Adjuvant capecitabine is an effective and better tolerated alternative to chemotherapy following chemoradiation for locoregionally advanced nasopharyngeal carcinoma, according to two phase 3 trials from China.
Despite using different dosing strategies, 3-year failure-free survival approached 90% in both trials, comparable to the standard approach with adjuvant platinum doublets, but with better compliance.
The study teams were looking for “a way to make adjuvant therapy more tolerable,” said oncologist Herbert Loong, MBBS, clinical associate professor at the Chinese University of Hong Kong, who discussed both trials after they were presented at the American Society for Clinical Oncology annual meeting.
Compliance is low with platinum doublets because of the toxicity. About 60%-70% of patients can tolerate 2-3 cycles after chemoradiation, and about a third can’t even start because of the toll chemoradiation took on their bodies, he said.
Induction chemotherapy is an alternative, but patients seem to derive more benefit form adjuvant therapy after chemoradiation. Indeed, “given the fact that we may now have a well established, well tolerated adjuvant therapy for our patients” – capecitabine – “the role of induction therapy” is in question, Dr. Loong said.
Metronomic dosing
One trial randomized 204 patients to metronomic dosing of capecitabine, 650 mg/m2 twice daily for 1 year within 12 to 16 weeks after the last radiation, and 202 others to observation.
The idea of metronomic dosing was to give a lower dose of the agent over a longer period to reduce side effects and perhaps improve efficacy.
Subjects had high-risk stage III to IVA disease with no locoregional disease or distant metastasis after chemoradiotherapy. Almost 80% in both arms also had induction chemotherapy, most commonly docetaxel and cisplatin.
Almost three-quarters of people in the treatment arm complied with capecitabine for an entire year.
At a median follow-up of 38 months, 3-year failure-free survival was 85.3% with metronomic capecitabine vs. 75.7% with observation (hazard ratio, .50, P = .002). Three-year overall survival was 93.3% with capecitabine and 88.6% with observation (HR .44, P = .018).
The incidence of grade 3/4 adverse events was 17.4% with metronomic capecitabine vs. 5.5% with observation. Hand-foot syndrome was the most common complication, occurring in 9% of capecitabine subjects. There were no treatment-related deaths, and there was no clinically meaningful deterioration in quality of life associated with treatment.
The approach “significantly improved” outcomes, “with a manageable safety profile and no compromise to quality of life ... Metronomic adjuvant capecitabine can be an option for first-line treatment in this high-risk” group, concluded investigators led by Jun Ma, MD, professor of radiation oncology and deputy president of Sun Yat-sen University Cancer Center in Guangzhou, China.
Standard dosing
The second trial used standard dosing. The researchers randomized 90 subjects to capecitabine 1,000 mg/m2 twice daily for 14 days in eight 21-day cycles after chemoradiation; 90 subjects were randomized to observation. None of the subjects received induction chemotherapy.
Patients had stage III-IVb disease plus at least one high-risk feature, such as high Epstein Barr virus DNA titers. The majority of patients in both arms had three or more high risk features.
Over 80% of capecitabine subjects completed all eight cycles of treatment.
At a median follow-up of 44.8 months, 3-year failure-free survival was 87.7% with capecitabine vs. 73.3% in the control arm (HR .52, P = .037). Three-year overall survival was 92.6% with capecitabine vs. 88.9% with observation, which wasn’t statistically significant.
The incidence of acute grade 3/4 adverse events was 57.8% with standard dose capecitabine. Rates of hand foot syndrome, mucositis, anemia, and other problems were substantially higher than with observation.
For high-risk patients unable to tolerate chemotherapy, adjuvant capecitabine is a “suitable alternative treatment option,” said lead investigator Jingjing Miao, MD, of the department of nasopharyngeal carcinoma at Sun Yat-sen University Cancer Center, Guangzhou, China.
The trials were funded by Sun Yat-sen University and others. The investigators had no disclosures. Dr. Loong is an adviser, speaker, and/or researcher for a number of companies, including Novartis, Pfizer, and Lilly.