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: Phase Ib Study of the Oral Proteasome Inhibitor Ixazomib ( MLN9708 ) and Fulvestrant in Advanced ER+ Breast Cancer Progressing on Fulvestrant . fulvestrant is a selective estrogen receptor (ER)-downregulating anti-estrogen that blocks ER transcriptional activity and is approved for ER+ breast cancer. fulvestrant also induces accumulation of insoluble ER and activates an unfolded protein response; proteasome inhibitors have been shown to enhance these effects in preclinical models. ### background fulvestrant is a selective estrogen receptor (ER)-downregulating anti-estrogen that blocks ER transcriptional activity and is approved for ER+ breast cancer. fulvestrant also induces accumulation of insoluble ER and activates an unfolded protein response; proteasome inhibitors have been shown to enhance these effects in preclinical models. ### methods This is a single-center phase Ib study with a 3+3 design of fulvestrant and the proteasome inhibitor ixazomib (MLN9708) in patients with advanced ER+ breast cancer that was progressing on fulvestrant. A dose-escalation design allowed establishment of the ixazomib maximum tolerated dose (MTD). Secondary objectives included progression-free survival, pharmacokinetics, and tumor molecular analyses. ### results Among nine evaluable subjects, treatment was well-tolerated without dose-limiting toxicities The MTD of ixazomib was 4 mg in combination with fulvestrant. Plasma concentrations of the active form of ixazomib (MLN2238) in the 4-mg dose cohort had a median (range) Cmax of 155 (122-171) ng/mL; Tmax of 1 (1-1.5) h; terminal elimination half-life of 66.6 (57.3-102.6) hr after initial dose; AUC of 5,025 (4,160-5,345) ng*h/mL. One partial response was observed, and median progression-free survival was 51 days (range 47-137). ### conclusion This drug combination has a favorable safety profile and anti-tumor activity in patients with fulvestrant-resistant advanced ER+ breast cancer that justifies future testing.

sentence: Phase Ib Study of the Oral Proteasome Inhibitor Ixazomib ( MLN9708 ) and Fulvestrant in Advanced ER+ Breast Cancer Progressing on Fulvestrant .
[["Ixazomib", "Fulvestrant", "POS"]]