Arsenal Biosciences Layoffs
Yes. Arsenal Biosciences filed 2 WARN notices to cut 158 jobs in South San Francisco, California, with the layoffs effective Oct 29, 2026. The most recent was filed Aug 31, 2026 under the federal WARN Act.
158 roles affected across 2 filings.
Filing history
Arsenal Biosciences has filed 2 WARN notices between 2025 and 2026, cutting 158 jobs in total. Activity picked back up in the last 12 months (158 jobs) after a quiet prior year.
Every filing
Questions
Yes. Arsenal Biosciences filed 2 WARN notices to cut 158 jobs in South San Francisco, California, with the layoffs effective Oct 29, 2026. The most recent was filed Aug 31, 2026 under the federal WARN Act.
158 jobs, across 2 official WARN filings.
The most recent filing lists an effective date of Oct 29, 2026. The WARN Act requires roughly 60 days' advance notice, so the filing date precedes the job losses.
We'll email you if there are further filings, expansions, or new locations affected.