porfimer sodium + gemcitabine + cisplatin

Porfimer sodium + gemcitabine + cisplatin is a **combination regimen** of three pharmaceuticals used in oncology. **Porfimer sodium** is a photosensitizer utilized in photodynamic therapy, generating cytotoxic species upon light activation and resulting in direct tumor cell death and microvascular damage. **Gemcitabine** is a nucleoside analog that inhibits DNA synthesis by incorporation into DNA and by inhibition of ribonucleotide reductase, leading to apoptosis. **Cisplatin** is a platinum-based compound that causes crosslinking of DNA, blocking replication and transcription and resulting in apoptosis. The combination aims to utilize multiple distinct mechanisms for synergistic antitumor effects and is potentially used for cancers where platinum agents and nucleoside analogs are established, sometimes with additional modalities like photodynamic therapy. Clinical use of gemcitabine plus cisplatin is established in cancers such as biliary tract cancer, non-small cell lung cancer, and bladder cancer; studies of triple regimens with photodynamic therapy agents such as porfimer sodium are under investigation but are not standard therapy.