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: Long-term safety and outcome of fludarabine , cyclophosphamide and mitoxantrone ( FCM ) regimen in previously untreated patients with advanced follicular lymphoma : 12 years follow-up of a phase 2 trial . fludarabine combinations are very affective in follicular lymphoma (FL) with high rates of complete response and prolonged survival. However, late toxicities could be a concern. The aim of the present study was to analyze the long-term impact on survival, relapse and late toxicities of a trial of treatment with fludarabine, mitoxantrone and cyclophosphamide (FCM regimen) for untreated patients with advanced stage FL. One hundred and twenty patients enrolled in a phase 2 trial of treatment with FCM regimen between 2000 and 2003 were evaluated. After a median follow-up of 12 years, 52 patients eventually relapsed/progressed with 10 year progression-free survival (PFS) of 46 %. Ten patients showed histological transformation to aggressive lymphoma with a risk of transformation of 2 and 9 % at 5 and 10 years, respectively. Three patients developed therapy-related myelodysplastic syndrome/acute myeloid leukaemia (MDS/AML) and seven solid neoplasms with an overall risk of 3 and 8 % at 5 and 10 years, respectively. Twenty-six patients eventually died during the follow-up. Overall survival at 10 years was 83 %. In conclusion, FCM regimen allows excellent long-lasting response in previously untreated patients with FL. The incidence of late events including histological transformation and secondary neoplasia is low but not negligible.

sentence: Long-term safety and outcome of fludarabine , cyclophosphamide and mitoxantrone ( FCM ) regimen in previously untreated patients with advanced follicular lymphoma : 12 years follow-up of a phase 2 trial .
[["fludarabine", "cyclophosphamide", "mitoxantrone", "POS"]]