Cetuximab Plus Platinum and Taxane-based Chemotherapy, Followed by Avelumab and Cetuximab, as First-line Treatment for Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma (HNSCC) Patients With a PD-L1 Combined Positive Score (CPS)≥1≤19.

This clinical study, titled AVEC-119, is a phase II, single-arm trial designed to evaluate the efficacy and safety of an innovative treatment approach for recurrent and metastatic head and neck squamous cell carcinoma (R/M HNSCC). The study aims to explore whether reversing the conventional immunotherapy sequence-initiating treatment with anti-EGFR-based chemotherapy induction followed by checkpoint inhibition-can significantly improve patient outcomes. The therapy consists of Cetuximab in combination with platinum- and taxane-based chemotherapy during the induction phase, followed by maintenance therapy with Avelumab (a PD-L1 inhibitor) and Cetuximab.

Objective:

The primary goal of this study is to determine whether this unique sequential treatment strategy can enhance six-month progression-free survival (PFS) rates in patients with PD-L1 CPS≥1≤19 R/M HNSCC. By leveraging the potential immune-stimulating effects of anti-EGFR therapy and chemotherapy, followed by immunotherapy maintenance, the study aims to improve overall survival and tumor response rates compared to standard treatment regimens.

Rationale:

Over the past decade, immune checkpoint inhibitors (ICIs) have reshaped the first-line treatment landscape for R/M HNSCC. Findings from the Keynote-048 trial demonstrated that pembrolizumab, administered alone or in combination with chemotherapy, led to prolonged overall survival (OS) compared to the EXTREME regimen (Cetuximab + platinum + 5-FU). However, these improvements were primarily observed in patients with a PD-L1 CPS≥20. In contrast, those with PD-L1 CPS between 1 and 19 did not achieve significant benefits in progression-free survival (PFS) or overall response rate (ORR), highlighting an area of unmet clinical need.

Previous studies have demonstrated that regimens incorporating Cetuximab with platinum- and taxane-based chemotherapy offer comparable efficacy and superior safety profiles compared to platinum + 5-FU regimens. Furthermore, taxanes and anti-EGFR therapies may enhance anti-tumor immune responses, priming the tumor microenvironment for subsequent immunotherapy.

AVEC-119 aims to harness this synergy by first reducing the tumor burden and modulating the immune microenvironment through induction therapy with Cetuximab and chemotherapy, followed by immune checkpoint inhibition with Avelumab in combination with Cetuximab. This innovative treatment approach is designed to improve response rates and extend survival in patients who typically derive limited benefit from standard checkpoint inhibitors.

Study Design:

Study Type: Multicenter, single-arm, phase II trial Participating Sites: 8 specialized oncology centers in Italy Target Population: Patients with R/M HNSCC and PD-L1 CPS between 1 and 19 Planned Enrollment: A total of 67 patients

Treatment Plan:

Induction Phase (TPE - 9 weeks):

• Paclitaxel: 175 mg/m² IV infusion every 21 days (3 cycles)
• Cisplatin: 75 mg/m² IV infusion every 21 days (3 cycles) (Carboplatin AUC 5 may be substituted for patients with renal impairment or neuropathy)
• Cetuximab: Initial dose of 400 mg/m² IV infusion, followed by 250 mg/m² weekly for 3 cycles

Maintenance Phase (AVEC - Until Disease Progression or Toxicity):

• Avelumab: 800 mg IV every 2 weeks
• Cetuximab: 500 mg/m² IV every 2 weeks Translational Research and Biomarker Analysis AVEC-119 integrates a comprehensive translational research component aimed at unraveling the molecular mechanisms underlying treatment response and resistance.

The study will:

• Conduct pre-treatment gene expression (GE) analysis in tumor samples to explore correlations between hypoxia, immune activity, and response to therapy.
• Utilize single-cell sequencing to track immune cell population changes in blood samples collected at four critical time points: pre-TPE, post-TPE, during maintenance (6 months), and at disease progression.
• Investigate whether the hypoxic and immune landscape of tumors shifts following EGFR inhibition, potentially enhancing response to subsequent PD-L1 blockade.

Ethical and Regulatory Aspects

• The study adheres to Good Clinical Practice (GCP) standards and has obtained approval from the relevant ethics committees.
• All participants provide informed consent prior to enrollment.
• Patient safety is continuously monitored, with predefined stopping criteria in place should unacceptable toxicity levels arise.

Conclusion AVEC-119 represents a paradigm shift in the treatment of R/M HNSCC, particularly for patients with PD-L1 CPS between 1 and 19, a group that has historically exhibited suboptimal responses to checkpoint inhibitors. By reversing the conventional immunotherapy sequence-priming the immune system with a chemotherapy/EGFR-targeted induction before introducing checkpoint blockade-this study aims to achieve higher response rates, prolong progression-free survival, and shed new light on tumor-immune dynamics. If successful, this approach may redefine first-line treatment strategies for a challenging subset of head and neck cancer patients, offering new hope and improved clinical outcomes.