Controversies on the possible role of immune checkpoint inhibitors in pediatric cancers: balancing irAEs and efficacy

Into the storm: the imbalance in the yin-yang immune response as the commonality of cytokine storm syndromes

There is a continuous cycle of activation and contraction in the immune response against pathogens and other threats to human health in life. This intrinsic yin-yang of the immune response ensures that inflammatory processes can be appropriately controlled once that threat has been resolved, preventing unnecessary tissue and organ damage. Various factors may contribute to a state of perpetual immune activation, leading to a failure to undergo immune contraction and development of cytokine storm syndromes. A literature review was performed to consider how the trajectory of the immune response in certain individuals leads to cytokine storm, hyperinflammation, and multiorgan damage seen in cytokine storm syndromes. The goal of this review is to evaluate how underlying factors contribute to cytokine storm syndromes, as well as the symptomatology, pathology, and long-term implications of these conditions. Although the recognition of cytokine storm syndromes allows for universal treatment with steroids, this therapy shows limitations for symptom resolution and survival. By identifying cytokine storm syndromes as a continuum of disease, this will allow for a thorough evaluation of disease pathogenesis, consideration of targeted therapies, and eventual restoration of the balance in the yin-yang immune response.

Anti-PD-1 Therapy in Advanced Pediatric Malignancies in Nationwide Study: Good Outcome in Skin Melanoma and Hodgkin Lymphoma

BACKGROUND/AIM

The role of immune checkpoint inhibitors (ICIs; anti-PD1) in the treatment of childhood cancers is still evolving. The aim of this nationwide retrospective study was to assess the safety and effectiveness of ICIs used in a group of 42 patients, with a median age of 13.6 years, with various types of advanced malignancies treated in pediatric oncology centers in Poland between 2015 and 2023.

RESULTS

The indications for treatment with anti-PD1 were as follows: Hodgkin lymphoma (11); malignant skin melanoma (9); neuroblastoma (8); and other malignancies (14). At the end of follow-up, complete remission (CR) was observed in 37.7% (15/42) of children and disease stabilization in 9.5% (4/42), with a mean survival 3.6 (95% CI = 2.6-4.6) years. The best survival (OS = 1.0) was observed in the group of patients with Hodgkin lymphoma. For malignant melanoma of the skin, neuroblastoma, and other rare malignancies, the estimated 3-year OS values were, respectively, 0.78, 0.33, and 0.25 (p = 0.002). The best progression-free survival value (0.78) was observed in the group with malignant melanoma. Significantly better effects of immunotherapy were confirmed in patients ≥ 14 years of age and good overall performance ECOG status. Severe adverse events were observed in 30.9% (13/42) patients.

Indoximod-based chemo-immunotherapy for pediatric brain tumors: A first-in-children phase I trial

BACKGROUND

Recurrent brain tumors are the leading cause of cancer death in children. Indoleamine 2,3-dioxygenase (IDO) is a targetable metabolic checkpoint that, in preclinical models, inhibits anti-tumor immunity following chemotherapy.

METHODS

We conducted a phase I trial (NCT02502708) of the oral IDO-pathway inhibitor indoximod in children with recurrent brain tumors or newly diagnosed diffuse intrinsic pontine glioma (DIPG). Separate dose-finding arms were performed for indoximod in combination with oral temozolomide (200 mg/m2/day x 5 days in 28-day cycles), or with palliative conformal radiation. Blood samples were collected at baseline and monthly for single-cell RNA-sequencing with paired single-cell T cell receptor sequencing.

RESULTS

Eighty-one patients were treated with indoximod-based combination therapy. Median follow-up was 52 months (range 39-77 months). Maximum tolerated dose was not reached, and the pediatric dose of indoximod was determined as 19.2 mg/kg/dose, twice daily. Median overall survival was 13.3 months (n = 68, range 0.2-62.7) for all patients with recurrent disease and 14.4 months (n = 13, range 4.7-29.7) for DIPG. The subset of n = 26 patients who showed evidence of objective response (even a partial or mixed response) had over 3-fold longer median OS (25.2 months, range 5.4-61.9, p = 0.006) compared to n = 37 nonresponders (7.3 months, range 0.2-62.7). Four patients remain free of active disease longer than 36 months. Single-cell sequencing confirmed emergence of new circulating CD8 T cell clonotypes with late effector phenotype.

CONCLUSIONS

Indoximod was well tolerated and could be safely combined with chemotherapy and radiation. Encouraging preliminary evidence of efficacy supports advancing to Phase II/III trials for pediatric brain tumors.

PD-1/PD-L1 inhibitors-associated cardiac adverse events: a retrospective and real-world study based on the FDA Adverse Event Reporting System (FAERS)

BACKGROUND

Programmed cell death protein-1 (PD-1) and programmed cell death ligand-1 (PD-L1) inhibitors have reformed the treatment landscape for various malignancies and improved prognosis of patients. However, they also lead to events that although rare may prove to be fatal.

RESEARCH DESIGN AND METHODS

Data from July 2014 to June 2022 based on FDA Adverse Event Reporting System (FAERS) were analyzed. The signal index reporting odds ratio (ROR) was used to evaluate the correlation between cardiac AEs and given medications. The indications and the median time to onset (TTO) of different PD-1/PD-L1 inhibitors were compared.

RESULTS

Cardiac AEs are rare but may be fatal with particular profiles in primary tumor, onset time, and especially gender. We identified 11,538 reports that were related to cardiotoxicity of PD-1/PD-L1 inhibitors, in which 178 different preferred terms (PTs) were distinguished, and nivolumab reported the most PTs with signal. All targeted medications showed signals in myocardial disorders and pericardial disorders, which tend to occur in the first 1-2 months. Non-small cell neoplasm was the top and common indication during anti-PD-1 or anti-PD-L1 therapy with cardiotoxicity.

CONCLUSIONS

This study could help early diagnosis and surveillance of ICIs-related cardiotoxicity.

Immune checkpoint inhibitors therapy as the game-changing approach for pediatric lymphoma: A brief landscape

Lymphoma is known as the third most common malignancy in children, and its prevalence and mortality are increasing. Common treatments, including chemotherapy, radiotherapy, and also surgery, despite their efficacy, have many side effects and, have a high chance of disease relapse. Immune Checkpoint Inhibitors (ICIs) offer a promising alternative with potentially fewer risks of relapse and toxicity. This review article aims to investigate the efficacy and safety of ICIs, either as monotherapy or in combination, for pediatric lymphoma patients. ICIs have revolutionized cancer treatment in recent years and have shown remarkable results in several adult cancers. However, their efficacy in treating pediatrics requires further investigation. Nevertheless, some ICIs, including nivolumab, pembrolizumab, and ipilimumab, have demonstrated encouraging outcomes. ICIs therapy is not without risks and can cause side effects, including rash, itching, vitiligo, abdominal pain, diarrhea, dysphagia, epigastric pain, nausea, vomiting, thyroid, and pituitary dysfunction. Overall, this review article highlights the potential benefits and risks of ICIs in treating pediatric lymphoma.

Hepatoblastoma Cancer Stem Cells Express PD-L1, Reveal Plasticity and Can Emerge upon Chemotherapy

The biology of cancer stem cells (CSCs) of pediatric cancers, such as hepatoblastoma, is sparsely explored. This is mainly due to the very immature nature of these tumors, which complicates the distinction of CSCs from the other tumor cells. Previously, we identified a CSC population in hepatoblastoma cell lines expressing the CSC markers CD34 and CD90, cell surface Vimentin (csVimentin) and binding of OV-6. In this study, we detected the co-expression of the immune escape factor PD-L1 in the CSC population, whereas the other tumor cells remained negative. FACS data revealed that non-CSCs give rise to CSCs, reflecting plasticity of CSCs and non-CSCs in hepatoblastoma as seen in other tumors. When we treated cells with cisplatin and decitabine, a new CD34^+/lowOV-6^lowCD90⁺ population emerged that lacked csVimentin and PD-L1 expression. Expression analyses showed that this new CSC subset shared similar pluripotency and EMT features with the already-known CSCs. FACS results further revealed that this subset is also generated from non-CSCs. In conclusion, we showed that hepatoblastoma CSCs express PD-L1 and that the biology of hepatoblastoma CSCs is of a plastic nature. Chemotherapeutic treatment leads to another CSC subset, which is highly chemoresistant and could be responsible for a poor prognosis after postoperative chemotherapy.