Using a rhabdomyosarcoma patient-derived xenograft to examine precision medicine approaches and model acquired resistance.

BACKGROUND: Precision (Personalized) medicine has the potential to revolutionize patient health care especially for many cancers where the fundamental disease etiology remains either elusive or has no available therapy. Here we outline a study in alveolar rhabdomyosarcoma, in which we use gene expression profiling and a series of drug prediction algorithms combined with a matched patient-derived xenograft (PDX) model to test bioinformatically predicted therapies. PROCEDURE: A PDX model was developed from a patient biopsy and a number of drugs identified using gene expression analysis in combination with drug prediction algorithms. Drugs chosen from each of the predictive methodologies, along with the patient's standard-of-care therapy (ICE-T), were tested in vivo in the PDX tumor. A second study was initiated using the tumors that re-grew following the ICE-T treatment. Further expression analysis identified additional therapies with potential anti-tumor efficacy. RESULTS: A number of the predicted therapies were found to be active against the tumors in particular BGJ398 (FGFR2) and ICE-T. Re-transplanted ICE-T treated tumorgrafts demonstrated a decreased response to ICE-T recapitulating the patient's refractory disease. Gene expression profiling of the ICE-T treated tumorgrafts identified cytarabine (SLC29A1) as a potential therapy, which was shown, along with BGJ398, to be highly active in vivo. CONCLUSIONS: This study illustrates that PDX models are suitable surrogates for testing potential therapeutic strategies based on gene expression analysis, modeling clinical drug resistance and hold the potential to assist in guiding prospective patient care.

Epidermal growth factor receptor inhibitor gefitinib added to chemoradiotherapy in locally advanced head and neck cancer.

PURPOSE: Assess efficacy and toxicity of gefitinib, an epidermal growth factor receptor (EGFR) inhibitor, added to, and in maintenance after, concurrent chemoradiotherapy (CCRT) in locally advanced head and neck cancer (LA-HNC) and correlate outcomes with EGFR gene copy number alterations. PATIENTS AND METHODS: Patients with stage III to IV LA-HNC received two cycles of carboplatin/paclitaxel induction chemotherapy (IC) followed by split-course CCRT with fluorouracil, hydroxyurea, twice daily radiotherapy (FHX), and gefitinib (250 mg daily) followed by continued gefitinib for 2 years total. The primary end point was complete response (CR) rate after CCRT. EGFR gene copy number was assessed by fluorescent in situ hybridization. RESULTS: Sixty-nine patients (66 with stage IV disease, 37 with oropharynx primary tumors, and 67 with performance status 0 to 1) were enrolled with a median age of 55 years. Predominant grade 3 or 4 toxicities during IC and CCRT were neutropenia (n = 20) and in-field mucositis (n = 59) and dermatitis (n = 23), respectively. CR rate after CCRT was 90%. After median follow-up of 3.5 years, 4-year overall, progression-free, and disease-specific survival rates were 74%, 72%, and 89%, respectively. To date, one patient has developed a second primary tumor in the aerodigestive tract. In 31 patients with available tissue, high EGFR gene copy number was associated with worse overall survival (P = .02). CONCLUSION: Gefitinib can be administered with FHX and as maintenance therapy for at least 2 years, demonstrating CR and survival rates that compare favorably with prior experience. High EGFR gene copy number may be associated with poor outcome in patients with LA-HNC treated with this regimen.

Prospective evaluation of the relationship of patient age and paclitaxel clinical pharmacology: Cancer and Leukemia Group B (CALGB 9762).

PURPOSE: To prospectively evaluate the pharmacokinetics and toxicity profile of paclitaxel in relation to patient age in adults > or = 55 years old. PATIENTS AND METHODS: Paclitaxel was administered at 175 mg/m2 for 3 hours to 153 patients, 46 of whom were > or = 75 years of age. Pharmacokinetic and toxicity assessments were performed. Data were analyzed by cohort (cohort 1, age 55 to 64 years; cohort 2, age 65 to 74 years; cohort 3, age > or = 75 years). RESULTS: Paclitaxel concentration versus time (AUC) and total-body clearance (CL(tb)) data were available for 122 patients (cohort 1, 46 patients; cohort 2, 44 patients; cohort 3, 32 patients). Mean paclitaxel AUC increased across cohorts (P = .01). Mean (SE) AUCs were 22.4 (2.5) micromol/L x hour, 26.2 (2.8) micromol/L x hour, and 31.7 (5.6) micromol/L x hour for cohorts 1, 2, and 3, respectively. There was a corresponding significant (P = .007) age-related decrease in mean (SE) paclitaxel CL(tb) (cohort 1, 11.0 [0.7] L/h/m2; cohort 2, 9.3 [0.6] L/h/m2; cohort 3, 8.2 [0.6] L/h/m2). Patients in cohort 3 experienced significantly lower absolute neutrophil count nadirs than did younger groups (P = .02). There was also a significant increase in percentage of patients with > or = grade 3 neutropenia across age cohorts (cohort 1, 22%; cohort 2, 35%; cohort 3, 49%; P = .006). However, the increased exposure of patients to paclitaxel and increased neutropenia were not reflected in adverse clinical sequelae such as hospitalization for toxicity (P = .82), receiving intravenous antibiotics (P = .21), or experiencing a temperature more than 38 degrees C (P = .45). CONCLUSION: Although paclitaxel CL(tb) decreases with increasing patient age, there is great interpatient variability. Cooperative group studies to evaluate the effect of aging on pharmacokinetics are feasible.

A randomized controlled trial of darbepoetin alfa administered as a fixed or weight-based dose using a front-loading schedule in patients with anemia who have nonmyeloid malignancies.

BACKGROUND: The effect of using fixed versus weight-based doses for erythropoietic agents has not been reported previously. To investigate this issue, the authors conducted a randomized Phase II study of darbepoetin alfa administered as either a fixed dose or a weight-based dose using an accelerated correction and maintenance dosing regimen (front-loading). METHODS: During the correction phase, patients with anemia (hemoglobin < 11.0 g/dL) who had nonmyeloid malignancies and who were receiving chemotherapy were given darbepoetin alfa at a fixed dose of 325 microg (n = 122) or at a weight-based dose of 4.5 microg/kg (n = 120) once weekly until they achieved a hemoglobin concentration > or = 12.0 g/dL. Patients then received darbepoetin alfa (325 microg or 4.5 microg/kg) once every 3 weeks for the remainder of the 16-week treatment period (maintenance phase). RESULTS: Darbepoetin alfa resulted in high Kaplan-Meier rates of hematopoietic response (> or = 2 g/dL increase from the baseline level or a hemoglobin level > or = 12 g/dL) in both the fixed-dose group (86%; 95% confidence interval [95% CI], 78- 94%) and the weight-based dose group (84%; 95% CI, 76-92%). The median time to hematopoietic response was 34 days (95% CI, 28-44 days) for the fixed-dose group and 36 days (95% CI, 30-45 days) for the weight-based dose group. Hemoglobin concentrations were maintained at target levels for up to 16 weeks in both groups. Darbepoetin alfa was well tolerated, and no clinically significant differences between fixed doses and weight-based doses were observed. CONCLUSIONS: Darbepoetin alfa was effective when administered as either a fixed dose or a weight-based dose using a front-loading approach to rapidly correct anemia and effectively maintain hemoglobin levels in patients with anemia who had malignant disease.