Association of plasma tumor tissue modified viral HPV DNA (TTMV) with tumor burden, treatment type, and outcome: A translational analysis from NRG-HN002.
Authors: Sue S. Yom, Pedro A. Torres-Saavedra, Charlotte Kuperwasser, Sunil Kumar, Piyush B. Gupta, Patrick Ha, Jessica Lyn Geiger, Robyn Banerjee, Wade Thorstad, Dukagjin Blakaj, William A. Stokes, Khalil Sultanem, Pencilla Lang, Christopher Erik Lominska, Melissa R. Young, Jonathan Harris, Quynh-Thu Le
Journal: Journal of Clinical Oncology (2022)

6006 Background: NRG-HN002 was a phase II trial that randomized patients with p16-positive oropharynx cancer to 60 Gy IMRT with concurrent cisplatin (IMRT-C) or 60 Gy accelerated IMRT. The protocol specified plasma collection at pretreatment (t0), intratreatment (20-28 Gy, t1), and 2 weeks to 1 month posttreatment (t2); at these timepoints, TTMV was assayed. A prespecified analysis evaluated: association of t0 TTMV to gross tumor volume (GTV) of primary and lymph nodes; t0-t1 decrease in TTMV; and association of t2 TTMV to treatment and outcome. Methods: TTMV was quantified as fragments/mL of plasma. If TTMV-HPV16 was not detected (&lt;5 fragments/mL) or was a low value, the specimen was tested for TTMV-HPV18, -HPV31, -HPV33, and -HPV35. The distribution of t0 TTMV fragments was highly skewed, so these data were log-transformed; their correlation to GTV was measured by Pearson coefficient. Paired and two-sample t-tests were used to compare t0 and t1 log-transformed fragments within and between arms. Proportions of TTMV detection at t2 between arms were compared using Fisher’s exact test. Rates of undetectability and fragment clearance (≥94% reduction from t0) at t2 were estimated. The negative predictive value (NPV) was estimated for 2-year locoregional failure (LRF) and progression-free survival (PFS). Results: Of 306 eligible patients, 164 (53.6%) donated at least one specimen. The median collection time/RT dose was -2.6 days before RT (Q1-Q3, -4.0-0.0), at 24 Gy (22-28), and 25.5 days after RT end (18-31). The t0, t1, and t2 patient participation rates were 53.6%, 45.4%, and 42.5%. Zero TTMV fragments were detected in 10.4% at t0, 19.4% at t1, and 93.1% at t2. At t0, t1, and t2, 83.5%, 79.1%, and 6.2% had detectable TTMV; 78.0%, 73.4%, and 5.4% had TTMV-HPV16. In correlating GTV to t0 TTMV fragments, the Pearson coefficient was 0.30 (95% CI 0.15-0.44). In a linear model, T stage (p=0.01) and N stage (p=0.004) were positively associated with t0 TTMV fragments. On the IMRT-C arm, the t0-to-t1 mean change was -1.06 (p=0.0009), and for IMRT, it was -0.22 (p=0.35) (p=0.03 between arms). The t2 TTMV detectability rate was 3.3% for IMRT-C vs 8.7% for IMRT (p=0.28). The t2 TTMV undetectability rate was 93.8% and the fragment clearance rate was 95.4%. Two-year LRF and PFS were 6.2% and 91.4%. The NPV of t2 undetectability was 95.0% (95% CI 89.4-98.1) for 2-year LRF and 93.3% (95% CI 87.3-97.1) for 2-year PFS, and for fragment clearance was 94.3% and 92.7%. Conclusions: Feasibility of the TTMV-HPV assay in clinical trial specimens was established. About 10% of p16-positive patients had zero TTMV fragments at baseline. Among those with TTMV detectability, 6.6% had types other than TTMV-HPV16. T and N stage were positively associated with TTMV fragments. The IMRT-C arm achieved rapid TTMV undetectability unlike IMRT. The NPV of posttreatment undetectability was 93-95% for 2-year LRF and PFS.