ABSTRACT
PURPOSE: This study determined the range of tolerable doses, clinical safety, pharmacokinetics, and preliminary evidence of clinical activity following once or twice daily administration of lapatinib in patients with solid malignancies. EXPERIMENTAL DESIGN: Cancer patients (n = 81) received oral doses of lapatinib ranging from 175 to 1,800 mg once daily or 500 to 900 mg twice daily. Clinical assessments of safety and antitumor activity were recorded and blood was sampled for pharmacokinetic assessments. The effect of a low-fat meal on lapatinib pharmacokinetics was assessed in a subset of patients. RESULTS: Lapatinib was well tolerated, such that dose escalation was limited at 1,800 mg once daily only by pill burden. Twice-daily dosing was implemented to further explore tolerability, and was limited by diarrhea to 500 mg twice daily. The most commonly reported adverse events with once-daily dosing were diarrhea (48%), nausea (40%), rash (40%), and fatigue (38%) and with twice-daily dosing were diarrhea (85%), rash (54%), and nausea (34%). Lapatinib serum concentrations accumulated upon repeated dosing, increasing nearly in proportion with dose, and were significantly increased when dosed with food or administered twice daily. One patient with head and neck cancer achieved a confirmed complete response and 22 patients had stable disease of >or=8 weeks including three patients with stable disease of >10 months (renal, lung, and salivary gland cancers). CONCLUSION: Lapatinib was well tolerated following once and twice daily administration. Systemic exposure to lapatinib was dependent on the dose, duration and frequency of dosing, and prandial state. Clinical activity was observed.
Subject(s)
Neoplasms/drug therapy , Protein Kinase Inhibitors/therapeutic use , Quinazolines/therapeutic use , Administration, Oral , Adult , Aged , Aged, 80 and over , Antineoplastic Agents , Drug Administration Schedule , ErbB Receptors/antagonists & inhibitors , Female , Humans , Lapatinib , Male , Middle Aged , Quinazolines/administration & dosage , Quinazolines/adverse effects , Quinazolines/pharmacokinetics , Receptor, ErbB-2/antagonists & inhibitorsABSTRACT
PURPOSE: This phase I trial (EGF10005) assessed the safety, optimally tolerated regimen (OTR), and pharmacokinetics of lapatinib and capecitabine in combination in patients with advanced solid malignancies. PATIENTS AND METHODS: Patients with previously treated, advanced solid malignancies were eligible. Cohorts of at least three patients each received once-daily oral lapatinib (continuous) and capecitabine (twice daily for 14 days every 21 days). Doses of lapatinib and capecitabine were escalated based on dose-limiting toxicities in the first treatment cycle until the OTR was reached. Additional patients were treated at the OTR dose level to further evaluate safety and for pharmacokinetic analyses. RESULTS: Forty-five patients were treated in the study. The OTR was determined to be lapatinib 1,250 mg/d plus capecitabine 2,000 mg/m(2)/d. The majority of drug-related adverse events were grade 1 to grade 2 in severity, with few grade 3 and no grade 4 toxicities. The most common drug-related toxicities (> 15% of patients) were diarrhea, nausea, rash, palmar-plantar erythrodysesthesia, mucositis, vomiting, and stomatitis. There were four confirmed responses (one complete response and three partial responses). The pharmacokinetics (area under the curve and maximum concentration) of lapatinib, capecitabine and its metabolites, fluorouracil, and alpha-fluoro-beta-alanine, were not meaningfully altered by coadministration. CONCLUSION: Lapatinib and capecitabine administered on a 3-week schedule were well tolerated, and no pharmacokinetic interaction was observed. Clinical activity was observed in patients with previously treated, advanced solid malignancies.
