secwatch.observer — SEC 8-K summary
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Issuer:     REGENXBIO Inc. (RGNX)
CIK:        0001590877
Form:       8-K
Filed at:   2026-02-10T23:59:59+00:00
Accession:  0001193125-26-043342
Event type: regulatory
Sentiment:  negative
Materiality: 0.85
Item codes: 7.01, 8.01, 9.01
LLM model:  deepseek-v4-flash:cloud@v2

FDA rejects REGENXBIO's RGX-121 BLA for MPS II; company plans resubmission
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- FDA issued CRL on Feb 7, 2026 for RGX-121 (clemidsogene lanparvovec) to treat MPS II (Hunter syndrome).
- CRL cites uncertainty in defining neuronopathic population, external control comparability, and surrogate endpoint CSF HS D2S6.
- FDA suggests new study, additional patients, longer follow-up, or untreated control arm; company calls it 'devastating'.
- REGENXBIO plans to request Type A meeting and aim for BLA resubmission with additional data.
- Company had believed it addressed FDA's concerns during BLA review; independent experts supported data.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1590877/000119312526043342/0001193125-26-043342-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1590877/000119312526043342/rgnx-20260207.htm
  HTML page:      https://secwatch.observer/filing/0001193125-26-043342

License: Source filings: public domain (SEC EDGAR). Summaries (headline + bullets): CC-BY-4.0; attribute https://secwatch.observer