Poziotinib is a targeted therapy medication that interferes with the growth and spread of cancer cells. It functions as a tyrosine kinase inhibitor, blocking specific signals within cells. This approach differs from traditional chemotherapy, which often affects both healthy and cancerous cells, aiming for a more precise attack on cancer.
How Poziotinib Targets Cancer Cells
Poziotinib works by inhibiting tyrosine kinases, proteins involved in cell growth and division. It is an irreversible pan-HER inhibitor, broadly blocking the activity of HER1 (EGFR), HER2, and HER4 receptors. When mutated, these receptors send continuous signals that promote uncontrolled cancer cell proliferation.
The drug is particularly effective against specific genetic alterations, such as exon 20 insertion mutations in the EGFR (Epidermal Growth Factor Receptor) and HER2 genes. These mutations change the kinase’s drug-binding pocket, making it difficult for many inhibitors to attach. Poziotinib’s small size and flexible structure allow it to access this altered binding site and inhibit the enzyme’s activity. By blocking these signals, poziotinib impedes the downstream effects that drive cell proliferation, leading to cancer cell death.
Conditions Poziotinib Addresses
Poziotinib has been primarily investigated for treating non-small cell lung cancer (NSCLC) with EGFR exon 20 insertion mutations and HER2 exon 20 insertion mutations. These mutations lead to hyperactivation of the EGFR and HER2 proteins, driving tumor growth.
The presence of these exon 20 insertion mutations makes a patient’s cancer suitable for treatment with poziotinib. Clinical trials, such as the ZENITH20 study, have explored its efficacy. While NSCLC is the primary focus, poziotinib has also been studied in clinical trials for other solid tumors, including breast and gastric cancers.
Understanding Poziotinib Treatment and Side Effects
Poziotinib is administered as an oral medication. In clinical trials, a common daily dose has been 16 mg, though dosage adjustments or interruptions may occur based on patient tolerance. Healthcare professionals closely monitor patients during treatment to assess its effectiveness and manage any side effects.
Like many cancer treatments, poziotinib can cause side effects. Common side effects include skin rash, diarrhea, and stomatitis (mouth sores or inflammation). Other side effects include paronychia (nail changes) and dry skin. While many of these are mild to moderate, some can be more severe, requiring dose reductions or temporary pauses in treatment.
Rash and diarrhea were reported in a high percentage of patients. Severe forms of these side effects, such as grade 3 rash and diarrhea, were observed in a notable proportion of patients, sometimes leading to dose modifications. Managing these side effects often involves supportive care and close communication with the healthcare team to ensure continued treatment when possible.