According to the sources provided, there is no specific mention of adjusting the dosage of Yervoy (ipilimumab) for underweight patients.

The drug patent information [1] and the FDA label [3] for Yervoy do not mention any specific dosage adjustments for underweight patients. However, the FDA label does state that the recommended dose of Yervoy is 3 mg/kg administered intravenously over 90 minutes every 3 weeks for a total of 4 doses.

The article published in the Journal of Oncology Pharmacy Practice [2] discusses the management of immune-related adverse events associated with Yervoy treatment, but it does not mention adjusting the dosage for underweight patients.

Overall, while there is no specific mention of adjusting the dosage of Yervoy for underweight patients in the sources provided, it is important for healthcare providers to carefully consider individual patient factors when determining the appropriate dose of any medication.

Sources:
[1] https://www.drugpatentwatch.com/p/biologics/tradename/YERVOY
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8134762/
[3] https://www.accessdata.fda.gov/drugsatfda_docs/label/2020/125377s110lbl.pdf