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: [Ewing sarcoma]. Ewing sarcoma is the second most frequent primary bone cancer affecting children or young adults. Advances in molecular biology have revealed common chromosomal translocations such as EWS-FLI 1 among Ewing sarcoma and related diseases such as primitive neuroectodermal tumor (PNET), so these are considered as Ewing sarcoma family tumor (ESFT). Although fewer than 10% of patients with ESFT survived before establishment of modern multiagent chemotherapy, the multimodal therapeutic regimens including combination chemotherapy, radiotherapy, and surgery can cure 60% of patients with localized disease, due to the collaborative research in European-American or the international trials. The standard chemotherapy for localized ESFT now comprises vincristine , actinomycin D , cyclophosphamide and doxorubicin ( VACD ) in Europe or vincristine , doxorubicin , cyclophosphamide , ifosfamide and etoposide ( VDC-IE ) in North America . Meanwhile, those with metastatic disease have a much worse outcome with an approximately 10-30% 5-year event-free survival rate. New American-European collaborative trials such as EURO-E.W.I.N.G.99 are in progress for further improvement of the cure rate in localized and metastatic ESFT. In Japan, Japan Ewing Sarcoma Study Group (JESS) phase II clinical trial for localized ESFT, and some clinical trials including new drugs are ongoing and waiting for results.

sentence: The standard chemotherapy for localized ESFT now comprises vincristine , actinomycin D , cyclophosphamide and doxorubicin ( VACD ) in Europe or vincristine , doxorubicin , cyclophosphamide , ifosfamide and etoposide ( VDC-IE ) in North America .
[["vincristine", "actinomycin D", "cyclophosphamide", "doxorubicin", "COMB"], ["vincristine", "doxorubicin", "cyclophosphamide", "ifosfamide", "etoposide", "COMB"]]