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# Cancer Drug Tabloid ANDA Restrictions Sought
- URL: https://www.fdaweb.com/cancer-drug-tabloid-anda-restrictions-sought/
- Published: 2025-02-06T12:00:00.000Z
- Updated: 2026-09-14T14:52:34.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5158619

A Buchanan Ingersoll & Rooney petition asks FDA to impose two restrictions on ANDAs citing Waylis Therapeutics’ Tabloid (thioguanine) 40 mg tablets as the reference-listed drug. The 2/3 [petition](https://downloads.regulations.gov/FDA-2025-P-0393-0001/attachment%5F1.pdf?ref=fdaweb.com) asks FDA to:

- maintain and strictly apply the requirements of the current product-specific guidance (PSG) for thioguanine, which it says represents scientifically appropriate standards for this class of drugs (oral chemotherapeutic dosage forms), to all pending, newly submitted, and future ANDAs for thioguanine tablets; and
- under FDA’s biopharmaceutics classification system, refrain from granting a waiver of the requirement to perform *in vivo* bioequivalence testing for any generic formulation of thioguanine.

The petition says Tabloid is a cytotoxic orally administered chemotherapeutic drug indicated for remission induction and remission consolidation treatment of acute nonlymphocytic leukemias. It says that as with other cancer drugs, it poses the risk of causing myelosuppression, a side effect where cell production by bone marrow is inhibited.

“Using a method of determining bioequivalence that is not suitably accurate nor considered a sensitive method would result in therapeutic inequivalence and also pose significant safety risks or otherwise endanger the lives of patients,” the petition says. “The request herein is not only consistent with current bioequivalence guidance established within the PSG for thioguanine but will also make certain that the scientific standards and criteria set forth in such guidance to ensure safety and effectiveness remain in effect and are equitably applied to all ANDAs before they may be approved.”