How many boxes of pemetinib/pemetinib are needed per month?

Pemigatinib is an oral, selective fibroblast growth factor receptor (FGFR) inhibitor. It is mainly suitable for patients with locally advanced or metastatic cholangiocarcinoma (CCA) with FGFR2 fusion or rearrangement, as well as some patients with hematological tumors carrying FGFR1 rearrangement. According to the currently recommended standard dosage, the medication regimen for patients with cholangiocarcinoma is 13.5 mg per day, with 14 consecutive days of taking and 7 days of discontinuation, forming a 21-day cycle. For patients with FGFR1 abnormalities in the bone marrow or lymphatic system, 13.5mg needs to be continuously administered daily until disease progression or intolerable toxicity occurs.

From the perspective of market supply, the current main specifications of pemetinib are 4.5 mg × 14 tablets and 9 mg × 14 tablets. Therefore, in order to reach the recommended daily dose of 13.5 mg, patients usually need to take one 9 mg tablet and one 4.5 mg tablet daily. Taking cholangiocarcinoma as an example, patients who take the drug continuously for 14 days in every 21-day treatment cycle require a total of 14 9mg tablets and 14 4.5mg tablets. For patients with hematological tumors, due to continuous daily medication, an average of 30 9mg tablets and 30 4.5mg tablets are required per month. Therefore, in actual procurement, a cholangiocarcinoma patient's dosage for one cycle is one box of each specification, while patients who continue to receive treatment may need to purchase more than two boxes each month. The specific dosage can be adjusted according to the cycle time.

It should be noted that pemetinib treatment should be carried out under the guidance of a professional doctor, as it may cause adverse reactions such as hyperphosphatemia, visual impairment, stomatitis, and rash. Regular monitoring of blood phosphorus levels and ophthalmological evaluation is very important. At the same time, there may be interactions between drugs, and combination with strong CYP3A4 inhibitors or inducers should be avoided to avoid affecting the efficacy or toxic reactions. In addition, patients should strictly follow the dosage combination prescribed by the doctor during the medication period to avoid increasing the risk of side effects or weakening the therapeutic effect due to improper dosage adjustment.

Reference materials:https://go.drugbank.com/drugs/DB15102