mitómycín

Mitómycín, also known as mitomycin C, is an antineoplastic antibiotic produced by the bacterium Streptomyces caespitosus. It belongs to the mitomycins class and is used in chemotherapy for its ability to crosslink DNA after bioreductive activation.

Mitomycin C acts as a bioreductive alkylating agent. In hypoxic tumor cells, cellular reductases activate the molecule, enabling aziridine rings to form DNA crosslinks. These interstrand crosslinks inhibit DNA replication and transcription, leading to cell death. The drug's cytotoxicity is enhanced in rapidly dividing cells and can affect both tumor and normal tissues.

Clinical uses include systemic chemotherapy for various cancers as part of combination regimens. It is also used intravesically to reduce recurrence of non-muscle invasive bladder cancer after tumor resection and, in ophthalmology, applied topically to help prevent proliferative vitreoretinopathy after retinal detachment surgery.

Administration and dosing vary by indication. Systemic therapy is given by intravenous infusion; intravesical therapy involves catheter-based instillation with a retention period in the bladder; ophthalmic use employs topical application at low concentrations during surgery. Dosing is guided by cancer type, schedule, and patient tolerability.

Adverse effects commonly include bone marrow suppression (the dose-limiting toxicity), nausea, vomiting, mucositis, and fatigue. Intravesical use can cause cystitis and urinary symptoms; ocular use may cause local irritation. Severe hypersensitivity and renal or hepatic impairment can complicate treatment; extravasation during IV administration is a risk that requires careful monitoring.