Tisotumab vedotin in head and neck squamous cell carcinoma: Updated analysis from innovaTV 207 Part C.

Abstract

6012 Background: Recurrent or metastatic (r/m) head and neck squamous cell carcinoma (HNSCC) is treated in the first-line with an immunotherapy-based approach, including in combination with platinum-based chemotherapy or as monotherapy, or platinum-based combination plus targeted therapy. Still, most pts experience disease progression, and the efficacy of subsequent line treatment options is limited. Tisotumab vedotin (TV) is an investigational antibody-drug conjugate directed to tissue factor. TV at 1.7 mg/kg IV Q2W has demonstrated encouraging antitumor activity in 2L-4L r/m HNSCC from the innovaTV 207 (NCT03485209) study. Here, we present data from the full cohort, Part C. Methods: innovaTV 207 is an open-label, global, phase 2, multicohort, multicenter study evaluating TV monotherapy or in combination for advanced solid tumors. In Part C, pts with r/m HNSCC received TV monotherapy (1.7 mg/kg IV Q2W). All pts were required to have received a platinum-based regimen, either in the r/m setting, or have persistent disease following platinum-based chemoradiation and a checkpoint inhibitor (CPI), if eligible. Primary endpoint was confirmed objective response rate (cORR) per investigator. Secondary endpoints included duration of response (DOR), time-to-response (TTR), and safety. Results: As of 6 Sept 2023, 40 pts with HNSCC were treated. 39 (97.5%) pts received prior platinum-based therapy. In the r/m setting, 25 (62.5%) pts received ≤2 prior lines of systemic therapy (median: 2; range: 1-3), 40 (100%) pts received prior CPI, 23 (57.5%) pts received prior taxane, and 27 (67.5%) pts received prior cetuximab. The most common subsites at diagnosis were oropharynx (n=16, of which 12 were p16 positive), larynx (n=10), and oral cavity (n=9). In the full cohort, cORR was 32.5% (95% CI, 18.6-49.1), with 1 complete response and 12 partial responses. Median DOR was 5.6 mo (95% CI, 3.0-NR) and median TTR was 1.4 mo. Among pts with ≤2 prior lines (n=25), cORR was 40.0% (95% CI, 21.1-61.3). In this subgroup, DOR is not yet mature (range: 1.2+ to 7.9+ mo), and among the 10 responders, 6 pts remain in response; median TTR was 1.5 mo. In the full cohort, 85.0% of pts had at least 1 treatment-related adverse event (TRAE). Grade ≥3 TRAEs occurred in 25.0% of pts, of which the most common were peripheral neuropathy events (12.5%). Adverse events of special interest were prespecified for ocular, peripheral neuropathy, and bleeding events, and occurred in 21 (52.5%), 19 (47.5%), and 15 (37.5%) pts, respectively. Updated efficacy and safety data are planned. Conclusions: TV demonstrated encouraging antitumor activity in a heavily pretreated r/m HNSCC population with a manageable safety profile consistent with previous TV monotherapy data. The study is ongoing; TV represents a promising treatment option for pts with r/m HNSCC who have progressed after prior platinum-based therapy and immunotherapy. Clinical trial information: NCT03485209 .