Association of Immune-Related Adverse Events, Hospitalization, and Therapy Resumption With Survival Among Patients With Metastatic Melanoma Receiving Single-Agent or Combination Immunotherapy.

Importance: Immune-related adverse events (irAEs) due to immune checkpoint blockade (ICB) have been shown to be positively associated with survival. Among patients with metastatic melanoma, evidence supporting this association has been conflicting, while ipilimumab-nivolumab combination ICB has been examined only in small clinical cohorts. Objective: To examine the association between irAEs and survival among patients with metastatic melanoma, in particular for those receiving combination ICB. Design, Setting, and Participants: A retrospective cohort of 492 consecutive patients with metastatic melanoma treated with ICB at 2 tertiary and 4 regional cancer centers in Alberta, Canada, from August 1, 2013, to May 31, 2020, was observed. Patients were aged 18 years or older with metastatic melanoma agnostic to primary site, who received 1 or more doses of an anti-programmed cell death protein 1 agent as single or combination ICB. Clinically significant irAEs requiring systemic corticosteroids and/or treatment delay were captured. To minimize immortal time bias, only patients surviving 12 weeks after ICB initiation were included in survival analyses. Statistical analysis was conducted on December 10, 2021. Exposures: Development of irAEs requiring systemic corticosteroids and/or treatment delay. Main Outcomes and Measures: The primary outcome was overall survival (OS), with the association of irAE development with OS assessed via Kaplan-Meier and Cox proportional hazards regression analyses. The association of hospitalization for irAEs and ICB resumption after irAE with OS was examined. Results: Among 492 patients, the median age of those with irAEs was 61.8 years (IQR, 52.9-72.1 years), and the median age of those without irAEs was 65.5 years (IQR, 56.5-76.9 years), while sex distribution was comparable (137 of 198 men [69.2%] with irAEs vs 183 of 294 men [62.2%] without irAEs). There was an association between irAEs and OS both in the overall cohort (with irAEs: median OS, 56.3 months [95% CI, 38.2 months to not evaluable] vs without irAEs: median OS, 18.5 months [95% CI, 14.4-23.2 months]; P < .001) and in the 124 patients (25.2%) receiving combination ICB (with irAEs: median OS, 56.2 months [95% CI, 52.2 months to not evaluable] vs without irAEs: median OS, 19.0 months [95% CI, 6.6 months to not evaluable]; P < .001). Hospitalization for irAE did not alter this positive association with OS compared with outpatient treatment (median OS, not evaluable [95% CI, 31.5 months to not evaluable] vs median OS, 52.2 months [95% CI, 35.2 months to not evaluable]; P = .53), while resumption of ICB was associated with longer OS than not resuming ICB (median, 56.3 months [95% CI, 40.8 months to not evaluable] vs 31.5 months [95% CI, 21.0 months to not evaluable]; P = .009). A favorable independent association of irAEs with OS was confirmed in multivariable analysis (hazard ratio for death, 0.382 [95% CI, 0.254-0.576]; P < .001). Conclusions and Relevance: This study suggests an association between irAEs and OS for patients with metastatic melanoma, including those treated with combination ICB and those with severe irAEs requiring hospitalization. The potential benefit associated with ICB resumption after irAEs warrants further investigation.

Real-World Cabazitaxel Use and Outcomes in Metastatic Castrate-Resistant Prostate Cancer: The Impact of Response to First ARPI.

BACKGROUND: For post-docetaxel treatment of metastatic castrate-resistant prostate cancer (mCRPC), cabazitaxel has demonstrated superior third line PFS and OS compared to androgen receptor pathway inhibitors (ARPIs) in patients who progress within 12 months on first ARPI. The impact of first ARPI response, in particular responses beyond 12 months, on cabazitaxel outcomes in real-world populations is uncertain, as are other factors impacting cabazitaxel use. MATERIALS AND METHODS: mCRPC patients in Alberta, Canada who received docetaxel from October 1, 2012 to December 31, 2017 were included. We reviewed mCRPC therapies, correlating cabazitaxel use with patient characteristics and TROPIC trial inclusion/exclusion criteria. OS and PFS were evaluated in patients who received cabazitaxel, stratified by time to progression on first ARPI ≤ 12 months (poor ARPI responders, PAR) or >12 months (strong ARPI responders, SAR), using the Kaplan-Meier method. RESULTS: PAR patients had inferior OS compared to SAR patients (12.3 vs. 24.8 months, P < .001). OS was longer in PAR patients receiving cabazitaxel compared to those not treated with cabazitaxel (16.9 vs. 10.3 months, P = .015), but this benefit was not seen in the SAR group (17.1 vs. 32 months, P = .084). Cabazitaxel use was associated with reduced PFS first line post-docetaxel in SAR (3.5 vs. 14.7 months, P < .001) but not PAR patients. Of 592 patients, 170 (29%) received cabazitaxel post-docetaxel, compared to 280 (47%) and 250 (42%) for abiraterone and enzalutamide. 238 patients (40%) did not have a discussion of cabazitaxel documented. Cabazitaxel use was increased in patients who fit TROPIC trial criteria (P < .001). CONCLUSIONS: In a real-world mCRPC cohort, cabazitaxel use was associated with longer OS among PAR patients, but crucially not among strong ARPI responders. Cabazitaxel was used less frequently and later than ARPIs post-docetaxel. These data help support first ARPI progression time as a consideration in treatment sequencing.

Autophagy limits proliferation and glycolytic metabolism in acute myeloid leukemia.

Decreased autophagy contributes to malignancies, however it is unclear how autophagy impacts on tumour growth. Acute myeloid leukemia (AML) is an ideal model to address this as (i) patient samples are easily accessible, (ii) the hematopoietic stem and progenitor population (HSPC) where transformation occurs is well characterized, and (iii) loss of the key autophagy gene Atg7 in hematopoietic stem and progenitor cells (HSPCs) leads to a lethal pre-leukemic phenotype in mice. Here we demonstrate that loss of Atg5 results in an identical HSPC phenotype as loss of Atg7, confirming a general role for autophagy in HSPC regulation. Compared to more committed/mature hematopoietic cells, healthy human and mouse HSCs displayed enhanced basal autophagic flux, limiting mitochondrial damage and reactive oxygen species in this long-lived population. Taken together, with our previous findings these data are compatible with autophagy limiting leukemic transformation. In line with this, autophagy gene losses are found within chromosomal regions that are commonly deleted in human AML. Moreover, human AML blasts showed reduced expression of autophagy genes, and displayed decreased autophagic flux with accumulation of unhealthy mitochondria indicating that deficient autophagy may be beneficial to human AML. Crucially, heterozygous loss of autophagy in an MLL-ENL model of AML led to increased proliferation in vitro, a glycolytic shift, and more aggressive leukemias in vivo. With autophagy gene losses also identified in multiple other malignancies, these findings point to low autophagy providing a general advantage for tumour growth.

Detection of p62 on Paraffin Sections by Immunohistochemistry.

The study of autophagy in human disease is a rapidly expanding field. Diagnostic paraffin sections of a variety of patient tissues, including bone marrow, are available to researchers-yet are unsuitable for traditional autophagy quantification methods such as western blot or electron microscopy. This protocol outlines the immunohistochemical detection of the protein p62 (sequestosome-1, encoded by the gene SQSTM1)-an indicator of autophagic degradative activity-in slide-mounted paraffin sections such as bone marrow samples cut by a trephine. The p62 protein is an autophagic cargo adaptor, capable of binding to ubiquitylated proteins as well as autophagosome membrane proteins (LC3B and GABA(A) receptor-associated protein [GABARAP] family members) and hypothesized thus to target protein aggregates for lysosomal degradation. p62 itself is degraded by autophagy, remaining at low levels when autophagy is induced, and has been shown to accumulate when autophagy is deficient. Qualitative assessment and comparison of p62 staining between healthy and disease sections or disease subtypes will help target further investigation into the potential roles for autophagy in a variety of disorders.

Autophagy is a critical regulator of memory CD8(+) T cell formation.

During infection, CD8(+) T cells initially expand then contract, leaving a small memory pool providing long lasting immunity. While it has been described that CD8(+) T cell memory formation becomes defective in old age, the cellular mechanism is largely unknown. Autophagy is a major cellular lysosomal degradation pathway of bulk material, and levels are known to fall with age. In this study, we describe a novel role for autophagy in CD8(+) T cell memory formation. Mice lacking the autophagy gene Atg7 in T cells failed to establish CD8(+) T cell memory to influenza and MCMV infection. Interestingly, autophagy levels were diminished in CD8(+) T cells from aged mice. We could rejuvenate CD8(+) T cell responses in elderly mice in an autophagy dependent manner using the compound spermidine. This study reveals a cell intrinsic explanation for poor CD8(+) T cell memory in the elderly and potentially offers novel immune modulators to improve aged immunity.