Effect of Capecitabine Maintenance Therapy Plus Best Supportive Care vs Best Supportive Care Alone on Progression-Free Survival Among Patients With Newly Diagnosed Metastatic Nasopharyngeal Carcinoma Who Had Received Induction Chemotherapy: A Phase 3 Randomized Clinical Trial

IMPORTANCE

Capecitabine maintenance therapy improves survival outcomes in various cancer types, but data are limited on the efficacy and safety of capecitabine maintenance therapy in metastatic nasopharyngeal carcinoma (NPC).

OBJECTIVE

To investigate the efficacy and safety of capecitabine maintenance therapy in metastatic NPC.

DESIGN, SETTING, AND PARTICIPANTS

This randomized phase 3 clinical trial was conducted at Sun Yat-sen University Cancer Center from May 16, 2015, to January 9, 2020, among 104 patients with newly diagnosed metastatic NPC who had achieved disease control after 4 to 6 cycles of induction chemotherapy with paclitaxel, cisplatin, and capecitabine. The final follow-up date was May 30, 2021. All efficacy analyses were conducted in the intention-to-treat population.

INTERVENTIONS

Eligible patients were randomly assigned (1:1) to receive either capecitabine maintenance therapy (1000 mg/m2 orally twice daily on days 1-14) every 3 weeks plus best supportive care (BSC) (capecitabine maintenance group) or BSC alone after 4 to 6 cycles of induction chemotherapy.

MAIN OUTCOMES AND MEASURES

Progression-free survival (PFS). Secondary end points were objective response rate, duration of response, overall survival, and safety.

RESULTS

This study included 104 patients (84 men [80.8%]; median age, 47 years [IQR, 38-54 years]), with 52 assigned to the capecitabine maintenance group and 52 assigned to the BSC group. After a median follow-up of 33.8 months (IQR, 22.9-50.7 months), there were 23 events (44.2%) of progression or death in the capecitabine maintenance group and 37 events (71.2%) of progression or death in the BSC group. Median PFS survival was significantly higher in the capecitabine maintenance group (35.9 months [95% CI, 20.5 months-not reached]) than in the BSC group (8.2 months [95% CI, 6.4-10.0 months]), with a hazard ratio of 0.44 (95% CI, 0.26-0.74; P = .002). Higher objective response rates and longer median duration of response were observed in the capecitabine maintenance group (25.0%; 40.0 months) compared with the BSC group (objective response rate, 25.0% [n = 13] vs 11.5% [n = 6]; and median duration of response, 40.0 months [95% CI, not reached-not reached] vs 13.2 months [95% CI, 9.9-16.5 months]). The most common grade 3 or 4 adverse events during maintenance therapy were anemia (6 of 50 [12.0%]), hand-foot syndrome (5 of 50 [10.0%]), nausea and vomiting (3 of 50 [6.0%]), fatigue (2 of 50 [4.0%]), and mucositis (2 of 50 [4.0%]). No deaths in the maintenance group were deemed treatment-related.

CONCLUSIONS AND RELEVANCE

In this phase 3 randomized clinical trial, capecitabine maintenance therapy significantly improved PFS for patients with newly diagnosed metastatic NPC who achieved disease control after capecitabine-containing induction chemotherapy. Capecitabine exhibited manageable toxic effects.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02460419.

Phase II, Randomized Study of Spartalizumab (PDR001), an Anti-PD-1 Antibody, versus Chemotherapy in Patients with Recurrent/Metastatic Nasopharyngeal Cancer

BACKGROUND

No standard treatment exists for platinum-refractory, recurrent/metastatic nasopharyngeal cancer (NPC). This phase II study (NCT02605967) evaluated progression-free survival (PFS) of spartalizumab, an antiprogrammed cell death protein-1 (PD-1) monoclonal antibody, versus chemotherapy, in NPC.

PATIENTS AND METHODS

Patients with nonkeratinizing recurrent/metastatic NPC who progressed on/after platinum-based chemotherapy were enrolled. Spartalizumab was dosed 400 mg once every 4 weeks, and chemotherapy was received per investigator's choice.

RESULTS

Patients were randomized to receive either spartalizumab (82 patients) or chemotherapy (40 patients). The most common spartalizumab treatment-related adverse events were fatigue (10.3%) and pruritus (9.3%). Median PFS in the spartalizumab arm was 1.9 months versus 6.6 months in the chemotherapy arm (P = 0.915). The overall response rate in the spartalizumab arm was 17.1% versus 35.0% in the chemotherapy arm. Median duration of response was 10.2 versus 5.7 months in the spartalizumab versus chemotherapy arms, respectively. Median overall survival was 25.2 and 15.5 months in the spartalizumab and chemotherapy arms, respectively. Tumor RNA sequencing showed a correlation between response to spartalizumab and IFNγ, LAG-3, and TIM-3 gene expression.

CONCLUSIONS

Spartalizumab demonstrated a safety profile consistent with other anti-PD-1 antibodies. The primary endpoint of median PFS was not met; however, median overall survival and median duration of response were longer with spartalizumab compared with chemotherapy.

The Role of Immunotherapy to Overcome Resistance in Viral-Associated Head and Neck Cancer

A subset of head and neck cancers arising in the oropharynx and the nasopharynx are associated with human papillomavirus or Epstein-Barr virus. Unfortunately, limited treatment options exist once patients develop recurrent or metastatic disease in these cancers. Interest has risen in utilizing novel strategies including combination immune checkpoint inhibitors, vaccines, and adoptive cellular therapy, to improve treatment response and outcomes. Several ongoing studies are investigating the potential to overcome resistance to standard of care chemoradiation therapy with monotherapy or combination immunotherapy strategies in these viral-associated head and neck cancers.