General Information

Herceptin (trastuzumab) is a humanized IgG1 kappa monoclonal antibody that selectively binds with high affinity to the extracellular domain of the human epidermal growth factor receptor 2 protein (HER2). HER2 is a cell membrane surface-bound receptor tyrosine kinase and is normally involved in the signal transduction pathways leading to cell growth and differentiation. HER2 is overexpresed in certain cancers.

Herceptin is specifically indicated, in combination with cisplatin and capecitabine or 5-fluorouracil, for the treatment of patients with HER2 overexpressing metastatic gastric or gastroesophageal junction enocarcinoma, who have not received prior treatment for metastatic disease.

Herceptin is supplied as a solution for intravenous administration. The recommended initial dose of Herceptin for gastric cancer is 8 mg/kg as a 90 minute intravenous infusion followed by subsequent doses of 6 mg/kg as an intravenous infusion over 30-90 minutes every three weeks until disease progression.

Clinical Results

FDA Approval
The FDA approval of Herceptin for gastric cancer was based on an open-label, multi-center trial in 594 patients with HER2 gene amplified or overexpressing cancer who were not previously treated for metastatic gastric or gastroesophageal junction adenocarcinoma. The subjects received Herceptin administered in combination with cisplatin and a fluoropyrimidine (FC+H) or chemotherapy alone (FC). The Herceptin arm received an IV infusion at an initial dose of 8 mg/kg followed by 6 mg/kg every 3 weeks until disease progression. In both study arms, cisplatin was administered at a dose of 80 mg/m2 Day 1 every 3 weeks for 6 cycles as a 2 hour IV infusion and capecitabine was administered at 1000 mg/m2 dose orally twice daily (total daily dose 2000 mg/m2) for 14 days of each 21 day cycle for 6 cycles. Alternatively continuous intravenous infusion (CIV) 5-fluorouracil was administered at a dose of 800 mg/m2/day from Day 1 through Day 5 every three weeks for 6 cycles. The primary endpoint was overall survival. The final overall survival analysis based on 351 deaths was statistically significant. In the FC arm, 62.2% of the subjects had passed versus 56% in the FC+H arm (p=0.0193). A follow-up analysis was conducted one year after the final analysis. At this timepoint, in the FC arm 76.7% of the subjects had passed versus 74.2% in the FC+H arm.

Side Effects

Adverse events associated with the use of Herceptin for gastric cancer may include, but are not limited to, the following:<br.

neutropenia

diarrhea

fatigue

anemia

stomatitis

weight loss

upper respiratory tract infections

fever

thrombocytopenia

mucosal inflammation

nasopharyngitis

dysgeusia

The Herceptin drug label comes with the following Black Box Warning: Cardiomyopathy: Herceptin can result in subclinical and clinical cardiac failure manifesting as CHF, and decreased LVEF, with greatest risk when administered concurrently with anthracyclines. Evaluate cardiac function prior to and during treatment. Discontinue Herceptin for cardiomyopathy. Infusion Reactions, Pulmonary Toxicity: Discontinue Herceptin for anaphylaxis, angioedema, interstitial pneumonitis, or acute respiratory distress syndrome. Embryo-Fetal Toxicity: Exposure to Herceptin during pregnancy can result in oligohydramnios, in some cases complicated by pulmonary hypoplasia and neonatal death. Advise patients of these risks and the need for effective contraception

Mechanism of Action

Literature References

Bang YJ, Van Cutsem E, Feyereislova A, Chung HC, Shen L, Sawaki A, Lordick F, Ohtsu A, Omuro Y, Satoh T, Aprile G, Kulikov E, Hill J, Lehle M, Rüschoff J, Kang YK; ToGA Trial Investigators Trastuzumab in combination with chemotherapy versus chemotherapy alone for treatment of HER2-positive advanced gastric or gastro-oesophageal junction cancer (ToGA): a phase 3, open-label, randomised controlled trial. The Lancet Aug 28;376(9742):687-97