On November 5, 2026, the U.S. Food and Drug Administration granted accelerated approval to subcutaneous amivantamab and hyaluronidase-lpuj, marking the first new treatment option for advanced head and neck cancer in a decade. This approval is significant not just for the availability of a new drug, but for the specific mechanism it employs: a bispecific antibody that simultaneously blocks two distinct escape pathways used by tumor cells to resist previous therapies.
The Problem of Resistance in Head and Neck Cancer
For patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC), the landscape of treatment has historically been difficult. Once standard platinum-based chemotherapy and immunotherapy stop working, options have been limited to agents with modest response rates. According to the FDA, currently approved therapies in this setting yield response rates of roughly 20% or lower. For many patients, this meant that after initial treatment, the disease often progressed with few effective alternatives.
The biological challenge lies in how these tumors evolve. Head and neck squamous cell carcinoma is a complex disease that can arise in the oral cavity, pharynx, or larynx. While immune checkpoint inhibitors changed the treatment landscape, many patients eventually experience disease progression. A key driver of this progression is the activation of specific signaling pathways that allow cancer cells to bypass the effects of standard EGFR-targeted therapies. Understanding how to block these pathways is where amivantamab offers a different approach.
How the Bispecific Mechanism Works
Amivantamab is a bispecific monoclonal antibody, a class of drugs that can bind to two different targets at the same time. Unlike standard inhibitors that might focus on a single receptor, amivantamab targets both the epidermal growth factor receptor (EGFR) and the mesenchymal-epithelial transition (MET) receptor. This dual targeting is the core of its mechanism for overcoming resistance.
In head and neck cancer, MET activation is a known escape mechanism. When tumors are treated with EGFR inhibitors, they can sometimes become resistant by upregulating or activating the MET pathway, effectively bypassing the blockade on EGFR. By inhibiting both EGFR and MET simultaneously, amivantamab aims to prevent the tumor from using this alternative route. The drug blocks ligand binding to both receptors, prevents receptor activation, and triggers antibody-dependent cellular cytotoxicity (ADCC) and trogocytosis, processes that help the immune system recognize and destroy cancer cells.
This approach differs from earlier generations of EGFR-targeted therapies, such as cetuximab, which were used in this setting but had limited duration and activity. The development of amivantamab reflects a broader shift toward targeting the specific resistance pathways that emerge during treatment, rather than just the primary driver of the cancer.
OrigAMI-4 Trial Results and Clinical Data
The approval is based on data from the phase 1b/2 OrigAMI-4 trial, specifically Cohort 1, which included 102 adults who had previously received platinum-based chemotherapy and an anti-PD-(L)1 antibody. In this cohort, the confirmed overall response rate (ORR) by blinded independent central review was 42%, with a 95% confidence interval of 32% to 52%. This included complete responses in 15% of patients and partial responses in 28%.
These numbers stand in contrast to the historical response rates of approximately 20% or lower for previously approved therapies in this setting. Among the patients who did respond, 56% maintained their response for at least six months, with a range extending from 1.4+ to 19.7+ months. The median time to first response was 6.6 weeks, and at the time of analysis, 63% of responses were still ongoing. While the median duration of response was not reached, the data suggests that for a significant portion of patients, the tumor shrinkage was sustained.
It is important to note that this approval is based on an accelerated approval pathway, meaning continued approval may be dependent on verification of clinical benefit in the ongoing confirmatory phase 3 OrigAMI-5 trial. The trial data also showed that investigator-assessed ORR was 47%, and 84% of evaluable patients experienced shrinkage of target lesions. At a median follow-up of 11.8 months, the median progression-free survival was 6.8 months, and the median overall survival was 12.5 months.
Safety Profile and Side Effects
The safety profile of subcutaneous amivantamab in the OrigAMI-4 trial was comparable with previous reports of the agent, with no new safety signals identified. Rash was the most frequently reported side effect, occurring in 79% of patients. Fatigue was reported in 39%, and nail toxicity in 35%. Stomatitis, or inflammation of the mouth, occurred in 32% of patients.
Serious adverse effects included pneumonia in 8% of patients, hemorrhage in 4.9%, and dysphagia in 2.9%. The subcutaneous formulation, which includes hyaluronidase-lpuj to facilitate injection under the skin, reduces infusion-related reactions compared to intravenous administration. However, skin toxicity and paronychia, which are related to EGFR inhibition, persist regardless of the route of administration. Patients should be aware that these side effects are common and require management, but they are a known part of the treatment profile.
Implications for HPV-Unrelated Disease
The approval specifically excludes patients with HPV-associated oropharyngeal squamous cell carcinoma, as determined by p16 immunohistochemistry. This distinction is crucial because HPV-positive head and neck cancers often have different biological behaviors and prognoses compared to HPV-negative, or HPV-unrelated, diseases. The exclusion suggests that the benefit of amivantamab is most pronounced in patients with HPV-unrelated tumors, where EGFR and MET pathways play a more dominant role in resistance.
Data from other cohorts of the OrigAMI-4 trial support this focus. In Cohort 5, which evaluated amivantamab in combination with carboplatin and pembrolizumab in the first-line setting, the overall response rate was 66%. However, among patients with HPV-unrelated tumors, the response rate was 77%. This higher response rate in the HPV-unrelated subgroup reinforces the idea that EGFR-targeted therapies may have greater efficacy in this specific population. For patients with HPV-related disease, other treatment strategies may be more appropriate, and the data from this approval does not apply to them.
What This Means for Patients
For patients with recurrent or metastatic HNSCC who have progressed on platinum-based chemotherapy and immunotherapy, this approval offers a new option after a decade without a new drug in this setting. The dual-targeting mechanism addresses a specific biological challenge, providing a rationale for why it may work when other options have failed. The encouraging part is that the response rates in the trial are significantly higher than historical benchmarks, and a portion of patients experienced long-lasting responses.
However, patients should approach this with realistic expectations. The trial was relatively small, with 102 patients in the primary cohort, and the data are from a phase 1b/2 study. While the response rates are promising, they do not guarantee that every patient will benefit. Non-responders make up the majority of the cohort, and the long-term survival benefits are still being established in ongoing phase 3 trials. The side effects, while manageable, are significant and require active monitoring and support from a multidisciplinary team, including oncology nurses, pharmacists, and dermatology specialists.
Amivantamab was first approved in May 2021 for non-small cell lung cancer with specific EGFR exon 20 insertion mutations, and its use in head and neck cancer represents an expansion of its application based on the shared biology of EGFR and MET pathways. The development by Johnson & Johnson’s Janssen Biotech highlights the ongoing effort to refine targeted therapies for different cancer types. For patients, the key takeaway is that there is now a new tool in the oncologist’s toolkit, one that targets the specific mechanisms of resistance that have limited previous treatments. As with any new therapy, it is essential to discuss the potential benefits and risks with a healthcare provider who can evaluate individual circumstances. Talk to your doctor or oncologist to determine if this treatment is appropriate for your specific case.
Sources
- After a Decade Without a New Option, FDA Approves Amivantamab for Head and Neck Cancer – OncoDaily
- Amivantamab
- FDA Approves SC Amivantamab for Recurrent/Metastatic HNSCC | CancerNetwork
- FDA Approves Amivantamab and Hyaluronidase for Recurrent/Metastatic HNSCC | Targeted Onc – Immunotherapy, Biomarkers, and Cancer Pathways
- PAPILLON Overall Survival and Subcutaneous Amivantamab | OncLive
- OrigAMI-4 Highlights Promise of Amivantamab in Head and Neck Cancer | Cancer Nursing Today
Photo: ajay_suresh (CC BY 4.0)
