(288) Indirect treatment comparison of efgartigimod vs immunoglobulins in Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)

Background: : Immunoglobulins are standard of care for CIDP, a rare disease leading to demyelinating damage to peripheral nerves. Efgartigimod is a newly FDA-approved neonatal Fc receptor blocker for treating CIDP.

Objective: : As direct efficacy comparisons of the two treatments are not available, we have conducted an indirect treatment comparison (ITC).

Methods: : A systematic literature review (SLR) was conducted to identify evidence relevant for the research question, considering only clinical phase 3 trials. The results of the SLR were narrowed to EMA-authorized immunoglobulins for CIDP and to relevant endpoints. Among the studies that met the predefined criteria, an ITC was considered feasible against Hizentra (IgPro20) and HyQvia (fSCIg). The matching-adjusted indirect comparison method was chosen to control for heterogeneity in key patient characteristics.

Results: : The difference in I-RODS change from baseline was better for efgartigimod than IgPro20 (mean difference [95%CI]: 11.35 [3.00, 19.71, p=0.008, for low-dose; 9.35 [0.78, 17.93], p=0.033, for high-dose) and fSCIg (12.16 [2.67, 21.65], p=0.012).
The difference in aINCAT change from baseline was better for efgartigimod than low-dose IgPro20 and fSCIg (-1.13 [-2.05, -0.21], p=0.02; -0.88 [-1.72, -0.04]; p=0.04, respectively). In comparison vs. high-dose IgPro20, the change was not statistically significant (-0.58 [-1.45, 0.29]; p=0.19).
The difference in mean grip strength (MGS) change from baseline in the dominant hand was better for efgartigimod than high-dose IgPro20 (11.61 [0.14, 23.08]; p=0.047). In comparison vs. low-dose IgPro20, the difference was not statistically significant (8.14 [-2.29, 18.57]; p=0.13).
The difference in MGS change from baseline in the non-dominant hand vs. both doses of IgPro20 was not statistically significant (8.35 [-1.21, 17.90, p=0.09, for low dose; 9.30 [-1.04, -19.64], p=0.08, for high dose).
The difference in MRC Sum Score change from baseline vs. fSCIg was not statistically significant (2.83 [-0.82, 6.47], p=0.13). Time to aINCAT deterioration was comparable between efgartigimod and both IgPro20 and fSCIg.

Conclusions: : Despite the limitations of the analysis such as differences in baseline scores and limited comparability of the studies, the results of the ITC indicates that efgartigimod might have a comparable or slightly better efficacy profile than EMA-approved subcutaneous immunoglobulins. Further prospective comparative studies are needed to confirm these results.

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