Immune checkpoint blockade in solid organ tumours: Choice, dose and predictors of response

Novel engineered IL-2 Nemvaleukin alfa combined with PD1 checkpoint blockade enhances the systemic anti-tumor responses of radiation therapy

BACKGROUND

Combining interleukin-2 (IL-2) with radiotherapy (RT) and immune checkpoint blockade (ICB) has emerged as a promising approach to address ICB resistance. However, conventional IL-2 cytokine therapy faces constraints owing to its brief half-life and adverse effects. RDB 1462, the mouse ortholog of Nemvaleukin alfa, is an engineered IL-2 with an intermediate affinity that selectively stimulates antitumor CD8 T and NK cells while limiting regulatory T cell expansion. This study aimed to evaluate the antitumor activity and mechanism of action of the combination of RDB 1462, RT, and anti-PD1 in mouse tumor models.

METHODS

Two bilateral lung adenocarcinoma murine models were established using 344SQ-Parental and 344SQ anti-PD1-resistant cell lines. Primary tumors were treated with RT, and secondary tumors were observed for evidence of abscopal effects. We performed immune phenotyping by flow cytometry, analyzed 770 immune-related genes using NanoString, and performed T cell receptor (TCR) repertoire analysis. Serum pro-inflammatory cytokine markers were analyzed by 23-plex kit.

RESULTS

Compared to native IL-2 (RDB 1475), RDB 1462 demonstrated superior systemic antitumoral responses, attributable, at least in part, to augmented levels of CD4 and CD8 T cells with the latter. Our findings reveal substantial reductions in primary and secondary tumor volumes compared to monotherapy controls, with some variability observed among different dosing schedules of RDB 1462 combined with RT. Blood and tumor tissue-based flow cytometric phenotyping reveals an increase in effector memory CD8 and CD4 T cells and a decrease in immunosuppressive cells accompanied by a significant increase in IL-2, IFN-γ, and GM-CSF levels in the combination group. Transcriptomic profiling and TCR sequencing reveal favorable gene expression and T cell repertoire patterns with the dual combination. Furthermore, integrating anti-PD1 therapy with RT and RDB 1462 further reduced primary and secondary tumor volumes, prolonged survival, and decreased lung metastasis. Observations of immune cell profiles indicated that RT with escalating doses of RDB 1462 significantly reduced tumor growth and increased tumor-specific immune cell populations.

CONCLUSION

The addition of Nemvaleukin therapy may enhance responses to RT alone and in combination with anti-PD1.

Imaging response to immune checkpoint inhibitors in patients with advanced melanoma: a retrospective observational cohort study

Background

The association between objective imaging response and first line immune checkpoint inhibitor (ICI) therapy regimes in advanced melanoma remains uncharacterized in routine practice.

Methods

We conducted a multi-center retrospective cohort analysis of advanced melanoma patients receiving first line ICI therapy from August 2013-May 2020 in Alberta, Canada. The primary outcome was likelihood of RECIST v1.1 assessed objective imaging response between patients receiving anti-programmed cell death protein 1 (anti-PD1) monotherapy and those receiving combination ipilimumab-nivolumab. Secondary outcomes were identification of baseline characteristics associated with non-response and the association of imaging response with overall survival (OS) and time to next treatment (TTNT).

Results

198 patients were included, 41/198 (20.7%) had complete response, 86/198 (43.4%) had partial response, 23/198 (11.6%) had stable disease, and 48/198 (24.2%) had progressive disease. Median OS was not reached (NR) (95% CI 49.0-NR) months for complete responders, NR (95%CI 52.9-NR) months for partial responders, 33.7 (95%CI 15.8-NR) months for stable disease, and 6.4 (95%CI 5.2-10.1) months for progressive disease (log-rank p<0.001). Likelihood of objective imaging response remained similar between anti-PD1 monotherapy and ipilimumab-nivolumab groups (OR 1.95 95%CI 0.85-4.63, p=0.121). Elevated LDH level (OR 0.46; 95%CI 0.21-0.98, p=0.043), mucosal primary site (OR 0.14; 95%CI 0.03-0.48, p=0.003), and BRAF V600E mutation status (OR 0.31; 95%CI 0.13-0.72, p=0.007) were associated with decreased likelihood of response.

Conclusion

No significant difference in likelihood of imaging response between anti-PD1 monotherapy and combination ipilimumab-nivolumab was observed. Elevated LDH level, mucosal primary site, and BRAF V600E mutation status were associated with decreased likelihood of response. Given that pivotal clinical trials of ipilimumab-nivolumab did not formally compare ipilimumab-nivolumab with nivolumab monotherapy, this work adds context to differences in outcomes when these agents are used. These results may inform treatment selection, and aid in counseling of patients treated with first-line ICI therapy in routine clinical practice settings.

Development and Validation of a Prognostic Risk Model for Patients with Advanced Melanoma Treated with Immune Checkpoint Inhibitors

BACKGROUND

Risk stratification tools for patients with advanced melanoma (AM) treated with immune checkpoint inhibitors (ICI) are lacking. We identified a new prognostic model associated with overall survival (OS).

PATIENTS AND METHODS

A total of 318 treatment naïve patients with AM receiving ICI were collected from a multi-centre retrospective cohort study. LASSO Cox regression identified independent prognostic factors associated with OS. Model validation was carried out on 500 iterations of bootstrapped samples. Harrel's C-index was calculated and internally validated to outline the model's discriminatory performance. External validation was carried out in 142 advanced melanoma patients receiving ICI in later lines.

RESULTS

High white blood cell count (WBC), high lactate dehydrogenase (LDH), low albumin, Eastern Cooperative Oncology Group (ECOG) performance status ≥1, and the presence of liver metastases were included in the model. Patients were parsed into 3 risk groups: favorable (0-1 factors) OS of 52.9 months, intermediate (2-3 factors) OS 13.0 months, and poor (≥4 factors) OS 2.7 months. The C-index of the model from the discovery cohort was 0.69. External validation in later-lines (N = 142) of therapy demonstrated a c-index of 0.65.

CONCLUSIONS

Liver metastases, low albumin, high LDH, high WBC, and ECOG≥1 can be combined into a prognostic model for AM patients treated with ICI.

Treatment-Free Survival After Nivolumab vs Pembrolizumab vs Nivolumab-Ipilimumab for Advanced Melanoma

Importance

Treatment-free survival (TFS) represents an alternative time-to-event end point, accurately characterizing time spent free of systemic therapy, providing a more patient-centric view of immune checkpoint inhibitor (ICI) therapy regimens. There remains a lack of studies evaluating TFS outcomes among patients with advanced melanoma who are receiving immunotherapy, especially outside of the clinical trial setting.

Objective

To evaluate TFS outcomes for patients with advanced melanoma receiving first-line ICI therapy outside of a clinical trial setting.

Design, Setting, and Participants

This multicenter cohort study of patients with advanced melanoma receiving first-line ICI therapy between August 1, 2013, and May 31, 2020, was conducted in Alberta, Canada. Data analysis was performed in August 2022.

Exposures

Patients received standard-of-care, first-line ICI therapy treatment regimens including single-agent nivolumab, single-agent pembrolizumab, or ipilimumab-nivolumab.

Main Outcomes and Measures

Treatment-free survival was defined as the difference in the 36-month restricted mean survival time between 2 conventional survival end points: (1) time from treatment initiation to ICI cessation, death, or censoring at last follow-up and (2) time from treatment initiation to subsequent systemic anticancer therapy, death, or censoring at last follow-up.

Results

A total of 316 patients with advanced melanoma receiving first-line nivolumab (n = 51; median age, 66 years [IQR, 56-78 years]; 31 men [60.8%]), pembrolizumab (n = 158; median age, 69 years [IQR, 60-78 years]; 112 men [70.9%]), or combination nivolumab-ipilimumab (n = 107; median age, 53 years [IQR, 42-60 years]; 72 men [67.3%]) were included. Treatment groups were similar with regard to sex, primary tumor location, and presence of metastasis, although patients receiving combination nivolumab-ipilimumab had a lower Eastern Cooperative Oncology Group status, were younger, and were more likely to be BRAF V600E positive than those receiving anti-programmed cell death protein 1 (anti-PD-1) monotherapy. The restricted mean TFS was longer for nivolumab-ipilimumab (12.4 months [95% CI, 8.8-16.0 months]) compared with nivolumab (8.9 months [95% CI, 4.4-13.5 months]) and pembrolizumab (11.1 months [95% CI, 8.5-13.8 months]). During the 36-month follow-up interval, patients treated with nivolumab-ipilimumab spent 34.4% of their time (12.4 of 36 months) not receiving systemic anticancer treatments compared with 30.8% (11.1 of 36 months) and 24.7% (8.9 of 36 months) of the time for the pembrolizumab and nivolumab treatment groups, respectively.

Conclusions and Relevance

This cohort study of patients with advanced melanoma receiving first-line ICI therapy suggests that TFS represents a patient-centric, informative end point. Patients treated with combination nivolumab-ipilimumab spent more time alive and free from systemic anticancer therapy than those treated with anti-PD-1 monotherapy alone.

Identification and validation of an anoikis-associated gene signature to predict clinical character, stemness, IDH mutation, and immune filtration in glioblastoma

Background

Glioblastoma (GBM) is the most prominent and aggressive primary brain tumor in adults. Anoikis is a specific form of programmed cell death that plays a key role in tumor invasion and metastasis. The presence of anti-anoikis factors is associated with tumor aggressiveness and drug resistance.

Methods

The non-negative matrix factorization algorithm was used for effective dimension reduction for integrated datasets. Differences in the tumor microenvironment (TME), stemness indices, and clinical characteristics between the two clusters were analyzed. Difference analysis, weighted gene coexpression network analysis (WGCNA), univariate Cox regression, and least absolute shrinkage and selection operator regression were leveraged to screen prognosis-related genes and construct a risk score model. Immunohistochemistry was performed to evaluate the expression of representative genes in clinical specimens. The relationship between the risk score and the TME, stemness, clinical traits, and immunotherapy response was assessed in GBM and pancancer.

Results

Two definite clusters were identified on the basis of anoikis-related gene expression. Patients with GBM assigned to C1 were characterized by shortened overall survival, higher suppressive immune infiltration levels, and lower stemness indices. We further constructed a risk scoring model to quantify the regulatory patterns of anoikis-related genes. The higher risk score group was characterized by a poor prognosis, the infiltration of suppressive immune cells and a differentiated phenotype, whereas the lower risk score group exhibited the opposite effects. In addition, patients in the lower risk score group exhibited a higher frequency of isocitrate dehydrogenase (IDH) mutations and a more sensitive response to immunotherapy. Drug sensitivity analysis was performed, revealing that the higher risk group may benefit more from drugs targeting the PI3K/mTOR signaling pathway.

Conclusion

We revealed potential relationships between anoikis-related genes and clinical features, TME, stemness, IDH mutation, and immunotherapy and elucidated their therapeutic value.

PD-1 Inhibitor Combined With Radiotherapy and GM-CSF (PRaG) in Patients With Metastatic Solid Tumors: An Open-Label Phase II Study

Patients with metastatic cancer refractory to standard systemic therapies have a poor prognosis and few therapeutic options. Radiotherapy can shape the tumor microenvironment (TME) by inducing immunogenic cell death and promoting tumor recognition by natural killer cells and T lymphocytes. Granulocyte macrophage-colony stimulating factor (GM-CSF) was known to promote dendric cell maturation and function, and might also induce the macrophage polarization with anti-tumor capabilities. A phase II trial (ChiCTR1900026175) was conducted to assess the clinical efficacy and safety of radiotherapy, PD-1 inhibitor and GM-CSF (PRaG regimen). This trial was registered at http://www.chictr.org.cn/index.aspx. A PRaG cycle consisted of 3 fractions of 5 or 8 Gy delivered for one metastatic lesion from day 1, followed by 200 μg subcutaneous injection of GM-CSF once daily for 2 weeks, and intravenous infusion of PD-1 inhibitor once within one week after completion of radiotherapy. The PRaG regimen was repeated every 21 days for at least two cycles. Once the PRaG therapy was completed, the patient continued PD-1 inhibitor monotherapy until confirmed disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR). A total of 54 patients were enrolled with a median follow-up time of 16.4 months. The ORR was 16.7%, and the disease control rate was 46.3% in intent-to-treat patients. Median progression-free survival was 4.0 months (95% confidence interval [CI], 3.3 to 4.8), and median overall survival was 10.5 months (95% CI, 8.7 to 12.2). Grade 3 treatment-related adverse events occurred in five patients (10.0%) and grade 4 in one patient (2.0%). Therefore, the PRaG regimen was well tolerated with acceptable toxicity and may represent a promising salvage treatment for patients with chemotherapy-refractory solid tumors. It is likely that PRaG acts via heating upthe TME with radiotherapy and GM-CSF, which was further boosted by PD-1 inhibitors.

Melanoma: An immunotherapy journey from bench to bedside

Melanoma gave science a window into the role immune evasion plays in the development of malignancy. The entire spectrum of immune focused anti-cancer therapies has been subjected to clinical trials in this disease, with limited success until the immune checkpoint blockade era. That revolution launched first in melanoma, heralded a landscape change throughout cancer that continues to reverberate today.

Vascular Microenvironment, Tumor Immunity and Immunotherapy

Immunotherapy holds great promise for treating cancer. Nonetheless, T cell-based immunotherapy of solid tumors has remained challenging, largely due to the lack of universal tumor-specific antigens and an immunosuppressive tumor microenvironment (TME) that inhibits lymphocyte infiltration and activation. Aberrant vascularity characterizes malignant solid tumors, which fuels the formation of an immune-hostile microenvironment and induces tumor resistance to immunotherapy, emerging as a crucial target for adjuvant treatment in cancer immunotherapy. In this review, we discuss the molecular and cellular basis of vascular microenvironment-mediated tumor evasion of immune responses and resistance to immunotherapy, with a focus on vessel abnormality, dysfunctional adhesion, immunosuppressive niche, and microenvironmental stress in tumor vasculature. We provide an overview of opportunities and challenges related to these mechanisms. We also propose genetic programming of tumor endothelial cells as an alternative approach to recondition the vascular microenvironment and to overcome tumor resistance to immunotherapy.

Overall survival in metastatic melanoma correlates with pembrolizumab exposure and T cell exhaustion markers

Trial data support an absence of an exposure-survival relationship for pembrolizumab. As these relationships remain unexamined in a real-world setting, we determined them in metastatic melanoma prospectively in an observational study. Translational objectives included identifying biomarkers of progressive disease (PD). Checkpoint blockade naïve patients receiving 2 mg/kg Q3W pembrolizumab had pharmacokinetic and clinical outcome data collected. Trough, a valid surrogate for drug exposure, was assessed using ELISA. T-cell exhaustion and chemokine markers were determined using flow cytometry. Geometric means of exposures and biomarkers were tested against objective response groups using one-way ANOVA. The cohort was split by the median into high versus low pembrolizumab exposure groups. Kaplan-Meier progression-free survival (PFS) and overall survival (OS) curves were estimated for high versus low exposure, compared using the log rank test. The high pembrolizumab exposure group (n = 14) experienced substantially longer median OS (not reached vs. 48 months, p = .014), than the low exposure group (n = 14). A similar positive exposure PFS relationship was found (median not reached vs. 48 months, p = .045). The frequency of TIM-3 expression on CD4+ T cells was significantly higher in PD (mean 27.8%) than complete response (CR) (13.38%, p = .01) and partial response (12.4%, p = .05). There was a near doubling of CXCR6 and TIM-3 co-expression on CD4+ T cells in PD (mean 23.3%) versus CR (mean 11.4, p = .003) and partial response (9.8%, p = .0001). We describe positive exposure-PFS and exposure-OS relationships for pembrolizumab in metastatic melanoma. TIM-3, alongside co-expression of CXCR6 and TIM-3 on circulating CD4+ T cells are potential bio markers of treatment failure.

Immune checkpoint blockade in solid organ tumours: Choice, dose and predictors of response

Immune checkpoint blockade has transformed outcomes across solid organ tumours. Monoclonal antibodies targeting the negative inhibitory cytotoxic T lymphocyte-associated protein 4 and programmed-death 1/programmed death-ligand 1 axis can lead to deep and durable responses across several tumour streams in the advanced setting. This immunotherapy approach is increasingly used earlier in the treatment paradigm. A rapidly evolving regulatory, reimbursement and drug development landscape has accompanied this novel class of immunotherapy. Unfortunately, only a small proportion of patients respond meaningfully to these agents. Here we review how the underlying tumoural genomic, histological and immunological characteristics interact within various patient phenotypes, leading to variations in response to checkpoint blockade. Concurrently, we outline the clinical trial and real-world evidence that allows for appropriate selection of agent, dose and schedule in solid organ malignancies. An exploration of current trends in basic and translational research in immune checkpoint blockade accompanies a commentary on future clinical directions for checkpoint blockade in oncology.