In an era of rapid evolution to HPV primary screening, data on assay performance matters. The BD Onclarity™ HPV Assay (Onclarity) is a Real-Time PCR assay that utilizes gene-specific E6 and E7 targets for 14 types, enabling integrated extended high-risk HPV genotyping with individual genotyping of HPV 16, 18, 31, 45, 51 and 52 and reporting the remaining HPV types in three distinct groups (33/58, 56/59/66, and 35/39/68). The assay also detects the human beta-globin gene, which acts as a sample adequacy control. Onclarity is run on the fully integrated BD Viper™ LT System (Viper LT) which can process both BD SurePath™ (SurePath) and Hologic PreservCyt® (PreservCyt) liquid-based cytology (LBC) specimens.

The clinical validity of Onclarity, and equivalence to other HPV assays has been established. A systematic review and meta-analysis listed Onclarity among hrHPV assays that fulfill international criteria for use in primary screening.¹ The VALGENT 2 study demonstrated non-inferior sensitivity and specificity of Onclarity for CIN2+ compared to GP5+/6+ PCR using ThinPrep samples from the Scottish cervical cancer screening program.²

Furthermore, the Predictors 2, 3, and 4 studies established that Onclarity sensitivity for ≥CIN2/3 was not significantly different from HC2 or Roche cobas® HPV (Cobas), out of PreservCyt^3,4,5 and not significantly different from HC2 out of SurePath.⁶ Specificity for ≥CIN2 for Onclarity and Cobas were equivalent,^3,6 but HC2 was significantly less specific in one study⁴and not significantly different in another study.⁶

Risk discrimination by extended genotyping results from the Clinical Evaluation of the BD Onclarity HPV Assay on the BD Viper LT System with Cervical Specimens Clinical Trial (Onclarity Clinical Trial)⁷ for the subset of women ≥25 are presented in Table 1. Similar risk discrimination by Onclarity extended genotyping results from studies conducted with Kaiser Permanente Northern California (KPNC) subjects by the National Cancer Institute (NCI), for the subsets of 1903 women with ASC-US tested with Onclarity and for 8664 subjects with positive HPV are presented in Table 2.^9,10

The KPNC/NCI authors stratified extended genotype results into 5 tiers (HPV 16, else 18/45, else 31/33/58/52, else 51/35/39/56/59/66/68, else HPV-negative). The LBC results were stratified into 3 tiers (high-grade (HSIL, ASC-H, AGC), LSIL/ASC-US, NILM). For the resultant 15 combinations of hrHPV genotype and cytology, the 3-year CIN3+ risks ranged 1000-fold from 60.6% (HPV 16 and HSIL) to 0.06% (hrHPV- -negative and NILM). Onclarity combined with cytology predicts risks of cervical precancer/cancer in refined strata varying from extremely high to extremely low risk.¹⁰ The Onclarity assay design also overcomes the issue of pooled masking of the true underlying genotype-specific risks for CIN3+ disease posed by non HPV16/18 types (Figure 1).

Other recent studies for risk stratification included a proof-of-principle study that demonstrated that a totally automated algorithm using features from the BD FocalPoint™ Slide Profiler system performing computer-interpreted cytology and matched ≥ASC-US by human-interpreted Bethesda system cytology demonstrated excellent risk based triage when genotyping was added to the triage strategy.¹¹Such studies demonstrate the feasibility of automation of triage especially in areas lacking in cytology expertise.

In summary, the Onclarity HPV assay is clinical- ly validated and as of mid-February 2018, US FDA approved for use in ASCUS triage, HPV primary screening and co-testing. The ability to collect a single sample that generates both a cytology result and an HPV result with geno- typing as well as potentially end to end automated processing that can be applied to virtually all algo- rithms for cervical cancer screening is certainly an attractive package from both the laboratory as well as clinical standpoint.

References

1. Arbyn M, Snijders PJ, Meijer CJ, et al. Which high-risk HPV assays fulfil criteria for use in primary cervical cancer screening? Clin Microbiol Infect 2015;21(9):817-26.
2. Cuschieri K, Geraets DT, Moore C, et al. Clinical and analytical performance of the Onclarity HPV assay using the VALGENT framework. J Clin Microbiol 2015; 53: 3272-9.
3. Szarewski A, Mesher D, Cadman L, et al. Comparison of seven tests for high-grade cervical intraepithelial neoplasia in women with abnormal smears: the Predictors 2 study. J Clin Microbiol 2012;50:1867-73.
4. Cuzick J, Cadman L, Mesher D, et al. Comparing the performance of six human papillomavirus tests in a screen- ing population. Br J Cancer 2013;108:908-13.
5. Mesher D, Szarewski A, Cadman, L, et al. Comparison of human papillomavirus testing strategies for triage of women referred with low-grade cytological abnormalities. Eur J Cancer 2013;49:2179–86.
6. Cuzick J, Ahmad AS, Austin J, et al. A comparison of different human papillomavirus tests in PreservCyt versus SurePath in a referral population-PREDICTORS 4. J. Clin. Virol 2016;82:145-51.
7. Food and Drug Administration (FDA) BD Onclarity HPV Assay Premarket Approval (PMA). [Available from https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpma/pma.cfm].
8. Stoler M, Wright TW. (2018). [Onclarity Registrational Clinical Trial]. Unpublished raw data.
9. Schiffman M, Vaughan LM, Raine-Bennett TR, et al. A study of HPV typing for the management of HPV-positive ASC-US cervical cytologic results. Gynecol Oncol. 2015;138(3):573-8.
10. Schiffman M, Hyun N, Raine-Bennett TR, et al. A cohort study of cervical screening using partial HPV typing and cytology triage. Int J Cancer. 2016;139(11):2606-15.
11. Schiffman M, Yu K, Zuna R, et al. Proof-of-principle study of a novel cervical screening and triage strategy: Computer-analyzed cytology to decide which HPV-positive women are likely to have ≥CIN2. Int J Cancer 2017;140(3):718-725.