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: Bilateral orchiectomy with or without flutamide for metastatic prostate cancer. Combined androgen blockade for the treatment of metastatic prostate cancer consists of an antiandrogen drug plus castration. In a previous trial , we found that adding the antiandrogen flutamide to leuprolide acetate ( a synthetic gonadotropin-releasing hormone that results in medical ablation of testicular function ) significantly improved survival as compared with that achieved with placebo plus leuprolide acetate . In the current trial, we compared flutamide plus bilateral orchiectomy with placebo plus orchiectomy. ### methods We randomly assigned patients who had never received antiandrogen therapy and who had distant metastases from adenocarcinoma of the prostate to treatment with bilateral orchiectomy and either flutamide or placebo. Patients were stratified according to the extent of disease and according to performance status. ### results Of the 1387 patients who were enrolled in the trial, 700 were randomly assigned to the flutamide group and 687 to the placebo group. Overall, the incidence of toxic effects was minimal; the only notable differences between the groups were the greater rates of diarrhea and anemia with flutamide. There was no significant difference between the two groups in overall survival (P=0.14). The estimated risk of death (hazard ratio) for flutamide as compared with placebo was 0.91 (90 percent confidence interval, 0.81 to 1.01). flutamide was not associated with enhanced benefit in patients with minimal disease. ### conclusions The addition of flutamide to bilateral orchiectomy does not result in a clinically meaningful improvement in survival among patients with metastatic prostate cancer.

sentence: In a previous trial , we found that adding the antiandrogen flutamide to leuprolide acetate ( a synthetic gonadotropin-releasing hormone that results in medical ablation of testicular function ) significantly improved survival as compared with that achieved with placebo plus leuprolide acetate .
[["flutamide", "leuprolide acetate", "POS"]]