Clinical experience and management of adverse events in patients with advanced ALK-positive non-small-cell lung cancer receiving alectinib

Alectinib is a preferred first-line therapy for patients with advanced anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer (NSCLC) in several national clinical practice guidelines. The randomized, global, phase III ALEX study has demonstrated significant improvement in progression-free survival for alectinib over crizotinib in treatment-naive ALK-positive NSCLC. It was also the first study to show clinically meaningful improvement in overall survival for a next-generation ALK tyrosine kinase inhibitor relative to crizotinib. The J-ALEX and ALESIA phase III studies confirmed the clinical benefit of alectinib relative to crizotinib in the first-line ALK-positive NSCLC treatment setting in Japanese and Asian patients, respectively. Across these pivotal phase III trials, alectinib had a manageable, well-characterized safety profile. Here, we review the safety and tolerability of long-term alectinib treatment in patients with advanced ALK-positive NSCLC and provide guidance for physicians, based on clinical experience, on the management of the most frequently reported adverse events (AEs). Most AEs associated with alectinib can be managed by dose reduction. Some alectinib-related AEs are not yet fully characterized, including myalgia and peripheral oedema and deciphering their underlying mechanism of action could enhance their management. With longer-term follow-up, the safety profile of alectinib continues to remain consistent in the ALEX study, with no new safety signals observed. Safety and tolerability data from the first-line phase III alectinib trials are also consistent with those observed in clinical trials of alectinib in later-line settings. These results add to the weight of evidence recommending alectinib as a preferred therapy for treatment-naive advanced ALK-positive NSCLC.

Glomerular filtration rate determined from a single plasma sample after intravenous iohexol injection: is it reliable?

The iohexol injection plasma clearance method is a good alternative to the inulin clearance method for determination of GFR, but requires multiple blood samples. To avoid this, methods have been developed which derive GFR from a formula that uses a single plasma concentration of the tracer and anthropometric data. The aim of this study was to evaluate whether a single plasma sample taken after iohexol injection allows reliable estimation of GFR. In this study, results of single-point determination were compared with those obtained by multiple-point plasma clearance. The GFR of 686 outpatients with different degrees of renal function were recalculated by use of the Jacobsson formula. The optimum time for sampling was found at 10 h after injection of the marker for clearances < 40 mL/min per 1.73 m2, 4 h for clearances between 40 and 99 mL/min per 1.73 m2, and 3 h for clearances > 100 mL/min per 1.73 m2. Results documented that for 75% of the patients, the simplified technique gave an error between -5% to +5% in the evaluation of GFR; for the remaining 25% of the patients, prediction error ranged from -22% to +40%. Furthermore, despite a highly significant correlation between multiple-point iohexol clearance (six plasma samples) and the single-point method (Y = 0.968X + 1.704, r2 = 0.988), the regression intercept was statistically different from 0 and the standard error of the slope estimate established that 95% confidence interval did not include 1.0 (the line of identity), thus indicating that the model can be rejected by the data at a significance level of 0.05. Thus the single-plasma-sample method to determine GFR after radiocontrast injection does not represent a real advantage over the multiple-point method and may lead to unacceptable errors in GFR calculation.

Plasma clearance of nonradioactive iohexol as a measure of glomerular filtration rate

Renal clearance of inulin is the best available indicator of GFR but cannot be used routinely for clinical purposes and is also difficult to perform for clinical investigation when repeated measurements are required. The aim of this study was to find a reliable alternative to inulin clearance that would allow one to avoid the use of radioactivity and problems related to the continuous infusion of the marker. The plasma clearance of unlabeled iohexol, a nonionic contrast agent, was used. Forty-one patients (creatinine clearance 6 to 160 mL/min per 1.73 m2) underwent simultaneous measurements of renal clearance of inulin and plasma clearance of iohexol. Iohexol was given as a single iv dose, and blood samples were drawn up to 600 min after the administration. Iohexol concentrations (by HPLC) were analyzed by a two-compartment, open-model system. A highly significant correlation between the plasma clearance of iohexol and the renal clearance of inulin over a wide range of GFR values was found. By analyzing the data with a simplified method that uses a one-compartment model corrected with the Bröchner-Mortensen formula, an excellent correlation with the inulin clearance was also observed. When only patients with moderate to severe renal failure were considered, a significant correlation between the two methods was found. A further comparison between GFR determined with iohexol and iopromide, a new low-osmolarity, low-viscosity contrast medium, was also performed in a subgroup of patients.(ABSTRACT TRUNCATED AT 250 WORDS)