A Multicentric, Retrospective, Real-world Study on Immune-related Adverse Events in Patients with Advanced Non-small Cell Lung Cancers Treated with Pembrolizumab Monotherapy

AIMS

We present 7 years of clinical experience with single-agent pembrolizumab immune checkpoint inhibitor immunotherapy in non-small cell lung cancers (NSCLC) from four UK cancer centres.

MATERIALS AND METHODS

This multi-institutional retrospective cohort study included 226 metastatic NSCLC patients. Outcomes were number and severity of immune-related adverse events (irAEs), median progression-free survival (mPFS) and median overall survival (mOS).

RESULTS

Within our cohort, 119/226 (53%) patients developed irAEs. Of these, 54/119 (45%) experienced irAEs affecting two or more organ systems. The most common irAEs were diarrhoea and rash. The development of an irAE was associated with better mOS (20.7 versus 8.0 months; P < 0.001) and mPFS (12.0 versus 3.9 months; P < 0.001). The development of grade 3/4 toxicities was associated with worse outcomes compared with the development of grade 1/2 toxicities (mOS 6.1 months versus 25.2 months, P < 0.01; mPFS 5.6 months versus 19.3 months, P = 0.01, respectively). Females had a higher proportion of reported grade 3/4 toxicities (13/44 [29.5%] versus 10/74 [13.5%], P = 0.03). Using a multiple Cox regression model, the presence of irAEs was associated with a better overall survival (hazard ratio = 0.42, 95% confidence interval 0.29-0.61; P < 0.01) and better PFS (hazard ratio 0.38, 95% confidence interval 0.27-0.53; P < 0.001).

CONCLUSION

In this multicentre retrospective cohort study, the development of at least one irAE was associated with significantly longer mPFS and mOS; however, more severe grade 3 and 4 irAEs were associated with worse outcomes. Delayed-onset irAEs, after the 3-month timepoint, were associated with better clinical outcomes.

Systematic Review of Molecular Biomarkers Predictive of Resistance to CDK4/6 Inhibition in Metastatic Breast Cancer

Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors have revolutionized the treatment of hormone-positive metastatic breast cancers (mBCs). They are currently established as standard therapies in combination with endocrine therapy as first- and second-line systemic treatment options for both endocrine-sensitive and endocrine-resistant mBC populations. In the first-line metastatic setting, the median progression-free survival for the three currently approved CDK4/6 inhibitors, palbociclib, ribociclib, and abemaciclib, with aromatase inhibitors is greater than 2 years (palbociclib 27.6 months; ribociclib 25.3 months; and abemaciclib 28.18 months). Although CDK4/6 inhibitors have significant clinical benefits and enable physicians to delay starting chemotherapy, they are expensive and can be associated with drug toxicities. Here, we have performed a systemic review of the reported molecular markers predictive of drug response including intrinsic and acquired resistance for CDK4/6 inhibition in mBC. The rapidly emerging molecular landscape is captured through next-generation sequencing of breast cancers (DNA with or without RNA), liquid biopsies (circulating tumor DNA), and protein analyses. Individual molecular candidates with robust and reliable evidence are discussed in more depth.

Single-Cell Dynamics Determines Response to CDK4/6 Inhibition in Triple-Negative Breast Cancer

Purpose: Triple-negative breast cancer (TNBC) is a heterogeneous subgroup of breast cancer that is associated with a poor prognosis. We evaluated the activity of CDK4/6 inhibitors across the TNBC subtypes and investigated mechanisms of sensitivity.Experimental Design: A panel of cell lines representative of TNBC was tested for in vitro and in vivo sensitivity to CDK4/6 inhibition. A fluorescent CDK2 activity reporter was used for single-cell analysis in conjunction with time-lapse imaging.Results: The luminal androgen receptor (LAR) subtype of TNBC was highly sensitive to CDK4/6 inhibition both in vitro (P < 0.001 LAR vs. basal-like) and in vivo in MDA-MB-453 LAR cell line xenografts. Single-cell analysis of CDK2 activity demonstrated differences in cell-cycle dynamics between LAR and basal-like cells. Palbociclib-sensitive LAR cells exit mitosis with low levels of CDK2 activity, into a quiescent state that requires CDK4/6 activity for cell-cycle reentry. Palbociclib-resistant basal-like cells exit mitosis directly into a proliferative state, with high levels of CDK2 activity, bypassing the restriction point and the requirement for CDK4/6 activity. High CDK2 activity after mitosis is driven by temporal deregulation of cyclin E1 expression. CDK4/6 inhibitors were synergistic with PI3 kinase inhibitors in PIK3CA-mutant TNBC cell lines, extending CDK4/6 inhibitor sensitivity to additional TNBC subtypes.Conclusions: Cell-cycle dynamics determine the response to CDK4/6 inhibition in TNBC. CDK4/6 inhibitors, alone and in combination, are a novel therapeutic strategy for specific subgroups of TNBC. Clin Cancer Res; 23(18); 5561-72. ©2017 AACR.