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: [In vivo assessment on the therapeutic effects of etoposide, vincristine and mitomycin C against human neuroblastoma].  Anti-tumor effects of etoposide ( VP-16 ) , vincristine and mitomycin C were evaluated with four human neuroblastoma xenograft , according to Battelle Columbus Laboratories protocol . etoposide is one of the agents which has been reported to be effective against advanced neuroblastoma clinically, if combined with other agents. While vincristine was effective against 1 out 4 neuroblastoma xenografts, TS-N-2, with 58.1% maximum inhibition rate, etoposide was assessed ineffective as a single agent in all of the 3 xenografts used. Since etoposide had no effect on the weight gain in nude mice in this xenograft experiment, the dose of etoposide was increased two-fold against 2 xenografts, but found ineffective also in the increased dose. mitomycin C, which has not been used in childhood malignant tumors, was effective against 2 out of 4 xenografts, TNB-9 and SK-N-AS, with 72.0% and 78.4% maximum inhibition rates, respectively.

sentence: Anti-tumor effects of etoposide ( VP-16 ) , vincristine and mitomycin C were evaluated with four human neuroblastoma xenograft , according to Battelle Columbus Laboratories protocol .
[]