On Thursday, Sanofi SA (NASDAQ:SNY) stock tumbled after late-stage trial results for amlitelimab, its potential successor to blockbuster eczema drug Dupixent, failed to match investor expectations, raising fresh doubts about the company’s ability to sustain its dermatology franchise once patent protections expire.
Results from the global COAST 1 phase 3 study showed that amlitelimab met all primary and key secondary endpoints, demonstrating statistically significant and clinically meaningful skin clearance and disease severity compared to placebo at Week 24 in patients aged 12 years and older with moderate-to-severe atopic dermatitis.
William Blair noted that the second anti-OX40 ligand (OX40L) antibody, amlitelimab, fell short of benchmark expectations. The efficacy of Amgen Inc.’s (NASDAQ:AMGN) rocatinlimab and amlitelimab in Phase 3 studies has fallen short of Dupixent, which led to a roughly 36% improvement on EASI-75 over placebo.
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Analyst Matt Phipps notes that rocatinlimab and amlitelimab have a more favorable, less frequent dosing schedule compared to Dupixent, with the potential for monthly or quarterly dosing, respectively.
The results suggest OX40/OX40L therapies deliver slower, less robust responses than IL-13/4 drugs, likely limiting their use to second-line treatment for patients who fail IL-13/4 options.
The analyst says advanced therapies make up less than 20% of the atopic dermatitis market, with only three approved mechanisms (IL-13/4, IL-31, JAK).
This leaves room for OX40 drugs, though the opportunity is smaller than for therapies matching or surpassing IL-13/4 efficacy.
William Blair highlighted the ongoing debate over differences between amlitelimab and rocatinlimab, focusing on pyrexia and chills.
Amgen’s rocatinlimab depletes OX40-positive T cells, which is linked to immune-related side effects, pyrexia (10%) and chills (6%).
These events are thought to have capped dosing in Phase 3 at 300 mg, below the 600 mg dose tested in Phase 2, potentially limiting efficacy.
Amlitelimab, by contrast, showed far lower rates of pyrexia (1.1% vs. 0.7% placebo) and chills (0.4% vs. 0.0% placebo), while still achieving efficacy comparable to rocatinlimab at higher dose levels.
In April, amlitelimab missed the primary endpoint of the annualized exacerbation rate at week 48 at the highest dose level, leading to nominal significance at the medium and low doses in heterogeneous inflammatory asthma.
Price Action: SNY stock is trading lower by 8.59% to $45.61 at last check Thursday.
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