Gemcitabine(Drug information on gemcitabine) (Gemzar), recently approved by the FDA as a treatment IND for patients with advanced or metastatic pancreatic cancer, has shown promise in the treatment of non-small-cell lung cancer (NSCLC), both as a single agent and in combination with other chemotherapy drugs, Alan Sandler, md, reported at a symposium held at the Chemotherapy Foundation meeting last year.
Structurally related to cytarabine(Drug information on cytarabine) (ara-C), gemcitabine accumulates to a greater degree and is less readily eliminated from tumor cells than ara-C. Incorporated into DNA, gemcitabine results in chain termination and inhibits enzymes required for DNA synthesis, he explained.
Gemcitabine has been studied extensively as a single agent in previously untreated NSCLC in Europe, Japan, South Africa, and Canada. In several studies involving nearly 600 evaluable patients, responses ranged from 20% to 27%, said Dr. Sandler assistant professor of hematology/oncology, and medical director, Thoracic Oncology Program, Indiana University School of Medicine, Indianapolis.
Phase I/II studies have established a maximally tolerated gemcitabine dose of 1,250 mg/m²/wk, with myelosuppression and thrombocytopenia the dose-limiting toxicities. Nonhematologic toxicities include reversible hepatotoxicity, proteinuria, mild skin rash with or without pruritus, and nausea with vomiting.
Dr. Sandler reported on five recent phase II studies of gemcitabine in combination with cisplatin(Drug information on cisplatin) (Platinol). All included a regimen of weekly gemcitabine for 3 weeks, with 1 week off; cisplatin was given in varying doses.
In patients with previously untreated stage III NSCLC, response rates ranged from 31% to 55%, and median survival rates were as high as 9.9 months. The most favorable response was seen in an Italian study that administered gemcitabine weekly, 1,000 mg/m² on days 1, 8, and 15, with cisplatin 100 mg/m² on day 2. With a median follow-up of 11 months, median survival has not yet been reached for that regimen.
Studies are ongoing for gemcitabine in combination with carboplatin(Drug information on carboplatin) (Paraplatin) and ifosfamide(Drug information on ifosfamide) (Ifex), with no response results yet reported, he said.