In 2017, Sanofi/Regeneron announced the FDA approval for the first biologic agent to treat atopic dermatitis (AD). The success of that drug, Dupixent (dupilumab), inspired competitors to scramble for a place in the AD market, with the second drug arriving nearly five years later. Sanofi/Regeneron followed with indications in asthma, chronic rhinosinusitis with nasal polyps, eosinophilic esophagitis (EoE) and most recently prurigo nodularis.

With EoE, it seems Sanofi/Regeneron has caught lightning in a bottle once again. The May 2022 approval of Dupixent for EoE opened the door to another untapped market, with the closest competitor entry likely several years away.

Physician caseload data from Spherix Global Insights suggests the EoE market is currently half the size of the inflammatory bowel disease (IBD) market, with evidence that the market is poised for even further growth given the current number of EoE patients that go undiagnosed. Indeed, gastroenterologists and allergists (n=125) surveyed as part of Spherix's Market Dynamix: EoE series, estimate that nearly half of all EoE patients are currently undiagnosed.

Spherix has been tracking the launch of Dupixent via their Launch Dynamix™ advisory series and data from March reveals Dupixent use tripling since its launch, with the majority of EoE treaters report Dupixent as a moderate to substantial advance over prior treatment options.  Furthermore, prescribers express a high degree of satisfaction with Dupixent when treating EoE.  

Despite physicians' favorable response, nearly all feel the level of unmet need for treating EoE remains high. Both gastroenterologist and allergists feel more options are needed; however, they differ slightly on which options might be more attractive. Of the two broad classes of therapies under development, additional biologic agents and novel steroids, gastroenterologists lean toward steroid options to a slightly higher degree, while allergist favor biologics.

Both options present unique benefits for doctors. While EoE is largely understood to be an eosinophil driven disease, a number of additional inflammatory factors are implicated, including interleukin (IL)-5 expressing T cells, B cells, eotaxin-3, IL-13, and IgE-bearing mast cells. 

Doctors interviewed by Spherix refer to biologics as a targeted, "rifle like," approach to treatment delivering strong efficacy while reducing risk of side effects. Steroids act more broadly, described as a "shotgun" approach to lowering inflammatory agents.

Gastroenterologists who spoke with Spherix speculated the broader inflammatory pathways at play in EoE might have been one of the factors implicated in AstraZeneca's recent failed EoE trial (MESSINA) for benralizumab. While one co-primary endpoint was achieved (histologic reduction of eosinophils), the second (improvement in swallowing) was not. In a contrasting opinion, several allergists speculated the outcome might have been a factor of treatment timing, suggesting targeted biologics may be more suited earlier in the treatment pathway.  It is possible that biologics and steroids evolve to a complimentary role as physicians learn how best to use each tool in managing the chronic inflammatory condition. Much like asthma, EOE may be managed with chronic therapy but occasionally require acute flare control.

Two candidates in development, BMS's cendakimab and Ellodi's APT-1011, are currently the leading agents vying for second-to-market status. When shown published data on each agent, APT-1011 was slightly favored by gastroenterologists, while allergists viewed each equally. Of note, Takeda abandoned their EoE agent, TAK-721, a competing oral steroid to Ellodi's asset, after the FDA issued a Complete Response Letter in late 2022.

Spherix will continue to track the performance of Dupixent's launch for the first eighteen months on the market. Performance to date suggests Dupixent will continue to carve out a commanding ownership of the advanced treatment market in EoE, while also paving the way for future competitors to meet the needs of this underserved, growing market.