ChemoCentryx Stock Plunges As FDA Briefing Document Casts Doubt On Vasculitis Candidate Avacopan's Data

ChemoCentryx Inc CCXI shares plunged after an FDA briefing document indicates the agency has “several areas of concerns” with its vasculitis candidate, avacopan.
The FDA document raised questions regarding the “interpretability of the data and the clinical meaningfulness of these results” as summarized below:
- At Week 26, the proportion of patients in disease remission in the avacopan group (72.3%) was non-inferior to the prednisone group (70.1%) according to the Applicant’s testing plan.
- Interpretation of the non-inferiority at Week 26 is limited by a large number of patients in the avacopan arm (86%) who received non-study-supplied glucocorticoids from Week 0 to 26.
- While the mean cumulative glucocorticoid dose per patient over Week 0 to 26 was lower (1072.9 mg) in the avacopan-treated patients, compared to the mean cumulative dose in the prednisone-treated patients (3192.5 mg), the non-inferiority assessment is not a comparison of avacopan vs. prednisone, but instead avacopan plus lower dose glucocorticoids vs. higher dose glucocorticoids.
- The document also takes issue with the complex trial design and the lack of long-term safety data.
Price Action: CCXI shares dropped 52.3% at $23.27 during the market trading session on the last check Tuesday.