Keytruda (pembrolizumab) is an immune checkpoint inhibitor drug used to treat various types of cancer. It works by blocking the PD-1 protein on T cells, which helps the immune system to attack cancer cells.

According to Drug Patent Watch [1], Keytruda was first approved by the FDA in 2014 for the treatment of advanced melanoma. Since then, it has been approved for the treatment of various other types of cancer, including lung cancer, head and neck cancer, and bladder cancer. The drug is administered intravenously and is usually given every three weeks.

Although Keytruda has been shown to be effective in treating cancer, there are concerns about its long-term safety. A study published in Cancer Currents [2] suggests that immune checkpoint inhibitors like Keytruda can cause long-term side effects, including autoimmune disorders, endocrine disorders, and other complications. These side effects can occur months or even years after treatment with the drug has ended.

The study also found that patients who received immune checkpoint inhibitors were more likely to experience long-term side effects than those who received other types of cancer treatment. However, the study's authors noted that the benefits of Keytruda and other immune checkpoint inhibitors in treating cancer outweigh the risks of long-term side effects.

According to GoodRx [3], some of the long-term side effects of Keytruda may include fatigue, joint pain, skin rash, and diarrhea. However, the severity and duration of these side effects can vary from person to person.

In conclusion, Keytruda has been shown to be effective in treating various types of cancer, but there are concerns about its long-term safety. Patients who receive Keytruda may experience long-term side effects, including autoimmune disorders and other complications. However, the benefits of the drug in treating cancer outweigh the risks of long-term side effects. Patients should discuss the potential risks and benefits of Keytruda with their healthcare provider before starting treatment.

Sources:
[1] https://www.drugpatentwatch.com/p/biologics/tradename/KEYTRUDA
[2] https://www.cancer.gov/news-events/cancer-currents-blog/2021/immune-checkpoint-inhibitors-melanoma-long-term-side-effects
[3] https://www.goodrx.com/pembrolizumab/long-term-effects-of-keytruda