Combinations of Chemotherapy and PD-1/PD-L1 Inhibitors in Sarcoma

Unexpected outcomes of tislelizumab treatment in thoracic metastasis of malignant phyllodes tumors: a case report and literature review

Phyllodes tumo (PT) of the breast are classified into benign, borderline, and malignant types. Malignant phyllodes tumor (MPT) with metastasis, particularly those containing sarcomatous components, have a notably poor prognosis. The most common sites of metastasis are the lungs, although metastases can also occur in the pleura and other areas. Metastatic PT is typically treated according to NCCN guidelines for soft tissue sarcomas. The prognosis for patients is extremely poor, with survival typically not exceeding five years. Therefore, the treatment of metastatic MPT presents significant challenges. A 67-year-old female with a history of PT surgery was hospitalized due to acute chest tightness and shortness of breath. MRI revealed a large mass in the left thoracic region, measuring 7.9 × 10.8 × 11.4 cm. A biopsy conducted prior to hospitalization indicated spindle cell soft tissue sarcoma. Due to critical vital signs, she underwent an emergency thoracotomy. Postoperative analysis confirmed the diagnosis of thoracic metastasis from MPT with sarcomatous components. Genetic analysis of the tumor tissue post-surgery revealed a KDM6A gene mutation. Unfortunately, subsequent imaging showed a recurring mass in the left thoracic space, approximately 8 cm in size. Considering the side effects of NCCN-recommended treatments (doxorubicin and ifosfamide) and the high cost of targeted therapies, the patient and her family chose tislelizumab. After six cycles of treatment, the patient's progression-free survival reached 15 weeks. Due to unsatisfactory treatment effects, the patient and her family decided to discontinue therapy, and the patient passed away in July 2024. Although the combination of surgery and postoperative immune checkpoint inhibitors remains to be validated, this case provides valuable insights into the management of thoracic metastasis from MPT. It offers potential new options for personalized immunotherapy in metastatic MPT.

PD‑1/PD‑L1 immune checkpoint in bone and soft tissue tumors (Review)

Anti-programmed cell death 1 (PD-1)/PD-1 ligand-1 (PD-L1) drugs have been used clinically, including those for skin cancer, with reasonable efficacy. Despite extensive ongoing research on bone and soft tissue sarcomas, there is a paucity of reviews that present a coherent picture. The present article is a comprehensive narrative review on the role of the PD-1/PD-L1 immune checkpoint in bone and soft tissue tumors. The review outlines the biological functions and mechanisms of action of PD-1/PD-L1 and its expression and clinical significance in various tumor types, including osteosarcoma and soft tissue sarcoma. Clinical trial results of immune checkpoint inhibitors, their association with prognosis, mechanisms of resistance to therapy, immune-related adverse events, and their potential in combination therapies, were also discussed.

Efficacy of immune checkpoint inhibitors in the treatment of soft tissue sarcoma: A systematic review and meta-analysis of clinical trials

BACKGROUND

Soft tissue sarcomas (STS) are a heterogeneous group of tumors with diverse clinical and molecular characteristics, characterized by limited treatment options and poor prognosis. Immune checkpoint inhibitors (ICIs) have emerged as promising therapies for STS, yet comprehensive evaluations of their efficacy, especially in combination with other treatments, are scarce.

METHODS

We conducted a systematic review and meta-analysis of clinical trials on ICIs in STS treatment, sourced from PubMed, Embase, and the Cochrane Central Register of Controlled Trials up to May 31, 2024. The studies included both monotherapy and combination therapies with ICIs. We assessed the methodological quality using the Cochrane Risk of Bias 2 tool and the Methodological Index for Non-Randomized Studies. Data synthesis involved random-effects meta-analysis to determine pooled proportions and 95% confidence intervals (CIs) for objective response rates (ORR), disease control rates (DCR), and high-grade treatment-related adverse events (TRAEs).

RESULTS

The analysis included 38 studies with 1349 patients covering 24 STS subtypes. The overall ORR was 16% (95% CI 0.12-0.21), DCR was 64% (95% CI 0.57-0.70), and the rate of Grade 3-5 TRAEs was 19% (95% CI 0.13-0.27). Treatments combining ICIs with tyrosine kinase inhibitors (TKIs) showed the highest efficacy (ORR 28%, 95% CI 0.18-0.40), albeit with increased adverse events. ORRs in first-line treatments were substantially higher (28%) compared to second-line treatments or beyond (11%). Subtypes like alveolar soft part sarcoma (ASPS), angiosarcoma (AS), and epithelioid sarcoma (ES) exhibited favorable responses exceeding 30%.

CONCLUSIONS

This systematic review and meta-analysis indicate that ICIs, particularly when combined with TKIs, provide substantial therapeutic benefits in treating STS, significantly enhancing response rates in specific subtypes such as ASPS and AS. The results underscore the transformative potential of ICIs in STS treatment strategies. However, the variability across subtypes and treatment lines emphasizes the need for further randomized controlled trials to refine and personalize therapeutic approaches, ensuring optimal outcomes for patients with these diverse malignancies.

Steady survival improvements in soft tissue and bone sarcoma in the Nordic countries through 50 years

PURPOSE

Sarcomas are rare cancers with many subtypes in soft tissues, bone and cartilage. International survival trends in these cancers are not well known. We present 50-year survival trends for soft tissue sarcoma (STS) and bone sarcoma (BS) in Denmark (DK), Finland (FI), Norway (NO) and Sweden (SE).

METHODS

Relative 1-, 5/1 conditional- and 5-year survival data were obtained from the NORDCAN database for years 1971-20. We additionally estimated annual changes in survival rates and determined significant break points.

RESULTS

In the last period, 2016-20, 5-year survival in STS was best for NO men (74.6%) and FI women (71.1%). For the rarer BS, survival rates for SE men (72.0%) and DK women (71.1%) were best. Survival in BS was lower than that in STS in 1971-75 and the difference remained in 2016-20 for men, but for women the rates were almost equal. Sex- and country-specific differences in survival in STS were small. The 50-year improvement in 5-year survival in STS was highest in NO men, 34.0 % units and FI women, 30.0 % units. The highest improvements in BS were in SE men 26.2 % units and in FI women 29.2 % units.

CONCLUSIONS

The steady development in survival over the half century suggests contribution by stepwise improvements in diagnostics, treatment and care. The 10-15% mortality in the first year probably indicates diagnostic delays which could be improved by organizing patient pathways for aggressive rare diseases. Early diagnosis would also reduce metastatic disease and breakthroughs in treatment are a current challenge.

Machine learning combined with single-cell analysis reveals predictive capacity and immunotherapy response of T cell exhaustion-associated lncRNAs in uterine corpus endometrial carcinoma

BACKGROUND

The exhaustion of T-cells is a primary factor contributing to immune dysfunction in cancer. Long non-coding RNAs (lncRNAs) play a significant role in the advancement, survival, and treatment of Uterine Corpus Endometrial Carcinoma (UCEC). Nevertheless, there has been no investigation into the involvement of lncRNAs associated with T-cell exhaustion (TEXLs) in UCEC. The goal of this work is to establish predictive models for TEXLs in UCEC and study their related immune features.

METHODS

Using transcriptome and single-cell sequencing data from The Cancer Genome Atlas and Gene Expression Omnibus databases, we employed co-expression analysis and univariate Cox regression to identify prognostic-associated TEXLs (pTEXLs). The prognostic model was developed using the Least Absolute Contraction and Selection Operator. The immunotherapy characteristics of the prognostic model risk score were studied. Then molecular subgroups were identified through non-negative Matrix Factorization based on pTEXLs. The identification of co-expressed genes was done using a weighted correlation network analysis. Subsequently, a diagnostic model for UCEC was created. In-depth investigations, both in vitro and in vivo, were carried out to elucidate the molecular mechanism of the key gene within the diagnostic model.

RESULTS

Receiver operating characteristic curve, calibration curve, and decision curve analysis proved the validity of the predictive models established according to pTEXLs. The subgroup with lower risk scores in the prognostic model has better responses to blocking immune checkpoint therapy. Single-cell analysis suggests that the expression level of MIEN1 is relatively high in immune cells among diagnostic genes. Furthermore, the targeted suppression of MIEN1 via sh-MIEN1 diminishes the proliferative, migratory, and invasive capacities of UCEC cells, potentially associated with CD8+ T cell exhaustion.

CONCLUSIONS

The association between TEXLs and UCEC was methodically elucidated by our investigation. A stable pTEXLs risk prediction model and a diagnosis model for UCEC were also established.

CDK4/6-MEK Inhibition in MPNSTs Causes Plasma Cell Infiltration, Sensitization to PD-L1 Blockade, and Tumor Regression

PURPOSE

Malignant peripheral nerve sheath tumors (MPNST) are lethal, Ras-driven sarcomas that lack effective therapies. We investigated effects of targeting cyclin-dependent kinases 4 and 6 (CDK4/6), MEK, and/or programmed death-ligand 1 (PD-L1) in preclinical MPNST models.

EXPERIMENTAL DESIGN

Patient-matched MPNSTs and precursor lesions were examined by FISH, RNA sequencing, IHC, and Connectivity-Map analyses. Antitumor activity of CDK4/6 and MEK inhibitors was measured in MPNST cell lines, patient-derived xenografts (PDX), and de novo mouse MPNSTs, with the latter used to determine anti-PD-L1 response.

RESULTS

Patient tumor analyses identified CDK4/6 and MEK as actionable targets for MPNST therapy. Low-dose combinations of CDK4/6 and MEK inhibitors synergistically reactivated the retinoblastoma (RB1) tumor suppressor, induced cell death, and decreased clonogenic survival of MPNST cells. In immune-deficient mice, dual CDK4/6-MEK inhibition slowed tumor growth in 4 of 5 MPNST PDXs. In immunocompetent mice, combination therapy of de novo MPNSTs caused tumor regression, delayed resistant tumor outgrowth, and improved survival relative to monotherapies. Drug-sensitive tumors that regressed contained plasma cells and increased cytotoxic T cells, whereas drug-resistant tumors adopted an immunosuppressive microenvironment with elevated MHC II-low macrophages and increased tumor cell PD-L1 expression. Excitingly, CDK4/6-MEK inhibition sensitized MPNSTs to anti-PD-L1 immune checkpoint blockade (ICB) with some mice showing complete tumor regression.

CONCLUSIONS

CDK4/6-MEK inhibition induces a novel plasma cell-associated immune response and extended antitumor activity in MPNSTs, which dramatically enhances anti-PD-L1 therapy. These preclinical findings provide strong rationale for clinical translation of CDK4/6-MEK-ICB targeted therapies in MPNST as they may yield sustained antitumor responses and improved patient outcomes.