Phase 1 study of twice weekly pulse dose and daily low-dose erlotinib as initial treatment for patients with EGFR-mutant lung cancers

Background

Patients with EGFR-mutant lung cancers treated with EGFR tyrosine kinase inhibitors (TKIs) develop clinical resistance, most commonly with acquisition of EGFR T790M. Evolutionary modeling suggests that a schedule of twice weekly pulse and daily low-dose erlotinib may delay emergence of EGFR T790M. Pulse dose erlotinib has superior central nervous system (CNS) penetration and may result in superior CNS disease control.

Methods

We evaluated toxicity, pharmacokinetics, and efficacy of twice weekly pulse and daily low-dose erlotinib. We assessed six escalating pulse doses of erlotinib.

Results

We enrolled 34 patients; 11 patients (32%) had brain metastases at study entry. We observed 3 dose-limiting toxicities in dose escalation: transaminitis, mucositis, and rash. The MTD was erlotinib 1200 mg days 1-2 and 50 mg days 3-7 weekly. The most frequent toxicities (any grade) were rash, diarrhea, nausea, fatigue, and mucositis. 1 complete and 24 partial responses were observed (74%, 95% CI 60-84%). Median progression-free survival was 9.9 months (95% CI 5.8-15.4 months). No patient had progression of an untreated CNS metastasis or developed a new CNS lesion while on study (0%, 95% CI 0-13%). Of the 18 patients with biopsies at progression, EGFR T790M was identified in 78% (95% CI 54-91%).

Conclusion

This is the first clinical implementation of an anti-cancer TKI regimen combining pulse and daily low-dose administration. This evolutionary modeling-based dosing schedule was well-tolerated but did not improve progression-free survival or prevent emergence of EGFR T790M, likely due to insufficient peak serum concentrations of erlotinib. This dosing schedule prevented progression of untreated or any new central nervous system metastases in all patients.

The interpersonal theory of suicide and adolescent suicidal behavior

BACKGROUND

Joiner's interpersonal theory of suicide (IPTS) proposes that suicide results from the combination of a perception of burdening others, social alienation, and the capability for self-harm. The theory gained some empirical support, however the overall model has yet to be tested. This study aimed to test the main predictions of IPTS in a large community sample of Israeli adolescents.

METHOD

1196 Israeli Jewish and Arab high-school pupils participating in the SEYLE project completed a self-report questionnaire measuring perceived burdensomeness, thwarted belongingness, health risk behaviors, and non-suicidal self-injury (risk variables), and suicidal ideation and suicide attempts (outcome measures). The data were tested in cross-sectional regression models.

RESULTS

Consistent with IPTS, perceived burdensomeness was found to interact with thwarted belongingness, predicting suicidal ideation. Depression mediated most of the effect of thwarted belongingness and perceived burdensomeness on suicidal ideation. Acquired capability for self-harm, as measured by health risk behaviors and direct non-suicidal self-injurious behaviors, predicted suicide attempt. However, this mechanism operated independently from ideation rather than in interaction with it, at variance with IPTS-based predictions.

LIMITATIONS

The cross-sectional design precludes conclusions about causality and directionality. Proxy measures were used to test the interpersonal theory constructs.

CONCLUSION

The findings support some of the IPTS predictions but not all, and imply two separate pathways for suicidal behavior in adolescents: one related to internalizing psychopathology and the other to self-harm behaviors. This conceptualization has clinical implications for the differential identification of adolescents at risk for suicidal behavior and for the development of prevention strategies.

Report from a forum on US heart allocation policy

Since the latest revision in US heart allocation policy (2006), the landscape and volume of transplant waitlists have changed considerably. Advances in mechanical circulatory support (MCS) prolong survival, but Status 1A mortality remains high. Several patient subgroups may be disadvantaged by current listing criteria and geographical disparity remains in waitlist time. This forum on US heart allocation policy was organized to discuss these issues and highlight concepts for consideration in the policy development process. A 25-question survey on heart allocation policy was conducted. Among attendees/respondents were 84 participants with clinical/published experience in heart transplant representing 51 US transplant centers, and OPTN/UNOS and SRTR representatives. The survey results and forum discussions demonstrated very strong interest in change to a further-tiered system, accounting for disadvantaged subgroups and lowering use of exceptions. However, a heart allocation score is not yet viable due to the long-term viability of variables (used in the score) in an ever-developing field. There is strong interest in more refined prioritization of patients with MCS complications, highly sensitized patients and those with severe arrhythmias or restrictive physiology. There is also strong interest in distribution by geographic boundaries modified according to population. Differences of opinion exist between small and large centers.

PKPD modelling of the interrelationship between mean arterial BP, cardiac output and total peripheral resistance in conscious rats

BACKGROUND AND PURPOSE

The homeostatic control of arterial BP is well understood with changes in BP resulting from changes in cardiac output (CO) and/or total peripheral resistance (TPR). A mechanism-based and quantitative analysis of drug effects on this interrelationship could provide a basis for the prediction of drug effects on BP. Hence, we aimed to develop a mechanism-based pharmacokinetic-pharmacodynamic (PKPD) model in rats that could be used to characterize the effects of cardiovascular drugs with different mechanisms of action (MoA) on the interrelationship between BP, CO and TPR.

EXPERIMENTAL APPROACH

The cardiovascular effects of six drugs with diverse MoA, (amlodipine, fasudil, enalapril, propranolol, hydrochlorothiazide and prazosin) were characterized in spontaneously hypertensive rats. The rats were chronically instrumented with ascending aortic flow probes and/or aortic catheters/radiotransmitters for continuous recording of CO and/or BP. Data were analysed in conjunction with independent information on the time course of drug concentration using a mechanism-based PKPD modelling approach.

KEY RESULTS

By simultaneous analysis of the effects of six different compounds, the dynamics of the interrelationship between BP, CO and TPR were quantified. System-specific parameters could be distinguished from drug-specific parameters indicating that the model developed is drug-independent.

CONCLUSIONS AND IMPLICATIONS

A system-specific model characterizing the interrelationship between BP, CO and TPR was obtained, which can be used to quantify and predict the cardiovascular effects of a drug and to elucidate the MoA for novel compounds. Ultimately, the proposed PKPD model could be used to predict the effects of a particular drug on BP in humans based on preclinical data.