> ## Content Index
> Fetch the complete content index at: https://www.fdaweb.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# FDA Hits Neoleukin with Clinical Hold on Immunotherapy
- URL: https://www.fdaweb.com/fda-hits-neoleukin-with-clinical-hold-on-immunotherapy/
- Published: 2021-01-08T12:00:00.000Z
- Updated: 2026-09-14T16:41:57.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5148410

FDA has placed a clinical hold on a Neoleukin Therapeutics Phase1 clinical trial of its immunotherapeutic candidate, NL-201\. The agency told the company that it needs to develop a new assay that more precisely measures the amount of protein being administered and demonstrate with this assay that dose and administration procedures will accurately deliver the intended dose of NL-201, according to Neoleukin. It also had additional requests not related to the clinical hold to be addressed by an IND amendment, it says.

NL-201 is a *de novo* receptor agonist of the IL-2 and IL-15 receptors, Neoleukin says, adding that it was “designed to expand cancer-fighting CD8 T cells and natural killer (NK) cells without any bias toward cells expressing the alpha receptor subunit (CD25).” Previously presented preclinical data demonstrated the therapy’s ability to stimulate and expand CD8+ and NK cells at low doses with minimal impact on immunosuppressive regulatory T cells.