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Test for FRα via IHC early to understand her treatment options at platinum resistance1,2

FRα=folate receptor alpha; IHC=immunohistochemistry.

 Eligibility for ELAHERE Eligibility for ELAHERE Assessing Results of Staining Why Testing Matters Why Testing Matters How to Test What Results Mean

FRα expression scoring algorithm determines eligibility for ELAHERE, a targeted treatment USED IN PROC3,4

A positive FOLR1 IHC result may make a patient with ovarian cancer a candidate for ELAHERE monotherapy once they become resistant to platinum-based chemotherapy.3,4

*Rereading by additional pathologists for FOLR1 scoring. To decrease variability of FOLR1 results for cases with %TCs near the threshold of 75% (65% to 85%), rereading of the slide by a second pathologist is recommended.3
EOC=epithelial ovarian cancer; FOLR1=folate receptor 1; FRα=folate receptor alpha; IHC=immunohistochemistry; PROC=platinum-resistant ovarian cancer; TC=tumor cell.

Results of FRα testing can impact treatment decisions3,4

Positive

95% with 2+ and 3+ membrane staining or ≥75% with 2+ and/or 3+ membrane staining with complete circumferential pattern†

85% with 2+ and 3+ apical membranous staining or ≥75% of the tumor cells with 2+ and/or 3+ apical membrane staining

Images shown for illustrative purposes only.

†Partial circumferential membrane staining patterns are also acceptable for FOLR1 positivity.

FOLR1 positivity does not require complete circumferential membrane staining.3

Negative

0% with 2+ and 3+ tumor cell membrane staining or <75% of tumor cells with 2+ and/or 3+ tumor cell membrane staining relative to the negative control slide. This case is assigned a negative FOLR1 status

20% with 2+ and 3+ membrane staining or <75% with 2+ and/or 3+ tumor cell membrane staining

Images shown for illustrative purposes only.

†Partial circumferential membrane staining patterns are also acceptable for FOLR1 positivity.

FOLR1 positivity does not require complete circumferential membrane staining.3

Refer to the VENTANA FOLR1 (FOLR1-2.1) RxDx Assay Interpretation Guide for Epithelial Ovarian, Fallopian Tube, or Primary Peritoneal Cancer to aid in clinical evaluation of stained samples, including photographic images that illustrate staining patterns.

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  1. Referenced with permission from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Ovarian Cancer Including Fallopian Tube Cancer and Primary Peritoneal Cancer V.3.2025. © National Comprehensive Cancer Network, Inc. 2025. All rights reserved. Accessed October 28, 2025. To view the most recent and complete version of the guideline, go online to NCCN.org. NCCN makes no warranties of any kind whatsoever regarding their content, use or application and disclaims any responsibility for their application or use in any way.
  2. James RL, Sisserson T, Cai Z, et al. Arch Pathol Lab Med. 2024;148(11):1226-1233. doi:10.5858/arpa.2023-0149-OA
  3. VENTANA FOLR1 (FOLR1-2.1) RxDx Assay. Package insert. Roche; 2022.
  4. ELAHERE. Package insert. AbbVie; 2025.