FDG PET/CT Imaging 1 Week after a Single Dose of Pembrolizumab Predicts Treatment Response in Patients with Advanced Melanoma

PURPOSE

Immunologic response to anti-programmed cell death protein 1 (PD-1) therapy can occur rapidly with T-cell responses detectable in as little as one week. Given that activated immune cells are FDG avid, we hypothesized that an early FDG PET/CT obtained approximately 1 week after starting pembrolizumab could be used to visualize a metabolic flare (MF), with increased tumor FDG activity due to infiltration by activated immune cells, or a metabolic response (MR), due to tumor cell death, that would predict response.

PATIENTS AND METHODS

Nineteen patients with advanced melanoma scheduled to receive pembrolizumab were prospectively enrolled. FDG PET/CT imaging was performed at baseline and approximately 1 week after starting treatment. FDG PET/CT scans were evaluated for changes in maximum standardized uptake value (SUVmax) and thresholds were identified by ROC analysis; MF was defined as >70% increase in tumor SUVmax, and MR as >30% decrease in tumor SUVmax.

RESULTS

An MF or MR was identified in 6 of 11 (55%) responders and 0 of 8 (0%) nonresponders, with an objective response rate (ORR) of 100% in the MF-MR group and an ORR of 38% in the stable metabolism (SM) group. An MF or MR was associated with T-cell reinvigoration in the peripheral blood and immune infiltration in the tumor. Overall survival at 3 years was 83% in the MF-MR group and 62% in the SM group. Median progression-free survival (PFS) was >38 months (median not reached) in the MF-MR group and 2.8 months (95% confidence interval, 0.3-5.2) in the SM group (P = 0.017).

CONCLUSIONS

Early FDG PET/CT can identify metabolic changes in melanoma metastases that are potentially predictive of response to pembrolizumab and significantly correlated with PFS.

Long-term outcomes to neoadjuvant pembrolizumab based on pathological response for patients with resectable stage III/IV cutaneous melanoma

BACKGROUND

While neoadjuvant immunotherapy for melanoma has shown promising results, the data have been limited by a relatively short follow-up time, with most studies reporting 2-year outcomes. The goal of this study was to determine long-term outcomes for stage III/IV melanoma patients treated with neoadjuvant and adjuvant programmed cell death receptor 1 (PD-1) inhibition.

PATIENTS AND METHODS

This is a follow-up study of a previously published phase Ib clinical trial of 30 patients with resectable stage III/IV cutaneous melanoma who received one dose of 200 mg IV neoadjuvant pembrolizumab 3 weeks before surgical resection, followed by 1 year of adjuvant pembrolizumab. The primary outcomes were 5-year overall survival (OS), 5-year recurrence-free survival (RFS), and recurrence patterns.

RESULTS

We report updated results at 5 years of follow-up with a median follow-up of 61.9 months. No deaths occurred in patients with a major pathological response (MPR, <10% viable tumor) or complete pathological response (pCR, no viable tumor) (n = 8), compared to a 5-year OS of 72.8% for the remainder of the cohort (P = 0.12). Two of eight patients with a pCR or MPR had a recurrence. Of the patients with >10% viable tumor remaining, 8 of 22 patients (36%) had a recurrence. Additionally, the median time to recurrence was 3.9 years for patients with ≤10% viable tumor and 0.6 years for patients with >10% viable tumor (P = 0.044).

CONCLUSIONS

The 5-year results from this trial represent the longest follow-up of a single-agent neoadjuvant PD-1 trial to date. Response to neoadjuvant therapy continues to be an important prognosticator with regard to OS and RFS. Additionally, recurrences in patients with pCR occur later and are salvageable, with a 5-year OS of 100%. These results demonstrate the long-term efficacy of single-agent neoadjuvant/adjuvant PD-1 blockade in patients with a pCR and the importance of long-term follow-up for these patients.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT02434354.

Phase I Trial of Autologous RNA-electroporated cMET-directed CAR T Cells Administered Intravenously in Patients with Melanoma and Breast Carcinoma

Purpose

Treatments are limited for metastatic melanoma and metastatic triple-negative breast cancer (mTNBC). This pilot phase I trial (NCT03060356) examined the safety and feasibility of intravenous RNA-electroporated chimeric antigen receptor (CAR) T cells targeting the cell-surface antigen cMET.

Experimental Design

Metastatic melanoma or mTNBC subjects had at least 30% tumor expression of cMET, measurable disease and progression on prior therapy. Patients received up to six infusions (1 × 10e8 T cells/dose) of CAR T cells without lymphodepleting chemotherapy. Forty-eight percent of prescreened subjects met the cMET expression threshold. Seven (3 metastatic melanoma, 4 mTNBC) were treated.

Results

Mean age was 50 years (35-64); median Eastern Cooperative Oncology Group 0 (0-1); median prior lines of chemotherapy/immunotherapy were 4/0 for TNBC and 1/3 for melanoma subjects. Six patients experienced grade 1 or 2 toxicity. Toxicities in at least 1 patient included anemia, fatigue, and malaise. One subject had grade 1 cytokine release syndrome. No grade 3 or higher toxicity, neurotoxicity, or treatment discontinuation occurred. Best response was stable disease in 4 and disease progression in 3 subjects. mRNA signals corresponding to CAR T cells were detected by RT-PCR in all patients' blood including in 3 subjects on day +1 (no infusion administered on this day). Five subjects underwent postinfusion biopsy with no CAR T-cell signals seen in tumor. Three subjects had paired tumor tissue; IHC showed increases in CD8 and CD3 and decreases in pS6 and Ki67.

Conclusions

Intravenous administration of RNA-electroporated cMET-directed CAR T cells is safe and feasible.

Significance

Data evaluating CAR T therapy in patients with solid tumors are limited. This pilot clinical trial demonstrates that intravenous cMET-directed CAR T-cell therapy is safe and feasible in patients with metastatic melanoma and metastatic breast cancer, supporting the continued evaluation of cellular therapy for patients with these malignancies.

Recent advances in targeting autophagy in cancer

Autophagy is a cellular homeostasis mechanism that fuels the proliferation and survival of advanced cancers by degrading and recycling organelles and proteins. Preclinical studies have identified that within an established tumor, tumor cell autophagy and host cell autophagy conspire to support tumor growth. A growing body of evidence suggests that autophagy inhibition can augment the efficacy of chemotherapy, targeted therapy, or immunotherapy to enhance tumor shrinkage. First-generation autophagy inhibition trials in cancer using the lysosomal inhibitor hydroxychloroquine (HCQ) have produced mixed results but have guided the way for the development of more potent and specific autophagy inhibitors in clinical trials. In this review, we will discuss the role of autophagy in cancer, newly discovered molecular mechanisms of the autophagy pathway, the effects of autophagy modulation in cancer and host cells, and novel autophagy inhibitors that are entering clinical trials.

Data from Autophagy Inhibition Sensitizes Colon Cancer Cells to Antiangiogenic and Cytotoxic Therapy.. [DOI: 10.1158/1078-0432.c.6522138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

<div>Abstract<p><b>Purpose:</b> Autophagy is a critical survival pathway for cancer cells under conditions of nutrient or oxygen limitation, or cell stress. As a consequence of antiangiogenic therapy, solid tumors encounter hypoxia induction and imbalances in nutrient supply. We wished to determine the role of autophagy in protection of tumor cells from the effects of antiangiogenic therapy and chemotherapy. We examined the effect of inhibiting autophagy on hypoxic colon cancer cells <i>in vitro</i> and on bevacizumab- and oxaliplatin-treated mouse xenografts <i>in vivo</i>.</p><p><b>Experimental Design:</b> The autophagic response to hypoxia and DNA-damaging agents was assessed by fluorescent microscopic imaging, autophagy-related gene expression, and by electron microscopic ultrastructural analysis. Pharmacologic and molecular approaches to autophagy inhibition were taken in a panel of colon cancer cell lines. Mouse xenograft models were treated with combinations of oxaliplatin, bevacizumab, and chloroquine to assess effects on tumor growth reduction and on pharmacodynamic markers of autophagy inhibition.</p><p><b>Results:</b> Autophagy was induced in colon cancer models by exposure to both hypoxia and oxaliplatin. Inhibition of autophagy, either with chloroquine or by downregulation of beclin1 or of ATG5, enhanced sensitivity to oxaliplatin under normal and hypoxic conditions in a synergistic manner. Both bevacizumab and oxaliplatin treatments activate autophagy in HT29 murine xenografts. The addition of chloroquine to bevacizumab-based treatment provided greater tumor control in concert with evidence of autophagy inhibition.</p><p><b>Conclusions:</b> These findings implicate autophagy as a mechanism of resistance to antiangiogenic therapies and support investigation of inhibitory approaches in the management of this disease. <i>Clin Cancer Res; 19(11); 2995–3007. ©2013 AACR</i>.</p></div>

Data from Autophagy Inhibition Sensitizes Colon Cancer Cells to Antiangiogenic and Cytotoxic Therapy.. [DOI: 10.1158/1078-0432.c.6522138.v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

<div>Abstract<p><b>Purpose:</b> Autophagy is a critical survival pathway for cancer cells under conditions of nutrient or oxygen limitation, or cell stress. As a consequence of antiangiogenic therapy, solid tumors encounter hypoxia induction and imbalances in nutrient supply. We wished to determine the role of autophagy in protection of tumor cells from the effects of antiangiogenic therapy and chemotherapy. We examined the effect of inhibiting autophagy on hypoxic colon cancer cells <i>in vitro</i> and on bevacizumab- and oxaliplatin-treated mouse xenografts <i>in vivo</i>.</p><p><b>Experimental Design:</b> The autophagic response to hypoxia and DNA-damaging agents was assessed by fluorescent microscopic imaging, autophagy-related gene expression, and by electron microscopic ultrastructural analysis. Pharmacologic and molecular approaches to autophagy inhibition were taken in a panel of colon cancer cell lines. Mouse xenograft models were treated with combinations of oxaliplatin, bevacizumab, and chloroquine to assess effects on tumor growth reduction and on pharmacodynamic markers of autophagy inhibition.</p><p><b>Results:</b> Autophagy was induced in colon cancer models by exposure to both hypoxia and oxaliplatin. Inhibition of autophagy, either with chloroquine or by downregulation of beclin1 or of ATG5, enhanced sensitivity to oxaliplatin under normal and hypoxic conditions in a synergistic manner. Both bevacizumab and oxaliplatin treatments activate autophagy in HT29 murine xenografts. The addition of chloroquine to bevacizumab-based treatment provided greater tumor control in concert with evidence of autophagy inhibition.</p><p><b>Conclusions:</b> These findings implicate autophagy as a mechanism of resistance to antiangiogenic therapies and support investigation of inhibitory approaches in the management of this disease. <i>Clin Cancer Res; 19(11); 2995–3007. ©2013 AACR</i>.</p></div>

Lysosomal lipid peroxidation regulates tumor immunity

Lysosomal inhibition elicited by palmitoyl protein transferase 1 (PPT1) inhibitors such as DC661 can produce cell death, but the mechanism is not completely understood. Programmed cell death pathways (autophagy, apoptosis, necroptosis, ferroptosis, and pyroptosis) were not required to achieve the cytotoxic effect of DC661. Inhibition of cathepsins, or iron or calcium chelation, did not rescue DC661-induced cytotoxicity. PPT1 inhibition induced lysosomal lipid peroxidation (LLP), which led to lysosomal membrane permeabilization and cell death that could be reversed by the antioxidant N-acetylcysteine (NAC), but not by other lipid peroxidation antioxidants. The lysosomal cysteine transporter MFSD12, was required for intralysosomal transport of NAC and rescue of LLP. PPT1 inhibition produced cell-intrinsic immunogenicity with surface expression of calreticulin that could only be reversed with NAC. DC661-treated cells primed naïve T cells, and enhanced T cell-mediated toxicity. Mice vaccinated with DC661-treated cells, engendered adaptive immunity and tumor rejection in "immune hot" tumors but not in "immune cold" tumors. These findings demonstrate LLP drives lysosomal cell death, a unique immunogenic form of cell death, pointing the way to rational combinations of immunotherapy and lysosomal inhibition that can be tested in clinical trials.

Targeting UGCG Overcomes Resistance to Lysosomal Autophagy Inhibition

Lysosomal autophagy inhibition (LAI) with hydroxychloroquine or DC661 can enhance cancer therapy, but tumor regrowth is common. To elucidate LAI resistance, proteomics and immunoblotting demonstrated that LAI induced lipid metabolism enzymes in multiple cancer cell lines. Lipidomics showed that LAI increased cholesterol, sphingolipids, and glycosphingolipids. These changes were associated with striking levels of GM1+ membrane microdomains (GMM) in plasma membranes and lysosomes. Inhibition of cholesterol/sphingolipid metabolism proteins enhanced LAI cytotoxicity. Targeting UDP-glucose ceramide glucosyltransferase (UGCG) synergistically augmented LAI cytotoxicity. Although UGCG inhibition decreased LAI-induced GMM and augmented cell death, UGCG overexpression led to LAI resistance. Melanoma patients with high UGCG expression had significantly shorter disease-specific survival. The FDA-approved UGCG inhibitor eliglustat combined with LAI significantly inhibited tumor growth and improved survival in syngeneic tumors and a therapy-resistant patient-derived xenograft. These findings nominate UGCG as a new cancer target, and clinical trials testing UGCG inhibition in combination with LAI are warranted.

SIGNIFICANCE

We discovered UGCG-dependent lipid remodeling drives resistance to LAI. Targeting UGCG with a drug approved for a lysosomal storage disorder enhanced LAI antitumor activity without toxicity. LAI and UGCG inhibition could be tested clinically in multiple cancers. This article is highlighted in the In This Issue feature, p. 247.

Peroxynitrite in the tumor microenvironment changes the profile of antigens allowing escape from cancer immunotherapy

Cancer immunotherapy often depends on recognition of peptide epitopes by cytotoxic T lymphocytes (CTLs). The tumor microenvironment (TME) is enriched for peroxynitrite (PNT), a potent oxidant produced by infiltrating myeloid cells and some tumor cells. We demonstrate that PNT alters the profile of MHC class I bound peptides presented on tumor cells. Only CTLs specific for PNT-resistant peptides have a strong antitumor effect in vivo, whereas CTLs specific for PNT-sensitive peptides are not effective. Therapeutic targeting of PNT in mice reduces resistance of tumor cells to CTLs. Melanoma patients with low PNT activity in their tumors demonstrate a better clinical response to immunotherapy than patients with high PNT activity. Our data suggest that intratumoral PNT activity should be considered for the design of neoantigen-based therapy and also may be an important immunotherapeutic target.

Pumping Iron: Ferritinophagy Promotes Survival and Therapy Resistance in Pancreatic Cancer

SUMMARY

Autophagy is an adaptive response to metabolic and therapeutic stress, especially in treatment-refractory cancers such as pancreatic cancer. In this issue of Cancer Discovery, two groups establish ferritinophagy, a selective autophagy program that could become a drug target, as the mechanism that pumps iron into mitochondria via the lysosome, enabling survival and therapy resistance in pancreas cancer. See related article by Santana-Codina et al., p. 2180 (3). See related article by Ravichandran et al., p. 2198 (4).

HRS phosphorylation drives immunosuppressive exosome secretion and restricts CD8+ T-cell infiltration into tumors

The lack of tumor infiltration by CD8⁺ T cells is associated with poor patient response to anti-PD-1 therapy. Understanding how tumor infiltration is regulated is key to improving treatment efficacy. Here, we report that phosphorylation of HRS, a pivotal component of the ESCRT complex involved in exosome biogenesis, restricts tumor infiltration of cytolytic CD8⁺ T cells. Following ERK-mediated phosphorylation, HRS interacts with and mediates the selective loading of PD-L1 to exosomes, which inhibits the migration of CD8⁺ T cells into tumors. In tissue samples from patients with melanoma, CD8⁺ T cells are excluded from the regions where tumor cells contain high levels of phosphorylated HRS. In murine tumor models, overexpression of phosphorylated HRS increases resistance to anti-PD-1 treatment, whereas inhibition of HRS phosphorylation enhances treatment efficacy. Our study reveals a mechanism by which phosphorylation of HRS in tumor cells regulates anti-tumor immunity by inducing PD-L1⁺ immunosuppressive exosomes, and suggests HRS phosphorylation blockade as a potential strategy to improve the efficacy of cancer immunotherapy.

Moderate Colitis Not Requiring IV Steroids Is Associated with Improved Survival in Stage IV Melanoma after Anti-CTLA4 Monotherapy, But Not Combination Therapy

Background

For patients with melanoma, gastrointestinal immune-related adverse events are common after receipt of anti-CTLA4 therapy. These present difficult decision points regarding whether to discontinue therapy. Detailing the situations in which colitis might predict for improved survival and how this is affected by discontinuation or resumption of therapy can help guide clinical decision-making.

Materials and Methods

Patients with stage IV melanoma receiving anti-CTLA4 therapy from 2008 to 2019 were analyzed. Immune-related colitis treated with ≥50 mg prednisone or equivalent daily or secondary immunosuppression was included. Moderate colitis was defined as receipt of oral glucocorticoids only; severe colitis was defined as requiring intravenous glucocorticoids or secondary immunosuppression. The primary outcome was overall survival (OS).

Results

In total, 171 patients received monotherapy, and 91 received dual checkpoint therapy. In the monotherapy group, 25 patients developed colitis and a nonsignificant trend toward improved OS was observed in this group. Notably, when colitis was categorized as none, moderate or severe, OS was significantly improved for moderate colitis only. This survival difference was not present after dual checkpoint therapy. There were no differences in known prognostic variables between groups, and on multivariable analysis neither completion of all ipilimumab cycles nor resumption of immunotherapy correlated with OS, while the development of moderate colitis did significantly affect OS.

Conclusion

This single-institution retrospective series suggests moderate colitis correlates with improved OS for patients with stage IV melanoma treated with single-agent anti-CTLA4, but not dual agent, and that this is true regardless of whether the immune-checkpoint blockade is permanently discontinued.

Clinical trial results show promise of targeting autophagy BRAF mutant melanoma

Macroautophagy/autophagy is a resistance mechanism to targeted therapy in BRAF mutant cancers. Preclinical evidence and clinical trial data demonstrate that hydroxychloroquine (HCQ) is an effective autophagy inhibitor at clinically achievable concentrations. Here we highlight the results of a recently published single-arm phase I/II multi-institution trial of dabrafenib, trametinib, and the autophagy inhibitor HCQ (the BAMM trial) that established the safety and activity of this regimen in BRAF V600-mutant melanoma patients. Compared to the pivotal trials that led to FDA approval of dabrafenib and trametinib, the BAMM trial enrolled a high percentage of patients with elevated LDH and prior immunotherapy, reflecting the trend that poorer-prognosis patients are treated with targeted therapy in the modern era where multiple immunotherapy regimens are available for melanoma. Dabrafenib, trametinib, and hydroxychloroquine are safe and produce a high response rate (85%). Progression-free survival does not meet the pre-specified threshold for the entire cohort but looks especially promising in patients with elevated LDH and prior treatment. A national randomized study has been launched to study this regimen further in poor-prognosis BRAF V600-mutant melanoma patients.

BAMM (BRAF Autophagy and MEK Inhibition in Melanoma): A Phase I/II Trial of Dabrafenib, Trametinib, and Hydroxychloroquine in Advanced BRAFV600-mutant Melanoma

PURPOSE

Autophagy is a resistance mechanism to BRAF/MEK inhibition in BRAFV600-mutant melanoma. Here we used hydroxychloroquine (HCQ) to inhibit autophagy in combination with dabrafenib 150 mg twice daily and trametinib 2 mg every day (D+T).

PATIENTS AND METHODS

We conducted a phase I/II clinical trial in four centers of HCQ + D+T in patients with advanced BRAFV600-mutant melanoma. The primary objectives were the recommended phase II dose (RP2D) and the one-year progression-free survival (PFS) rate of >53%.

RESULTS

Thirty-four patients were evaluable for one-year PFS rate. Patient demographics were as follows: elevated lactate dehydrogenase: 47%; stage IV M1c/M1d: 52%; prior immunotherapy: 50%. In phase I, there was no dose-limiting toxicity. HCQ 600 mg orally twice daily with D+T was the RP2D. The one-year PFS rate was 48.2% [95% confidence interval (CI), 31.0%-65.5%], median PFS was 11.2 months (95% CI, 5.4-16.9 months), and response rate (RR) was 85% (95% CI, 64%-95%). The complete RR was 41% and median overall survival (OS) was 26.5 months. In a patient with elevated LDH (n = 16), the RR was 88% and median PFS and OS were 7.3 and 22 months, respectively.

CONCLUSIONS

HCQ + D+T was well tolerated and produced a high RR but did not meet criteria for success for the one-year PFS rate. There was a high proportion of patients with pretreated and elevated LDH, an increasingly common demographic in patients receiving targeted therapy. In this difficult-to-treat population, the RR and PFS were encouraging. A randomized trial of D+T + HCQ or placebo in patients with BRAFV600-mutant melanoma with elevated LDH and previous immunotherapy is being conducted.

Human epigenetic and transcriptional T cell differentiation atlas for identifying functional T cell-specific enhancers

The clinical benefit of T cell immunotherapies remains limited by incomplete understanding of T cell differentiation and dysfunction. We generated an epigenetic and transcriptional atlas of T cell differentiation from healthy humans that included exhausted CD8 T cells and applied this resource in three ways. First, we identified modules of gene expression and chromatin accessibility, revealing molecular coordination of differentiation after activation and between central memory and effector memory. Second, we applied this healthy molecular framework to three settings-a neoadjuvant anti-PD1 melanoma trial, a basal cell carcinoma scATAC-seq dataset, and autoimmune disease-associated SNPs-yielding insights into disease-specific biology. Third, we predicted genome-wide cis-regulatory elements and validated this approach for key effector genes using CRISPR interference, providing functional annotation and demonstrating the ability to identify targets for non-coding cellular engineering. These studies define epigenetic and transcriptional regulation of human T cells and illustrate the utility of interrogating disease in the context of a healthy T cell atlas.

OUP accepted manuscript

BACKGROUND

The antiangiogenic tyrosine kinase inhibitor regorafenib provides a survival benefit in patients with previously treated metastatic colorectal cancer (CRC). Antiangiogenic therapy causes hypoxic stress within tumor cells, which activates autophagy as a survival mechanism. The histone deacetylase inhibitor (HDAC) entinostat increases dependence on autophagy through epigenetic mechanisms. Hydroxychloroquine (HCQ) blocks autophagy by blunting lysosomal acidification. We hypothesized that HCQ and entinostat would be tolerable with regorafenib and potentiate the antitumor response.

METHODS

This was a 3+3 phase I trial of HCQ and entinostat with regorafenib in patients with metastatic CRC. The primary objective was safety, and the secondary objective was clinical efficacy.

RESULTS

Twenty patients received study therapy. Six evaluable patients were enrolled at each of the three planned dose levels, one patient at an intermediate dose level, and one additional patient withdrew consent after 4 days to receive treatment closer to home. One dose-limiting toxicity was noted in the study at dose level 2 (grade 3 fatigue). Seven patients discontinued therapy due to related toxicities; rapid weight loss was near universal, with a median weight loss of 4.4 kg (range 1.5-12.2 kg) in the first 2 weeks of treatment. No objective responses were observed.

CONCLUSION

The combination of regorafenib, HCQ, and entinostat was poorly tolerated without evident activity in metastatic CRC.

CLINICALTRIALS.GOV IDENTIFIER

NCT03215264.

Neural Crest-Like Stem Cell Transcriptome Analysis Identifies LPAR1 in Melanoma Progression and Therapy Resistance

Metastatic melanoma is challenging to clinically address. Although standard-of-care targeted therapy has high response rates in patients with BRAF-mutant melanoma, therapy relapse occurs in most cases. Intrinsically resistant melanoma cells drive therapy resistance and display molecular and biologic properties akin to neural crest-like stem cells (NCLSC) including high invasiveness, plasticity, and self-renewal capacity. The shared transcriptional programs and vulnerabilities between NCLSCs and cancer cells remains poorly understood. Here, we identify a developmental LPAR1-axis critical for NCLSC viability and melanoma cell survival. LPAR1 activity increased during progression and following acquisition of therapeutic resistance. Notably, genetic inhibition of LPAR1 potentiated BRAFi ± MEKi efficacy and ablated melanoma migration and invasion. Our data define LPAR1 as a new therapeutic target in melanoma and highlights the promise of dissecting stem cell-like pathways hijacked by tumor cells. SIGNIFICANCE: This study identifies an LPAR1-axis critical for melanoma invasion and intrinsic/acquired therapy resistance.

Anticancer properties of bisaminoquinolines with modified linkers

We have previously reported the unique features of dimeric bisaminoquinolines as anticancer agents and have identified their cellular target as PPT1, a protein palmitoyl-thioesterase. We now report a systematic study on the role of the linker in these constructs, both with respect to the distance between the heterocycles, the linker hydrophobicity and the methylation status (primary vs. secondary vs. tertiary) of the central nitrogen atom on the observed biological activity.

Autophagy in major human diseases

Autophagy is a core molecular pathway for the preservation of cellular and organismal homeostasis. Pharmacological and genetic interventions impairing autophagy responses promote or aggravate disease in a plethora of experimental models. Consistently, mutations in autophagy-related processes cause severe human pathologies. Here, we review and discuss preclinical data linking autophagy dysfunction to the pathogenesis of major human disorders including cancer as well as cardiovascular, neurodegenerative, metabolic, pulmonary, renal, infectious, musculoskeletal, and ocular disorders.

Compliance with sentinel lymph node biopsy guidelines for invasive melanomas treated with Mohs micrographic surgery

BACKGROUND

Sentinel lymph node biopsy (SLNB) has not been studied for invasive melanomas treated with Mohs micrographic surgery using frozen-section MART-1 immunohistochemical stains (MMS-IHC). The primary objective of this study was to assess the accuracy and compliance with National Comprehensive Cancer Network (NCCN) guidelines for SLNB in a cohort of patients who had invasive melanoma treated with MMS-IHC.

METHODS

This retrospective cohort study included all patients who had primary, invasive, cutaneous melanomas treated with MMS-IHC at a single academic center between March 2006 and April 2018. The primary outcomes were the rates of documenting discussion and performing SLNB in patients who were eligible based on NCCN guidelines. Secondary outcomes were the rate of identifying the sentinel lymph node and the percentage of positive lymph nodes.

RESULTS

In total, 667 primary, invasive, cutaneous melanomas (American Joint Committee on Cancer T1a-T4b) were treated with MMS-IHC. The median patient age was 69 years (range, 25-101 years). Ninety-two percent of tumors were located on specialty sites (head and/or neck, hands and/or feet, pretibial leg). Discussion of SLNB was documented for 162 of 176 (92%) SLNB-eligible patients, including 127 of 127 (100%) who had melanomas with a Breslow depth >1 mm. SLNB was performed in 109 of 176 (62%) SLNB-eligible patients, including 102 of 158 melanomas (65%) that met NCCN criteria to discuss and offer SLNB and 7 of 18 melanomas (39%) that met criteria to discuss and consider SLNB. The sentinel lymph node was successfully identified in 98 of 109 patients (90%) and was positive in 6 of those 98 patients (6%).

CONCLUSIONS

Combining SLNB and MMS-IHC allows full pathologic staging and confirmation of clear microscopic margins before reconstruction of specialty site invasive melanomas. SLNB can be performed accurately and in compliance with consensus guidelines in patients with melanoma using MMS-IHC.

Association of Antibiotic Exposure With Survival and Toxicity in Patients With Melanoma Receiving Immunotherapy

BACKGROUND

Gut microbial diversity is associated with improved response to immune checkpoint inhibitors (ICI). Based on the known detrimental impact that antibiotics have on microbiome diversity, we hypothesized that antibiotic receipt prior to ICI would be associated with decreased survival.

METHODS

Patients with stage III and IV melanoma treated with ICI between 2008 and 2019 were selected from an institutional database. A window of antibiotic receipt within 3 months prior to the first infusion of ICI was prespecified. The primary outcome was overall survival (OS), and secondary outcomes were melanoma-specific mortality and immune-mediated colitis requiring intravenous steroids. All statistical tests were two-sided.

RESULTS

There were 568 patients in our database of which 114 received antibiotics prior to ICI. Of the patients, 35.9% had stage III disease. On multivariable Cox proportional hazards analysis of patients with stage IV disease, the antibiotic-exposed group had statistically significantly worse OS (hazard ratio [HR] = 1.81, 95% confidence interval [CI] = 1.27 to 2.57; P <.001). The same effect was observed among antibiotic-exposed patients with stage III disease (HR = 2.78, 95% CI = 1.31 to 5.87; P =.007). When limited to only patients who received adjuvant ICI (n = 89), antibiotic-exposed patients also had statistically significantly worse OS (HR = 4.84, 95% CI = 1.09 to 21.50; P =.04). The antibiotic group had a greater incidence of colitis (HR = 2.14, 95% CI = 1.02 to 4.52; P =.046).

CONCLUSION

Patients with stage III and IV melanoma exposed to antibiotics prior to ICI had statistically significantly worse OS than unexposed patients. Antibiotic exposure was associated with greater incidence of moderate to severe immune-mediated colitis. Given the large number of antibiotics prescribed annually, physicians should be judicious with their use in cancer populations likely to receive ICI.

Final results of a phase I “RadVax” trial of hypofractionated radiation combined with pembrolizumab in patients with metastatic solid tumors

2576

Background: Many patients treated with anti-PD-1 therapy do not show a clinical response. Preclinical studies suggest that adding hypofractionated radiotherapy (HFRT) to anti-PD1 can increase the efficacy of immunotherapy through several mechanisms including increased antigen presentation. We conducted a prospective trial testing the combination of pembrolizumab and HFRT in patients with metastatic solid tumors. Methods: This prospective single-institution phase I trial tested pembrolizumab in combination with HFRT in patients with metastatic cancers (NSCLC, melanoma, pancreas, breast, others) and an ECOG performance status of 0-1. Melanoma and NSCLC patients were required to have progression of disease on anti-PD1, having received ≥ 2 doses of anti-PD1 and progression documented by RECIST v1.1. Patients were required to have an index lesion ≥1 cm that was amenable to HFRT and at least one other lesion that was not irradiated and could be followed for response using RECIST criteria. Pembrolizumab 200 mg IV every 3 weeks was administered beginning 1 week prior to the first fraction of radiation. The HFRT dose was 8 Gy x 3 fractions or 17 Gy x 1 fraction, determined by randomization during the Expansion phase. The primary objective was the safety of HFRT combined with pembrolizumab, with dose-limiting toxicity (DLT) defined as Grade ≥ 3 non-hematological toxicity related to the combination of Pembrolizumab and HFRT. The secondary objective was the radiographic response of metastatic lesions outside the radiation field as measured by RECIST. Results: 59 patients aged 27-90 years (median 60) were enrolled from March 2015 to December 2018 (24 in the Safety Phase and 35 in Expansion Phase). 40 patients (67.7%) had treatment-related AEs, of which 4 were grade 3 and none were grade 4. One patient experienced hepatitis, classified as DLT. While most patients did not have a radiologic response, in patients with metastatic melanoma, 7 of 16 (43.8%, exact 95% CI 19.8-70.1%) had an objective response to HFRT + pembrolizumab, including 3 complete and 4 partial responses. Responses are durable with 3/3 complete responders alive with no progression, and 3/4 partial responders alive with 2 having no evidence of progression. Among melanoma patients, only 2 of 7 (29%) responders received ipilimumab prior to enrollment, compared to 8 of 9 (89%) non-responders (p = 0.035). An increase in Ki67+ PD-1+ non-naïve CD8 T-cells was observed in the blood 2 weeks after HFRT, but the magnitude did not correlate with likelihood of response. Responses were observed after either 17 Gy x 1 fraction or 8 Gy x 3 fractions, with no difference in response rate by fractionation. Conclusions: This study suggests that HFRT administered with concurrent pembrolizumab is associated with acceptable toxicity and that in patients with metastatic melanoma progressing on anti-PD-1 therapy, this approach yields an ORR of 44%. Clinical trial information: NCT02303990.

Phase I trial of regorafenib, hydroxychloroquine, and entinostat in metastatic colorectal cancer

e15580

Background: The antiangiogenic tyrosine kinase inhibitor regorafenib provides a survival benefit in patients with previously treated metastatic colorectal cancer. Antiangiogenic therapy causes hypoxic stress within tumor cells, which activate autophagy as a survival mechanism. Entinostat, a histone deacetylase (HDAC) inhibitor, increases dependence on autophagy through epigenetic mechanisms. Hydroxychloroquine (HCQ) blocks autophagy by blunting lysosomal acidification and is synergistic with antiangiogenic therapies. We hypothesized that HCQ and entinostat would be tolerable with regorafenib and potentiate the antitumor response. Methods: This was a 3+3 phase I trial to find the recommended phase II dose (RP2D) of HCQ and entinostat with regorafenib in patients with metastatic colorectal cancer previously treated with a fluoropyrimidine, oxaliplatin, and irinotecan. No prior regorafenib or HDAC inhibitor therapy was permitted. Regorafenib was dosed at 160mg daily on days 1-21 of 28-day cycles, with provision to lower the starting dose to 80mg if toxicity was excessive. Entinostat was dosed at 3mg weekly in dose level 1 and at 5mg weekly in dose levels 2 and 3 while HCQ was dosed at 200mg qAM and 400mg qPM in dose levels 1 and 2 and at 600mg BID at dose level 3. Expansion was planned at the RP2D with a primary endpoint of objective response rate. Results: Twenty-eight patients were screened, and 20 patients were enrolled from November 2017 to January 2020. Six patients were treated at dose level 1 with no dose-limiting toxicity. The starting regorafenib dose was reduced to 80mg after 3 patients discontinued therapy early due to fatigue or rash due to regorafenib. At dose level 2, 7 patients were enrolled to achieve 6 evaluable patients. One DLT (G3 fatigue) was noted and one patient withdrew consent after 14 days due to fever and tumor pain flare possibly related to treatment. Six patients enrolled at dose level 3; no DLTs were seen. One additional patient received HCQ 400mg BID instead of 600mg BID due to a clerical error. Weight loss (60%), fatigue (50%), and anorexia (50%) were the most common toxicities. Thirteen grade 3 toxicities were noted, with rash (15%), fatigue (10%), and alkaline phosphatase elevation (10%) the most common. No grade 4 toxicities were observed. Seven patients discontinued therapy early due to toxicity. Nearly all patients experienced rapid weight loss, with a range of 1.5 lbs to 27.1 lbs and a median weight loss of 9.5 lbs at two weeks. No objective responses were observed. The median PFS was 1.8 months, the median OS was 5.2 months, and no patient remained on study longer than 4 months. Expansion was not pursued due to toxicity and lack of efficacy. Conclusions: The combination of regorafenib, HCQ, and entinostat was poorly tolerated without evident activity in metastatic colorectal cancer. The substantial weight loss suggests a potential adverse metabolic interaction between these drugs. Clinical trial information: NCT03215264.

Role of nuclear localization in the regulation and function of T-bet and Eomes in exhausted CD8 T cells

The transcription factors T-bet and Eomesodermin (Eomes) regulate CD8 T cell exhaustion through undefined mechanisms. Here, we show that the subcellular localization of T-bet and Eomes dictate their regulatory activity in exhausted T cells (T_EXs). T_EXs had a higher ratio of nuclear Eomes:T-bet than memory T cells (T_MEMs) during chronic lymphocytic choriomeningitis virus (LCMV) infection in preclinical cancer models and in human tumors. Biochemically, T-bet and Eomes compete for the same DNA sequences, including the Pdcd1 T-box. High nuclear T-bet strongly represses Pdcd1 transcription in T_MEM, whereas low nuclear T-bet in T_EX leads to a dominant effect of Eomes that acts as a weaker repressor of Pdcd1. Blocking PD-1 signaling in T_EXs increases nuclear T-bet, restoring stronger repression of Pdcd1, and driving T-bet-associated gene expression programs of chemotaxis, homing, and activation. These data identify a mechanism whereby the T-bet-Eomes axis regulates exhaustion through their nuclear localization, providing insights into how these transcription factors regulate T_EX biology.

McLane et al. demonstrate that T-bet and Eomes expression contributes to exhaustion, but also their nuclear localization, and therefore functional activity, plays a key role. PD-1 blockade restores nuclear T-bet and promotes T cell homing and activation through direct competition with Eomes at gene promoters, such as Pdcd1.

Mortality outcomes with hydroxychloroquine and chloroquine in COVID-19 from an international collaborative meta-analysis of randomized trials

Substantial COVID-19 research investment has been allocated to randomized clinical trials (RCTs) on hydroxychloroquine/chloroquine, which currently face recruitment challenges or early discontinuation. We aim to estimate the effects of hydroxychloroquine and chloroquine on survival in COVID-19 from all currently available RCT evidence, published and unpublished. We present a rapid meta-analysis of ongoing, completed, or discontinued RCTs on hydroxychloroquine or chloroquine treatment for any COVID-19 patients (protocol: https://osf.io/QESV4/ ). We systematically identified unpublished RCTs (ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, Cochrane COVID-registry up to June 11, 2020), and published RCTs (PubMed, medRxiv and bioRxiv up to October 16, 2020). All-cause mortality has been extracted (publications/preprints) or requested from investigators and combined in random-effects meta-analyses, calculating odds ratios (ORs) with 95% confidence intervals (CIs), separately for hydroxychloroquine and chloroquine. Prespecified subgroup analyses include patient setting, diagnostic confirmation, control type, and publication status. Sixty-three trials were potentially eligible. We included 14 unpublished trials (1308 patients) and 14 publications/preprints (9011 patients). Results for hydroxychloroquine are dominated by RECOVERY and WHO SOLIDARITY, two highly pragmatic trials, which employed relatively high doses and included 4716 and 1853 patients, respectively (67% of the total sample size). The combined OR on all-cause mortality for hydroxychloroquine is 1.11 (95% CI: 1.02, 1.20; I² = 0%; 26 trials; 10,012 patients) and for chloroquine 1.77 (95%CI: 0.15, 21.13, I² = 0%; 4 trials; 307 patients). We identified no subgroup effects. We found that treatment with hydroxychloroquine is associated with increased mortality in COVID-19 patients, and there is no benefit of chloroquine. Findings have unclear generalizability to outpatients, children, pregnant women, and people with comorbidities.

Efficacy and Safety of Hydroxychloroquine vs Placebo for Pre-exposure SARS-CoV-2 Prophylaxis Among Health Care Workers: A Randomized Clinical Trial

IMPORTANCE

Health care workers (HCWs) caring for patients with coronavirus disease 2019 (COVID-19) are at risk of exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, to our knowledge, there is no effective pharmacologic prophylaxis for individuals at risk.

OBJECTIVE

To evaluate the efficacy of hydroxychloroquine to prevent transmission of SARS-CoV-2 in hospital-based HCWs with exposure to patients with COVID-19 using a pre-exposure prophylaxis strategy.

DESIGN, SETTING, AND PARTICIPANTS

This randomized, double-blind, placebo-controlled clinical trial (the Prevention and Treatment of COVID-19 With Hydroxychloroquine Study) was conducted at 2 tertiary urban hospitals, with enrollment from April 9, 2020, to July 14, 2020; follow-up ended August 4, 2020. The trial randomized 132 full-time, hospital-based HCWs (physicians, nurses, certified nursing assistants, emergency technicians, and respiratory therapists), of whom 125 were initially asymptomatic and had negative results for SARS-CoV-2 by nasopharyngeal swab. The trial was terminated early for futility before reaching a planned enrollment of 200 participants.

INTERVENTIONS

Hydroxychloroquine, 600 mg, daily, or size-matched placebo taken orally for 8 weeks.

MAIN OUTCOMES AND MEASURES

The primary outcome was the incidence of SARS-CoV-2 infection as determined by a nasopharyngeal swab during the 8 weeks of treatment. Secondary outcomes included adverse effects, treatment discontinuation, presence of SARS-CoV-2 antibodies, frequency of QTc prolongation, and clinical outcomes for SARS-CoV-2-positive participants.

RESULTS

Of the 132 randomized participants (median age, 33 years [range, 20-66 years]; 91 women [69%]), 125 (94.7%) were evaluable for the primary outcome. There was no significant difference in infection rates in participants randomized to receive hydroxychloroquine compared with placebo (4 of 64 [6.3%] vs 4 of 61 [6.6%]; P > .99). Mild adverse events were more common in participants taking hydroxychloroquine compared with placebo (45% vs 26%; P = .04); rates of treatment discontinuation were similar in both arms (19% vs 16%; P = .81). The median change in QTc (baseline to 4-week evaluation) did not differ between arms (hydroxychloroquine: 4 milliseconds; 95% CI, -9 to 17; vs placebo: 3 milliseconds; 95% CI, -5 to 11; P = .98). Of the 8 participants with positive results for SARS-CoV-2 (6.4%), 6 developed viral symptoms; none required hospitalization, and all clinically recovered.

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial, although limited by early termination, there was no clinical benefit of hydroxychloroquine administered daily for 8 weeks as pre-exposure prophylaxis in hospital-based HCWs exposed to patients with COVID-19.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04329923.

A stratified phase I dose escalation trial of hypofractionated radiotherapy followed by ipilimumab in metastatic melanoma: long-term follow-up and final outcomes

We conducted a phase I dose-escalation trial of radiation with ipilimumab in patients with melanoma with ≥2 metastatic lesions. Here, we report the final full clinical analysis. Patients received RT (6 or 8 Gy x 2 or 3 doses) to a single lesion followed by 4 cycles of ipilimumab. The primary endpoint was maximum tolerated dose of RT, and secondary endpoint was response at non-radiated sites. Twenty-two patients with treatment-naïve (n = 11) or treatment-refractory (n = 11) Stage IV melanoma were enrolled. There were 31 treatment-related adverse events (AEs), of which 16 were deemed immune-related. Eleven patients had grade 3 AEs (no grade 4/5). There were no dose-limiting toxicities related to the radiation/ipilimumab combination. Five of 22 patients (22.7%, 95% CI 7.8-45.4%) had partial response as best response and three (13.6%) had stable disease. Median overall survival was 10.7 months (95% CI, 4.9 months to not-estimable) and median progression-free survival 3.6 months (95% CI, 2.9 months to 7.8 months). Seven patients were still alive at the time of last follow-up (median follow-up 89.2 months), most of whom received pembrolizumab after progression. Radiotherapy followed by ipilimumab was well tolerated and yielded a response rate that compares favorably to the objective response rate with ipilimumab alone. Furthermore, 32% of patients are long-term survivors, most of whom received pembrolizumab. Based on these results, the recommended dose that was used in subsequent Phase 2 trials was 8 Gy x 3 doses. Clinical Trial Registration: NCT01497808 (www.clinicaltrials.gov).

Distinct Populations of Immune-Suppressive Macrophages Differentiate from Monocytic Myeloid-Derived Suppressor Cells in Cancer

Here, we report that functional heterogeneity of macrophages in cancer could be determined by the nature of their precursors: monocytes (Mons) and monocytic myeloid-derived suppressor cells (M-MDSCs). Macrophages that are differentiated from M-MDSCs, but not from Mons, are immune suppressive, with a genomic profile matching that of M-MDSCs. Immune-suppressive activity of M-MDSC-derived macrophages is dependent on the persistent expression of S100A9 protein in these cells. S100A9 also promotes M2 polarization of macrophages. Tissue-resident- and Mon-derived macrophages lack expression of this protein. S100A9-dependent immune-suppressive activity of macrophages involves transcription factor C/EBPβ. The presence of S100A9-positive macrophages in tumor tissues is associated with shorter survival in patients with head and neck cancer and poor response to PD-1 antibody treatment in patients with metastatic melanoma. Thus, this study reveals the pathway of the development of immune-suppressive macrophages and suggests an approach to their selective targeting.

Mortality outcomes with hydroxychloroquine and chloroquine in COVID-19: an international collaborative meta-analysis of randomized trials.. [DOI: 10.1101/2020.09.16.20194571]

Background

Substantial COVID-19 research investment has been allocated to randomized clinical trials (RCTs) on hydroxychloroquine/chloroquine, which currently face recruitment challenges or early discontinuation. We aimed to estimate the effects of hydroxychloroquine and chloroquine on survival in COVID-19 from all currently available RCT evidence, published and unpublished. Methods: Rapid meta-analysis of ongoing, completed, or discontinued RCTs on hydroxychloroquine or chloroquine treatment for any COVID-19 patients (protocol: https://osf.io/QESV4/). We systematically identified published and unpublished RCTs by September 14, 2020 (ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, PubMed, Cochrane COVID-19 registry). All-cause mortality was extracted (publications/preprints) or requested from investigators and combined in random-effects meta-analyses, calculating odds ratios (ORs) with 95% confidence intervals (CIs), separately for hydroxychloroquine/chloroquine. Prespecified subgroup analyses included patient setting, diagnostic confirmation, control type, and publication status.

Results

Sixty-two trials were potentially eligible. We included 16 unpublished trials (1596 patients) and 10 publications/preprints (6317 patients). The combined summary OR on all-cause mortality for hydroxychloroquine was 1.08 (95%CI: 0.99, 1.18; I2=0%; 24 trials; 7659 patients) and for chloroquine 1.77 (95%CI: 0.15, 21.13, I2=0%; 4 trials; 307 patients). We identified no subgroup effects.

Conclusions

We found no benefit of hydroxychloroquine or chloroquine on the survival of COVID-19 patients. For hydroxychloroquine, the confidence interval is compatible with increased mortality (OR 1.18) or negligibly reduced mortality (OR 0.99). Findings have unclear generalizability to outpatients, children, pregnant women, and people with comorbidities.

PPT1 inhibition enhances the antitumor activity of anti-PD-1 antibody in melanoma

New strategies are needed to enhance the efficacy of anti–programmed cell death protein antibody (anti–PD-1 Ab) in cancer. Here, we report that inhibiting palmitoyl-protein thioesterase 1 (PPT1), a target of chloroquine derivatives like hydroxychloroquine (HCQ), enhances the antitumor efficacy of anti–PD-1 Ab in melanoma. The combination resulted in tumor growth impairment and improved survival in mouse models. Genetic suppression of core autophagy genes, but not Ppt1, in cancer cells reduced priming and cytotoxic capacity of primed T cells. Exposure of antigen-primed T cells to macrophage-conditioned medium derived from macrophages treated with PPT1 inhibitors enhanced melanoma-specific killing. Genetic or chemical Ppt1 inhibition resulted in M2 to M1 phenotype switching in macrophages. The combination was associated with a reduction in myeloid-derived suppressor cells in the tumor. Ppt1 inhibition by HCQ, or DC661, induced cyclic GMP-AMP synthase/stimulator of interferon genes/TANK binding kinase 1 pathway activation and the secretion of interferon-β in macrophages, the latter being a key component for augmented T cell–mediated cytotoxicity. Genetic Ppt1 inhibition produced similar findings. These data provide the rationale for this combination in melanoma clinical trials and further investigation in other cancers.

Inhibiting palmitoyl-protein thioesterase 1 (PPT1), a target of CQ derivatives like hydroxychloroquine (HCQ), enhances the antitumor efficacy of anti-PD-1 Ab in murine melanoma models.

The effect of sonidegib (LDE225) on the pharmacokinetics of bupropion and warfarin in patients with advanced solid tumours

AIMS

We evaluated the potential effect of sonidegib at an oral dose of 800 mg once daily (QD) on the pharmacokinetics (PK) of the probe drugs warfarin (CYP2C9) and bupropion (CYP2B6).

METHODS

This was a multicentre, open-label study to evaluate the effect of sonidegib on the PK of the probe drugs warfarin and bupropion in patients with advanced solid tumours. Cohort 1 patients received a single warfarin 15-mg dose on Day 1 of the run-in period and on Cycle 2 Day 22 (C2D22) of sonidegib administration. Cohort 2 patients received a single bupropion 75-mg dose on Day 1 of run-in period and on C2D22 of sonidegib administration. Sonidegib 800 mg QD oral dosing began on Cycle 1 Day 1 of a 28-day cycle after the run-in period in both cohorts.

RESULTS

The geometric means ratios [90% confidence interval] for (S)-warfarin with and without sonidegib were: area under the concentration-time curve from time 0 to infinity (AUC_inf ) 1.15 [1.07, 1.24] and maximum plasma concentration (C_max ) 0.88 [0.81, 0.97]; and for (R)-warfarin were: AUC_inf 1.10 [0.98, 1.24] and C_max 0.93 [0.87, 1.0]. The geometric means ratios [90% confidence interval] of bupropion with and without sonidegib were: AUC_inf 1.10 [0.99, 1.23] and C_max 1.16 [0.95, 1.42]. Sonidegib 800 mg had a safety profile that was similar to that of lower dose sonidegib 200 mg and was unaffected by single doses of the probe drugs.

CONCLUSIONS

Sonidegib dosed orally at 800 mg QD (higher than the Food and Drug Administration-approved dose) did not impact the PK or pharmacodynamics of warfarin (CYP2C9 probe substrate) or the PK of bupropion (CYP2B6 probe substrate).

Landmark analysis of immunotherapy duration and disease free survival in advanced melanoma patients with a complete response

10054

Background: Checkpoint blockade improves survival in patients with melanoma, with durable complete responses (CR) after stopping therapy. Based on data from KEYNOTE-001, immunotherapy is often continued for 24 months in patients with confirmed CR. Outcomes with treatment of less than 24 months hav not been adequately evaluated and reported. If equally efficacious, shorter courses would potentially reduce health care costs and toxicity. Methods: 45 patients with locally advanced stage III and IV melanoma who received immunotherapy (pembrolizumab, nivolumab or ipilimumab/nivolumab) as 1st line or subsequent therapy, achieved a CR, and stopped therapy were identified under an IRB approved protocol at Penn. Disease Free Survival (DFS) was defined as time from declaration of CR until recurrence or date of analysis (1/15/20). Landmark DFS from time of CR was analyzed based on duration of therapy (less than or greater than 7 months, based on early trial requirements to treat patients with confirmed CR for at least 6 months). Rationale for stopping (toxicity or CR) was also analyzed. Results: Of 45 patients with CR, 27 (60%) were treated less then 7 months (median 4.8, range 1 day to 6.7 months) and 18 (40%) were treated for greater than 7 months (median 12.4, range 7.5 to 24.2 months). Patients who were treated for less than 7 months had a median DFS from time of CR of 30.4 months (95% CI 23.7 to 37.2, range 2.9 to 65.7 months). Patients treated for greater than 7 months had a median DFS of 28.0 months (95% CI 18.9 to 37, range 8.5 to 73.7 months). Patients who stopped due to toxicity (N = 17, 40%) had a median treatment duration of 3.7 months. Their median DFS from time of CR was 30.4 months (95% CI 20.7 to 40.1, range of 2.9 to 65.7 months). Patients who stopped due to CR (N = 28, 60%) had a median treatment duration of 8.5 months. Their median DFS was 27.6 months (95% CI 21.2 to 34 range 7.2 to 73.7 months). Two of 27 (7.4%) patients treated for less then 7 months and 3 out of 18 (16%) patients treated greater than 7 months recurred after stopping. One out of 17 (5.8%) recurred after stopping for toxicity vs. 4/28 (14.3%) who stopped after CR. Conclusions: Patients who stop therapy at less than 7 months have CRs that are equally durable as those treated longer than 7 months, without reduction in landmark DFS. Patients who stopped therapy due to toxicity and then achieved a CR had no difference in DFS compared to patients treated until CR. There was no significant difference in recurrence after achieving a complete response in patients treated for a longer vs shorter treatment course.

Phase I trial of autologous cMET-directed CAR-t cells administered intravenously in patients with melanoma & breast carcinoma

10035

Background: Advanced relapsed/refractory melanoma and metastatic triple-negative breast cancer are lethal diseases for which effective therapies are limited. We conducted a pilot phase I clinical trial (NCT03060356) to establish the safety and feasibility of intravenous autologous chimeric antigen receptor (CAR) T cell immunotherapy targeting cMET, a cell-surface antigen that is highly expressed in these cancers. Methods: Subjects had metastatic or unresectable melanoma (Mel) or triple-negative breast cancer (BC) with ≥30% expression of cMET on archival tissue or screening biopsy. Eligible subjects had measurable disease and progression on at least 1 prior therapy. Patients (pts) received up to 6 doses (1x108 total T-cells per dose) of RNA electroporated anti-cMET CAR T cells over a 2-week period without antecedent lymphodepleting chemotherapy. Subjects underwent pre- and post-infusion biopsies. The primary objective was to determine feasibility and safety of treatment. Results: 77 subjects (39 mel, 38 BC) were prescreened for tumor cMET expression and 37 (17 mel, 20 BC) met the eligibility threshold. Seven pts (4 BC, 3 Mel) received cMET-directed CAR T infusions on study. Mean age was 50 years (35-64); median (M) ECOG 0 (0-1); M prior lines of chemotherapy/immunotherapy were 4/0 for BC pts and 1/3 for Mel pts. 6 of 7 pts received all planned CAR T cell infusions, and 1 received 5 infusions. 5 pts experienced grade (G) 1 or G 2 toxicity that was possibly or definitely related to study. Toxicities occurring in ≥1 pt included: anemia (n = 3), fatigue (n = 2), and malaise (n = 2). No G ≥3 toxicities or cytokine release syndrome were observed. No pts discontinued therapy due to toxicity. Best response was stable disease in 4 pts (2 BC, 2 Mel) and PD in 3 pts (2 BC, 1 Mel). Messenger RNA signals corresponding to CAR T cells were detected by RT-PCR in the peripheral blood of all pts during the infusion period and in 2 pts after the infusion period. 6 pts underwent baseline biopsy and 4 pts underwent post-infusion biopsy. Immunohistochemical stains of CD3, CD4, CD8, CD163, L26, PD1, PDL1, Foxp3, Ki67, Granzyme B and Phospho-S6 were performed on pre- and post-treatment tissue biopsies and are being evaluated. Conclusions: Intravenous administration of RNA-electroporated cMET-directed CAR T cells was safe and feasible. Future directions include examination of this target using a lentiviral construct in combination with lymphodepleting chemotherapy. Clinical trial information: NCT03060356.

Developmental Relationships of Four Exhausted CD8+ T Cell Subsets Reveals Underlying Transcriptional and Epigenetic Landscape Control Mechanisms

CD8⁺ T cell exhaustion is a major barrier to current anti-cancer immunotherapies. Despite this, the developmental biology of exhausted CD8⁺ T cells (Tex) remains poorly defined, restraining improvement of strategies aimed at "re-invigorating" Tex cells. Here, we defined a four-cell-stage developmental framework for Tex cells. Two TCF1⁺ progenitor subsets were identified, one tissue restricted and quiescent and one more blood accessible, that gradually lost TCF1 as it divided and converted to a third intermediate Tex subset. This intermediate subset re-engaged some effector biology and increased upon PD-L1 blockade but ultimately converted into a fourth, terminally exhausted subset. By using transcriptional and epigenetic analyses, we identified the control mechanisms underlying subset transitions and defined a key interplay between TCF1, T-bet, and Tox in the process. These data reveal a four-stage developmental hierarchy for Tex cells and define the molecular, transcriptional, and epigenetic mechanisms that could provide opportunities to improve cancer immunotherapy.

Inhibition of Vps34 reprograms cold into hot inflamed tumors and improves anti-PD-1/PD-L1 immunotherapy

One of the major challenges limiting the efficacy of anti-PD-1/PD-L1 therapy in nonresponding patients is the failure of T cells to penetrate the tumor microenvironment. We showed that genetic or pharmacological inhibition of Vps34 kinase activity using SB02024 or SAR405 (Vps34i) decreased the tumor growth and improved mice survival in multiple tumor models by inducing an infiltration of NK, CD8⁺, and CD4⁺ T effector cells in melanoma and CRC tumors. Such infiltration resulted in the establishment of a T cell-inflamed tumor microenvironment, characterized by the up-regulation of pro-inflammatory chemokines and cytokines, CCL5, CXCL10, and IFNγ. Vps34i treatment induced STAT1 and IRF7, involved in the up-regulation of CCL5 and CXCL10. Combining Vps34i improved the therapeutic benefit of anti-PD-L1/PD-1 in melanoma and CRC and prolonged mice survival. Our study revealed that targeting Vps34 turns cold into hot inflamed tumors, thus enhancing the efficacy of anti-PD-L1/PD-1 blockade.

Targeting TNFR2 to overcome acquired adaptive resistance to immune checkpoint blockade

Overcoming acquired adaptive immune resistance to anti-PD-1 therapy is imperative for enhancing the efficacy of immune checkpoint blockade (ICB) in solid tumors. Regulatory T cells (Tregs) play a prominent role in the suppressive tumor microenvironment (TME) and are major contributors to adaptive immune resistance. Tregs limit CD8+ T cell reinvigoration and are a promising target for combination therapy. While the clinical efficacy of anti-CTLA4 may be partially explained by restriction of Tregs, its co-administration with anti-PD1 causes significant toxicity. Thus, safer approaches to limit Treg activity are needed. To elucidate the dynamic changes in immuno-regulatory circuits within the TME during ICB, we performed deep immune profiling of peripheral blood and tumors from patients with advanced melanoma prior to (n=7) and after 1 cycle of anti-PD-1 therapy with pembrolizumab (n=9). Tregs were abundant in the TME and retained their immunosuppressive phenotype and functionality following anti-PD-1. Epigenetic, transcriptomic, and proteomic analysis of Tregs after ICB identified tumor necrosis factor receptor 2 (TNFR2) signaling as a possible driver of CD8+ T cell suppression. TNFR2 was preferentially expressed by Tregs in the TME (mean 18.03 %, SD +/− 10.13 %) relative to CD8+ T cells (mean 0.64 %, SD +/− 0.82 %) and peripheral Tregs (mean 3.16 %, SD +/− 3.21 %), suggesting it might be a safe and effective target for combination therapy. Indeed, dual blockade of TNFR2 and PD-1 led to potent CD8+ T cell expansion in two mouse tumor models, and restored sensitivity to ICB in a resistant murine model of melanoma. Our data suggest that anti-TNFR2 might synergize with current ICB by countering the development of adaptive immune resistance.

A Randomized Phase II Preoperative Study of Autophagy Inhibition with High-Dose Hydroxychloroquine and Gemcitabine/Nab-Paclitaxel in Pancreatic Cancer Patients

PURPOSE

We hypothesized that autophagy inhibition would increase response to chemotherapy in the preoperative setting for patients with pancreatic adenocarcinoma. We performed a randomized controlled trial to assess the autophagy inhibitor hydroxychloroquine in combination with gemcitabine and nab-paclitaxel.

PATIENTS AND METHODS

Participants with potentially resectable tumors were randomized to two cycles of nab-paclitaxel and gemcitabine (PG) alone or with hydroxychloroquine (PGH), followed by resection. The primary endpoint was histopathologic response in the resected specimen. Secondary clinical endpoints included serum CA 19-9 biomarker response and margin negative R0 resection. Exploratory endpoints included markers of autophagy, immune infiltrate, and serum cytokines.

RESULTS

Thirty-four patients in the PGH arm and 30 in the PG arm were evaluable for the primary endpoint. The PGH arm demonstrated statistically improved Evans grade histopathologic responses (P = 0.00016), compared with control. In patients with elevated CA 19-9, a return to normal was associated with improved overall and recurrence-free survival (P < 0.0001). There were no differences in serious adverse events between arms and chemotherapy dose number was equivalent. The PGH arm had greater evidence of autophagy inhibition in their resected specimens (increased SQSTM1, P = 0.027, as well as increased immune cell tumor infiltration, P = 0.033). Overall survival (P = 0.59) and relapse-free survival (P = 0.55) did not differ between the two arms.

CONCLUSIONS

The addition of hydroxychloroquine to preoperative gemcitabine and nab-paclitaxel chemotherapy in patients with resectable pancreatic adenocarcinoma resulted in greater pathologic tumor response, improved serum biomarker response, and evidence of autophagy inhibition and immune activity.

Poly(adenosine diphosphate ribose) polymerase inhibitors induce autophagy-mediated drug resistance in ovarian cancer cells, xenografts, and patient-derived xenograft models

BACKGROUND

Poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors exhibit promising activity against ovarian cancers, but their efficacy can be limited by acquired drug resistance. This study explores the role of autophagy in regulating the sensitivity of ovarian cancer cells to PARP inhibitors.

METHODS

Induction of autophagy was detected by punctate LC3 fluorescence staining, LC3I to LC3II conversion on Western blot analysis, and electron microscopy. Enhanced growth inhibition and apoptosis were observed when PARP inhibitors were used with hydroxychloroquine, chloroquine (CQ), or LYS05 to block the hydrolysis of proteins and lipids in autophagosomes or with small interfering RNA against ATG5 or ATG7 to prevent the formation of autophagosomes. The preclinical efficacy of the combination of CQ and olaparib was evaluated with a patient-derived xenograft (PDX) and the OVCAR8 human ovarian cancer cell line.

RESULTS

Four PARP inhibitors (olaparib, niraparib, rucaparib, and talazoparib) induced autophagy in a panel of ovarian cancer cells. Inhibition of autophagy with CQ enhanced the sensitivity of ovarian cancer cells to PARP inhibitors. In vivo, olaparib and CQ produced additive growth inhibition in OVCAR8 xenografts and a PDX. Olaparib inhibited PARP activity, and this led to increased reactive oxygen species (ROS) and an accumulation of γ-H2AX. Inhibition of autophagy also increased ROS and γ-H2AX and enhanced the effect of olaparib on both entities. Treatment with olaparib increased phosphorylation of ATM and PTEN while decreasing the phosphorylation of AKT and mTOR and inducing autophagy.

CONCLUSIONS

PARP inhibitor-induced autophagy provides an adaptive mechanism of resistance to PARP inhibitors in cancer cells with wild-type BRCA, and a combination of PARP inhibitors with CQ or other autophagy inhibitors could improve outcomes for patients with ovarian cancer.

Association of antibiotic exposure with overall survival and colitis in patients with stage III and IV melanoma receiving immune checkpoint inhibitors

56

Background: Recent studies suggest that changes in the gut microbiome modulate response to cancer treatment, including immune checkpoint inhibitors (ICI). Broad-spectrum antibiotics (Abx) are known to cause significant dysbiosis. We hypothesize that recent Abx exposure worsens outcomes in patients (pts) with stage III/IV melanoma (MM) receiving ICI. Methods: We identified MM pts treated with ICI from our institutional database. All received their first ICI between 2004-2019. Antibiotic exposure was defined as receipt of Abx within 3 months prior to the first infusion of ICI. The primary outcome was overall survival (OS) and the secondary outcome was immune-mediated colitis requiring intravenous (IV) steroids. Stage III and IV pts were analyzed separately for the primary analysis. Results: Of 568 pts in our database, 20% received Abx within the 3 months prior to ICI. 36% of pts had stage III disease and 26% of pts were treated with either adjuvant or neoadjuvant ICI. 1.6% of pts died of causes other than MM. The Abx+ and Abx- groups were balanced in terms of stage, race, age, sex, BRAF status, LDH, prior systemic therapies, and class of ICI received. Only 4 pts were hospitalized due to the infection prompting the Abx, and no pts died due to the infection. In the Stage IV group, Abx+ pts had worse OS on MV analysis (HR 1.6, 95% CI 1.1-2.2). Stage III Abx+ also had worse OS (HR 2.8, 95% CI 1.3-5.9). In a sensitivity analysis excluding pts who received IV Abx or were admitted due to infection, survival was still worse for Abx+ pts (HR 1.7, 95% CI 1.2-2.4). In a Fine-Grey competing risk MV model, Abx+ had a higher rate of immune-mediated colitis requiring IV steroids (HR 2.1, 95% CI 1.02-4.5). Conclusions: In MM pts treated with ICI, receipt of Abx within 3 months prior to ICI initiation was associated with decreased OS and increased colitis. Future research should include prospective studies to better define the risk/benefit profile of antibiotics in close proximity to ICI. [Table: see text]

Effect of Gemcitabine and nab-Paclitaxel With or Without Hydroxychloroquine on Patients With Advanced Pancreatic Cancer: A Phase 2 Randomized Clinical Trial

Importance

Autophagy is a mechanism of treatment resistance to chemotherapy that has a role in the maintenance of pancreatic cancer. Hydroxychloroquine sulfate (HCQ) is an inhibitor of autophagy that inhibits the fusion of the autophagosome to the lysosome.

Objective

To determine whether HCQ improves overall survival at 1 year in combination with gemcitabine hydrochloride and nab-paclitaxel (GA) among patients with metastatic pancreatic cancer.

Design, Setting, and Participants

Open-label, phase 2 randomized clinical trial conducted between March 18, 2013, and November 16, 2017, at the University of Pennsylvania, HonorHealth, and The Johns Hopkins University among 112 patients with previously untreated metastatic or advanced pancreatic ductal adenocarcinoma, Eastern Cooperative Oncology Group performance status of 0 or 1, and adequate marrow and organ function. All efficacy analyses were performed for the intention-to-treat population.

Interventions

Patients were randomized in a 1:1 ratio to receive GA with or without HCQ. All patients received standard doses of GA, and those randomized to receive HCQ were treated continuously with 600 mg orally twice daily.

Main Outcome and Measure

Overall survival at 1 year.

Results

A total of 112 patients (45 women and 67 men; median age, 65 years; range, 43-86 years) were enrolled; 55 were randomized to receive GA plus HCQ, and 57 to receive GA. Overall survival at 12 months was 41% (95% CI, 27%-53%) in the HCQ group and 49% (95% CI, 35%-61%) in the non-HCQ group. Median progression-free survival was 5.7 months (95% CI, 4.0-9.3 months) in the HCQ group and 6.4 months (95% CI, 4.5-7.6 months) in the non-HCQ group. Median overall survival was 11.1 months (95% CI, 9.0-14.2 months) in the HCQ group and 12.1 months (95% CI, 9.3-15.5 months) in the non-HCQ group. Overall response rate was 38.2% (n = 21) in the HCQ group and 21.1% (n = 12) in the non-HCQ group (P = .047). Treatment-related grade 3 or 4 adverse events that differed between the HCQ and non-HCQ groups were neutropenia (23 of 54 [42.6%] vs 12 of 53 [22.6%]), anemia (2 of 54 [3.7%] vs 9 of 53 [17.0%]), fatigue (4 of 54 [7.4%] vs 0), nausea (5 of 54 [9.3%] vs 0), peripheral neuropathy (7 of 54 [13.0%] vs 3 of 53 [5.7%]), visual changes (3 of 54 [5.6%] vs 0), and neuropsychiatric symptoms (3 of 54 [5.6%] vs 0).

Conclusions and Relevance

The addition of HCQ to block autophagy did not improve the primary end point of overall survival at 12 months. These data do not support the routine use of GA plus HCQ for metastatic pancreatic cancer in the absence of a biomarker. However, improvement seen in the overall response rate with HCQ may indicate a role for HCQ in the locally advanced setting, where tumor response may permit resection.

Trial Registration

ClinicalTrials.gov identifier: NCT01506973.

Neoadjuvant Versus Adjuvant Immune Checkpoint Blockade in the Treatment of Clinical Stage III Melanoma

BACKGROUND

Immune checkpoint blockade (ICB) has transformed melanoma treatment, but optimal sequencing of ICB and surgery for clinically evident nodal metastasis remains undefined. We evaluated adjuvant-only (AT) and neoadjuvant/adjuvant (NAT) ICB with respect to survival outcomes in this patient population.

METHODS

Patients who underwent lymphadenectomy (1 January 2011 to 31 July 2018) and received perioperative ICB at an academic center were identified. AT was defined as postoperative ICB, and NAT was defined as one to two cycles of ICB prior to resection with continuation of therapy following surgery. Three-year disease-free survival (DFS), locoregional recurrence-free survival (LRFS), distant disease-free survival (DDFS), and melanoma-specific survival (MSS) were estimated.

RESULTS

Of 59 patients, 18 (31%) received AT and 41 (69%) received NAT. The AT and NAT groups did not differ in age (median 53 vs. 62 years, p = 0.16) or stage (IIIB 33% vs. 29%, IIIC 56% vs. 68%, IIID 11% vs. 2%, p = 0.34). Although 3-year DFS did not differ significantly by treatment sequencing (NAT vs. AT, hazard ratio [HR] 0.56, p = 0.17), NAT was associated with improved 3-year DDFS (HR 0.38, p = 0.028). Of 39 NAT patients with evaluable pathologic response, 23 (59%) and 5 (13%) had a pathologic partial response (pPR) and pathologic complete response (pCR), respectively. Patients with pPR/pCR experienced improved 3-year DFS (HR 0.16, p = 0.001), LRFS (HR 0.17, p = 0.003), and DDFS (HR 0.26, p = 0.029) compared with those with no response. Three-year MSS did not differ significantly by response (p = 0.062).

CONCLUSION

NAT may be associated with improved 3-year DDFS compared with AT sequencing, and allows for early assessment of pathologic response. Further prospective evaluation of treatment sequencing is warranted.

Paradoxical Role for Wild-Type p53 in Driving Therapy Resistance in Melanoma

Metastatic melanoma is an aggressive disease, despite recent improvements in therapy. Eradicating all melanoma cells even in drug-sensitive tumors is unsuccessful in patients because a subset of cells can transition to a slow-cycling state, rendering them resistant to most targeted therapy. It is still unclear what pathways define these subpopulations and promote this resistant phenotype. In the current study, we show that Wnt5A, a non-canonical Wnt ligand that drives a metastatic, therapy-resistant phenotype, stabilizes the half-life of p53 and uses p53 to initiate a slow-cycling state following stress (DNA damage, targeted therapy, and aging). Inhibiting p53 blocks the slow-cycling phenotype and sensitizes melanoma cells to BRAF/MEK inhibition. In vivo, this can be accomplished with a single dose of p53 inhibitor at the commencement of BRAF/MEK inhibitor therapy. These data suggest that taking the paradoxical approach of inhibiting rather than activating wild-type p53 may sensitize previously resistant metastatic melanoma cells to therapy.

Autophagy in the Tumor or in the Host: Which Plays a Greater Supportive Role?

<b/> Autophagy has been identified as a potential therapeutic target in pancreatic ductal adenocarcinoma, one of the most lethal cancers, with few therapeutic options. Yang and colleagues successfully created a genetically engineered mouse model focused on the autophagy gene Atg4b that allows the study of therapeutic autophagy inhibition in fully formed tumors. Using this tool, they demonstrated that selective autophagy inhibition in either the tumor cells, normal host cells, or both suppresses tumor growth. Cancer Discov; 8(3); 266-8. ©2018 AACRSee related article by Yang et al., p. 276.

Targeting Autophagy in Cancer: Recent Advances and Future Directions

Autophagy, a multistep lysosomal degradation pathway that supports nutrient recycling and metabolic adaptation, has been implicated as a process that regulates cancer. Although autophagy induction may limit the development of tumors, evidence in mouse models demonstrates that autophagy inhibition can limit the growth of established tumors and improve response to cancer therapeutics. Certain cancer genotypes may be especially prone to autophagy inhibition. Different strategies for autophagy modulation may be needed depending on the cancer context. Here, we review new advances in the molecular control of autophagy, the role of selective autophagy in cancer, and the role of autophagy within the tumor microenvironment and tumor immunity. We also highlight clinical efforts to repurpose lysosomal inhibitors, such as hydroxychloroquine, as anticancer agents that block autophagy, as well as the development of more potent and specific autophagy inhibitors for cancer treatment, and review future directions for autophagy research. SIGNIFICANCE: Autophagy plays a complex role in cancer, but autophagy inhibition may be an effective therapeutic strategy in advanced cancer. A deeper understanding of autophagy within the tumor microenvironment has enabled the development of novel inhibitors and clinical trial strategies. Challenges and opportunities remain to identify patients most likely to benefit from this approach.