A 24-Hour Extended Calibration Strategy for Quantitating Tacrolimus Concentrations by Liquid Chromatography-Tandem Mass Spectrometry.

BACKGROUND: Tacrolimus has a low therapeutic index requiring strict control of whole blood concentrations. Although random access immunoassay platforms exist that rapidly provide quantitative values for tacrolimus, LC-MS/MS may provide more accurate quantitation. However, batch testing in many LC-MS/MS assays is not efficient, particularly when testing patients suspected of having tacrolimus toxicity. Extending calibration curve stability beyond the traditionally accepted single batch may facilitate improved turnaround time and reduce testing costs. A 24-h extended calibration of LC-MS/MS tacrolimus was designed and validated to reduce calibrator usage, improve turnaround time, and provide a more efficient workflow for urgent requests. METHODS: Patient samples included in the study were extracted and assayed with coextracted calibrators and quality control in real time. The same patient samples were extracted again 24 h later without coextracted calibrators. The data acquired from the second patient sample extraction was applied to the original calibration curve acquired 24 h prior and compared to the data for the same samples coextracted with calibrators, creating a value set utilizing extended curve stability. RESULTS: A linear regression compared the results using the extended curve to the results of the coextracted acquisitions. This yielded a strong correlation between the 2 data populations, with a slope of 1.0061 and a correlation coefficient of >0.95. The average bias between original patient values and patient values 24 h later was 3.4% across all patient samples. CONCLUSIONS: Patient tacrolimus values were comparable when extracted within 24 h of calibration versus values coextracted with calibrators. Demonstrating comparability within 24 h of calibration allows the laboratory to provide rapid turnaround time for urgent samples without the need for an entirely new calibration curve.

Final results of a prospective clinical trial with VAMP and low-dose involved-field radiation for children with low-risk Hodgkin's disease.

PURPOSE: To evaluate outcome and assess complications in children and adolescents with low-risk Hodgkin's disease treated with vinblastine, doxorubicin, methotrexate, and prednisone (VAMP) chemotherapy and low-dose, involved-field radiation therapy (IFRT). PATIENTS AND METHODS: One hundred ten children with low-risk Hodgkin's disease were treated with four cycles of VAMP and 15 Gy IFRT for those who achieved a complete response (CR) or 25.5 Gy for those with a partial response after two cycles of VAMP. RESULTS: With median follow-up of 9.6 years (range, 1.7 to 15.0), 5- and 10-year overall survival were 99.1% and 96.1%, respectively, and 5-and 10-year event-free survival (EFS) were 92.7% and 89.4%. Factors contributing to 10-year EFS were: early CR (P = .02), absence of B symptoms (P = .01), lymphocyte predominant histologic subtype (P = .04), and less than three initial sites of disease (P = .02). Organ toxicity has been limited to correctable hypothyroidism in 42% of irradiated patients, and one case of cardiac dysfunction. Seventeen healthy babies have been born to 106 survivors. There have been two malignant tumors: one thyroid cancer within the radiation therapy field and one Ewing's sarcoma outside the radiation therapy field. CONCLUSION: Risk-adapted, combined-modality therapy using VAMP chemotherapy with radiation is effective and well tolerated. Pediatric patients with low-risk Hodgkin's disease can be cured with therapy without an alkylating agent, bleomycin, etoposide, or high-dose, extended-field radiotherapy. Thus, these children are expected to retain normal fertility, organ function, and be at low risk of a second malignant tumor.

Risk-adapted, combined-modality therapy with VAMP/COP and response-based, involved-field radiation for unfavorable pediatric Hodgkin's disease.

PURPOSE: To evaluate the efficacy of vinblastine, doxorubicin, methotrexate, and prednisone (VAMP) and cyclophosphamide, vincristine, and procarbazine (COP) chemotherapy and response-based, involved-field radiation, a combined-modality regimen that limits doses of alkylating agents, anthracyclines, and radiation, in children with advanced and unfavorable Hodgkin's disease. PATIENTS AND METHODS: From 1993 to 2000, 159 children and adolescents with unfavorable Hodgkin's disease received three alternating cycles (total of six cycles) of VAMP/COP chemotherapy followed by response-based, involved-field radiation therapy: 15 Gy was administered to patients achieving a complete response, and 25.5 Gy was administered to those achieving a partial response after the first two cycles of chemotherapy and to all sites of bulky lymphadenopathy. Unfavorable disease was defined as clinical stage I and II with bulky peripheral nodal disease greater than 6 cm, initial bulky mediastinal mass 33% or more of the intrathoracic diameter, and/or "B" symptoms and all stage III and IV. RESULTS: Study enrollment was closed after an interim analysis estimated a 5-year event-free survival (EFS) rate below a predefined level. Disease presentation was localized (stage I/II) in 77 patients (48.4%) and advanced (stage III/IV) in 82 patients (51.6%). At a median follow-up of 5.8 years (range, 1.3 to 10.0 years), 38 patients had events, including relapse/progression (n = 35), second malignancy (n = 2), and accidental death (n = 1); nine relapses (25.7%) occurred greater than 4 years from diagnosis. Five-year survival and EFS estimates are 92.7% +/- 2.5% and 75.6% +/- 4.1%, respectively. CONCLUSION: Risk-adapted combined-modality therapy with VAMP/COP and response-based, involved-field radiation therapy results in an unsatisfactory outcome for pediatric patients with unfavorable presentations of Hodgkin's disease.

VAMP and low-dose, involved-field radiation for children and adolescents with favorable, early-stage Hodgkin's disease: results of a prospective clinical trial.

PURPOSE: To evaluate outcome and assess toxicity of children and adolescents with early-stage, favorable Hodgkin's disease treated with vinblastine, doxorubicin, methotrexate, and prednisone (VAMP) and low-dose, involved-field radiation. PATIENTS AND METHODS: One hundred ten patients with clinical stages I and II, favorable (nonbulky) Hodgkin's disease were treated with four cycles of VAMP chemotherapy and 15 Gy involved-field radiation for those who achieved a complete response, or 25.5 Gy for those who achieved a partial response to two cycles of VAMP. RESULTS: With a median follow-up of 5.6 years (range, 1.1 to 10.4 years), the 5-year survival and event-free survival were 99% (lower confidence limit [CL], 97.4%) and 93% (lower CL, 88.6%), respectively. Factors associated with event-free survival of 100% were complete response to two cycles of VAMP and histology other than nodular sclerosing Hodgkin's disease (NSHD). No serious early or late toxicity has been observed. Patients presenting with clinical stages I and IIA, nonbulky disease involving fewer than three nodal sites have a projected survival and event-free survival of 100% and 97% (lower CL, 93%), respectively, at 5 years. CONCLUSION: Risk-adapted, combined-modality therapy using only four cycles of VAMP chemotherapy with 15 to 25.5 Gy of involved-field radiation for patients with early-stage/favorable Hodgkin's disease is highly effective and without demonstrable late effects. These results indicate that pediatric patients with stages I and II favorable Hodgkin's disease can be cured with limited therapy that does not include an alkylating agent, bleomycin, etoposide, or high-dose, extended-field radiation therapy.