Inclusion Criteria:

1. Have given written informed consent, prior to pre-study screening, with the understanding that consent may be withdrawn at any time without prejudice.
2. A histological diagnosis of nasopharyngeal cancer (NPC) must have been established at some time and the investigator must review and confirm the diagnosis prior to randomization.
3. Loco-regional advanced NPC UICC/AJCC Stages IIB, III, IVA or IVB.
4. No evidence of distant metastases in the staging work up at diagnosis.
5. Must have detectable plasma EBV-DNA (> 0 copies/ml) at 6-8 weeks after completion of primary RT or chemo-RT
6. No clinical evidence of persistent loco-regional disease after primary treatment
7. Performance status of ECOG grade 0 or 1.

8. Patients must have adequate organ and marrow function as defined below:

   leukocytes >3,000/L; absolute neutrophil count >1,500/L; platelets >100,000/L; total bilirubin <1.5 X institutional upper limit of normal; AST(SGOT)/ALT(SGPT) <2.5 X institutional upper limit of normal; Creatinine clearance > 50 ml/min

9. At least 18 years of age, of either sex.
10. If female, must be either (i) post-menopausal or surgically sterilized, or (ii) use a hormonal contraceptive, intra-uterine device, diaphragm with spermicide for the duration of the study and must be neither pregnant nor breast-feeding.

Exclusion Criteria:

1. Hypercalcaemia: calcium >= 2.7 mmol/L (10.8 mg/dL).
2. Second primary malignancy (except in situ carcinoma of the cervix or adequately treated basal cell carcinoma of the skin).
3. More that 12 weeks after completion of primary radiotherapy.
4. Had received prior adjuvant chemotherapy.
5. Other serious concomitant systemic disorders incompatible with the study (at the discretion of the investigator).
6. Have serious active infection.
7. Patients with peripheral or ototoxicity with a grade of greater than or equal to 2.
8. Pregnant or lactating female subjects and subjects with reproductive potential not implementing adequate contraceptive measures.