Maintenance Capecitabin Yields Significant PFS Improvement in Newly Diagnosed Nasopharyngeal Cancer

Improved progression-free survival (PFS) was observed following maintenance capecitabine in patients newly diagnosed metastatic nasopharyngeal carcinoma who experienced disease control following capecitabine-containing induction chemotherapy compared with best supportive care, according to findings from a phase 3 trial (NCT02460419).

The median PFS was 35.9 months (95% CI, 20.5–not reached [NR]) in the capecitabine arm compared with 8.2 months (95% CI, 6.4-10.0) in the best supportive care arm (HR, 0.44; 95% CI, 0.26-0.74; P = .002). An objective response of 25.0% was seen in the capecitabine arm vs 11.5% in the best supportive care arm. The capecitabine arm also had a longer median duration of response at 40.0 months (95% CI, NR-NR) vs 13.2 months (95% CI, 9.9-16.5) in the best supportive care arm (HR, 0.44; 95% CI, 0.26-0.75; P = .002).

A total of 104 patients enrolled on the trial, the majority of whom were men (80.8%). The median age was 47 years. Patients were randomly assigned to either the capecitabine arm (n = 52) or the best supportive care arm (n = 52). Additionally, 96.2% of patients had undifferentiated nonkeratinizing carcinoma, and 58.7% had synchronous metastatic nasopharyngeal carcinoma.

A median of 24 cycles of capecitabine was administered. By May 2021, 39 patients had discontinued after completing the 2-years of therapy (n = 18), intolerable adverse effects (AEs; n = 1), disease progression (n = 16), death (n = 2), and consent withdrawal (n = 2). Neither death was considered to be related to treatment and occurred due to disease progression. Those in the best supportive care group discontinued (n = 40) because of disease progression (n = 35), death (n = 1), or withdrawal of consent (n = 4).

The median follow-up in the intent-to-treat population was 33.8 months. The post-hoc analysis found patients in all subgroups had consistent PFS results when treated with capecitabine. The only difference was found in patients who had synchronous metastatic nasopharyngeal carcinoma.

In the capecitabine arm, 14 patients died during follow-up vs 23 in the best supportive care arm. The overall survival (OS) data were still immature. Median OS was not reached in the capecitabine arm and was 41.5 months in the best supportive care arm. No major difference in OS between the arms was observed (HR, 0.59; 95% CI, 0.30-1.16; P = .13). Investigators excluded patients who had crossover treatment and found a significant OS difference between groups.

Patients had a low overall incidence of grade 3 or 4 AEs. In the capecitabine arm, patients experienced anemia (12.0%), hand-foot syndrome (10.0%), nausea and vomiting (6.0%), fatigue (4.0%), mucositis (4.0%), neutropenia (2.0%), and thrombocytopenia (2.0%). Patients had dose modifications because of neutropenia (n = 1), fatigue (n = 1), nausea and vomiting (n = 2), and hand-foot syndrome (n = 3). Investigators did not observe any treatment-related deaths.

Reference

Liu GY, Li WZ, Wang DS, et al. 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 Published Online February 17, 2022. JAMA Oncol. doi:10.1001/jamaoncol.2021.7366