RAPT Therapeutics' RPT193, an oral drug targeting CCR4 on Th2 cells, has experienced a setback in its development for moderate-to-severe atopic dermatitis. The drug's Phase Transition Success Rate (PTSR) decreased by 13 points to 78% following the announcement of positive topline Phase Ib trial results on June 14. The updated PTSR was reported on June 18.
The Phase Ia/Ib trial (NCT04271514) involved 21 patients treated with RPT193 and 10 patients in the placebo arm. After four weeks, RPT193 demonstrated a 36.3% improvement from baseline in the Eczema Area and Severity Index (EASI) score, while the placebo group showed a 17% improvement. The EASI score was one of the trial's efficacy endpoints. RAPT Therapeutics has expressed intentions to advance RPT193 into a Phase IIb trial for atopic dermatitis.
Impact on Approval Odds
In addition to the PTSR decrease, RPT193's Likelihood of Approval (LoA) also declined by one point to 3%. GlobalData's analysis, which uses a combination of machine learning and a proprietary algorithm, calculates LoA by compounding the PTSR at each stage the drug has yet to progress through. These metrics consider factors such as therapy area, indication, and molecule type.
RAPT's Market Position
Rapt Therapeutics currently has a market capitalization of $1.02 billion.
