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: Sorafenib and continued erlotinib or sorafenib alone in patients with advanced non-small cell lung cancer progressing on erlotinib: A randomized phase II study of the Sarah Cannon Research Institute (SCRI). To evaluate the efficacy of erlotinib, continued after tumor progression, plus sorafenib versus sorafenib alone in patients with refractory metastatic non-small cell lung cancer (NSCLC) who previously benefitted from single-agent erlotinib. ### Patients And Methods Patients with progressive refractory NSCLC who had previously benefitted from erlotinib ( objective response or stable disease > 8weeks ) were randomized to receive treatment with either erlotinib and sorafenib ( 400 mg orally twice daily ) or sorafenib alone . Patients were evaluated for response every 8 weeks, and continued treatment until disease progression or intolerable toxicity. ### results Fifty-three patients were randomized (erlotinib/sorafenib, 25; sorafenib, 28) and 52 patients received study treatment. Patients in both groups received a median of 8weeks of treatment. The median PFS was 3.1months for erlotinib/sorafenib versus 1.7months for sorafenib alone; response rates were 8% and 4%, respectively. Both regimens were tolerable, but toxicity was more frequent with erlotinib/sorafenib. ### conclusions These results do not suggest any benefit in continuing erlotinib after tumor progression in patients with refractory metastatic NSCLC. Both regimens tested had limited efficacy, consistent with results from other studies. ClinicalTrials.gov ID:NCT00609804.

sentence: Patients with progressive refractory NSCLC who had previously benefitted from erlotinib ( objective response or stable disease > 8weeks ) were randomized to receive treatment with either erlotinib and sorafenib ( 400 mg orally twice daily ) or sorafenib alone .
[["erlotinib", "sorafenib", "NEG"]]