Highlights
The secondary analysis of the CAPTAIN-1st trial provides the first five-year evidence for the efficacy of PD-1-based chemoimmunotherapy in recurrent or metastatic nasopharyngeal carcinoma (RM-NPC). Key highlights include:
- A significant improvement in median overall survival (OS) to 34.5 months with camrelizumab plus chemotherapy, compared to 26.6 months with chemotherapy alone.
- A 13.6% absolute increase in the five-year survival rate (37.8% vs. 24.2%).
- The identification of rapid Epstein-Barr virus (EBV) DNA clearance as a powerful predictor of long-term survival benefit.
- Consistent clinical benefit across various subgroups, reinforcing the combination as a standard-of-care first-line treatment.
Disease Burden and Clinical Context
Nasopharyngeal carcinoma (NPC) is a distinct head and neck malignancy with a unique geographical distribution, being highly prevalent in Southern China and Southeast Asia. Unlike other head and neck cancers, NPC is strongly associated with Epstein-Barr virus (EBV) infection and is known for its high sensitivity to both radiotherapy and chemotherapy. However, for patients presenting with recurrent or metastatic (RM) disease, the prognosis has historically been poor.
For several years, the combination of gemcitabine and cisplatin (GP) served as the global standard for first-line treatment of RM-NPC. While this regimen improved progression-free survival (PFS), the long-term survival remained limited, with many patients progressing within a year. The advent of immune checkpoint inhibitors, specifically those targeting the programmed cell death 1 (PD-1) pathway, has revolutionized the treatment landscape. While early results from trials like CAPTAIN-1st, JUPITER-02, and RATIONALE-309 demonstrated significant PFS benefits, the medical community has eagerly awaited long-term survival data to confirm whether these initial gains translate into durable, five-year survival—the gold standard for oncology benchmarks.
Study Design: The CAPTAIN-1st Trial
The CAPTAIN-1st trial was a multicenter, randomized, double-blind, phase 3 clinical trial conducted across 28 hospitals in China. The study enrolled 263 patients with treatment-naive RM-NPC between November 2018 and November 2019. This secondary analysis was prespecified to evaluate the long-term survival outcomes after a minimum follow-up of five years.
Patient Selection and Randomization
Patients were randomized in a 1:1 ratio to receive either camrelizumab (a humanized anti-PD-1 IgG4 antibody) or a placebo, both in combination with gemcitabine and cisplatin. The camrelizumab group consisted of 134 patients, while the placebo group included 129 patients. The baseline characteristics were well-balanced, though a slight age imbalance was noted (mean age 49 years) and adjusted for in the final statistical analysis.
Intervention Protocol
The treatment phase involved 4 to 6 cycles of the chemoimmunotherapy combination, followed by a maintenance phase. In the maintenance phase, patients received either camrelizumab or placebo until disease progression, the occurrence of unacceptable toxic effects, or the completion of two years of treatment. The primary endpoint was PFS as determined by an independent review committee, while the secondary endpoint reported in this analysis was overall survival (OS).
Key Findings: Five-Year Survival and Statistical Significance
With a median follow-up of over 63 months, the CAPTAIN-1st trial results provide a robust picture of the long-term impact of camrelizumab. The findings underscore a statistically significant and clinically meaningful improvement in OS for patients receiving the triple-drug regimen.
Overall Survival Metrics
The median OS was 34.5 months (95% CI, 29.4-45.7) for the camrelizumab group compared to 26.6 months (95% CI, 19.8-33.5) for the placebo group. This represents a hazard ratio (HR) of 0.74 (95% CI, 0.55-0.99; P = .047). When the researchers adjusted for the baseline age imbalance, the HR improved to 0.65 (95% CI, 0.48-0.89; P = .01), indicating a 35% reduction in the risk of death.
The Five-Year Benchmark
Perhaps the most compelling data point is the 5-year OS rate. At the 60-month mark, 37.8% of patients in the camrelizumab group were alive, compared to only 24.2% in the placebo group. The absolute difference of 13.6% (95% CI, 2.4%-24.8%; P = .02) demonstrates that a substantial portion of patients can achieve long-term survival when immunotherapy is integrated into the first-line setting.
The Role of EBV DNA as a Biomarker
One of the most clinically relevant findings from this secondary analysis is the correlation between Epstein-Barr virus (EBV) DNA clearance and survival outcomes. EBV DNA levels have long been used in NPC for screening, staging, and monitoring recurrence, but their role as a dynamic biomarker during immunotherapy is increasingly clear.
In the camrelizumab group, patients who achieved rapid clearance of EBV DNA (defined as undetectable levels after early treatment cycles) experienced significantly longer OS. The hazard ratio for death in patients with rapid EBV DNA clearance versus those without was 0.32 (95% CI, 0.18-0.58; P < .001). This suggests that early viral response is a critical indicator of the immune system's successful engagement with the tumor, potentially allowing clinicians to identify a subset of 'super-responders' who are likely to achieve the five-year survival milestone.
Expert Commentary and Clinical Implications
The results of the CAPTAIN-1st secondary analysis are poised to solidify the role of camrelizumab in the standard of care for RM-NPC. While previous reports focused on progression-free survival, the confirmation of OS benefits at five years addresses a major gap in the evidence base. For clinicians, these data provide the confidence to recommend chemoimmunotherapy not just for delaying progression, but for extending life.
Translational Insight
The synergy between gemcitabine/cisplatin and camrelizumab is likely rooted in the immunogenic cell death caused by chemotherapy, which releases tumor antigens and enhances the visibility of NPC cells to the immune system. Given that NPC is a highly inflamed tumor type with a dense lymphocytic infiltrate (the ‘lymphoepithelioma’ morphology), it is uniquely primed for PD-1 inhibition.
Limitations and Considerations
While the results are overwhelmingly positive, the study was conducted entirely within a Chinese population. Given the distinct epidemiology of EBV-associated NPC in this region, the generalizability to non-EBV-associated NPC (more common in Western countries) remains a subject of discussion. Furthermore, the optimal duration of maintenance therapy—currently capped at two years in this trial—remains a point of clinical debate, as some patients may benefit from longer or shorter durations based on EBV DNA persistence.
Conclusion
The 5-year secondary analysis of the CAPTAIN-1st trial marks a milestone in the treatment of recurrent or metastatic nasopharyngeal carcinoma. By demonstrating a clear OS advantage and a significant 5-year survival rate of nearly 38%, camrelizumab plus gemcitabine and cisplatin establishes a high bar for first-line therapy. The integration of EBV DNA monitoring further offers a path toward personalized medicine, allowing for better prognostic stratification in this challenging disease setting.
Funding and Registration
The CAPTAIN-1st trial was supported by Jiangsu Hengrui Pharmaceuticals Co., Ltd. The trial is registered at ClinicalTrials.gov with the identifier NCT03707509.
References
1. Huang Y, Sun D, Zhou H, et al. Five-Year Outcome of Camrelizumab Plus Chemotherapy in Recurrent or Metastatic Nasopharyngeal Carcinoma: A Secondary Analysis of the CAPTAIN-1st Randomized Clinical Trial. JAMA Oncol. 2026;12(1). doi:10.1001/jamaoncol.2025.6245.
2. Zhang L, Huang J, Yang Y, et al. Gemcitabine plus cisplatin versus fluorouracil plus cisplatin in recurrent or metastatic nasopharyngeal carcinoma: a multicentre, randomised, open-label, phase 3 trial. Lancet. 2016;388(10054):1883-1892.
3. Mai HQ, Chen QY, Chen D, et al. Toripalimab or placebo plus chemotherapy as first-line treatment in advanced nasopharyngeal carcinoma: a multicenter, randomized, phase 3 trial (JUPITER-02). Nature Medicine. 2021;27(9):1536-1543.
