p16, HPV, and Cetuximab: What Is the Evidence?

Squamous cell carcinoma of the head and neck (SCCHN) is the sixth most common cancer worldwide. It has recently been appreciated that human papillomavirus (HPV) status (or p16 status, which is a frequently used surrogate for HPV status) is prognostic for oropharyngeal SCCHN. Here, we review and contextualize existing p16 and HPV data, focusing on the cetuximab registration trials in previously untreated, locoregionally advanced, nonmetastatic SCCHN (LA SCCHN) and in recurrent and/or metastatic SCCHN (R/M SCCHN): the IMCL-9815 and EXTREME clinical trials, respectively. Taken together, the available data suggest that, while p16 and HPV are prognostic biomarkers in patients with LA SCCHN and R/M SCCHN, it could not be shown that they are predictive for the outcomes of the described cetuximab-containing trial regimens. Consequently, although HPV status provides prognostic information, it is not shown to predict therapy response, and so is not helpful for assigning first-line therapy in patients with SCCHN. In addition, we discuss assays currently used to assess p16 and HPV status, as well as the differentiation between these two biomarkers. Ultimately, we believe HPV E6/E7 polymerase chain reaction-based mRNA testing may represent the most informative technique for assessing HPV status in patients with SCCHN. While p16 is a valid surrogate for HPV status in oropharyngeal carcinoma (OPC), there is a higher risk of discordance between p16 and HPV status in non-OPC SCCHN. Collectively, these discussions hold key implications for the clinical management of SCCHN. IMPLICATIONS FOR PRACTICE: Human papillomavirus (HPV) status (or its commonly utilized surrogate p16) is a known prognostic biomarker in oropharyngeal squamous-cell carcinoma of the head and neck (SCCHN). We evaluated implications of the available evidence, including cetuximab registration trials in previously untreated locoregionally advanced (LA) SCCHN and recurrent and/or metastatic (R/M) SCCHN. We conclude that, although p16 and HPV are prognostic biomarkers for both LA and R/M SCCHN, they have not been shown to be predictive of response to the described cetuximab-containing regimens for either indication. Thus, current evidence suggests that benefits of cetuximab are observed in both p16-/HPV-positive and -negative SCCHN.

First-line cetuximab + platinum-based therapy for recurrent/metastatic head and neck squamous cell carcinoma: A real-world observational study-ENCORE.

BACKGROUND: ENCORE, an observational, prospective, open-label study, investigated real-world treatment practices and outcomes with cetuximab plus platinum-based therapy (PBT) in first-line (1L) recurrent and/or metastatic squamous cell carcinoma of the head and neck (R/M SCCHN). AIMS: This multinational study aimed to investigate the long-term use of cetuximab plus PBT for 1L R/M SCCHN in a clinical setting. In particular, this study aimed to explore clinical considerations such as the decision to prescribe cetuximab plus PBT in R/M SCCHN, the mode and duration of treatment, and patient outcomes. METHODS AND RESULTS: Previously untreated patients with R/M SCCHN whose planned treatment was cetuximab plus PBT were enrolled from 6 countries. Among 221 evaluable patients, planned treatments included cetuximab plus carboplatin (31.2%), cisplatin plus 5-fluorouracil (31.7%), or carboplatin plus 5-fluorouracil (23.1%); 3.2% included a taxane, and 45.2% did not include 5-fluorouracil. Cetuximab treatment was planned for a fixed duration (≤24 weeks) in 15 patients (6.8%) and until disease progression in 206 (93.2%). Median progression-free survival and overall survival were 6.5 and 10.8 months, respectively. Grade ≥3 adverse events occurred in 39.8% of patients. Serious adverse events occurred in 25.8% of patients; 5.4% were cetuximab-related. CONCLUSION: In patients with R/M SCCHN, first-line cetuximab plus PBT was feasible and modifiable in a real-world setting with similar toxicity and efficacy as in the pivotal phase III EXTREME trial. CLINICAL TRIAL REGISTRATION NUMBER: EMR 062202-566.

Observational, prospective, phase 4 study in patients with first-line recurrent and/or metastatic squamous cell carcinoma of the head and neck treated with cetuximab and platinum-based therapy: DIRECT.

BACKGROUND: Cetuximab plus platinum-based therapy (PBT) followed by cetuximab maintenance until progression (EXTREME) is a guideline-recommended first-line treatment option in recurrent/metastatic squamous cell carcinoma of the head and neck (R/M SCCHN). DIRECT (Dose Intensity RElative to CeTuximab) was the first phase 4 observational study evaluating EXTREME administration in the real-world setting. AIMS: The primary aim of this study was to assess the relative dose intensity of cetuximab in patients with R/M SCCHN treated with first-line cetuximab according to the EXTREME regimen. METHODS AND RESULTS: Patients were ≥18 years old and eligible to receive cetuximab/PBT. Primary endpoint was cetuximab relative dose intensity (RDI). Of prospectively enrolled patients (n = 157), 119 received ≥1 cycle of EXTREME. Practices differing from the EXTREME trial were 5-fluorouracil omission (14%), maintenance cetuximab given every other week (54%), prior cetuximab, disease-free interval <6 months. 64% of patients reached cetuximab RDI ≥80%; mean cetuximab RDI was 88%. 46% of patients received maintenance cetuximab (mean RDI, 91%). Median progression-free survival and overall survival were 4.5 and 9.4 months. No new/unexpected safety findings were observed. CONCLUSIONS: The DIRECT study showed that first-line cetuximab plus PBT was a feasible, beneficial first-line treatment regimen in patients with R/M SCCHN in the real-world setting.

Rationale for combination of therapeutic antibodies targeting tumor cells and immune checkpoint receptors: Harnessing innate and adaptive immunity through IgG1 isotype immune effector stimulation.

Immunoglobulin (Ig) G1 antibodies stimulate antibody-dependent cell-mediated cytotoxicity (ADCC). Cetuximab, an IgG1 isotype monoclonal antibody, is a standard-of-care treatment for locally advanced and recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN) and metastatic colorectal cancer (CRC). Here we review evidence regarding the clinical relevance of cetuximab-mediated ADCC and other immune functions and provide a biological rationale concerning why this property positions cetuximab as an ideal partner for immune checkpoint inhibitors (ICIs) and other emerging immunotherapies. We performed a nonsystematic review of available preclinical and clinical data involving cetuximab-mediated immune activity and combination approaches of cetuximab with other immunotherapies, including ICIs, in SCCHN and CRC. Indeed, cetuximab mediates ADCC activity in the intratumoral space and primes adaptive and innate cellular immunity. However, counterregulatory mechanisms may lead to immunosuppressive feedback loops. Accordingly, there is a strong rationale for combining ICIs with cetuximab for the treatment of advanced tumors, as targeting CTLA-4, PD-1, and PD-L1 can ostensibly overcome these immunosuppressive counter-mechanisms in the tumor microenvironment. Moreover, combining ICIs (or other immunotherapies) with cetuximab is a promising strategy for boosting immune response and enhancing response rates and durability of response. Cetuximab immune activity-including, but not limited to, ADCC-provides a strong rationale for its combination with ICIs or other immunotherapies to synergistically and fully mobilize the adaptive and innate immunity against tumor cells. Ongoing prospective studies will evaluate the clinical effect of these combination regimens and their immune effect in CRC and SCCHN and in other indications.

Evidence-Based Treatment Options in Recurrent and/or Metastatic Squamous Cell Carcinoma of the Head and Neck.

The major development of the past decade in the first-line treatment of recurrent and/or metastatic squamous cell carcinoma of the head and neck (R/M SCCHN) was the introduction of cetuximab in combination with platinum plus 5-fluorouracil chemotherapy (CT), followed by maintenance cetuximab (the "EXTREME" regimen). This regimen is supported by a phase 3 randomized trial and subsequent observational studies, and it confers well-documented survival benefits, with median survival ranging between approximately 10 and 14 months, overall response rates between 36 and 44%, and disease control rates of over 80%. Furthermore, as indicated by patient-reported outcome measures, the addition of cetuximab to platinum-based CT leads to a significant reduction in pain and problems with social eating and speech. Conversely, until very recently, there has been a lack of evidence-based second-line treatment options, and the therapies that have been available have shown low response rates and poor survival outcomes. Presently, a promising new treatment option in R/M SCCHN has emerged: immune checkpoint inhibitors (ICIs), which have demonstrated favorable results in second-line clinical trials. Nivolumab and pembrolizumab are the first two ICIs that were approved by the US Food and Drug Administration. We note that the trials that showed benefit with ICIs included not only patients who previously received ≥1 platinum-based regimens for R/M SCCHN but also patients who experienced recurrence within 6 months after combined modality therapy with a platinum agent for locally advanced disease. In this review, we outline the available clinical and observational evidence for the EXTREME regimen and the initial results from clinical trials for ICIs in patients with R/M SCCHN. We propose that these treatment options can be integrated into a new continuum of care paradigm, with first-line EXTREME regimen followed by second-line ICIs. A number of ongoing clinical trials are comparing regimens with ICIs, alone and in combination with other ICIs or CT, with the EXTREME regimen for first-line treatment of R/M SCCHN. As we eagerly await the results of these trials, the EXTREME regimen remains the standard of care for the first-line treatment of R/M SCCHN.

Cetuximab and Radiotherapy in Laryngeal Preservation for Cancers of the Larynx and Hypopharynx: A Secondary Analysis of a Randomized Clinical Trial.

IMPORTANCE: The appropriate use of surgery or radiotherapy-based approaches for organ preservation has been the subject of much debate. Unfortunately, there has been a lack of improvement in overall survival for patients with laryngeal carcinoma in the last 30 years. OBJECTIVE: To assess the rates of laryngeal preservation and laryngectomy-free survival in patients receiving cetuximab and radiotherapy (CRT) and patients receiving radiotherapy alone. DESIGN, SETTING, AND PARTICIPANTS: Patients were enrolled in a multicenter, open-label, stratified, randomized, phase 3 study from April 1, 1999, through March 31, 2002, from 73 centers in the United States and 14 other countries. A secondary subgroup analysis of patients with hypopharyngeal and laryngeal carcinoma was undertaken. Rates of laryngeal preservation and laryngectomy-free survival were estimated by the Kaplan-Meier method. The hazard ratios (HRs) were calculated using a Cox proportional hazards regression model. Quality of life was evaluated using the European Organization for Research and Treatment of Cancer core questionnaire and head and neck module. MAIN OUTCOMES AND MEASURES: Laryngeal preservation and laryngectomy-free survival. RESULTS: Of the 424 patients included in the trial, 168 treated patients with cancer of the larynx or hypopharynx were included in this analysis (90 in the CRT group and 78 in the radiotherapy alone group). The median (range) age of the patients was 59 (40-80) years in the CRT group and 61 (35-81) years in the radiotherapy alone group. In the CRT group, 72 patients (80.0%) were male and 18 (20.0%) were female. In the radiotherapy alone group, 62 (79.5%) were male and 16 (20.5%) were female. The rates of laryngeal preservation at 2 years were 87.9% for CRT vs 85.7% for radiotherapy alone, with an HR of 0.57 (95% CI, 0.23-1.42; P = .22). Similarly, the HR for laryngectomy-free survival comparing CRT vs radiotherapy alone was 0.78 (95% CI, 0.54-1.11; P = .17). This study was not powered to assess organ preservation. Median overall survival was 27 (95% CI, 20-45) vs 21 (95% CI, 17-35) months for the CRT and radiotherapy alone groups, respectively, with an HR of 0.87 (95% CI, 0.60-1.27). No differences between treatments were reported regarding overall quality of life, need for a feeding tube, or speech. CONCLUSIONS AND RELEVANCE: The results of a possible cetuximab-related laryngeal preservation benefit for patients with hypopharyngeal or laryngeal cancer are intriguing; these results need to be interpreted in the context of a retrospective subset analysis with limited sample size. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00004227.

Association of human papillomavirus and p16 status with mucositis and dysphagia for head and neck cancer patients treated with radiotherapy with or without cetuximab: Assessment from a phase 3 registration trial.

BACKGROUND: Mucositis and dysphagia are common adverse effects of radiotherapy (RT) treatment of locally advanced squamous cell cancer of the head and neck (LA-SCCHN). Chemotherapy added to RT increases survival rates but causes worse mucositis and dysphagia. The aim of this analysis was to assess the impact of p16 status on mucositis, dysphagia, and feeding tube use in LA-SCCHN among patients treated with RT±cetuximab in the phase 3 IMCL-9815 trial. METHODS: Patients received RT plus weekly cetuximab or RT alone. Subgroup analyses were conducted on patients with p16-positive (n=75) or p16-negative (n=106) oropharyngeal cancer (OPC), as determined by immunohistochemical analysis. The onset and duration of mucositis and dysphagia by treatment arm and p16 status were displayed using Kaplan-Meier curves and the log-rank test. P values for the incidence of mucositis and dysphagia were calculated using the Fisher exact test. Feeding tube use was assessed as the percent of patients reporting use. RESULTS: The baseline characteristics of patients treated with RT±cetuximab were similar in both the p16-positive and p16-negative OPC subgroups. Patients within the p16-positive OPC subgroup had higher Karnofsky scores and were more likely to have stage T1-T3 cancer and be from the United States. Regardless of p16 status, there was no difference in the onset or duration of grade 3/4 mucositis or dysphagia in patients receiving RT plus cetuximab compared with those receiving RT alone. In the overall population, and the p16-positive and p16-negative OPC subpopulations, feeding tube use was not different for patients receiving RT plus cetuximab compared with RT alone. CONCLUSION: Regardless of p16 status, the addition of cetuximab to RT did not alter the incidence, time to onset, severity, or duration of mucositis and dysphagia and did not impact the frequency of feeding tube use.

Association of Human Papillomavirus and p16 Status With Outcomes in the IMCL-9815 Phase III Registration Trial for Patients With Locoregionally Advanced Oropharyngeal Squamous Cell Carcinoma of the Head and Neck Treated With Radiotherapy With or Without Cetuximab.

PURPOSE: We conducted a retrospective evaluation of the IMCL-9815 study to examine the association of human papillomavirus (HPV) and p16 protein expression status with outcomes in patients with oropharyngeal carcinoma (OPC) receiving radiotherapy (RT) plus cetuximab or RT alone. PATIENTS AND METHODS: In the IMCL-9815 study, patients were randomly allocated to receive RT plus weekly cetuximab or RT alone. A subpopulation of patients with p16-evaluable OPC was retrospectively evaluated on the basis of locoregional control (LRC), overall survival (OS), and progression-free survival (PFS). Evaluable samples from patients with p16-positive OPC were also tested for HPV DNA. RESULTS: Tumor p16 status was evaluable in 182 patients with OPC enrolled in the IMCL-9815 study; 41% were p16 positive. When treated with RT alone or RT plus cetuximab, p16-positive patients had a longer OS than p16-negative patients (hazard ratio, 0.40; 95% CI, 0.21 to 0.74 and hazard ratio, 0.16; 95% CI, 0.07 to 0.36, respectively). The addition of cetuximab to RT increased LRC, OS, and PFS in both patients with p16-positive OPC and those with p16-negative disease. Interaction tests for LRC, OS, and PFS did not demonstrate any significant interaction between p16 status and treatment effect (P = .087, .085, and .253, respectively). Similar trends were observed when patients with p16-positive/HPV-positive OPC (n = 49) and those with p16-positive/HPV-negative OPC (n = 14) were compared. CONCLUSION: p16 status was strongly prognostic for patients with OPC. The data suggest that the addition of cetuximab to RT improved clinical outcomes regardless of p16 or HPV status versus RT alone.

Calcium-vitamin D3 supplementation is cost-effective in hip fractures prevention.

OBJECTIVE: To assess the cost implications for a preventive treatment strategy for institutionalised elderly women with a combined 1200 mg/day calcium and 800 IU/day vitamin D(3) supplementation in seven European countries. DESIGN: Retrospective cost effectiveness analysis based on a prospective placebo-controlled randomised clinical trial. DATA SOURCES: Recently published cost studies in seven European countries. Clinical results from Decalyos, a 3-year placebo-controlled study in elderly institutionalised women. TRIALS: Decalyos study, with 36 months follow-up of 3270 mobile elderly women living in 180 nursing homes, allocated to two groups. One group received 1200 mg/day elemental calcium in the form of tricalcium phosphate together with 800 IU/day (20 microg) of cholecalciferol (vitamin D(3)), the other placebo. RESULTS: In the 36 months analysis of the Decalyos study, 138 hip fractures occurred in the group of 1176 women, receiving supplementation and 184 hip fractures in the placebo group of 1127 women. The mean duration of treatment was 625.4 days. Adjusted to 1000 women, 46 hip fractures were avoided by the calcium and vitamin D(3) supplementation. For all countries, the total costs in the placebo group were higher than in the group receiving supplementation, resulting in a net benefit of 79000-711000 per 1000 women. CONCLUSION: This analysis suggests that the supplementation strategy is cost saving. The results may underestimate the net benefits, as this treatment has also shown to be effective in decreasing the incidence of other non-vertebral fractures in elderly institutionalised women.

Cost-effectiveness of targeted therapy with cetuximab in patients with K-ras wild-type colorectal cancer presenting with initially unresectable metastases limited to the liver in a German setting.

BACKGROUND: In patients with metastases limited to the liver (liver-limited disease [LLD]), effective therapies such as monoclonal antibodies combined with chemotherapy may facilitate metastasis resection and improve long-term survival. OBJECTIVE: This study assessed the cost-effectiveness of bevacizumab and cetuximab in the treatment of patients with colorectal cancer presenting with initially unresectable liver metastases of the Kirsten rat sarcoma viral oncogene homolog (K-ras) wild type, from the perspective of German statutory health insurance. METHODS: The health-economic modeling approach presented here made indirect comparisons between available data on bevacizumab and cetuximab treatment outcomes using evidence synthesis techniques, extrapolating from the follow-up duration of identified clinical trials to a longer time horizon of up to 10 years and inferring costs and health outcomes based on modeled patient pathways. Expert opinion and Delphi panel methods were used for some assumptions, when evidence was missing. Probabilistic sensitivity analyses and different scenario analyses were applied to test for uncertainty around input parameters and assumptions. RESULTS: For the metastatic colorectal cancer LLD population with K-ras wild-type genotype, mean overall survival estimates were 37.7 months for first-line treatment with cetuximab plus FOLFIRI (irinotecan, leucovorin, fluorouracil) and 30.4 months for bevacizumab plus FOLFOX (oxaliplatin, leucovorin, fluorouracil). Corresponding discounted survival estimates were 2.88 life-years with cetuximab plus FOLFIRI versus 2.38 life-years with bevacizumab plus FOLFOX, an average gain of 0.50 discounted life-years. The incremental cost-effectiveness ratio of cetuximab plus FOLFIRI versus bevacizumab plus FOLFOX was €15,020 (year 2010 €) per life-year gained in the base case (with a 95% CI from the probabilistic sensitivity analysis of €3806-€24,660). Results were robust in different scenario analyses as well as in the probabilistic sensitivity analysis. CONCLUSIONS: First-line treatment with cetuximab plus FOLFIRI offers a cost-effective treatment option versus bevacizumab plus FOLFOX for the metastatic colorectal cancer LLD population with K-ras wild-type genotype in Germany. K-ras testing should be performed on all presenting cases of metastatic colorectal cancer to ensure access to this treatment option.