Prerefence for Oral presentation

Background
The WHO recommends HPV testing using clinically validated assays for cervical cancer screening, as infection with high-risk human papillomavirus (HPV) causes approximately 95% of cases. Most clinically validated assays target 12–14 HPV types and are developed in high-income countries, limiting affordability and accessibility in LMICs. Recently, several HPV assays have been developed in India, including reduced-valency tests targeting seven or eight oncogenic HPV types, with the potential to improve screening efficiency and reduce costs. Established validation frameworks exist for full-valency HPV assays, including the Meijer criteria, the VALGENT methodology, and the World Health Organization Target Product Profile (WHO-TPP) guidelines. However, only recently, in 2024, did the International Agency for Research on Cancer (IARC/WHO, France) convene an expert group to refine and adapt these frameworks for the evaluation of reduced-valency HPV assays (hereafter referred to as the IARC criteria), thereby addressing a critical evidence gap. This report presents the first formal validation of reduced-valency HPV, adapted for programmatic screening implementation in low-resource settings.

Objectives
To evaluate the clinical accuracy, reproducibility, and validation status of four indigenously developed HPV assays, including two reduced-valency tests, using internationally recognized validation frameworks for primary cervical cancer screening.

Methods
A clinical evaluation of four HPV assays developed in India was conducted: The PathoDetect-HPV-14 and HPV-Q (14-valent assays), the Truenat-HR-HPV-Plus (8-valent), and the PathoDetect-HPV-7 (7-valent). The performance of the assay was assessed against a series of clinically validated comparator assays, including the Cobas-4800, the Allplex-HP-HR, and reduced-valency comparators. The selection of samples for the validation process was conducted in accordance with VALGENT framework, encompassing a total of 1,159 cervical samples from the ESTAMPA study, which was conducted in Argentina and Costa Rica. Of these samples, 962 were classified as <CIN2, 19 as CIN2, 72 as CIN3, and 6 as invasive cancers. Sensitivity, specificity, agreement, repeatability, and κ statistics were calculated. Fourteen-valent assays were evaluated in accordance with the WHO-TPP guidelines, while reduced-valency assays were assessed using the IARC validation criteria.
Results
Truenat-HR-HPV-Plus (8-valent) demonstrated a sensitivity of 80.4% (95% CI: 71.1–87.8) and a specificity of 91.5% (95% CI: 89.5–93.2) for the detection of CIN2+. It met all IARC validation criteria and showed non-inferior performance compared with Allplex-HPV-HR-8, with relative sensitivity of 1.03 (95% CI: 0.96–1.09) for CIN2+ and 1.00 (95% CI: 0.96–1.04) for CIN3+, and relative specificity of 0.99 (95% CI: 0.97–1.00) and 0.98 (95% CI: 0.97–1.00), respectively. Repeatability was high (93.3%; κ = 0.79). In contrast, PathoDetect-HPV-7 showed lower sensitivity (68.1%) and specificity (89.0%) for CIN2+. Both 14-valent assays (HPV-Q and PathoDetect-HPV-14) failed to meet validation criteria.

Impact
This study provides the first formal validation of reduced-valency HPV assays using WHO-TPP and IARC criteria. It demonstrates that Truenat-HR-HPV-Plus achieves robust clinical performance against the most carcinogenic HPV types, with higher specificity than 14-valent assays. These findings support the potential role of validated reduced-valency HPV tests in improving screening efficiency, reducing unnecessary referrals, and expanding access to high-quality cervical cancer screening in LMICs.