You will be shown a paragraph from a biomedical research article. Your task is to extract all drug combinations appearing in a specific sentence within in the paragraph. Each drug combination should be assigned to one of the following three categories:

- POS: Indicates a positive interaction between the drugs in the combination; for instance, drugs that have an additive or synergistic effect.
- NEG: Indicates a negative interaction between the drugs in the combination; for instance, combining these drugs might result in adverse side effects, or might reduce their efficacy.
- COMB: Indicates that the drugs are given in combination, but the type of interaction between the drugs cannot be determined based on the provided context.

Please format your answer as a json array. Each entry in the array should itself be an array formatted as [<drug_1>, <drug_2>, ..., <drug_n>, <category>] where <category> is one of the three categories listed above and <drug_1>, ..., <drug_n> are drug names copied verbatim from the input sentence. Different combinations may involve different numbers of drugs; in other words, the `n` in <drug_n> may vary.

As an example, the following output describes two extracted drug combinations; one between two drugs, and one between three drugs:

[["artesunate", "artemether", "COMB"], ["Nifedipine", "Labetalol", "Prazosin", "POS"]]

The paragraph and specific sentence are below. You should only extract relationships expressed in the specific sentence; the paragraph is provided for context.

In your output, return only the json array and no other text. If no drug combinations appear, return an empty array `[]`.

paragraph: [ Effect of nedaplatin , 5-FU , and leucovorin combined with radiation therapy in unresectable esophageal carcinoma ] . A 51-year-old male was assessed as having esophageal squamous cell carcinoma with trachea invasion and cervical lymph node metastasis. After one course of chemotherapy using cisplatin (CDDP), 5-fluorouracil (5-FU) and leucovorin (LV), the patient had progressive disease (PD) of the primary lesion and metastatic lymph nodes, and a side effect of severe nausea. One course of nedaplatin, 5-FU and LV combined with radiation was performed alternatively. The effect was evaluated as a partial response (PR) of the primary lesion and metastatic lymph nodes. There were no adverse side effects such as nausea or renal dysfunction except for pancytopenia of grade 2. Increased serum levels of vascular endothelial growth factor (s-VEGF) decreased after the chemoradiotherapy and increased again during continued radiotherapy alone. More information is needed as to whether changes in s-VEGF relate to the clinical effects of the treatment.

sentence: [ Effect of nedaplatin , 5-FU , and leucovorin combined with radiation therapy in unresectable esophageal carcinoma ] .
[["nedaplatin", "leucovorin", "5-FU", "POS"]]