> ## 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.

# Maintain, Apply Tabloid Guidance: Petition
- URL: https://www.fdaweb.com/maintain-apply-tabloid-guidance-petition/
- Published: 2025-03-26T12:00:00.000Z
- Updated: 2026-09-14T14:56:16.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5158896

The Washington-based law firm of Buchanan Ingersoll & Rooney is asking FDA to continue restrictions on ANDAs citing Waylis’ Tabloid (thioguanine) as the reference-listed drug. The 3/24 [petition](https://downloads.regulations.gov/FDA-2025-P-0919-0001/attachment%5F1.pdf?ref=fdaweb.com) asks the agency to:

- maintain and strictly apply the requirements of the current product-specific guidance (PSG) to any ANDA for thioguanine tablets, particularly 40 mg tablets, to ensure such ANDAs contain the results of an *in vivo* study demonstrating bioequivalence to Tabloid before approval; and
- pursuant to FDA’s biopharmaceutics classification system, refrain from granting a waiver as to performing *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.

“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.”