<p><b>PURPOSE: </b>To investigate immune tolerance induction with transient low-dose methotrexate (TLD-MTX) initiated with recombinant human acid α-glucosidase (rhGAA), in treatment-naïve cross-reactive immunologic material (CRIM)-positive infantile-onset Pompe disease (IOPD) patients.</p><p><b>METHODS: </b>Newly diagnosed IOPD patients received subcutaneous or oral 0.4 mg/kg TLD-MTX for 3 cycles (3 doses/cycle) with the first 3 rhGAA infusions. Anti-rhGAA IgG titers, classified as high-sustained (HSAT; ≥51,200, ≥2 times after 6 months), sustained intermediate (SIT; ≥12,800 and <51,200 within 12 months), or low (LT; ≤6400 within 12 months), were compared with those of 37 CRIM-positive IOPD historic comparators receiving rhGAA alone.</p><p><b>RESULTS: </b>Fourteen IOPD TLD-MTX recipients at the median age of 3.8 months (range, 0.7-13.5 months) had a median last titer of 150 (range, 0-51,200) at median rhGAA duration ~83 weeks (range, 36-122 weeks). One IOPD patient (7.1%) developed titers in the SIT range and one patient (7.1%) developed titers in the HSAT range. Twelve of the 14 patients (85.7%) that received TLD-MTX remained LT, versus 5/37 HSAT (peak 51,200-409,600), 7/37 SIT (12,800-51,000), and 23/37 LT (200-12,800) among comparators.</p><p><b>CONCLUSION: </b>Results of TLD-MTX coinitiated with rhGAA are encouraging and merit a larger longitudinal study.</p>
Z. B. Kazi, Desai, A. K., R Troxler, B., Kronn, D., Packman, S., Sabbadini, M., Rizzo, W. B., Scherer, K., Abdul-Rahman, O., Tanpaiboon, P., Nampoothiri, S., Gupta, N., Feigenbaum, A., Niyazov, D. M., Sherry, L., Segel, R., McVie-Wylie, A., Sung, C., Joseph, A. M., Richards, S., and Kishnani, P. S., “An immune tolerance approach using transient low-dose methotrexate in the ERT-naïve setting of patients treated with a therapeutic protein: experience in infantile-onset Pompe disease.”, Genet Med, vol. 21, no. 4, pp. 887-895, 2019.