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: The modulatory effect of melatonin on genotoxicity of irinotecan in healthy human lymphocytes and cancer cells. Drug-target interactions can be modified by adding modulatory agents to increase treatment efficacy and clinical outcome. Combination chemotherapy has become increasingly important because drugs acting synergistically can achieve therapeutic effects at substantially lower doses and with a limited spectrum of side effects. irinotecan, known as one of the camptothecin analogs, has shown a broad spectrum of antitumor activity against various malignancies. In this study, we evaluated the effect of melatonin on the genotoxic activity of irinotecan in healthy human lymphocytes and a lung cancer cell line (A549) and a colorectal adenocarcinoma cell line (HT29) in vitro. irinotecan, as a single agent, was shown to induce DNA damage in all types of analyzed cells. The combination of melatonin at concentrations of 50 μM with increasing doses of irinotecan ( 7.5 , 15 , 30 , and 60 μM ) resulted in an increase in the amount of DNA damage in A549 and HT29 cancer cells , but was not effective in inducing DNA damage in healthy human lymphocytes . Analysis of the efficacy of DNA repair, performed after 60 and 120 minutes of postincubation, showed the gradual decrease of DNA percentage in comet tails during repair postincubation in all experimental samples. Our results indicate that melatonin can modulate the genotoxic activity of irinotecan and DNA repair efficacy in human cancer cells in vitro. These findings may be supportive for the optimization of therapeutic efficacy in irinotecan treatment.

sentence: The combination of melatonin at concentrations of 50 μM with increasing doses of irinotecan ( 7.5 , 15 , 30 , and 60 μM ) resulted in an increase in the amount of DNA damage in A549 and HT29 cancer cells , but was not effective in inducing DNA damage in healthy human lymphocytes .
[["melatonin", "irinotecan", "POS"]]