Masterkey-01: Phase I/II, open-label multicenter study to assess safety, tolerability, pharmacokinetics, and antitumor activity of BDTX-189, an inhibitor of allosteric ErbB mutations, in patients with advanced solid malignancies

TPS3665

Background: A significant unmet need exists for drugs targeting allosteric ErbB mutations (non-canonical mutations outside the ATP binding site). Current EGFR and HER2 tyrosine kinase inhibitors or mAbs have limited antitumor activity against allosteric mutations, resulting in toxicity before adequate drug exposure (Connell and Doherty, 2017). BDTX-189 is a potent and selective orally available irreversible inhibitor targeting unique oncogenic driver mutations of ErbB kinases in EGFR and HER2, while sparing WT EGFR. Preclinical studies demonstrated antitumor activity across a range of allosteric ErbB mutants, including extracellular domain allosteric mutations of HER2 as well as EGFR and HER2 kinase domain exon 20 insertions (Buck, 2019). This first-in-human trial (NCT04209465) is aimed to determine the recommended phase 2 dose (RP2) and schedule (Phase 1, P1), and evaluate the efficacy (Phase 2, P2) of BDTX-189. P1 primary objective is to determine the RP2 dose and schedule of monotherapy BDTX-189. Secondary objectives include assessment of safety, tolerability, pharmacokinetics (PK), pharmacodynamic (PD) effects in tumor, and preliminary efficacy. The P2 primary objective is to assess antitumor activity of monotherapy BDTX-189. Methods: The study will enroll patients (pts) ≥18 yrs with histologically or cytologically confirmed locally advanced or metastatic solid tumors with no standard therapy available or for whom standard therapy is unsuitable or intolerable. P1 dose-escalation will use a BOIN design (Yuan, 2016) and will enroll ≤ 88 pts with allosteric HER2 or HER3 mutation; EGFR or HER2 exon 20 insertion mutation; HER2 amplified or overexpressing tumor; or EGFR exon 19 deletion or L858R mutation. BDTX-189 will be dosed orally (PO) initially QD in 3 wk cycles. Regimen optimization will use PK, PD and safety data and may explore a BID schedule. An expansion cohort of ≤12 pts will further evaluate safety and preliminary efficacy of BDTX-189 prior to P2. P2, utilizing a Simon 2-stage design, will enroll ≤100 pts with NSCLC with EGFR or HER2 exon 20 insertion mutations (cohort 1); breast cancer with an allosteric ErbB mutation (cohort 2); tumors (except breast) with S310F/Y mutation (cohort 3); and other allosteric ErbB mutations not defined in cohorts 1-3 (cohort 4). Assessments include safety, tolerability, DLTs, evaluation of MTD, PK, PD, and preliminary antitumor activity. Enrollment began 1/2020. Clinical trial information: NCT04209465 .

Caring for yourself during times of organizational change

Mergers, acquisitions, and other organizational changes in the health care system pose many challenges and stresses for nursing leaders. Although considerable effort is expended helping staff adjust to change, nurse managers and executives often neglect their own vulnerability to occupational stress. The personal and organizational costs of managerial burnout are high, sometimes resulting in physical illness, mental exhaustion, and decreased productivity. This article emphasizes the importance of prevention through the recognition of potential or actual signs of organizational stress. Handy tips are provided on effective ways to cope with the stress of organizational change.

Diabetic ketoacidosis: implications for the medical-surgical nurse

Diabetic ketoacidosis (DKA) is an acute complication associated with type 1 diabetes mellitus. DKA accounts for a significant portion of annual health care expenditures and is considered a medical emergency. Previously treated in the ICU, DKA is now treated on general medical-surgical nursing units. To manage this crisis successfully, medical-surgical nurses must have a comprehensive knowledge and understanding of the pathophysiologic mechanisms, clinical manifestations, and treatment protocols. A critical pathway is presented to guide clinical care.

Retrospective biochemical screening of fatty acid oxidation disorders in postmortem livers of 418 cases of sudden death in the first year of life

OBJECTIVE

Fatty acid oxidation (FAO) disorders are frequently reported as the cause of sudden and unexpected death, but their postmortem recognition remains difficult. We have devised a biochemical protocol in which informative findings in liver tissue are microvesicular steatosis, elevated concentrations of C8-C16 fatty acids, glucose depletion, and low carnitine concentration.

STUDY DESIGN

We analyzed 27 cases representing five FAO disorders and compared the results with those obtained in a retrospective blinded analysis of 418 cases of sudden infant death (313 SIDS, 45 infections, and 34 accidents and abuse).

RESULTS

All cases of accidents and abuse correctly tested negative. Among the others, 25 (6%) showed at least two abnormal findings. Of these, 14 closely matched the biochemical profiles seen in specific FAO disorders. These included 2 cases with medium-chain acyl-CoA dehydrogenase deficiency, 4 cases consistent with glutaric acidemia type 2, 4 cases with either very long-chain acylcoenzyme A dehydrogenase deficiency or long-chain 3-hydroxy-acyl-coenzyme A dehydrogenase deficiency, and 4 cases predicted to be affected with carnitine uptake defect.

CONCLUSION

The results of this study support the view that approximately 5% of all cases of sudden infant death are likely caused by an FAO disorder.

Cloning, expression, and chromosomal assignment of the human mitochondrial intermediate peptidase gene (MIPEP)

The mitochondrial intermediate peptidase of Saccharomyces cerevisiae (YMIP) is a component of the yeast mitochondrial protein import machinery critically involved in the biogenesis of the oxidative phosphorylation (OXPHOS) system. This leader peptidase removes specific octapeptides from the amino terminus of nuclear-encoded OXPHOS subunits and components of the mitochondrial genetic apparatus. To address the biologic role of the human peptidase [MIPEP gene, HMIP polypeptide], we have initiated its molecular and functional characterization. A full-length cDNA was isolated by screening a human liver library using a rat MIP (RMIP) cDNA as a probe. The encoded protein contained a typical mitochondrial leader peptide and showed 92 and 54% homology to RMIP and YMIP, respectively. A survey of human mitochondrial protein precursors revealed that, similar to YMIP, HMIP is primarily involved in the maturation of OXPHOS-related proteins. Northern analysis showed that the MIPEP gene is differentially expressed in human tissues, with the highest levels of expression in the heart, skeletal muscle, and pancreas, three organ systems that are frequently affected in OXPHOS disorders. Using fluorescence in situ hybridization, the MIPEP locus was assigned to 13q12. This information offers the possibility of testing the potential involvement of HMIP in the pathophysiology of nuclear-driven OXPHOS disorders.

The nurse's role in facilitating compliance in clients with hypertension

Afflicting approximately 50 million people, hypertension costs over $500 million per year and accounts for the largest number of physician office visits per year and the greatest use of prescription drugs. Nurses play a vital role in assessing and managing hypertensive clients' and promoting clients' compliance with treatment regimens.

Weaning from mechanical ventilatory support

Weaning patients from mechanical ventilatory support continues to be a major challenge in critical care units. This article discusses recent research in the area of weaning and identifies specific parameters related to successful weaning in clinical practice.