treatment with IFX tented to inhibit TNF production, although the level of production was low, but changes in IL-6, IL-8, and ICAM-1 remained unaffected. Expression of TNFR was unaltered by IFX treatment. HTLV-1 proviral DNA was not significantly changed with treatment. No change in cell growth rate or apoptotic rate of ARPE-19 was seen with the addition of IFX. In conclusion, IFX did not exacerbate production of inflammatory cytokines, and did not affect expression of TNFR, proliferation of ARPE-19, HTLV-1 proviral load, or apoptosis of ARPE-19. These results suggest that IFX does not exacerbate HTLV-1-related inflammation in the eye and represents an acceptable treatment option under HTLV-1 infectious conditions.

Adalimumab Monotherapy and a Combination with Azathioprine for Crohn's Disease: A Prospective, Randomized Trial

BACKGROUND AND AIMS

The efficacy of azathioprine for Crohn's disease under adalimumab treatment remains obscure.

METHODS

In an open-labelled prospective study, we evaluated the efficacy of adalimumab with and without azathioprine in patients with active Crohn's disease, who were naïve to biologics and thiopurines. The patients were randomly assigned to subcutaneous administration of adalimumab [monotherapy group] or to exactly the same schedule of adalimumab with azathioprine [25-100mg daily] [combination group] for 52 Weeks. The primary endpoint was clinical remission at WWeek 26. We also evaluated the score for simple endoscopic severity of Crohn's disease before the therapy and at WWeeks 26 and 52.

RESULTS

A total of 176 patients were randomized to either the monotherapy group [n = 85] or to the combination group [n = 91]. Eighteen patients [21.2%] from the monotherapy group and 7 patients [7.7%] from the combination group withdrew owing to active disease, and 15 patients [16.5%] from the combination group and 1 patient [1.2%] from the monotherapy group withdrew due to side effects of the medications. Non-responder imputation analysis revealed that the remission rate at WWeek 26 did not differ between the monotherapy group and the combination group [71.8% vs 68.1%; OR 0.84, p = 0.63]. The rate of endoscopic improvement at WWeek 26 was significantly higher in the combination group [84.2%, n = 57] than in the monotherapy group [63.8%, n = 58] [p = 0.019].

CONCLUSION

The clinical efficacy of a combination of adalimumab and azathioprine at WWeek 26 did not differ from that of adalimumab monotherapy in patients with Crohn's disease naïve to both medications.