Based on the information provided, I cannot determine a specific recommended frequency for evaluating the effectiveness of lurbinectedin. However, I can provide some context that may help guide such decisions.

Lurbinectedin is a novel anticancer drug that has shown promise in treating small cell lung cancer and other types of cancer. It works by inhibiting the transcriptional activity of oncogenic proteins, which can lead to tumor cell death [1].

The effectiveness of lurbinectedin, like any other drug, may vary among patients due to factors such as individual genetic makeup, tumor characteristics, and the presence of other medical conditions. Therefore, it is essential to monitor each patient's response to the treatment and adjust the therapy as needed.

In general, oncologists evaluate a cancer drug's effectiveness by monitoring several factors, including tumor size, symptoms, and patient quality of life. These evaluations typically occur at regular intervals, such as every 1-3 months, depending on the type of cancer and the specific treatment plan [2].

For lurbinectedin, the frequency of evaluating its effectiveness should be determined on a case-by-case basis, considering the patient's overall health, the type and stage of cancer, and the patient's response to treatment. Regular follow-ups with the healthcare team are crucial to assessing the drug's effectiveness and making informed decisions about continuing, modifying, or discontinuing the treatment [1].

In summary, the frequency of evaluating lurbinectedin's effectiveness depends on individual patient factors and the specific treatment plan. Regular follow-ups with the healthcare team are essential for monitoring the drug's effectiveness and adjusting the treatment as needed.

Sources:
[1] DrugPatentWatch.com. (n.d.). Lurbinectedin. Retrieved from https://www.drugpatentwatch.com/drugs/lurbinectedin
[2] American Cancer Society. (2021, March 17). Follow-up care after cancer treatment. Retrieved from https://www.cancer.org/treatment/survivorship-during-and-after-treatment/follow-up-care.html