The National Institute on Neurological Disorders and Stroke (NINDS) intends to modify existing multiple-award IDIQ contracts under the Pharmacology and Toxicology for Therapeutics Program (PTTP) to extend the ordering period by two years, from September 12, 2026 to September 12, 2028. These contracts support preclinical pharmacology and toxicology testing for the NIH Blueprint Neurotherapeutics Network and other NINDS initiatives. The extension allows current holders to continue supporting studies while the requirement is recompeted and a new IDIQ contract is awarded. The modification is being pursued on a sole-source basis, and interested parties may respond with capability statements, though this is not a request for competitive proposals. The work is classified under NAICS code 541715 with a size standard of 1,000 employees.