Bone Metastases, Skeletal-Related Events, and Survival in Patients With Metastatic Non-Small Cell Lung Cancer Treated With Immune Checkpoint Inhibitors.

BACKGROUND: Bone metastases and skeletal-related events (SREs) are a frequent cause of morbidity in patients with metastatic non-small cell lung cancer (mNSCLC). Data are limited on bone metastases and SREs in patients with mNSCLC treated using immune checkpoint inhibitors (ICIs), and on the efficacy of bone-modifying agents (BMAs) in this setting. Here we report the incidence, impact on survival, risk factors for bone metastases and SREs, and impact of BMAs in patients with mNSCLC treated with ICIs in a multi-institutional cohort. PATIENTS AND METHODS: We conducted a retrospective study of patients with mNSCLC treated with ICIs at 2 tertiary care centers from 2014 through 2017. Overall survival (OS) was compared between patients with and without baseline bone metastases using a log-rank test. A Cox regression model was used to evaluate the association between OS and the presence of bone metastases at ICI initiation, controlling for other confounding factors. RESULTS: We identified a cohort of 330 patients who had received ICIs for metastatic disease. Median patient age was 63 years, most patients were treated in the second line or beyond (n=259; 78%), and nivolumab was the most common ICI (n=211; 64%). Median OS was 10 months (95% CI, 8.4-12.0). In our cohort, 124 patients (38%) had baseline bone metastases, and 43 (13%) developed SREs during or after ICI treatment. Patients with bone metastases had a higher hazard of death after controlling for performance status, histology, line of therapy, and disease burden (hazard ratio, 1.57; 95% CI, 1.19-2.08; P=.001). Use of BMAs was not associated with OS or a decreased risk of SREs. CONCLUSIONS: Presence of bone metastases at baseline was associated with a worse prognosis for patients with mNSCLC treated with ICI after controlling for multiple clinical characteristics. Use of BMAs was not associated with reduced SREs or a difference in survival.

Validation of the American Joint Committee on Cancer Eighth Edition Staging of Patients With Metastatic Cutaneous Melanoma Treated With Immune Checkpoint Inhibitors.

Importance: Immune checkpoint inhibitors (ICIs) have transformed the survival of patients with metastatic melanoma. Patient prognosis is reflected by the American Joint Committee on Cancer (AJCC) staging system; however, it is unknown whether the metastatic (M) stage categories for cutaneous melanoma remain informative of prognosis in patients who have received ICIs. Objectives: To evaluate the outcomes of patients with metastatic cutaneous melanoma based on the M stage category from the AJCC eighth edition and to determine whether these designations continue to inform the prognosis of patients who have received ICIs. Design, Setting, and Participants: This cohort study included patients with metastatic cutaneous melanoma who were treated between August 2006 and August 2019 at the University of Michigan. The estimated median follow-up time was 35.5 months. Patient data were collected via the electronic medical record system. Critical findings were externally validated in a multicenter nationwide cohort of patients treated within the Veterans Affairs health care system. Data analysis was conducted from February 2020 to January 2021. Exposures: All patients were treated with dual-agent concurrent ipilimumab and nivolumab followed by maintenance nivolumab or single-agent ipilimumab, nivolumab, or pembrolizumab therapy. Patients were staged using the AJCC eighth edition. Main Outcomes and Measures: Univariable and multivariable analyses were used to assess the prognostic value of predefined clinicopathologic baseline factors on survival. Results: In a discovery cohort of 357 patients (mean [SD] age, 62.6 [14.2] years; 254 [71.1%] men) with metastatic cutaneous melanoma treated with ICIs, the M category in the AJCC eighth edition showed limited prognostic stratification by both univariable and multivariable analyses. The presence of liver metastases and elevated levels of serum lactate dehydrogenase (LDH) offered superior prognostic separation compared with the M category (liver metastases: hazard ratio, 2.22; 95% CI, 1.48-3.33; P < .001; elevated serum LDH: hazard ratio, 1.73; 95% CI, 1.16-2.58; P = .007). An updated staging system based on these factors was externally validated in a cohort of 652 patients (mean [SD] age, 67.9 [11.6] years; 630 [96.6%] men), with patients without liver metastases or elevated LDH levels having the longest survival (median overall survival, 30.7 months). Conclusions and Relevance: This study found that the AJCC eighth edition M category was poorly reflective of prognosis in patients receiving ICIs. Future staging systems could consider emphasizing the presence of liver metastases and elevated LDH levels. Additional studies are needed to confirm the importance of these and other prognostic biomarkers.

Liver metastasis restrains immunotherapy efficacy via macrophage-mediated T cell elimination.

Metastasis is the primary cause of cancer mortality, and cancer frequently metastasizes to the liver. It is not clear whether liver immune tolerance mechanisms contribute to cancer outcomes. We report that liver metastases diminish immunotherapy efficacy systemically in patients and preclinical models. Patients with liver metastases derive limited benefit from immunotherapy independent of other established biomarkers of response. In multiple mouse models, we show that liver metastases siphon activated CD8+ T cells from systemic circulation. Within the liver, activated antigen-specific Fas+CD8+ T cells undergo apoptosis following their interaction with FasL+CD11b+F4/80+ monocyte-derived macrophages. Consequently, liver metastases create a systemic immune desert in preclinical models. Similarly, patients with liver metastases have reduced peripheral T cell numbers and diminished tumoral T cell diversity and function. In preclinical models, liver-directed radiotherapy eliminates immunosuppressive hepatic macrophages, increases hepatic T cell survival and reduces hepatic siphoning of T cells. Thus, liver metastases co-opt host peripheral tolerance mechanisms to cause acquired immunotherapy resistance through CD8+ T cell deletion, and the combination of liver-directed radiotherapy and immunotherapy could promote systemic antitumor immunity.

The impact of BRAF mutation status on clinical outcomes with anti-PD-1 monotherapy versus combination ipilimumab/nivolumab in treatment-naïve advanced stage melanoma.

Nearly half of all metastatic melanoma patients possess the BRAF V600 mutation. Several therapies are approved for advanced stage melanoma, but it is unclear if there is a differential outcome to various immunotherapy regimens based on BRAF mutation status. We retrospectively analyzed a cohort of metastatic or unresectable melanoma patients who were treated with combination ipilimumab/nivolumab (ipi/nivo) or anti-PD-1 monotherapy, nivolumab, or pembrolizumab, as first-line treatment. 235 previously untreated patients were identified in our study. Our univariate analysis showed no statistical difference in progression-free survival (PFS) or overall survival (OS) with ipi/nivo versus anti-PD-1 monotherapy in the BRAF V600 mutant cohort, but there was improved PFS [HR: 0.48, 95% CI, 0.28-0.80] and OS [HR: 0.50, 95% CI, 0.26-0.96] with ipi/nivo compared to anti-PD-1 monotherapy in the BRAF WT group. After adjusting for known prognostic variables in our multivariable analysis, the BRAF WT cohort continued to show PFS and OS benefit with ipi/nivo compared to anti-PD-1 monotherapy. Our single-institution analysis suggests ipi/nivo should be considered over anti-PD-1 monotherapy as the initial immunotherapy regimen for metastatic melanoma patients regardless of BRAF mutation status, but possibly with greater benefit in BRAF WT.

Exploration of Benzothiazole Rhodacyanines as Allosteric Inhibitors of Protein-Protein Interactions with Heat Shock Protein 70 (Hsp70).

Cancer cells rely on the chaperone heat shock protein 70 (Hsp70) for survival and proliferation. Recently, benzothiazole rhodacyanines have been shown to bind an allosteric site on Hsp70, interrupting its binding to nucleotide-exchange factors (NEFs) and promoting cell death in breast cancer cell lines. However, proof-of-concept molecules, such as JG-98, have relatively modest potency (EC50 ≈ 0.7-0.4 µM) and are rapidly metabolized in animals. Here, we explored this chemical series through structure- and property-based design of ∼300 analogs, showing that the most potent had >10-fold improved EC50 values (∼0.05 to 0.03 µM) against two breast cancer cells. Biomarkers and whole genome CRISPRi screens confirmed members of the Hsp70 family as cellular targets. On the basis of these results, JG-231 was found to reduce tumor burden in an MDA-MB-231 xenograft model (4 mg/kg, ip). Together, these studies support the hypothesis that Hsp70 may be a promising target for anticancer therapeutics.

Probing the hras-1Y i-motif with small molecules.

Non-B DNA structures represent intriguing and challenging targets for small molecules. For example, the promoter of the HRAS oncogene contains multiple G-quadruplex and i-motif structures, atypical globular folds that serve as molecular switches for gene expression. Of the two, i-motif structures are far less studied. Here, we report the first example of small organic compounds that directly interact with the hras-1Y i-motif. We use a small molecule microarray screen to identify drug-like small molecules that bind to the hras-1Y i-motif but not to several other DNA or RNA secondary structures. Two different lead compounds, 1 and 2, were discovered to have 7.4 ± 5.3 µM and 5.9 ± 3.7 µM binding affinity by surface plasmon resonance and similar affinity by fluorescence titration. A structure-activity relationship (SAR) was developed and two improved analogues of 2 demonstrated submicromolar binding affinities. Both compounds display pH-dependent binding, indicating that they interact with the DNA only when the i-motif is properly folded. Chemical shift perturbation shows that 1 alters the structure of the i-motif, while 2 has no effect on the i-motif conformation, indicating different modes of interaction.

Mechanically induced pyrogallol[4]arene hexamer assembly in the solid state extends the scope of molecular encapsulation.

Pyrogallol[4]arene hexamers are hydrogen-bonded molecular capsules of exceptional kinetic stability that can entrap small molecule guests indefinitely, without exchange, at ambient temperatures. Here, we report on the use of a ball mill to induce self-assembly of the capsule components and the guests in the solid state. Stoichiometric amounts of pyrogallol[4]arene and a guest, which can be an arene, alkane, amine, or carboxylic acid, were milled at 30 Hz for fixed durations, dissolved, and characterization by NMR. Most of the resulting encapsulation complexes were kinetically stable but thermodynamically unstable in solution, and the yield of their formation correlates with the duration of the milling and is related to the structures of guest and host. This method extends the scope of molecular encapsulation, as demonstrated by the preparation of kinetically trapped encapsulation complexes of [2.2]paracyclophane, for which we could find no other method of preparation. To gain mechanistic insights into the solid-state assembly process, we characterized the milled powders using 13C CP-MAS NMR, we studied the effects of changing the alkane domain of the host, and we examined how dissolution conditions impact on the distribution of observed encapsulation complexes once in solution. The results support a mechanism comprising mechanically induced solid-state reorganization to produce a mixture rich in nearly or fully assembled guest-filled capsules.