Tanguy Seiwert, MD
In August 2016, the FDA approved pembrolizumab (Keytruda) for patients with platinum-refractory squamous cell carcinoma of the head and neck (SCCHN).1
Not only was it the first immunotherapy approved for head and neck cancer (HNC), but it marked the first new drug approval for HNC in the United States in 20 years.
“Now we have an agent that really changes the paradigm—a new class of treatment—and we are seeing amazing benefit in some patients,” said Tanguy Seiwert, MD, during an OncLive
Peer Exchange® panel held during the 2016 European Society for Medical Oncology (ESMO) Annual Meeting.
Less than a month later, the menu of immunotherapy options expanded as the FDA approved nivolumab (Opdivo) for the treatment of patients with recurrent or metastatic SCCHN with disease progression on or after a platinum-based therapy.
During the Peer Exchange, the panelists provided an overview of the immunotherapy terrain in HNC, a discussion that was filled with considerable hope and excitement. “When we try immunotherapies in the second-line setting, we see objective responses—sometimes deep, clinically meaningful, extremely durable responses—and we’re beginning to think that maybe, on some occasions, we may be able to cure patients with relapsed metastatic head and neck cancer,” said Kevin Harrington, MD, PhD. This is especially remarkable since such patients have generally had a survival of ≤1 year.
The panelists concurred that the care of patients with HNC will evolve significantly over the next 5 to 10 years, as the tip of the immunotherapy iceberg is just starting to be scratched. During the Peer Exchange, they provided a rationale for using immunotherapies in HNC, including human papillomavirus (HPV)-positive and HPV-negative disease; outlined key immunotherapy studies; and offered their thoughts on the future of immunotherapies in HNC, including use of biomarkers to guide therapy and the opportunity to improve response by using combination treatments.
“Next-generation sequencing efforts are beginning to shed light on the hidden complexities of these tumors, leading to the identification of multiple molecular subtypes,” said Ezra Cohen, MD, who served as moderator for the session. “As key differences between tumors, with and without HPV infection, are beginning to emerge, the challenge is to find ways to use this information to personalize treatment for individual patients.”
Rationale for Immunotherapy in HNC
In patients with locally advanced HNC, HPV status has generally determined outcomes, with HPV-positive patients having a good prognosis and higher likelihood of cure, and HPV-negative patients having a poorer prognosis and a lower likelihood of cure.
However, outcomes with conventional therapy in recurrent metastatic disease have been poor across the board, especially in the setting of platinum- refractory disease, indicating a tremendous unmet need. Before pembrolizumab was approved in this setting, the recommendation was to use a taxane, such as methotrexate or cetuximab (Erbitux), as a single agent, but the outcomes have been unsatisfactory. In contrast, immunotherapy studies have shown promising results in these patients, with HPV-negative patients also benefiting.
“The rationale for [using immunotherapies] for HPV-positive tumors may be the virus, as well as mutations, and for HPV-negative tumors, it’s likely the mutation load,” said Seiwert. He explained that HPV-negative tumors are often smoking-associated tumors and, therefore, have high mutation loads, a factor that has been associated with good response to immunotherapy, whereas HPV-positive tumors resemble melanoma, with significant inflammation, another factor associated with good response.
Although efficacy was found to be the same for HPV-positive and HPV-negative tumors in KEYNOTE-012, which was the study that led to pembrolizumab’s approval for HNC, some CheckMate-141 subanalyses suggest there might be slightly more activity in HPV-positive patients, noted Seiwert.