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: Triplet chemotherapy in patients with metastatic colorectal cancer: toward the best way to safely administer a highly active regimen in clinical practice. A major problem concerning the addition of more drugs in a chemotherapy combination is designing a proper schedule assuring the balance between dose intensity of each drug, efficacy of the combination, and tolerability lessening the burden of drug toxicity. We evaluated triplet chemotherapy-based intensive regimens proposed as first-line treatment in patients with metastatic colorectal cancer. Using a FOLFOXIRI ( 5-fluorouracil [ 5-FU ] , irinotecan , and oxaliplatin ) combination regimen , patients with metastatic colorectal cancer now have the possibility of longer survival , but disappointingly , with increased toxicities . Triplet chemotherapy regimen according to 5-fluorouracil, irinotecan /5-fluorouracil, oxaliplatin, characterized by timed flat-infusion 5-FU administration, without leucovorin, obtained efficacy equivalent to other reported similar combination regimens (5-FU, irinotecan, and oxaliplatin), with increased received 5-FU dose intensity and lower grade 3 to 4 neutropenia. To guarantee the proper balance between dose intensities, efficacy, and toxicity, triplet chemotherapy schedules could be further improved by abrogation of folinic acid and bolus 5-FU, a new and easy modality of 5-FU administration, such as timed flat-infusion 5-FU, associated with alternating irinotecan and oxaliplatin; this could favor diffusion of this intensive treatment in clinical practice.

sentence: Using a FOLFOXIRI ( 5-fluorouracil [ 5-FU ] , irinotecan , and oxaliplatin ) combination regimen , patients with metastatic colorectal cancer now have the possibility of longer survival , but disappointingly , with increased toxicities .
[["5-FU", "irinotecan", "oxaliplatin", "POS"]]