Baird asked 33 neurologists about their perspectives on and use of Sarepta Therapeutics Inc.’s (NASDAQ:SRPT) Exondys 51 in the first quarter as a follow-up to a previous survey in November. Despite continued worry around the launch, docs estimate that prescribing has almost doubled since the firm’s last survey. Importantly, based on physicians' estimates, Exondys 51 could report around $17.5M in 1Q17, which would easily beat consensus of $13.8M.
The firm’s sample includes 13 "repeat respondents" from its November survey. The full sample of 33 neurologists treats ~6% of the U.S. DMD population, including >18% of exon 51 amenable patients.
Recall, Sarepta management indicated last year that up to 40% of DMD patients have not been genotyped, even at the larger centers, primarily due to the lack of available genotype-specific therapy. When Baird first surveyed neurologists in November, they too indicated that 42% of their patients had yet to be genotyped. This time, repeat respondents indicate that there was an increase in the genotyping rate of over 10%. This is encouraging, and suggests that now that there is a disease-modifying medication available, docs and patients are taking necessary steps to identify eligible patients.
In November, only 23% of the neurologists had started prescribing Exondys 51. This time the firm saw a modest increase to 30%, with a corresponding increase among repeat respondents. Within prescribers, the proportion of exon-51 amenable patients who have been prescribed increased, from 26% to 38%. By the end of 1Q17, surveyed docs indicated that they have prescribed Exondys 51 to 32 patients, up from 12, an over 167% increase on a percentage basis versus November.
After accounting for delays in initiating therapy due to ports being put in (~42% of patients, according to the firm’s survey) or reimbursement issues (79% of prescribed patients received coverage), docs estimated that 26 patients are on therapy, vs. eight in November. In November, docs estimated that by the end of 2016, they would have 15 patients on drug, meaning that 1Q17 could have seen ~70% growth in number of patients on therapy. Assuming $5.4M in 4Q16 represented only half a quarter of sales, 70% growth with a modest decline in price due to age mix would give Baird ~$17.5M for the first quarter. The firm is modeling $15.3M vs. consensus of $13.8 and guidance of $13M-$15M. However, it caveats these results by indicating that doc surveys are highly subject to variability and overestimation.