Severe acute myositis and myocarditis on initiation of 6-weekly pembrolizumab post-COVID-19 mRNA vaccination

We describe three cases of critical acute myositis with myocarditis occurring within 22 days of each other at a single institution, all within 1 month of receiving the initial cycle of the anti-PD-1 drug pembrolizumab. Analysis of T cell receptor repertoires from peripheral blood and tissues revealed a high degree of clonal expansion and public clones between cases, with several T cell clones expanded within the skeletal muscle putatively recognizing viral epitopes. All patients had recently received a COVID-19 mRNA booster vaccine prior to treatment and were positive for SARS-CoV2 Spike antibody. In conclusion, we report a series of unusually severe myositis and myocarditis following PD-1 blockade and the COVID-19 mRNA vaccination.

IL7 genetic variation and toxicity to immune checkpoint blockade in patients with melanoma

Treatment with immune checkpoint blockade (ICB) frequently triggers immune-related adverse events (irAEs), causing considerable morbidity. In 214 patients receiving ICB for melanoma, we observed increased severe irAE risk in minor allele carriers of rs16906115, intronic to IL7. We found that rs16906115 forms a B cell-specific expression quantitative trait locus (eQTL) to IL7 in patients. Patients carrying the risk allele demonstrate increased pre-treatment B cell IL7 expression, which independently associates with irAE risk, divergent immunoglobulin expression and more B cell receptor mutations. Consistent with the role of IL-7 in T cell development, risk allele carriers have distinct ICB-induced CD8+ T cell subset responses, skewing of T cell clonality and greater proportional repertoire occupancy by large clones. Finally, analysis of TCGA data suggests that risk allele carriers independently have improved melanoma survival. These observations highlight key roles for B cells and IL-7 in both ICB response and toxicity and clinical outcomes in melanoma.

A phase 1 first-in-human dose finding/randomized phase 2 study of IMM60 and pembrolizumab (PEM) in advanced melanoma and non–small cell lung cancer (NSCLC; IMP-MEL)

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Background: Invariant natural killer T-cells (iNKTs) share features of innate cells (NK-like) and T-cells (can prime and boost an adaptive immune response). The importance of this relatively rare lymphocyte subset has generated increased interest due to its dual ability to have a direct cytotoxic effect on CD1d expressing tumors and also its ability to induce long-lasting antitumor CD8 T cell responses mediated by cross priming and licensing of dendritic cells. Various clinical approaches involving the use of allogenic iNKT cells (both untransduced and CARs) are in development and here we describe initial clinical studies with IMM60, a synthetically derived agonist of iNKT cells which is formulated in a liposome( PORT-2). In preclinical studies, IMM-60 treatment results in maturation of DCs and B cells and a potent stimulation of iNKT cell-derived IFN-g. In efficacy studies, IMM60 demonstrated monotherapy activity in PD-1 resistant models, (eg., B16-F10), up-regulation of PD-L1 expression on cancer cells as a consequence of its priming effect, and was able to overcome resistance to PD-1 antibody therapy. Methods: IMP-MEL is an open-label first-in-man phase 1/2 study, currently enrolling adult subjects with advanced NSCLC and melanoma. IMM60 containing liposomes were administered IV Q3W at 3 escalating dose levels for 6 doses alone or with PEM 200mg Q3W. The study seeks to assess the safety and efficacy of IMM-60 alone and in combination with PEM. Results: 5 subjects have been enrolled in the monotherapy cohort having a median of 3 prior therapies (min 2, max 5). Median age was 64.5 years. No treatment related adverse events have been reported nor any objective disease responses in the evaluable monotherapy subjects (n=3) to date. Conclusions: IMM-60 is well tolerated when administered IV as monotherapy at the doses tested. The liposomal formulation leads to a favorable preliminary safety profile. Full results of the phase 1 will be reported at the meeting with analysis of circulating cytokines and flow cytometric analysis. The trial plans to transition to phase 2 testing IMM60-alone vs PEM monotherapy vs the combination of IMM60 with PEM. Clinical trial information: 80472712.

Interferon-Gamma-Producing CD8+ Tissue Resident Memory T Cells Are a Targetable Hallmark of Immune Checkpoint Inhibitor-Colitis

BACKGROUND & AIMS

The pathogenesis of immune checkpoint inhibitor (ICI)-colitis remains incompletely understood. We sought to identify key cellular drivers of ICI-colitis and their similarities to idiopathic ulcerative colitis, and to determine potential novel therapeutic targets.

METHODS

We used a cross-sectional approach to study patients with ICI-colitis, those receiving ICI without the development of colitis, idiopathic ulcerative colitis, and healthy controls. A subset of patients with ICI-colitis were studied longitudinally. We applied a range of methods, including multiparameter and spectral flow cytometry, spectral immunofluorescence microscopy, targeted gene panels, and bulk and single-cell RNA sequencing.

RESULTS

We demonstrate CD8⁺ tissue resident memory T (T_RM) cells are the dominant activated T cell subset in ICI-colitis. The pattern of gastrointestinal immunopathology is distinct from ulcerative colitis at both the immune and epithelial-signaling levels. CD8⁺ T_RM cell activation correlates with clinical and endoscopic ICI-colitis severity. Single-cell RNA sequencing analysis confirms activated CD8⁺ T_RM cells express high levels of transcripts for checkpoint inhibitors and interferon-gamma in ICI-colitis. We demonstrate similar findings in both anti-CTLA-4/PD-1 combination therapy and in anti-PD-1 inhibitor-associated colitis. On the basis of our data, we successfully targeted this pathway in a patient with refractory ICI-colitis, using the JAK inhibitor tofacitinib.

CONCLUSIONS

Interferon gamma-producing CD8⁺ T_RM cells are a pathological hallmark of ICI-colitis and a novel target for therapy.

P14.29 The treatment of melanoma brain metastases with stereotactic radiosurgery concurrently with immune checkpoint inhibition is associated with improved extracranial disease control and overall survival compared to the overall metastatic melanoma cohort - a synergistic effect reaching beyond local control?

BACKGROUND

Melanoma brain metastases (MBM) are an increasingly common referral to the neuro-oncology MDT in the context of lengthening survivorship of metastatic melanoma (MM) patients in the immunotherapy era. Stereotactic radiosurgery (SRS) and immune checkpoint inhibition (ICI) are both effective in the management of MBM and, when combined, 12-month local control rates of >85% and overall survival (OS) >80% have been reported.[4,5] Recent local analysis of patients treated at our tertiary SRS referral centre has revealed even greater outcomes in this patient cohort. This study aimed to compare the outcomes of patients with MBM treated with concurrent SRS and ICI compared to the overall metastatic melanoma cohort, to elucidate whether the addition of SRS to ICI may improve disease control outside of the brain as well as within.

MATERIAL AND METHODS

A retrospective analysis of our local SRS database and an ARIA ePrescribing database search was performed to identify a cohort of patients treated with concurrent SRS and ICI for MBM, as well as a control cohort of MM patients who received ICI alone, over a 4 year period until February 2020. The primary endpoints were the extracranial progression free survival (PFS) and overall survival (OS) at 12 months. Secondary endpoints were the median PFS (mPFS) and OS (mOS). Kaplan-Meier curves and survival statistics were generated using SPSS v26.

RESULTS

A total of 34 MBM from 19 patients were identified in the SRS+ICI group and there were 200 patients in the control group. The minimum follow up was 12 months. The median patient age, duration of ICI and use of combination ICI favoured the SRS+ICI group. The number of sites of extracranial disease pre-ICI and overall anti-PD-1 usage was well matched. In the SRS+ICI group, there were no cases of extracranial progression and no deaths within 12 months. In the control group, the 12-month PFS and OS rates were 50.5% and 77.5% respectively. In terms of mPFS, this was not reached (estimated 37.6 months) in the SRS+ICI group, versus 13.4 months in the control group (log rank test, p=0.001). In terms of mOS, this was not reached in the SRS+ICI group, versus 55.8 months in the control group (log rank test, p=0.016).

CONCLUSION

We demonstrate improved extracranial disease control and survivorship amongst metastatic melanoma patients who develop brain metastases and are treated with concurrent SRS and ICI compared to those who do not. The outcomes of our control cohort are comparable to the 4-year follow up of the CheckMate 067 trial (n=945),[6] which strengthens the validity of the statistical comparisons made in this study. The improved extracranial disease control seen when SRS and ICI are combined in the treatment of MBM questions whether an abscopal effect may be at play, and therefore further accents the utility of SRS in MBM beyond that of local control alone. This could influence management in cases of borderline decisions for SRS.

Checkpoint-blocker-induced autoimmunity is associated with favourable outcome in metastatic melanoma and distinct T-cell expression profiles

BACKGROUND

Immune checkpoint blockers (ICBs) activate CD8⁺ T cells, eliciting both anti-cancer activity and immune-related adverse events (irAEs). The relationship of irAEs with baseline parameters and clinical outcome is unclear.

METHODS

Retrospective evaluation of irAEs on survival was performed across primary (N = 144) and secondary (N = 211) independent cohorts of patients with metastatic melanoma receiving single agent (pembrolizumab/nivolumab-sICB) or combination (nivolumab and ipilimumab-cICB) checkpoint blockade. RNA from pre-treatment and post-treatment CD8⁺ T cells was sequenced and differential gene expression according to irAE development assessed.

RESULTS

58.3% of patients developed early irAEs and this was associated with longer progression-free (PFS) and overall survival (OS) across both cohorts (log-rank test, OS: P < 0.0001). Median survival for patients without irAEs was 16.6 months (95% CI: 10.9-33.4) versus not-reached (P = 2.8 × 10^-6). Pre-treatment monocyte and neutrophil counts, but not BMI, were additional predictors of clinical outcome. Differential expression of numerous gene pathway members was observed in CD8⁺ T cells according to irAE development, and patients not developing irAEs demonstrating upregulated CXCR1 pre- and post-treatment.

CONCLUSIONS

Early irAE development post-ICB is associated with favourable survival in MM. Development of irAEs is coupled to expression of numerous gene pathways, suggesting irAE development in-part reflects baseline immune activation.

sFRP2 Supersedes VEGF as an Age-related Driver of Angiogenesis in Melanoma, Affecting Response to Anti-VEGF Therapy in Older Patients

PURPOSE

Angiogenesis is thought to be critical for tumor metastasis. However, inhibiting angiogenesis using antibodies such as bevacizumab (Avastin), has had little impact on melanoma patient survival. We have demonstrated that both angiogenesis and metastasis are increased in older individuals, and therefore sought to investigate whether there was an age-related difference in response to bevacizumab, and if so, what the underlying mechanism could be.

EXPERIMENTAL DESIGN

We analyzed data from the AVAST-M trial of 1,343 patients with melanoma treated with bevacizumab to determine whether there is an age-dependent response to bevacizumab. We also examined the age-dependent expression of VEGF and its cognate receptors in patients with melanoma, while using syngeneic melanoma animal models to target VEGF in young versus old mice. We also examined the age-related proangiogenic factor secreted frizzled-related protein 2 (sFRP2) and whether it could modulate response to anti-VEGF therapy.

RESULTS

We show that older patients respond poorly to bevacizumab, whereas younger patients show improvement in both disease-free survival and overall survival. We find that targeting VEGF does not ablate angiogenesis in an aged mouse model, while sFRP2 promotes angiogenesis in vitro and in young mice. Targeting sFRP2 in aged mice successfully ablates angiogenesis, while the effects of targeting VEGF in young mice can be overcome by increasing sFRP2.

CONCLUSIONS

VEGF is decreased during aging, thereby reducing response to bevacizumab. Despite the decrease in VEGF, angiogenesis is increased because of an increase in sFRP2 in the aged tumor microenvironment. These results stress the importance of considering age as a factor for designing targeted therapies.

Toxicities associated with checkpoint inhibitors-an overview

Immunotherapy has an increasing role in the management of cancer, both in metastatic disease and as an adjuvant therapy. However, sensitization of the immune system with checkpoint inhibitors comes with a unique side effect profile. Full appreciation of this can take some time to emerge as some adverse events are rare, or can be subtle and potentially overlooked. Clinician awareness of these side effects can be particularly important in patients with pre-existing autoimmune conditions. Here we describe common symptoms and diagnostic strategies for organ-specific side effects of anti-CTLA-4 and anti-PD-1/PD-L1 immunotherapy agents.

A phase 1 study to assess the safety, tolerability, and pharmacokinetics of CXD101 in patients with advanced cancer

BACKGROUND

In the current study, the authors sought to determine the maximum tolerated dose (MTD) of the novel class 1 selective histone deacetylase inhibitor CXD101 in a dose escalation study in patients with advanced solid tumors or recurrent/refractory lymphoma.

METHODS

The authors escalated the dose of CXD101 from 1 mg twice daily orally for 5 days in a 21-day cycle (3+3 design).

RESULTS

A total of 39 patients were enrolled, 36 of whom received CXD101. Of the 30 patients in the escalation cohort, 29 were evaluable for determination of the dose-limiting toxicity (DLT). DLTs were noted at doses of 16 mg twice daily (1 of 6 patients), 20 mg twice daily (1 of 6 patients), and 24/25 mg twice daily (2 of 5 patients, both of whom developed neutropenic fever). The MTD was 20 mg twice daily, which achieved maximal plasma concentrations (±standard deviation) of 231±76 nM to 342±126 nM, which was within the biologically active range. Six patients received 20 mg twice daily in an expansion cohort. The most frequent adverse events were fatigue, nausea, and reversible cytopenia. Key grade 3 to 4 adverse events (according to Common Terminology Criteria for Adverse Events criteria [version 4.03]) included thrombocytopenia (11%), neutropenia (17%), and neutropenic fever (2%) across the 133 CXD101 cycles given. The toxicity profile was similar to that of licensing studies with other histone deacetylase inhibitors. In 22 evaluable patients receiving a dose of ≥16 mg twice daily (17 of whom had lymphoma and 5 of whom had solid tumors), 3 partial responses (2 in patients with classic Hodgkin lymphoma after allogenic stem cell transplantation and 1 in a patient with angioimmunoblastic T-cell lymphoma) and 1 complete response (in a patient with follicular lymphoma) were noted (overall response rate of 18%) in addition to 9 patients who achieved durable stable disease. Responses were noted predominantly among patients with lymphoma (tumor reduction noted in 63% of patients on standard computed tomography).

CONCLUSIONS

The MTD in the current study was found to be 20 mg twice daily. Encouraging and durable activity was observed in patients with Hodgkin lymphoma, T-cell lymphoma, and follicular lymphoma.

Early phase cancer clinical trials: design, ethics and future directions

The main role of early phase clinical trials in cancer is to determine the dose to take forward for future clinical study. However, study design is changing in order to account for the change in focus of drug development toward molecularly targeted agents.

PACMEL: a phase 1 dose escalation trial of trametinib (GSK1120212) in combination with paclitaxel

BACKGROUND

We sought to determine the maximal tolerated dose of the MEK inhibitor trametinib with weekly paclitaxel, with a view to exploring the combination's activity in melanoma lacking a BRAF V600 mutation.

METHODS

In this phase 1 study we used a fixed dose of paclitaxel (80 mg/m2 intravenous (IV) on days 1, 8 and 15 of each 4 week cycle) and escalated the dose of trametinib (to a maximum 2mg orally (PO) daily), following a 3+3 design. Eligible patients had advanced melanoma and could have received up to two previous lines of treatment for metastatic disease.

FINDINGS

15 patients were enrolled, all but one of whose melanoma was wild type for BRAF at codon 600. The maximal monotherapy dose of trametinib proved tolerable with weekly paclitaxel. The most frequent adverse events observed were rash and fatigue. Six (40%) partial responses were reported, including four of eight patients with NRAS mutations. Median progression free survival was 5.5 months (95% confidence interval (CI) 1.8-7.8 months) and overall survival, 14.1 months (95% CI 4.6-not reached).

INTERPRETATION

Trametinib can safely be given with weekly paclitaxel at the full monotherapy dose. In this small group promising progression free and overall survival were observed in patients with melanoma lacking a V600 BRAF mutation.