Gemcite

Gemcitabine (Gemcitabine) Instructions

Common name: Gemcitabine

Trade name: Gemzar

All names: Gemcitabine, Zephi, Gemcitabine, Gemcite, Gemzar, Infugem

Indications:

In combination with carboplatin, it is used to treat advanced ovarian cancer that relapses at least 6 months after completion of platinum therapy.

In combination with paclitaxel, it is indicated for the first-line treatment of metastatic breast cancer after failure of prior anthracycline-containing adjuvant chemotherapy, unless anthracyclines are used clinically.

In combination with cisplatin, it is used to treat non-small cell lung cancer.

As a single agent for the treatment of pancreatic cancer.

Usage and dosage:

Intravenous infusion: 1000 mg/m, infusion for 30 minutes, once a week for 3 consecutive weeks, with 1 week of rest, repeated every 4 weeks.

Ovarian cancer: 1000 mg/m2 over 30 minutes on days 1 and 8 of each 21-day cycle.

Breast cancer: 1250 mg/m2 over 30 minutes on days 1 and 8 of each 21-day cycle.

Non-small cell lung cancer: 1000 mg/m2 for 30 minutes on days 1, 8 and 15 of each 28-day cycle or 1250 mg/m2 for 30 minutes on days 1 and 8 of each 21-day cycle.

Pancreatic cancer: 1000mg/m2 over 30 minutes, once a week for the first 7 weeks, then a week off, then once a week for 28 days, 3 days a week.

Adverse Reactions:

The most common adverse reactions with a single dose (≥20%):

Nausea/vomiting, anemia, increased aspartate aminotransferase (AST), increased alanine aminotransferase (ALT), neutropenia, increased alkaline phosphatase, proteinuria, pyrexia, hematuria, rash, thrombocytopenia, dyspnea, and edema.

Contraindications:

Patients with known hypersensitivity to gemcitabine.

Contraindicated for pregnant and lactating women.

Notes:

Schedule-dependent toxicity: The infusion time exceeds 60 minutes or the dosing time exceeds one week, and the toxicity increases.

Myelosuppression: Monitor for myelosuppression before each cycle and reduce or discontinue dose for severe myelosuppression.

Pulmonary Toxicity and Respiratory Failure: Discontinue GEMZAR due to unexplained dyspnea or other evidence of severe pulmonary toxicity.

Hemolytic Uremic Syndrome (HUS): Monitor renal function before initiation and during treatment. Discontinue GEMZAR treatment for HUS with severe renal impairment.

Hepatotoxicity: Monitor liver function during initiation and during treatment. Discontinue GEMZAR treatment for severe hepatotoxicity.

Embryo-Fetotoxicity: May cause fetal harm. It is recommended that females and females of childbearing potential use effective contraception.

Radiation Therapy Worsening Toxicity: Serious and life-threatening toxicity may occur during or within 7 days of radiation therapy.

Capillary Leak Syndrome: Discontinue GEMZAR.

Posterior reversible encephalopathy syndrome (PRES): Discontinue GEMZAR.

Storage:

Store at controlled room temperature 20°C to 25°C (68°F to 77°F); excursions allowed between 15°C and 30°C (59°F and 86°F)

Mechanism of Action:

Gemcitabine kills cells undergoing DNA synthesis and blocks cell progression through the G1/S phase boundary.

Gemcitabine is metabolized by nucleoside kinases into nucleosides diphosphate (dFdCDP) and triphosphate (dFdCTP).

Gemcitabine diphosphate inhibits ribonucleotide reductase, the enzyme responsible for catalyzing the reaction that produces deoxynucleoside triphosphates for DNA synthesis, resulting in a decrease in deoxynucleoside concentrations, including dCTP. Gemcitabine triphosphate competes with dCTP for binding to DNA. Reducing intracellular dCTP concentration through the action of diphosphate enhances the incorporation of gemcitabine triphosphate into DNA (self-enhancement). Upon incorporation of gemcitabine nucleotides into DNA, only one extra nucleotide is added to the growing DNA strand, ultimately leading to the onset of apoptotic cell death.

Safety and efficacy:

Gemcitabine has the characteristics of broad anti-tumor spectrum and few adverse reactions. In recent years, several large-scale phase III studies have shown that it has good efficacy as a single agent or in combination with other chemotherapy drugs for advanced breast cancer. It has now become one of the first-choice chemotherapy drugs recommended by domestic and foreign guidelines for advanced breast cancer.

An interim analysis of a phase III study (Abstract No. 5536) reported that 449 patients with surgically resected stage Ic~IV ovarian epithelial cancer, primary peritoneal cancer or fallopian tube cancer were randomized to receive GC regimen or paclitaxel. Carboplatin (TC) regimen chemotherapy was followed by selective paclitaxel consolidation chemotherapy. There was no significant difference in the objective response rate (ORR) and disease control rate (DCR) between the two groups of patients, and the toxic effects were consistent with previous clinical experience. The results show that the GC regimen may have the same efficacy as the TC regimen in treating various pathological types of ovarian cancer, and GC may become a new first-line treatment option.