Antidrug Antibodies Against Immune Checkpoint Blockers: Impairment of Drug Efficacy or Indication of Immune Activation?

"Getting the Dose Right"-Revisiting the Topic With Focus on Biologic Agents

Nearly two decades after the Peck and Cross article '"Getting the dose right: facts, a blueprint, and encouragements" was published, a review of dose recommendations for biologics shows that the success in getting the dose right appears to have improved given the relatively low incidence of drug withdrawals and dosing/label changes. However, the clinical experience with monoclonal antibodies (MAbs) following approval has been less than perfect. In inflammatory diseases, the disease burden changes with time and high treatment failure rates have been reported. In addition, the use of concomitant steroids and immunosuppressant drugs with MAbs is common. These concomitant agents have their own safety issues and many immunosuppressant agents are not well-tolerated although they have been shown to reduce the incidence of anti-drug antibodies (ADA). This same complexity is seen in MAbs used in oncology as well, although with these agents the doses appear to be higher than needed, which results in high treatment costs and incidence of adverse events. Given the complexity of MAb pharmacokinetics, which makes providing a detailed description of dose options difficult, product labeling should include the options for alternative dose strategies and potentially include the use of therapeutic drug monitoring with dose individualization which have been shown to improve clinical response and reduce the incidence of ADA. So, while the recommended dosing for biologics seems improved over the issues noted 17 years ago, we still have some work to do.

Clinical Progresses and Challenges of Bispecific Antibodies for the Treatment of Solid Tumors

In recent years, bispecific antibodies (BsAbs) have emerged as a promising therapeutic strategy against tumors. BsAbs can recruit and activate immune cells, block multiple signaling pathways, and deliver therapeutic payloads directly to tumor sites. This review provides a comprehensive overview of the recent advances in the development and clinical application of BsAbs for the treatment of solid tumors. We discuss the different formats, the unique mechanisms of action, and the clinical outcomes of the most advanced BsAbs in solid tumor therapy. Several studies have also analyzed the clinical progress of bispecific antibodies. However, this review distinguishes itself by exploring the challenges associated with bispecific antibodies and proposing potential solutions. As the field progresses, BsAbs hold promise to redefine cancer treatment paradigms and offer new hope to patients with solid tumors.

Immunological Drug-Drug Interactions Affect the Efficacy and Safety of Immune Checkpoint Inhibitor Therapies

With the rapid expansion in the development and clinical utility of immune checkpoint inhibitors (ICIs) for oncology, the continual evaluation of the safety profile of such agents is imperative. The safety profile of ICIs as monotherapy is dominated by immune-related adverse events, which can be considered as an extension of the mechanism of action of these immunomodulatory drugs. Further to this, an emerging theme is that ICI treatment can significantly impact upon the tolerability of coadministered medications. Numerous reports in literature indicate that ICIs may alter the immunological perception of coadministered drugs, resulting in undesirable reactions to a variety of concomitant medications. These reactions can be severe in manifestation, including hepatotoxicity and Stevens-Johnson Syndrome (SJS)/toxic epidermal necrolysis (TEN), but may also have detrimental impact on malignancy control. To minimize the impact of such drug-drug interactions on patients, it is imperative to identify medications that may cause these reactions, understand the underlying mechanisms, consider the timing and dosing of comedication, and explore alternative medications with comparable efficacies. Improving our understanding of how concomitant medications affect the safety and efficacy of ICIs can allow for potential culprit drugs to be identified/removed/desensitized. This approach will allow the continuation of ICI therapy that may have been discontinued otherwise, thereby improving malignant control and patient and drug development outcomes.

Immunogenicity of Atezolizumab: Influence of Testing Method and Sampling Frequency on Reported Anti-drug Antibody Incidence Rates

Measurement of anti-drug antibodies (ADA) to assess the incidence of ADA in a clinical trial is a critical step in immunogenicity assessment during the development of a protein therapeutic. We developed novel graphical approaches to illustrate clinical trial ADA data for the PD-L1 inhibitor atezolizumab (Tecentriq) that included a systematic analysis of the impact of the timing of ADA sampling and ADA assay drug tolerance on reported ADA incidence. We found that approaches used across the industry for ADA incidence analysis provide a limited view of immunogenicity in oncology studies, where ADA detection may be confounded by both drug dosage and patient attrition. Moreover, these approaches can miss important temporal information about the immune response. Our results demonstrated that the methodology of ADA assessment for the atezolizumab program was specifically designed to capture most ADA responses to ensure accurate reporting of ADA incidence. We further showed that the use of sparse sampling and/or ADA test methods with insufficient drug tolerance may result in a significant underreporting of ADA incidence. We conclude that the comparison of ADA incidence between different drugs can be highly misleading and that a test method with appropriate sensitivity in the presence of the drug and a clinical sampling scheme that is aligned with ADA responses to a drug is required to accurately report ADA incidence.

A humanized Anti-YKL-40 antibody inhibits tumor development

Drugs specifically targeting YKL-40, an over-expressed gene (CHI3L1) in various diseases remain developed. The current study is to create a humanized anti-YKL-40 neutralizing antibody and characterize its potentially therapeutic signature. We utilized in silico CDR-grafting bioinformatics to replace the complementarity determining regions (CDRs) of human IgG1 with mouse CDRs of our previously established anti-YKL-40 antibody (mAY). In fifteen candidates (VL1-3/VH1-5) of heavy and light chain variable region combination, one antibody L3H4 named Rosazumab demonstrated strong binding affinity with YKL-40 (KD = 4.645 × 10-8 M) and high homology with human IgG (80 %). In addition, we established different overlapping amino acid peptides of YKL-40 and found that Rosazumab specifically bound to residues K337, K342, and R344, the KR-rich functional domain of YKL-40. Rosazumab inhibited migration and tube formation of YKL-40-expressing tumor cells and induced tumor cell apoptosis. Mechanistically, Rosazumab induced interaction of N-cadherin with β-catenin and activation of downstream MST1/RASSF1/Histone H2B axis, leading to chromosomal DNA breakage and cell apoptosis. Treatment of xenografted tumor mice with Rosazumab twice a week for 4 weeks inhibited tumor growth and angiogenesis, but induced tumor apoptosis. Rosazumab injected in mice distributed to blood, tumor, and other multiple organs, but did not impact in function or structure of liver and kidney, indicating non-detectable toxicity in vivo. Collectively, the study is the first one to demonstrate that a humanized YKL-40 neutralizing antibody offers a valuable means to block tumor development.

Overcoming Resistance to Immune Checkpoint Blockade in Liver Cancer with Combination Therapy: Stronger Together?

Primary liver cancer, represented mainly by hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (CCA), is one of the most common and deadliest tumors worldwide. While surgical resection or liver transplantation are the best option in early disease stages, these tumors often present in advanced stages and systemic treatment is required to improve survival time. The emergence of immune checkpoint inhibitor (ICI) therapy has had a positive impact especially on the treatment of advanced cancers, thereby establishing immunotherapy as part of first-line treatment in HCC and CCA. Nevertheless, low response rates reflect on the usually cold or immunosuppressed tumor microenvironment of primary liver cancer. In this review, we aim to summarize mechanisms of resistance leading to tumor immune escape with a special focus on the composition of tumor microenvironment in both HCC and CCA, also reflecting on recent important developments in ICI combination therapy. Furthermore, we discuss how combination of ICIs with established primary liver cancer treatments (e.g. multikinase inhibitors and chemotherapy) as well as more complex combinations with state-of-the-art therapeutic concepts may reshape the tumor microenvironment, leading to higher response rates and long-lasting antitumor immunity for primary liver cancer patients.

Immune checkpoint inhibitors in the treatment of hepatocellular carcinoma

Despite advances in cancer treatment, hepatocellular carcinoma (HCC), the most common form of liver cancer, remains a major public health problem worldwide. The immune microenvironment plays a critical role in regulating tumor progression and resistance to therapy, and in HCC, the tumor microenvironment (TME) is characterized by an abundance of immunosuppressive cells and signals that facilitate immune evasion and metastasis. Recently, anti-cancer immunotherapies, therapeutic interventions designed to modulate the immune system to recognize and eliminate cancer, have become an important cornerstone of cancer therapy. Immunotherapy has demonstrated the ability to improve survival and provide durable cancer control in certain groups of HCC patients, while reducing adverse side effects. These findings represent a significant step toward improving cancer treatment outcomes. As demonstrated in clinical trials, the administration of immune checkpoint inhibitors (ICIs), particularly in combination with anti-angiogenic agents and tyrosine kinase inhibitors, has prolonged survival in a subset of patients with HCC, providing an alternative for patients who progress on first-line therapy. In this review, we aimed to provide an overview of HCC and the role of the immune system in its development, and to summarize the findings of clinical trials involving ICIs, either as monotherapies or in combination with other agents in the treatment of the disease. Challenges and considerations regarding the administration of ICIs in the treatment of HCC are also outlined.

Immunogenicity of avelumab in patients with metastatic Merkel cell carcinoma or advanced urothelial carcinoma

Like other monoclonal antibodies, immune checkpoint inhibitors may be immunogenic in some patients, potentially affecting pharmacokinetics (PKs) and clinical outcomes. In post hoc analyses, we characterized antidrug antibody (ADA) development with avelumab monotherapy in patients with metastatic Merkel cell carcinoma (mMCC) from the JAVELIN Merkel 200 trial (first-line [1L; N = 116] and second-line or later [≥2L; N = 88] cohorts) or with advanced urothelial carcinoma (aUC) from the JAVELIN Bladder 100 (1L maintenance [N = 350]) and JAVELIN Solid Tumor (≥2L [N = 249]) trials. Treatment-emergent ADAs developed in a numerically higher proportion of patients with aUC (1L maintenance, 19.1%; ≥2L, 18.1%) versus mMCC (1L, 8.2%; ≥2L, 8.9%); incidences within tumor types were similar by line of therapy. In PK analyses, numerically lower avelumab trough concentration and higher baseline clearance were observed in treatment-emergent ADA+ versus ADA- subgroups; however, differences were not clinically relevant. Numerical differences in overall survival, progression-free survival, or objective response rate by ADA status were observed; however, no clinically meaningful trends were identified. Proportions of patients with treatment-emergent adverse events (TEAEs; any grade or grade 3/4), serious TEAEs, TEAEs leading to treatment discontinuation, or infusion-related reactions were similar, with overlapping 80% confidence intervals between ADA subgroups. Efficacy and safety observations were similar in subgroups defined by early development of ADA+ status during treatment. In conclusion, no meaningful differences in PKs, efficacy, and safety were observed between subgroups of avelumab-treated patients with different ADA status. Overall, these data suggest that ADAs are not relevant for treatment decisions with avelumab.

Antibody Drug Clearance: An Underexplored Marker of Outcomes with Checkpoint Inhibitors

Immune-checkpoint inhibitor (ICI) therapy has dramatically changed the clinical landscape for several cancers, and ICI use continues to expand across many cancer types. Low baseline clearance (CL) and/or a large reduction of CL during treatment correlates with better clinical response and longer survival. Similar phenomena have also been reported with other monoclonal antibodies (mAb) in cancer and other diseases, highlighting a characteristic of mAb clinical pharmacology that is potentially shared among various mAbs and diseases. Though tempting to attribute poor outcomes to low drug exposure and arguably low target engagement due to high CL, such speculation is not supported by the relatively flat exposure-response relationship of most ICIs, where a higher dose or exposure is not likely to provide additional benefit. Instead, an elevated and/or increasing CL could be a surrogate marker of the inherent resistant phenotype that cannot be reversed by maximizing drug exposure. The mechanisms connecting ICI clearance, therapeutic efficacy, and resistance are unclear and likely to be multifactorial. Therefore, to explore the potential of ICI CL as an early marker for efficacy, this review highlights the similarities and differences of CL characteristics and CL-response relationships for all FDA-approved ICIs, and we compare and contrast these to selected non-ICI mAbs. We also discuss underlying mechanisms that potentially link mAb CL with efficacy and highlight existing knowledge gaps and future directions where more clinical and preclinical investigations are warranted to clearly understand the value of baseline and/or time-varying CL in predicting response to ICI-based therapeutics.

Efficacy and safety of the combination of camrelizumab and apatinib in the treatment of liver cancer: a systematic review and single-arm meta-analysis

OBJECTIVE

To evaluate the efficacy and safety of the combination of camrelizumab and apatinib in the treatment of liver cancer and to furnish clinical recommendations for pharmacological interventions.

METHODS

PubMed, Embase, Web of Science and the Cochrane Library were scrutinized for research publications from their inception to 22 December 2023. Bibliographic perusal and data procurement were executed. The quality of the included studies was evaluated employing the MINORS tool. Meta-analysis was conducted utilizing Stata 15.0 software.

RESULTS

A total of 10 studies involving 849 patients were included in the meta-analysis. The study revealed that the objective response rate (ORR) of the combined therapy was 28% (95% CI: 23%-34%), the disease control rate (DCR) was 69% (95% CI: 64%-73%), the median progression-free survival (mPFS) was 5.87 months (95% CI: 4.96-6.78), the median overall survival (mOS) was 19.35 months (95% CI: 17.53-21.17), the incidence of any grade adverse events was 90% (95% CI: 85%-95%), and the occurrence of grade 3 or higher adverse events was 49% (95% CI: 27%-71%).

CONCLUSION

The combination of camrelizumab and apatinib exhibits commendable effectiveness in the management of liver cancer; nevertheless, vigilance should be exercised concerning potential adverse reactions in clinical applications to enhance the safety of pharmacological interventions.

Antibiotic Exposure Concurrently with Anti-PD1 Blockade Therapy Reduces Overall Survival in Patients with Child-Pugh Class A Advanced Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer death worldwide with a poor prognosis. Treatment with immune checkpoint inhibitors (ICIs) has improved overall survival in patients with HCC. However, not all patients benefit from the treatment. In this study, 59 patients with HCC were enrolled from two medical centers in Saudi Arabia, with 34% using antibiotics concurrently with their Nivolumab (anti-PD1 blockade). The impact of antibiotic use on the clinical outcomes of patients with HCC undergoing treatment with anti-PD1 blockade was examined. The patients' overall survival (OS) was 5 months (95% CI: 3.2, 6.7) compared to 10 months (95% CI: 0, 22.2) (p = 0.08). Notably, patients with Child-Pugh A cirrhosis receiving anti-PD1 blockade treatment without concurrent antibiotic use showed a significantly longer median OS reaching 22 months (95% CI: 6.5, 37.4) compared to those who were given antibiotics with a median OS of 6 months (95% CI: 2.7, 9.2) (p = 0.02). This difference in overall survival was particularly found in Child-Pugh class A patients receiving anti-PD1 blockade. These findings suggest that antibiotic use may negatively affect survival outcomes in HCC patients undergoing anti-PD1 blockade, potentially due to antibiotic-induced alterations to the gut microbiome impacting the anti-PD1 blockade response. This study suggests the need for careful consideration when prescribing antibiotics to patients with HCC receiving anti-PD1 blockade.

Current state and challenges of emerging biomarkers for immunotherapy in hepatocellular carcinoma (Review)

Hepatocellular carcinoma (HCC) is the most prevalent form of primary liver cancer. According to the American Cancer Society, among patients diagnosed with advanced liver cancer, HCC has the sixth-highest incident rate, resulting in a poor prognosis. Surgery, radiofrequency ablation, transcatheter arterial chemoembolization, radiation, chemotherapy, targeted therapy and immunotherapy are the current treatment options available. Immunotherapy, which has emerged as an innovative treatment strategy over the past decade, is serving a vital role in the treatment of advanced liver cancer. Since only a small number of individuals can benefit from immunotherapy, biomarkers are required to help clinicians identify the target populations for this precision medicine. These biomarkers, such as PD-1/PD-L1, tumor mutational burden and circulating tumor DNA, can be used to investigate interactions between immune checkpoint inhibitors and tumors. The present review summarizes information on the currently available biomarkers used for immunotherapy and the challenges that are present.

Mechanisms of Resistance to Immunotherapy in Hepatocellular Carcinoma

Systemic treatment for advanced hepatocellular carcinoma (HCC) has been revolutionized over the last few years following the approval of immune checkpoint inhibitors (ICI). Despite the promising survival extension seen with ICI combination regimens, responses are not universally seen and the optimal partner for programmed cell death 1 pathway inhibitors remains to be identified. Even fewer encouraging results have been demonstrated with ICI used for monotherapy. Several mechanisms of resistance have been described so far, involving characteristics of cancer cells (intrinsic mechanisms) and of the surrounding tumor microenvironment (extrinsic mechanisms). Factors related to therapy may also contribute to the development of resistance. Increasing research efforts are being dedicated to the discovery of novel approaches and targets to overcome resistance, some of which may be introduced into clinic in the future. Herein we describe a selection of resistance mechanisms that have been involved in impairing response to ICI and propose potential therapeutic approaches to overcome resistance.

Pharmacokinetic analysis of vilobelimab, anaphylatoxin C5a and antidrug antibodies in PANAMO: a phase 3 study in critically ill, invasively mechanically ventilated COVID-19 patients

BACKGROUND

Vilobelimab, a complement 5a (C5a)-specific monoclonal antibody, reduced mortality in critically ill COVID-19 patients in a phase 3 multicentre, randomized, double-blind, placebo-controlled study. As part of the study, vilobelimab concentrations and C5a levels as well as antidrug antibodies (ADAs) to vilobelimab were analysed.

RESULTS

From Oct 1, 2020 to Oct 4, 2021, 368 invasively mechanically ventilated COVID-19 patients were randomized: 177 patients were randomly assigned to receive vilobelimab while 191 patients received placebo. Pharmacokinetic sampling was only performed at sites in Western Europe. Blood samples for vilobelimab measurements were available for 93 of 177 (53%) patients in the vilobelimab group and 99 of 191 (52%) patients in the placebo group. On day 8, after three infusions, mean vilobelimab (trough) concentrations ranged from 21,799.3 to 302,972.1 ng/mL (geometric mean 137,881.3 ng/mL). Blood samples for C5a measurements were available for 94 of 177 (53%) patients in the vilobelimab group and 99 of 191 (52%) patients in the placebo group. At screening, C5a levels were highly elevated and comparable between groups. In the vilobelimab group, median C5a levels were 118.3 ng/mL [IQR 71.2-168.2 ng/mL] and in the placebo group, median C5a levels were 104.6 ng/mL [IQR 77.5-156.6 ng/mL]. By day 8, median C5a levels were reduced by 87% in the vilobelimab group (median 14.5 ng/mL [IQR 9.5-21.0 ng/mL], p < 0.001) versus an 11% increase in the placebo group (median 119.2 ng/mL [IQR 85.9-152.1 ng/mL]). Beyond day 8, though plasma sampling was sparse, C5a levels did not reach screening levels in the vilobelimab group while C5a levels remained elevated in the placebo group. Treatment-emergent ADAs were observed in one patient in the vilobelimab group at hospital discharge on day 40 and in one patient in the placebo group at hospital discharge on day 25.

CONCLUSIONS

This analysis shows that vilobelimab efficiently inhibits C5a in critically ill COVID-19 patients. There was no evidence of immunogenicity associated with vilobelimab treatment. Trial registration ClinicalTrials.gov, NCT04333420. Registered 3 April 2020, https://clinicaltrials.gov/ct2/show/NCT04333420.

Immunotherapy for hepatocellular carcinoma: Recent advances and future targets

Immunotherapy is a promising approach to treating various types of cancers, including hepatocellular carcinoma (HCC). While single immunotherapy drugs show limited effectiveness on a small subset of patients, the combination of the anti PD-L1 atezolizumab and anti-vascular endothelial growth factor bevacizumab has shown significant improvement in survival compared to sorafenib as a first-line treatment. However, the current treatment options still have a low success rate of about 30%. Thus, more effective treatments for HCC are urgently required. Several novel immunotherapeutic methods, including the use of novel immune checkpoint inhibitors, innovative immune cell therapies like chimeric antigen receptor T cells (CAR-T), TCR gene-modified T cells and stem cells, as well as combination strategies are being tested in clinical trials for the treatment of HCC. However, some crucial issues still exist such as the presence of heterogeneous antigens in solid tumors, the immune-suppressive environment within tumors, the risk of on-target/off-tumor, infiltrating CAR-T cells, immunosuppressive checkpoint molecules, and cytokines. Overall, immunotherapy is on the brink of major advancements in the fight against HCC.

Global Analysis of Aggregation Profiles of Three Kinds of Immuno-Oncology mAb Drug Products Using Flow Cytometry

Accurately quantifying the protein particles in both subvisible (1-100 μm) and submicron (≤1 μm) ranges remains a prominent challenge in the development and manufacturing of protein drugs. Due to the limitation of the sensitivity, resolution, or quantification level of various measurement systems, some instruments may not provide count information, while others can only count particles in a limited size range. Moreover, the reported concentrations of protein particles commonly have significant discrepancies owing to different methodological dynamic ranges and the detection efficiency of these analytical tools. Therefore, it is extremely difficult to accurately and comparably quantify protein particles within the desired size range at one time. To develop an efficient protein aggregation measurement method that can span the entire range of interest, we established, in this study, a single particle-sizing/counting method based on our highly sensitive lab-built flow cytometry (FCM) system. The performance of this method was assessed, and its capability of identifying and counting microspheres between 0.2 and 25 μm was demonstrated. It was also used to characterize and quantify both subvisible and submicron particles in three kinds of top-selling immuno-oncology antibody drugs and their lab-produced counterparts. These assessment and measurement results suggest that there may be a role for an enhanced FCM system as an efficient investigative tool for characterizing and learning the molecular aggregation behavior, stability, or safety risk of protein products.

Resistance to immune checkpoint inhibitors and the tumor microenvironment

Immune checkpoint inhibitors (ICIs) have contributed significantly to the treatment of various types of cancer, including skin cancer. However, not all patients respond; some patients do not respond at all (primary resistance), while others experience recurrence after the initial response (acquired resistance). Therefore, overcoming ICI resistance is an urgent priority. Numerous ICI resistance mechanisms have been reported. They are seemingly quite complex, varying from patient to patient. However, most involve T-cell activation processes, especially in the tumor microenvironment (TME). ICIs exert their effects in the TME by reactivating suppressed T cells through inhibition of immune checkpoint molecules, such as cytotoxic T-lymphocyte antigen-4 (CTLA-4) and programmed cell death protein 1 (PD-1). Thus, this review focuses on the resistance mechanisms based on the T-cell activation process. Here, we classify the main mechanisms of ICI resistance into three categories based on (1) antigen recognition, (2) T-cell migration and infiltration, and (3) effector functions of T cells. By identifying and understanding these resistance mechanisms individually, including unknown mechanisms, we seek to contribute to the development of novel treatments to overcome ICI resistance.

The role of immune checkpoint inhibitors (ICI) as adjuvant treatment in renal cell carcinoma (RCC): A systematic review and meta-analysis

Pembrolizumab, a PD-1 ICI is approved for the adjuvant treatment of postnephrectomy patients with clear cell RCC in some countries worldwide. However, recent negative data from randomized clinical trials (RCT) with another ICIs makes the benefit of this treatment uncertain. A systematic review and study-level meta-analysis was performed to evaluate the benefit of disease-free survival (DFS) with adjuvant ICI treatment for patients with localized and/or metastatic resected RCC. Using the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement, a systematic search was performed in PUBMED/MEDLINE, Scopus and EMBASE up to September 15, 2022. The statistical analysis was performed by ProMeta 3 software in intention-to-treat (ITT) population and in predetermined subgroups. Four RCT totalizing 3407 patients were included in this analysis. Systemic immunotherapy was pembrolizumab, atezolizumab, nivolumab, and ipilimumab plus nivolumab in 496, 390, 404, and 405 patients, respectively. In the ITT population there was a nonstatistically significant DFS benefit with adjuvant ICI (HR: 0.85, 95% CI: 0.69-1.04). Regarding the subgroups, there was a DFS benefit for PD-L1 positive (HR: 0.72; 95% CI: 0.55-0.94), intermediate-high risk patients (HR: 0.77; 95% CI: 0.63-0.94), and patients with sarcomatoid component (HR: 0.66; 95% CI: 0.43-0.99). This meta-analysis did not demonstrate a statistically significant DFS benefit in overall population, however considering the heterogeneity between the RCTs the use of adjuvant ICI should be individualized.

Association of High Levels of Antidrug Antibodies Against Atezolizumab With Clinical Outcomes and T-Cell Responses in Patients With Hepatocellular Carcinoma

Importance

Administration of atezolizumab could be immunogenic and induce undesirable antidrug antibody (ADA) responses. This may interfere with atezolizumab-mediated actions, affecting drug clearance and serum concentration or inducing antibody neutralization.

Objective

To determine the clinical and immunological associations of highly elevated ADA levels with clinical outcomes after atezolizumab/bevacizumab (Atezo/Bev) treatment in patients with advanced hepatocellular carcinoma (HCC).

Design, Setting, and Participants

This cohort study prospectively enrolled 174 patients with advanced HCC treated with first-line Atezo/Bev (discovery cohort: 61 patients from 1 center; validation cohort: 113 patients from 4 centers).

Exposures

Serum ADA levels at pretreatment and 3 weeks (cycle 2 day 1 [C2D1]) were analyzed using competitive enzyme-linked immunosorbent assays. In addition, samples were subjected to serological and flow cytometric analyses.

Main Outcomes and Measures

Overall, ADA positivity was associated with treatment outcomes and T-cell functions.

Results

After excluding patients with inadequate samples, follow-up loss, or consent withdrawal, 132 patients (discovery cohort: 50 patients; 41 [82.0%] men; median age [IQR], 61 [55-70] years; validation cohort: 82 patients; 70 [85.4%] men; median age [IQR], 61 [53-68] years) were analyzed, and robust ADA (≥1000 ng/mL) responses at C2D1 were identified in 23 (17.4%) of the patients. Patients with progressive disease exhibited higher ADA levels (median [IQR], 65.2 [0-520.4] ng/mL) at C2D1 than in responders (median [IQR], 0 [0-117.5] ng/mL). In both discovery and validation cohorts, patients with high ADA levels at C2D1 were associated with a reduced response rate (discovery cohort: 34% vs 11%; validation cohort: 29% vs. 7%) and worse progression-free survival (discovery cohort: hazard ratio [HR], 2.84; 95% CI, 1.31-6.13; P = .005; validation cohort: HR, 2.52; 95% CI, 1.27-5.01; P = .006) and overall survival (discovery cohort: HR, 3.30; 95% CI, 1.43-7.64; P = .003; validation cohort: HR, 5.81, 95% CI, 2.70-12.50; P = .001) with Atezo/Bev compared with those with low ADA levels. In multivariable Cox regression, the clinical implication of high ADA levels persisted even after adjusting for various confounding factors and was most significant at 1000 ng/mL or greater. Compared with patients with low ADA levels, patients with high ADA levels exhibited reduced serum atezolizumab concentrations, impaired CD8-positive T-cell proliferation, and had decreased interferon-γ and tumor necrosis factor-α from CD8-positive T cells compared with patients with low ADA levels.

Conclusions and Relevance

This cohort study found that highly elevated ADA levels at C2D1 may be associated with poor clinical outcomes in patients with advanced HCC treated with Atezo/Bev. High ADA levels may reduce atezolizumab exposure and attenuate the anticancer efficacy of the drug.

Can Soluble Immune Checkpoint Molecules on Exosomes Mediate Inflammation?

Immune checkpoints (ICPs) are major co-signaling pathways that trigger effector functions in immune cells, with isoforms that are either membrane bound, engaging in direct cell to cell activation locally, or soluble, acting at distant sites by circulating freely or potentially via extracellular vesicles (EVs). Exosomes are small EVs secreted by a variety of cells carrying various proteins and nucleic acids. They are distributed extensively through biological fluids and have major impacts on infectious diseases, cancer, and neuroinflammation. Similarly, ICPs play key roles in a variety of disease conditions and have been extensively utilized as a prognostic tool for various cancers. Herein, we explored if the association between exosomes and ICPs could be a significant contributor of inflammation, particularly in the setting of cancer, neuroinflammation and viral infections, wherein the up regulation in both exosomal proteins and ICPs correlate with immunosuppressive effects. The detailed literature review of existing data highlights the significance and complexity of these two important pathways in mediating cancer and potentiating neuroinflammation via modulating overall immune response. Cells increasingly secret exosomes in response to intracellular signals from invading pathogens or cancerous transformations. These exosomes can carry a variety of cargo including proteins, nucleic acids, cytokines, and receptors/ligands that have functional consequences on recipient cells. Illustration generated using BioRender software.

New Challenges Facing Systemic Therapies of Advanced HCC in the Era of Different First-Line Immunotherapy-Based Combinations

The standard of care of first-line systemic therapy for advanced hepatocellular carcinoma (HCC) is currently changing with the results of the IMbrave150 trial which are demonstrating superiority of the atezolizumab-bevacizumab combination over sorafenib, modifying this line of treatment for the first time in over 10 years. Recently, other immunotherapy-based combinations (durvalumab-tremelimumab, lenvatinib-pembrolizumab, cabozantinib-atezolizumab, and camrelizumab-rivoceranib) reported results in phase III studies, and might challenge this new standard of care. This revolution will lead to a considerable change in practice, and highlight challenges for future drug development. In this review, we will, firstly, describe results of the different combinations, and discuss the difficulties in selecting the first-line treatment. We will then present the different recommendations about second-line treatment following the first-line immunotherapy-based combination, discussing the rationale for the differences in existing recommendations. We will finally discuss the challenges for future drug development in advanced HCC.

Non-Invasive Biomarkers for Immunotherapy in Patients with Hepatocellular Carcinoma: Current Knowledge and Future Perspectives

Simple Summary

The search for non-invasive biomarkers is a hot topic in modern oncology, since a tissue biopsy has significant limitations in terms of cost and invasiveness. The treatment perspectives have been significantly improved after the approval of immunotherapy for patients with hepatocellular carcinoma; therefore, the quick identification of responders is crucial to define the best therapeutic strategy. In this review, the current knowledge on the available non-invasive biomarkers of the response to immunotherapy is described.

Abstract

The treatment perspectives of advanced hepatocellular carcinoma (HCC) have deeply changed after the introduction of immunotherapy. The results in responders show improved survival compared with Sorafenib, but only one-third of patients achieve a significant benefit from treatment. As the tumor microenvironment exerts a central role in shaping the response to immunotherapy, the future goal of HCC treatment should be to identify a proxy of the hepatic tissue condition that is easy to use in clinical practice. Therefore, the search for biomarkers that are accurate in predicting prognosis will be the hot topic in the therapeutic management of HCC in the near future. Understanding the mechanisms of resistance to immunotherapy may expand the patient population that will benefit from it, and help researchers to find new combination regimens to improve patients’ outcomes. In this review, we describe the current knowledge on the prognostic non-invasive biomarkers related to treatment with immune checkpoint inhibitors, focusing on serological markers and gut microbiota.

Translating questions to estimands in randomized clinical trials with intercurrent events

Intercurrent (post-treatment) events occur frequently in randomized trials, and investigators often express interest in treatment effects that suitably take account of these events. Contrasts that naively condition on intercurrent events do not have a straight-forward causal interpretation, and the practical relevance of other commonly used approaches is debated. In this work, we discuss how to formulate and choose an estimand, beyond the marginal intention-to-treat effect, from the point of view of a decision maker and drug developer. In particular, we argue that careful articulation of a practically useful research question should either reflect decision making at this point in time or future drug development. Indeed, a substantially interesting estimand is simply a formalization of the (plain English) description of a research question. A common feature of estimands that are practically useful is that they correspond to possibly hypothetical but well-defined interventions in identifiable (sub)populations. To illustrate our points, we consider five examples that were recently used to motivate consideration of principal stratum estimands in clinical trials. In all of these examples, we propose alternative causal estimands, such as conditional effects, sequential regime effects, and separable effects, that correspond to explicit research questions of substantial interest.

Mechanisms of resistance to immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) are effective for various types of cancer, and their application has led to paradigm shifts in cancer treatment. While many patients can obtain clinical benefits from ICI treatment, a large number of patients are primarily resistant to such treatment or acquire resistance after an initial response. Thus, elucidating the resistance mechanisms is warranted to improve the clinical outcomes of ICI treatment. ICIs exert their antitumor effects by activating T cells in the tumor microenvironment. There are various resistance mechanisms, such as insufficient antigen recognition by T cells, impaired T‐cell migration and/or infiltration, and reduced T‐cell cytotoxicity, most of which are related to the T‐cell activation process. Thus, we classify them into three main mechanisms: resistance mechanisms related to antigen recognition, T‐cell migration and/or infiltration, and effector functions of T cells. In this review, we summarize these mechanisms of resistance to ICIs related to the T‐cell activation process and progress in the development of novel therapies that can overcome resistance.

Could We Predict the Response of Immune Checkpoint Inhibitor Treatment in Hepatocellular Carcinoma?

The use of anti-programmed cell-death protein (ligand)-1 (PD-[L]1) is an important strategy for treating hepatocellular carcinoma (HCC). However, the treatment only benefits 10–20% of patients when used as a monotherapy. Therefore, the selection of patients for anti-PD-1/PD-L1 treatment is crucial for both patients and clinicians. This review aimed to explore the existing literature on tissue or circulating markers for the identification of responders or non-responders to anti-PD-1/PD-L1 in HCC. For the clinically available markers, both etiological factors (viral versus non-viral) and disease extent (intra-hepatic vs. extrahepatic) impact the responses to anti-PD-1/PD-L1, warranting further studies. Preliminary data suggested that inflammatory indices (e.g., neutrophil-lymphocyte ratio) may be associated with clinical outcomes of HCC during the anti-PD-1/PD-L1 treatment. Finally, although PD-L1 expression in tumor tissues is a predictive marker for multiple cancer types, its clinical application is less clear in HCC due to the lack of a clear-cut association with responders to anti-PD-1/PD-L1 treatment. Although all translational markers are not routinely measured in HCC, recent data suggest their potential roles in selecting patients for anti-PD-1/PD-L1 treatment. Such markers, including the immune classification of HCC, selected signaling pathways, tumor-infiltrating lymphocytes, and auto-antibodies, were discussed in this review.

T-cell mediated targeted delivery of anti-PD-L1 nanobody overcomes poor antibody penetration and improves PD-L1 blocking at the tumor site

Monoclonal antibodies blocking immune checkpoints such as PD-L1 have yielded strong clinical benefits in many cancer types. Still, the current limitations are the lack of clinical response in a majority of patients and the development of immune-related adverse events in some. As an alternative to PD-L1-specific antibody injection, we have developed an approach based on the engineering of tumor-targeting T cells to deliver intratumorally an anti-PD-L1 nanobody. In the MC38-OVA model, our strategy enhanced tumor control as compared to injection of PD-L1-specific antibody combined with adoptive transfer of tumor-targeting T cells. As a possible explanation for this, we demonstrated that PD-L1-specific antibody massively occupied PD-L1 in the periphery but failed to penetrate to PD-L1-expressing cells at the tumor site. In sharp contrast, locally delivered anti-PD-L1 nanobody improved PD-L1 blocking at the tumor site while avoiding systemic exposure. Our approach appears promising to overcome the limitations of immunotherapy based on PD-L1-specific antibody treatment.

Phase I/Ib dose-escalation study of avelumab in Chinese patients with advanced solid tumors

Aim: Data for avelumab (anti-PD-L1 antibody) in Chinese patients are limited. Patients & methods: Phase I/Ib, open-label, dose-escalation study of Chinese patients with advanced solid tumors. Primary study objectives were to evaluate the maximum tolerated dose (MTD) and pharmacokinetics (PK) of avelumab. Results: 24 patients received avelumab 3 mg/kg every 2 weeks (Q2W; n = 3), 10 mg/kg Q2W (n = 7), 20 mg/kg Q2W (n = 6) or 10 mg/kg weekly for 12 weeks and then Q2W thereafter (n = 8). MTD was not reached. Avelumab exposure was increased in higher dose groups. Partial responses occurred in two patients (confirmed in one patient); best overall response was stable disease in nine patients. Conclusion: Data for avelumab in Chinese patients with advanced solid tumors were consistent with previous global studies.

Anti-drug antibodies in the current management of cancer

Monoclonal antibodies (mAbs) have become one of the main therapeutic weapons in modern oncology, mainly as targeted therapies, and immune checkpoint inhibitors. The generation of anti-drug antibodies (ADAs) after their administration can alter their pharmacokinetic, pharmacodynamic, efficacy and safety profile causing infusion-related reactions. Several risk factors have been associated with ADAs development, notably host genetics and immune status, comorbidity, concomitant medications, mAbs molecular structure, dose and route of administration. ADAs are not usually tested on daily clinical practice, being their analysis generally placed in early stages of drug development. ELISA-type assay the most common method. ADAs detection can involve important implications for treatment strategies of cancer patients, guiding therapeutic adjustment. In oncology, some studies about ADAs synthesis related to targeted therapies and immune checkpoint inhibitors have been recently published. Several strategies are proposed to reduce mAbs immunogenicity, such as different schedules, routes of administration or even the use of immunosuppressants. Another question that arises in relation to ADAs generation is the need to measure the concentration levels of active drug to guide the administration schedule. In this review, we will discuss all the aspects that are currently under discussion in relation with ADAs in oncology.

Novel Perspectives in Immune Checkpoint Inhibitors and the Management of Non-Alcoholic Steatohepatitis-Related Hepatocellular Carcinoma

Immune checkpoint inhibitors have revolutionised the systemic treatment of advanced hepatocellular carcinoma. Although phase III trials, testing single agent nivolumab and pembrolizumab, failed to meet their primary endpoints, the combination of atezolizumab and bevacizumab has demonstrated a remarkable objective response and unprecedented survival benefits, replacing sorafenib as the standard first-line treatment for advanced hepatocellular carcinoma. Despite these successes observed in immune checkpoint inhibitors in the management of advanced hepatocellular carcinoma, not all patients responded to treatment, which has led to the search of risk factors and biomarkers that could predict the response to immune checkpoint inhibitors. Recent translational studies have begun to shed light on the impact of an underlying liver disease, namely NASH, which might affect the response to immune checkpoint inhibitors. In addition, antidrug-antibody and gene expression assays have demonstrated promises in predicting the response to immune checkpoint inhibitors. In this article, we will provide an overview of the use of ICI in the management of advanced HCC, review the evidence that surrounds the recent controversy regarding NASH-HCC, and discuss potential biomarkers that predict the response to immune checkpoint inhibitors.

Allelic Variation in HLA-DRB1 is Associated with Development ofAnti-Drug Antibodies in Cancer Patients Treated with Atezolizumab that are Neutralizing in Vitro

The treatment of diseases with biologic agents can result in the formation of anti-drug antibodies (ADA). Although drivers for ADA formation are unknown, a role for antigen presentation is likely, and variation in human leukocyte antigen (HLA) genes has been shown to be associated with occurrence of ADA for several biologics. Here, we performed an HLA-wide association study in 1,982 patients treated with the anti-PD-L1 antibody atezolizumab across 8 clinical trials. On average, 29.8% of patients were ADA positive (N=591, range of 13.5% - 38.4% per study), and 14.6% of patients were positive for ADA that were neutralizing in vitro (NAb, N=278, range of 6.4% - 21.9% per study). In a meta-analysis of logistic regression coefficients, we found statistically significant associations between HLA class II alleles and ADA status. The top-associated alleles were HLA-DRB1*01:01 in a comparison of ADA-positive versus ADA-negative patients (p=3.4*10^-5 , odds ratio=1.96, 95% confidence interval=1.64-2.28), and HLA-DQA1*01:01 when comparing NAb-positive with ADA-negative patients (p=2.8 x 10^-7 , OR=2.31, 95% CI=1.98-2.66). Both alleles occur together on a common HLA haplotype, and analyses considering only NAb-negative, ADA-positive patients did no yield significant results, suggesting that the genetic association is mainly driven by NAb status. In conclusion, our study showed that HLA class II genotype is associated with the risk of developing ADA, and specifically NAb, in patients treated with atezolizumab, but the effect estimates suggest that immunogenetic factors are not sufficient as clinically meaningful predictors.

Predictive Simulations in Preclinical Oncology to Guide the Translation of Biologics

Preclinical in vivo studies form the cornerstone of drug development and translation, bridging in vitro experiments with first-in-human trials. However, despite the utility of animal models, translation from the bench to bedside remains difficult, particularly for biologics and agents with unique mechanisms of action. The limitations of these animal models may advance agents that are ineffective in the clinic, or worse, screen out compounds that would be successful drugs. One reason for such failure is that animal models often allow clinically intolerable doses, which can undermine translation from otherwise promising efficacy studies. Other times, tolerability makes it challenging to identify the necessary dose range for clinical testing. With the ability to predict pharmacokinetic and pharmacodynamic responses, mechanistic simulations can help advance candidates from in vitro to in vivo and clinical studies. Here, we use basic insights into drug disposition to analyze the dosing of antibody drug conjugates (ADC) and checkpoint inhibitor dosing (PD-1 and PD-L1) in the clinic. The results demonstrate how simulations can identify the most promising clinical compounds rather than the most effective in vitro and preclinical in vivo agents. Likewise, the importance of quantifying absolute target expression and antibody internalization is critical to accurately scale dosing. These predictive models are capable of simulating clinical scenarios and providing results that can be validated and updated along the entire development pipeline starting in drug discovery. Combined with experimental approaches, simulations can guide the selection of compounds at early stages that are predicted to have the highest efficacy in the clinic.

Immunotherapies for hepatocellular carcinoma

Liver cancer, more specifically hepatocellular carcinoma (HCC), is the second leading cause of cancer-related death and its incidence is increasing globally. Around 50% of patients with HCC receive systemic therapies, traditionally sorafenib or lenvatinib in the first line and regorafenib, cabozantinib or ramucirumab in the second line. In the past 5 years, immune-checkpoint inhibitors have revolutionized the management of HCC. The combination of atezolizumab and bevacizumab has been shown to improve overall survival relative to sorafenib, resulting in FDA approval of this regimen. More recently, durvalumab plus tremelimumab yielded superior overall survival versus sorafenib and atezolizumab plus cabozantinib yielded superior progression-free survival. In addition, pembrolizumab monotherapy and the combination of nivolumab plus ipilimumab have received FDA Accelerated Approval in the second-line setting based on early efficacy data. Despite these major advances, the molecular underpinnings governing immune responses and evasion remain unclear. The immune microenvironment has crucial roles in the development and progression of HCC and distinct aetiology-dependent immune features have been defined. Inflamed and non-inflamed classes of HCC and genomic signatures have been associated with response to immune-checkpoint inhibitors, yet no validated biomarker is available to guide clinical decision-making. This Review provides information on the immune microenvironments underlying the response or resistance of HCC to immunotherapies. In addition, current evidence from phase III trials on the efficacy, immune-related adverse events and aetiology-dependent mechanisms of response are described. Finally, we discuss emerging trials assessing immunotherapies across all stages of HCC that might change the management of this disease in the near future.

Progress and challenges for the machine learning-based design of fit-for-purpose monoclonal antibodies

Although the therapeutic efficacy and commercial success of monoclonal antibodies (mAbs) are tremendous, the design and discovery of new candidates remain a time and cost-intensive endeavor. In this regard, progress in the generation of data describing antigen binding and developability, computational methodology, and artificial intelligence may pave the way for a new era of in silico on-demand immunotherapeutics design and discovery. Here, we argue that the main necessary machine learning (ML) components for an in silico mAb sequence generator are: understanding of the rules of mAb-antigen binding, capacity to modularly combine mAb design parameters, and algorithms for unconstrained parameter-driven in silico mAb sequence synthesis. We review the current progress toward the realization of these necessary components and discuss the challenges that must be overcome to allow the on-demand ML-based discovery and design of fit-for-purpose mAb therapeutic candidates.

Oral drug delivery for immunoengineering

The systemic pharmacotherapeutic efficacy of immunomodulatory drugs is heavily influenced by its route of administration. A few common routes for the systemic delivery of immunotherapeutics are intravenous, intraperitoneal, and intramuscular injections. However, the development of novel biomaterials, in adjunct to current progress in immunoengineering, is providing an exciting area of interest for oral drug delivery for systemic targeting. Oral immunotherapeutic delivery is a highly preferred route of administration due to its ease of administration, higher patient compliance, and increased ability to generate specialized immune responses. However, the harsh environment and slow systemic absorption, due to various biological barriers, reduces the immunotherapeutic bioavailability, and in turn prevents widespread use of oral delivery. Nonetheless, cutting edge biomaterials are being synthesized to combat these biological barriers within the gastrointestinal (GI) tract for the enhancement of drug bioavailability and targeting the immune system. For example, advancements in biomaterials and synthesized drug agents have provided distinctive methods to promote localized drug absorption for the modulation of local or systemic immune responses. Additionally, novel breakthroughs in the immunoengineering field show promise in the development of vaccine delivery systems for disease prevention as well as combating autoimmune diseases, inflammatory diseases, and cancer. This review will discuss current progress made within the field of biomaterials and drug delivery systems to enhance oral immunotherapeutic availability, and how these new delivery platforms can be utilized to deliver immunotherapeutics for resolution of immune-related diseases.

A competitive ligand-binding assay for the detection of neutralizing antibodies against dostarlimab (TSR-042)

Dostarlimab is a humanized anti–PD-1 monoclonal antibody. Dostarlimab (JEMPERLI; TSR-042) was recently approved in the USA and in the EU. The presence of neutralizing antibodies (NAbs) is a cause for concern because they block the therapeutic function of the antibody and reduce drug efficacy. Therefore, programs developing therapeutic biologics need to develop and validate assays that adequately assess the presence of NAbs in the serum of patients treated with biologic therapies. Presented here is the development and validation of a competitive ligand-binding assay that specifically detects anti-dostarlimab NAbs in human serum. Precision, sensitivity, hook effect, selectivity, assay robustness, stabilities, and system suitability were evaluated. In addition, drug tolerance of the assay with the implementation of a drug removal process was investigated. The cut point factor for the detection of NAbs in human serum at a 1% false-positive rate was determined. The assay’s precision, sensitivity, hook effect, selectivity, robustness, and drug interference were tested and found to be acceptable. With system suitability and stability established, this assay has been used to evaluate NAbs to guide the development of dostarlimab.

Trial registration: Clinicaltrials.gov, NCT02715284. Registered 9 March 2016

Identification of neutralising pembrolizumab anti-drug antibodies in patients with melanoma

Development of anti-drug antibodies (ADAs) can interfere with therapeutic monoclonal antibodies and may lead to drug neutralisation and clinical disease progression. Measurement of circulating drug levels and development of ADAs in the setting of anti-programmed cell death-1 agent pembrolizumab has not been well-studied. Enzyme-linked immunosorbent assays were used to measure pembrolizumab drug level and ADAs in 41 patients with melanoma at baseline, Time-point 1 (3 weeks) and Time-point 2 (21 weeks). Assay results were related to patient demographics and clinical outcome data at 6 months. The median pembrolizumab drug level at 3 weeks was 237 ng/μL and did not correlate with age, sex or body surface area.17/41 patients had an ADA detected at any timepoint, with the highest prevalence at Timepoint 1 (median concentration = 17 ng/μL). The presence of an ADA did not correlate with clinical progression at 6 months. 3/41 (7%) of patients displayed a falling pembrolizumab drug level and rising ADA titre between Timepoint 1 and 2 suggestive of a neutralising ADA. Pembrolizumab drug levels and ADAs can be readily measured. The rates of total and treatment-emergent ADAs may be higher in “real-word” settings than those previously reported. Larger studies are needed to determine effect of neutralising ADAs on long-term clinical outcome.

Evaluation of atezolizumab immunogenicity: Efficacy and safety (Part 2)

Antibody therapeutics can be associated with unwanted immune responses resulting in the development of anti‐drug antibodies (ADA). Optimal methods to evaluate the potential effects of ADA on clinical outcomes in oncology are not well established. In this study, we assessed efficacy and safety, based on ADA status, in patients from over 10 clinical trials that evaluated the immune checkpoint inhibitor atezolizumab as a single agent or as combination therapy for several types of advanced cancers. ADA can only be observed post randomization, and imbalances in baseline prognostic factors can confound the interpretation of ADA impact. We applied methodology to account for the confounding effects of baseline clinical characteristics and survivorship bias on efficacy. Adjusted meta‐analyses revealed that despite numerical differences in overall survival and progression‐free survival between ADA‐positive and ADA‐negative patients from some studies, ADA‐positive patients from studies with an overall treatment effect derived benefit from atezolizumab, compared with their adjusted controls. Based on large, pooled populations from atezolizumab monotherapy or combination studies, unadjusted descriptive analyses did not identify a clear relationship between ADA status and frequency or severity of adverse events. Data also suggested that any ADA impact is not driven by neutralizing activity. Collectively, this exploratory analysis suggests that the potential for ADA development should not impact treatment decisions with atezolizumab.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immunotherapy for the treatment of hepatocellular carcinoma

Patients with advanced hepatocellular carcinoma (HCC) have historically had few options and faced extremely poor prognoses if their disease progressed after standard-of-care tyrosine kinase inhibitors (TKIs). Recently, the standard of care for HCC has been transformed as a combination of the immune checkpoint inhibitor (ICI) atezolizumab plus the anti-vascular endothelial growth factor (VEGF) antibody bevacizumab was shown to offer improved overall survival in the first-line setting. Immunotherapy has demonstrated safety and efficacy in later lines of therapy as well, and ongoing trials are investigating novel combinations of ICIs and TKIs, in addition to interventions earlier in the course of disease or in combination with liver-directed therapies. Because HCC usually develops against a background of cirrhosis, immunotherapy for liver tumors is complex and oncologists need to account for both immunological and hepatological considerations when developing a treatment plan for their patients. To provide guidance to the oncology community on important concerns for the immunotherapeutic care of HCC, the Society for Immunotherapy of Cancer (SITC) convened a multidisciplinary panel of experts to develop a clinical practice guideline (CPG). The expert panel drew on the published literature as well as their clinical experience to develop recommendations for healthcare professionals on these important aspects of immunotherapeutic treatment for HCC, including diagnosis and staging, treatment planning, immune-related adverse events (irAEs), and patient quality of life (QOL) considerations. The evidence- and consensus-based recommendations in this CPG are intended to give guidance to cancer care providers treating patients with HCC.

First-Line Immune Checkpoint Inhibition for Advanced Non-Small-Cell Lung Cancer: State of the Art and Future Directions

The advent of PD-(L)1 and CTLA-4 immune check point inhibitors (CPIs) has dramatically changed the treatment landscape of advanced non-small-cell lung cancer (NSCLC). For up to a quarter of patients with advanced NSCLC, CPIs have the potential to induce durable responses with long-term survival outcomes. Since the approval of first-line pembrolizumab for patients whose tumors express a PD-L1 ≥ 50%, several pivotal first-line CPI-based phase 3 studies have been conducted investigating combination treatments combining CPIs with chemotherapy (ChT) or combining different CPIs with or without ChT. As a result, there has been an increase in front-line treatment options for advanced NSCLC, and treatment algorithms are changing very quickly. In fit patients with advanced NSCLC, combination treatments including CPI and ChT are considered the new standard of care with improved clinical outcomes. CPI combination treatments are well tolerated and quality of life also seems to be better when CPIs are implemented in the first-line setting. The aim of this review is to provide a summary of the recently published first-line phase 3 studies investigating CPIs as monotherapy or in combination with other CPIs or ChT in advanced NSCLC, and to suggest possible treatment algorithms.

Safety, Efficacy, and Pharmacodynamics of Tremelimumab Plus Durvalumab for Patients With Unresectable Hepatocellular Carcinoma: Randomized Expansion of a Phase I/II Study

This phase I/II study evaluated tremelimumab (anticytotoxic T-lymphocyte–associated antigen-4 monoclonal antibody) and durvalumab (antiprogrammed death ligand-1 monoclonal antibody) as monotherapies and in combination for patients with unresectable hepatocellular carcinoma (HCC), including a novel regimen featuring a single, priming dose of tremelimumab (ClinicalTrials.gov identifier: NCT02519348).

A structural perspective on the design of decoy immune modulators

Therapeutic mAbs have dominated the class of immunotherapeutics in general and immune checkpoint inhibitors in particular. The high specificity of mAbs to the target molecule as well as their extended half-life and (or) the effector functions raised by the Fc part are some of the important aspects that contribute to the success of this class of therapeutics. Equally potential candidates are decoys and their fusions that can address some of the inherent limitations of mAbs, like immunogenicity, resistance development, low bio-availability and so on, besides maintaining the advantages of mAbs. The decoys are molecules that trap the ligands and prevent them from interacting with the signaling receptors. Although a few FDA-approved decoy immune modulators are very successful, the potential of this class of drugs is yet to be fully realized. Here, we review various strategies employed in fusion protein therapeutics with a focus on the design of decoy immunomodulators from the structural perspective and discuss how the information on protein structure and function can strategically guide the development of next-generation immune modulators.

Which factors matter the most? Revisiting and dissecting antibody therapeutic doses

Factors such as antibody clearance and target affinity can influence antibodies' effective doses for specific indications. However, these factors vary considerably across antibody classes, precluding direct and quantitative comparisons. Here, we apply a dimensionless metric, the therapeutic exposure affinity ratio (TEAR), which normalizes the therapeutic doses by antibody bioavailability, systemic clearance and target-binding property to enable direct and quantitative comparisons of therapeutic doses. Using TEAR, we revisited and dissected the doses of up to 60 approved antibodies. We failed to detect a significant influence of target baselines, turnovers or anatomical locations on antibody therapeutic doses, challenging the traditional perceptions. We highlight the importance of antibodies' modes of action for therapeutic doses and dose selections; antibodies that work through neutralizing soluble targets show higher TEARs than those working through other mechanisms. Overall, our analysis provides insights into the factors that influence antibody doses, and the factors that are crucial for antibodies' pharmacological effects.

Recent Advances and Future Prospects in Immune Checkpoint (ICI)-Based Combination Therapy for Advanced HCC

Advanced, unresectable hepatocellular carcinoma has a dismal outcome. Multiple immune checkpoint inhibitors (ICIs) targeting the programmed-cell death 1 pathway (PD-1/L1) have been approved for the treatment of advanced HCC. However, outcomes remain undesirable and unpredictable on a patient-to-patient basis. The combination of anti-PD-1/L1 with alternative agents, chiefly cytotoxic T-lymphocyte antigen-4 (CTLA-4) ICIs or agents targeting other oncogenic pathways such as the vascular endothelial growth factor (VEGF) pathway and the c-MET pathway, has, in addition to the benefit of directly targeting alterative oncogenic pathways, in vitro evidence of synergism through altering the genomic and function signatures of T cells and expression of immune checkpoints. Several trials have been completed or are underway evaluating such combinations. Finally, studies utilizing transcriptomics and organoids are underway to establish biomarkers to predict ICI response. This review aims to discuss the biological rationale and clinical advances in ICI-based combinations in HCCs, as well as the progress and prospects of the search for the aforementioned biomarkers in ICI treatment of HCC.

Principal stratum strategy: Potential role in drug development

A randomized trial allows estimation of the causal effect of an intervention compared to a control in the overall population and in subpopulations defined by baseline characteristics. Often, however, clinical questions also arise regarding the treatment effect in subpopulations of patients, which would experience clinical or disease related events post-randomization. Events that occur after treatment initiation and potentially affect the interpretation or the existence of the measurements are called intercurrent events in the ICH E9(R1) guideline. If the intercurrent event is a consequence of treatment, randomization alone is no longer sufficient to meaningfully estimate the treatment effect. Analyses comparing the subgroups of patients without the intercurrent events for intervention and control will not estimate a causal effect. This is well known, but post-hoc analyses of this kind are commonly performed in drug development. An alternative approach is the principal stratum strategy, which classifies subjects according to their potential occurrence of an intercurrent event on both study arms. We illustrate with examples that questions formulated through principal strata occur naturally in drug development and argue that approaching these questions with the ICH E9(R1) estimand framework has the potential to lead to more transparent assumptions as well as more adequate analyses and conclusions. In addition, we provide an overview of assumptions required for estimation of effects in principal strata. Most of these assumptions are unverifiable and should hence be based on solid scientific understanding. Sensitivity analyses are needed to assess robustness of conclusions.

Anti-PD1 versus anti-PD-L1 immunotherapy in first-line therapy for advanced non-small cell lung cancer: A systematic review and meta-analysis

BACKGROUND

Due to the increasing number of trials with immune checkpoint inhibitors (ICIs) in the first-line therapy of non-small cell lung cancer (NSCLC) patients, we performed a systematic review and meta-analyses to investigate the difference between anti PD-1 and PD-L1 antibodies, used alone or in combination with chemotherapy, through adjusted indirect analysis to minimize the potential bias regarding overall survival (OS), progression-free survival (PFS), overall response rate (ORR) and grade 3-5 adverse events (AEs).

METHODS

A systematic review of studies reporting clinical outcomes and toxicity associated with first-line therapy employing anti-PD1 or anti-PD-L1 antibodies alone, or in combination with chemotherapy, to treat metastatic, treatment-naïve NSCLC patients was performed. Primary outcomes were OS, PFS, ORR and grade 3-5 AEs. We used a random-effects model to generate pooled estimates for proportions. Meta-analyses using pooled risk ratios were performed for binary outcomes from comparative studies with the random effects model.

RESULTS

A total of 13 eligible studies met our eligibility criteria, including 7673 patients. In the ICI-chemotherapy combination subgroup, we observed that anti-PD1 therapy was associated with better OS (p = 0.022) and PFS (p = 0.029) compared with anti-PD-L1 therapy. In the monotherapy subgroup, there was no statistical difference between the use of anti-PD-1 and anti-PD-L1 for OS and PFS. With regard to ORR and toxicity, in the ICI-chemotherapy combination subgroup, we observed a trend of better ORR (p = 0.12) with the use of anti-PD1 therapy and less frequent grade 3-5 AEs compared to the use of anti-PD-L1 therapy (p = 0.0302). In the monotherapy subgroup, there was no statistical difference between the use of anti-PD-1 and anti-PD-L1 regarding ORR and toxicity.

CONCLUSIONS

Our study suggests that PD-1 drug plus chemotherapy is superior to anti-PD-L1 plus chemotherapy for NSCLC; nevertheless, as monotherapy, both strategies appear to be similar.

The Impact of Product and Process Related Critical Quality Attributes on Immunogenicity and Adverse Immunological Effects of Biotherapeutics

The pharmaceutical industry has experienced great successes with protein therapeutics in the last two decades and with novel modalities, including cell therapies and gene therapies, more recently. Biotherapeutics are complex in structure and present challenges for discovery, development, regulatory, and life cycle management. Biotherapeutics can interact with the immune system that may lead to undesired immunological responses, including immunogenicity, hypersensitivity reactions (HSR), injection site reactions (ISR), and others. Many product and process related critical quality attributes (CQAs) have the potential to trigger or augment such immunological responses to the product. Tremendous efforts, both clinically and preclinically, have been invested to understand the impact of product and process related CQAs on adverse immunological effects. The information and knowledge are critical for the implementation of Quality by Design (QbD), which requires risk assessment and establishment of specifications and control strategies for CQAs. A quality target product profile (QTPP) that identifies the key CQAs through process development can help assign severity scores based on safety, immunogenicity, pharmacokinetics (PK) and pharmacodynamics (PD) of the molecule. Gaps and future directions related to biotherapeutics and emerging novel modalities are presented.

Intratumoral Immunotherapy: From Trial Design to Clinical Practice

Systemic immunotherapies such as immune checkpoint blockade targeted at PD(L)1 and CTLA4 have demonstrated their ability to provide durable tumor responses and long-term overall survival benefits for some patients in several solid tumor types. However, a majority of patients remain resistant to these treatments and a significant proportion of them develop severe autoimmune and inflammatory adverse events. Preclinical studies have demonstrated that intratumoral injections of immunostimulatory products (oncolytics, pattern recognition receptor agonists,…) that are able to trigger type I IFN release and enhance tumor antigen presentation on immune cells could generate a strong antitumor immunity and overcome the resistance to systemic immune checkpoint blockade therapies. The intratumoral immunotherapy strategies that are currently in clinical development offer a unique therapeutic and exploratory setting to better understand the immune contexture across tumor lesions of patients with metastatic cancer. Also these local therapeutic products could turn cold tumors into hot and improve the response rates to cancer immunotherapies while diminishing their systemic exposure and toxicities. Intratumoral immunotherapies could prime or boost the immunity against tumors and therefore radically change the combinatorial therapeutic strategies currently pursued for metastatic and local cancers to improve their long-term survival. We aimed to review and discuss the scientific rationale for intratumoral immunotherapy, the challenges raised by this strategy in terms of drug development within clinical trials and the current state-of-the-art regarding the clinical practice of this innovative approach.

Immune-related adverse events of checkpoint inhibitors

Cancer immunotherapies have changed the landscape of cancer treatment during the past few decades. Among them, immune checkpoint inhibitors, which target PD-1, PD-L1 and CTLA-4, are increasingly used for certain cancers; however, this increased use has resulted in increased reports of immune-related adverse events (irAEs). These irAEs are unique and are different to those of traditional cancer therapies, and typically have a delayed onset and prolonged duration. IrAEs can involve any organ or system. These effects are frequently low grade and are treatable and reversible; however, some adverse effects can be severe and lead to permanent disorders. Management is primarily based on corticosteroids and other immunomodulatory agents, which should be prescribed carefully to reduce the potential of short-term and long-term complications. Thoughtful management of irAEs is important in optimizing quality of life and long-term outcomes.