Last reviewed 2026-04-20 · How we verify

Gemzar (gemcitabine)

Gemzar works by mimicking a building block of DNA, tricking cancer cells into incorporating it into their DNA and then stopping the replication process.

Gemzar (gemcitabine) is a nucleoside metabolic inhibitor developed by Lilly and currently owned by Accord Healthcare. It targets DNA polymerase alpha, delta, and epsilon, inhibiting DNA synthesis in cancer cells. Gemzar is approved for treating adenocarcinoma of the pancreas, malignant tumors of the ovary, metastatic breast carcinoma, and non-small cell lung cancer. The drug is now off-patent, with 25 generic manufacturers available. Key safety considerations include its short half-life of 1 hour.

At a glance

Mechanism of action

Gemcitabine kills cells undergoing DNA synthesis and blocks the progression of cells through the G1/S-phase boundary. Gemcitabine is metabolized by nucleoside kinases to diphosphate (dFdCDP) and triphosphate (dFdCTP) nucleosides. Gemcitabine diphosphate inhibits ribonucleotide reductase, an enzyme responsible for catalyzing the reactions that generate deoxynucleoside triphosphates for DNA synthesis, resulting in reductions in deoxynucleotide concentrations, including dCTP. Gemcitabine triphosphate competes with dCTP for incorporation into DNA. The reduction in the intracellular concentration of dCTP by the action of the diphosphate enhances the incorporation of gemcitabine triphosphate into DNA (self-potentiation). After the gemcitabine nucleotide is incorporated into DNA, only one additional nucleotide is added to the growing DNA strands, which eventually results in the initiation of apoptotic cell death.

Approved indications

• Adenocarcinoma of pancreas
• Malignant tumor of ovary
• Metastatic Breast Carcinoma
• Non-small cell lung cancer

Common side effects

• Nausea and Vomiting
• Fever
• Rash
• Dyspnea
• Anemia
• Increased AST
• Increased ALT
• Neutropenia
• Increased Alkaline Phosphatase
• Proteinuria
• Hematuria
• Thrombocytopenia

Key clinical trials

• Testing the Addition of an Anti-cancer Drug, BAY 1895344, to the Usual Chemotherapy Treatment (Cisplatin, or Cisplatin and Gemcitabine) for Advanced Solid Tumors With Emphasis on Urothelial Cancer (PHASE1)
• Durvalumab in Combination With Chemotherapy in Treating Patients With Advanced Solid Tumors, DURVA+ Trial (PHASE2)
• Novel Combination Therapy in the Treatment of Relapsed and Refractory Aggressive B-Cell Lymphoma (PHASE2)
• Study BT8009-230 in Participants With Locally Advanced or Metastatic Urothelial Cancer (Duravelo-2) (PHASE2,PHASE3)
• Reduced-dose Carboplatin-doublet-chemotherapy + Cemiplimab vs Cemiplimab Monotherapy in Treatment Naive Older and Frail Patients With Metastatic NSCLC With PD-L1 <50% (PHASE2)
• A Study of Sacituzumab Tirumotecan (Sac-TMT, MK-2870) as Monotherapy and in Combination With Pembrolizumab (MK-3475) in Participants With Triple-Negative Breast Cancer (MK-2870-011/TroFuse-011) (PHASE3)
• Testing the Addition of an Anti-cancer Drug, Pembrolizumab, to the Usual Intravesical Chemotherapy Treatment (Gemcitabine) for the Treatment of BCG-Unresponsive Non-muscle Invasive Bladder Cancer (PHASE2)
• A Study of Zilovertamab Vedotin (MK-2140) in Combination With Standard of Care in Participants With Relapsed or Refractory Diffuse Large B-Cell Lymphoma (rrDLBCL) (MK-2140-003) (PHASE2,PHASE3)

Primary sources

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Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Gemzar CI brief — competitive landscape report
• Gemzar updates RSS · CI watch RSS
• Accord Hlthcare portfolio CI