Amgen's Rocatinlimab Shows Promise in Late-Stage Atopic Dermatitis Trial

Amgen's anti-OX40 antibody rocatinlimab has demonstrated strong efficacy in moderate to severe atopic dermatitis, according to new Phase III data presented at the 2024 annual meeting of the American Academy of Dermatology. The results from the ROCKET-IGNITE study, part of Amgen's late-stage ROCKET clinical development program, have reinvigorated interest in the drug candidate after mixed reactions to earlier trial data.

ROCKET-IGNITE Study Results

The ROCKET-IGNITE trial showed that 42.3% of patients receiving 300-mg rocatinlimab once every four weeks achieved at least a 75% reduction from baseline in Eczema Area and Severity Index scores (EASI-75) at 24 weeks. This represented a significant 29.5% difference compared to placebo. Additionally, 23.6% of patients in the treatment group achieved clear or almost-clear skin at 24 weeks, a 14.9% advantage over placebo.

These results mark a substantial improvement over the earlier ROCKET-HORIZON trial data released in September 2024, which found that 32.8% of rocatinlimab-treated patients achieved EASI-75, representing a 19.1% difference from placebo. While Amgen had declared the HORIZON results a "statistically significant improvement" in disease severity, analysts at the time were less enthusiastic, describing the effect as "modest" and potentially falling short of competing treatments.

Safety Profile and Additional Studies

Despite the positive efficacy data, analysts noted higher incidences of pyrexia (fever) and chills in rocatinlimab-treated patients. Amgen addressed these concerns, explaining that these side effects were "mainly a first dose effect and therefore not commonly seen on subsequent doses."

Amgen also presented data from two additional ROCKET studies. The SHUTTLE study demonstrated that rocatinlimab can achieve significant EASI-75 rates when combined with topical corticosteroids or topical calcineurin inhibitors. The VOYAGER study found that rocatinlimab does not interfere with patients' responses to tetanus and meningococcal vaccines, an important consideration for long-term treatment safety.

Analyst Reactions and Market Implications

Analysts at Leerink Partners described the ROCKET-IGNITE findings as "surprisingly positive" and "more compelling" than the previous HORIZON data, despite testing a similar dose. This positive reception marks a shift from the skepticism that followed the September 2024 readout, where firms such as Jefferies and BMO Capital Markets expressed reservations about rocatinlimab's efficacy compared to established treatments like Ebglyss and Dupixent.

The improved results from ROCKET-IGNITE could potentially strengthen Amgen's position in the competitive atopic dermatitis market. However, the full impact of these findings on rocatinlimab's market prospects will likely depend on forthcoming data from the remaining trials in the ROCKET program and how the drug's efficacy and safety profile compare to current standard-of-care treatments.