secwatch.observer — SEC 8-K summary
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Issuer:     REGENXBIO Inc. (RGNX)
CIK:        0001590877
Form:       8-K
Filed at:   2026-01-28T23:59:59+00:00
Accession:  0001193125-26-026139
Event type: regulatory
Sentiment:  negative
Materiality: 0.85
Item codes: 8.01, 9.01
LLM model:  deepseek-v4-flash:cloud@v2

FDA places clinical hold on REGENXBIO's RGX-111 and RGX-121 gene therapies after neoplasm case
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- Single neoplasm (intraventricular CNS tumor) found in 5-year-old asymptomatic patient 4 years post-RGX-111 dose; AAV vector integration detected near PLAG1 proto-oncogene.
- RGX-121 placed on hold due to product, population, and risk similarities with RGX-111.
- No neoplasms reported in 9 other RGX-111 or 32 RGX-121 patients.
- CEO surprised by RGX-121 hold while investigation continues; confident in benefit-risk based on positive safety and efficacy data.
- Company has not yet received full clinical hold letter and awaits FDA details.

Source:
  EDGAR index:    https://www.sec.gov/Archives/edgar/data/1590877/000119312526026139/0001193125-26-026139-index.htm
  Primary doc:    https://www.sec.gov/Archives/edgar/data/1590877/000119312526026139/rgnx-20260123.htm
  HTML page:      https://secwatch.observer/filing/0001193125-26-026139

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