Objective:

To characterize early adopters of subcutaneous (SC) neonatal receptor (FcRn) blockers efgartigimod alfa and hyaluronidase (SC efgartigimod) and rozanolixizumab, approved for generalized myasthenia gravis (gMG).

Background:

Monthly survey fielded by an independent market intelligence agency specializing in tracking neurological therapeutic markets, including benchmarking new product launch metrics.

Design/Methods:

Online survey fielded in October 2023, approximately two months after SC efgartigimod and rozanolixumab availability, among 65 US neurologists and neuromuscular specialists.

Results:

42% of surveyed neurologists reported prescribing either SC efgartigimod, rozanolixizumab, or both products within the first two months of commercial availability ("early adopters").

Early adopters reported significantly higher patient shares for originator FcRn blocker IV efgartigimod than non-adopters (11.3% vs 3.6%). Early adopters were more likely than non-adopters to rate themselves as highly familiar with SC efgartigimod (8.1 for adopters, 6.8 for non-adopters on 10-point scale) and to rate both SC FcRn blockers as a significant advance over other agents to treat gMG (7.6 vs 6.4 [SC efgartigimod], 7.1 vs 5.9 [rozanolixizumab]). They were more likely than non-adopters to view more of their patients as candidates for SC efgartigimod (23.4% vs 14.7%).

Early adopters rated market access as significantly better for both SC products than non-adopters (6.8 vs. 4.4; 6.0 vs 4.0). They also were more likely to have a positive perception of launch execution for both SC products (7.7 vs 6.3; 6.7 vs 5.1).

gMG patient load and past month sales representative contact did not significantly differ between early adopters and non-prescribers.

Conclusions:

Prior use of IV efgartigmod may have increased comfort with SC FcRn products, leading to faster uptake and more positive perceptions of both brands across degree of advance, market access, and launch execution.