Clinical outcomes of patients with advanced synovial sarcoma or myxoid/round cell liposarcoma treated at major cancer centers in the United States

Afamitresgene autoleucel for advanced synovial sarcoma and myxoid round cell liposarcoma (SPEARHEAD-1): an international, open-label, phase 2 trial

BACKGROUND

Afamitresgene autoleucel (afami-cel) showed acceptable safety and promising efficacy in a phase 1 trial (NCT03132922). The aim of this study was to further evaluate the efficacy of afami-cel for the treatment of patients with HLA-A*02 and MAGE-A4-expressing advanced synovial sarcoma or myxoid round cell liposarcoma.

METHODS

SPEARHEAD-1 was an open-label, non-randomised, phase 2 trial done across 23 sites in Canada, the USA, and Europe. The trial included three cohorts, of which the main investigational cohort (cohort 1) is reported here. Cohort 1 included patients with HLA-A*02, aged 16-75 years, with metastatic or unresectable synovial sarcoma or myxoid round cell liposarcoma (confirmed by cytogenetics) expressing MAGE-A4, and who had received at least one previous line of anthracycline-containing or ifosfamide-containing chemotherapy. Patients received a single intravenous dose of afami-cel (transduced dose range 1·0 × 109-10·0 × 109 T cells) after lymphodepletion. The primary endpoint was overall response rate in cohort 1, assessed by a masked independent review committee using Response Evaluation Criteria in Solid Tumours (version 1.1) in the modified intention-to-treat population (all patients who received afami-cel). Adverse events, including those of special interest (cytokine release syndrome, prolonged cytopenia, and neurotoxicity), were monitored and are reported for the modified intention-to-treat population. This trial is registered at ClinicalTrials.gov, NCT04044768; recruitment is closed and follow-up is ongoing for cohorts 1 and 2, and recruitment is open for cohort 3.

FINDINGS

Between Dec 17, 2019, and July 27, 2021, 52 patients with cytogenetically confirmed synovial sarcoma (n=44) and myxoid round cell liposarcoma (n=8) were enrolled and received afami-cel in cohort 1. Patients were heavily pre-treated (median three [IQR two to four] previous lines of systemic therapy). Median follow-up time was 32·6 months (IQR 29·4-36·1). Overall response rate was 37% (19 of 52; 95% CI 24-51) overall, 39% (17 of 44; 24-55) for patients with synovial sarcoma, and 25% (two of eight; 3-65) for patients with myxoid round cell liposarcoma. Cytokine release syndrome occurred in 37 (71%) of 52 of patients (one grade 3 event). Cytopenias were the most common grade 3 or worse adverse events (lymphopenia in 50 [96%], neutropenia 44 [85%], leukopenia 42 [81%] of 52 patients). No treatment-related deaths occurred.

INTERPRETATION

Afami-cel treatment resulted in durable responses in heavily pre-treated patients with HLA-A*02 and MAGE-A4-expressing synovial sarcoma. This study shows that T-cell receptor therapy can be used to effectively target solid tumours and provides rationale to expand this approach to other solid malignancies.

FUNDING

Adaptimmune.

Treatment patterns and outcomes in patients with metastatic synovial sarcoma in France, Germany, Italy, Spain and the United Kingdom

Aim: Describing the treatment patterns, outcomes by line of treatment (LOT), and healthcare resource utilization (HCRU) in patients with metastatic synovial sarcoma (mSS). Patients & methods: In this descriptive, non-interventional, retrospective cohort study, physicians from five European countries reported on patients with recent pharmacological treatment for mSS. Results: Among 296 patients with mSS, 86.1, 38.9 and 8.4% received 1 LOT (1L), 2 LOTs (2L) and 3+ LOTs (L3+), respectively. Common regimens were doxorubicin/ifosfamide-based (37.4%) for 1L and trabectedin-based for 2L (29.7%). For 1L, median time to next treatment was 13.1 and 6.0 months for living and deceased patients, respectively. Median OS was 22.0, 6.0 and 4.9 months in all patients, 2L and 3L, respectively. HCRU data showed median one inpatient hospital admission, 3 days in hospital and four outpatient visits yearly. Conclusion: This large-scale study documents high unmet needs in patients previously treated for mSS and for more effective therapies.

Myxoid Liposarcoma: How to Stage and Follow

OPINION STATEMENT

Myxoid liposarcoma (MLPS) is a rare soft tissue sarcoma, with propensity to metastasize to locations such as soft tissue and bone. Thus, whole-body MRI should be a consideration as part of staging for patients with a new diagnosis of MLPS since PET and CT may not identify extrapulmonary disease. Surveillance imaging should be tailored, with consideration of more frequent and longer duration of monitoring for large tumors or tumors with round cell component. This review focuses on studies evaluating imaging in MLPS as well as recent publications on survival and prognostic tools in MLPS.

Treatment patterns and outcomes in metastatic synovial sarcoma: a real-world study in the US oncology network

Aim: To examine and understand patient characteristics, treatment patterns and outcomes for patients with metastatic synovial sarcoma (mSS) treated in a US community setting. Materials & methods: Retrospective observational study in adults with mSS in The US Oncology Network (diagnosed January 2012-December 2018). Results: Of 202 patients diagnosed with synovial sarcoma (SS), 71 had mSS. Of 39 patients with mSS who received first-line (1L) systemic treatment, 25 and 16 continued to 2L and 3L+ treatment, respectively. With each subsequent treatment line, time-to-treatment-discontinuation (1L-3L: 3.9-2.7 months) and time-to-next-treatment (1L-3L: 9.3-4.6 months) decreased. At 1L, median overall survival was 24.5 months. Conclusion: This study highlights the ongoing need for effective therapies for mSS.

Meta-analysis of pazopanib and trabectedin effectiveness in previously treated metastatic synovial sarcoma (second-line setting and beyond)

Background: This study examined the efficacy/effectiveness of pazopanib and trabectedin in previously treated metastatic synovial sarcoma (mSS). Materials & methods: A literature search identified studies (2002-2019) reporting outcomes of pazopanib and trabectedin in previously treated mSS, including median overall survival (mOS) and overall response rate (ORR). A meta-analysis was conducted and sensitivity analyses examined outcomes by agent (pazopanib/trabectedin), study type (clinical trial [CT] or real-world [RW]) and sample size. Results: Sixteen studies were included (pazopanib: n = 7; trabectedin: n = 9). Pooled mOS was 10.4 months and was consistent across agents and in RW and CT (pazopanib: 10.3; trabectedin: 10.4; CT: 10.8; RW: 9.9). ORR results were more variable (pooled ORR: 14.7%). ORR was consistently higher for RW (17.7%) than for CT (9.5%) and for pazopanib (18.9%) compared with trabectedin (12.3%). Conclusion: Poor outcomes across agents and settings highlight a need for novel treatments with improved efficacy. This study serves as a benchmark for efficacy estimates in this rare disease.

Patterns of care and outcomes of 417 patients with METAstatic SYNovial sarcoma (METASYN): real-life data from the French Sarcoma Group (FSG)

Background

Synovial sarcoma (SS) occurs in both adult and pediatric patients. The primary aim of this study is to describe the outcomes, prognostic factors, and treatment of patients with metastatic SS within a nationwide cohort.

Patients and methods

All pediatric and adult patients with metastatic SS are registered in the French Sarcoma Group database. Data were collected from the national database https://conticabase.sarcomabcb.org/ up to March 2020. Descriptive and comparative analyses were conducted using SAS 9.4 and Stata Special Edition 16.1 software.

Results

Between January 1981 and December 2019, 417 patients with metastatic SS from 17 French sarcoma centers were included, including 64 (15.3%) under the age of 26 years. Median age was 42.5 years (range 9-87 years). The metastases were synchronous (cohort 1) or metachronous (cohort 2) in 18.9% (N = 79) and 81.1% (N = 338) patients, respectively. Median overall survival (OS) from the date of metastasis was 22.3 months (95% confidence interval 19.7-24.1 months). First-line chemotherapy without ifosfamide and/or doxorubicin was unfavorable for progression-free survival and OS (P < 0.001). Concerning cohort 1, young age, surgery of the primary tumor, and single metastatic site were independent favorable prognostic factors for OS. In cohort 2, surgery within an expert French Sarcoma Group center, absence of chemotherapy in the perioperative setting, the lungs as a single metastatic site, time to first metastasis >12 months, local therapy, and ifosfamide in the first metastatic line were independent favorable prognostic factors.

Conclusions

The outcome of patients with metastatic SS is influenced by local treatment, management in reference centers, and cytotoxic treatments given in the perioperative and metastatic setting.

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METASYN is the largest retrospective study on metastatic adult and pediatric SS.

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This study confirms that surgery remains the mainstay for improving OS in reference centers.

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METASYN emphasizes the importance of focal treatment of metastases for OS.

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This study offers real-life results in a metastatic setting and is a useful support for developing new strategies.

Phase II Randomized Study of CMB305 and Atezolizumab Compared With Atezolizumab Alone in Soft-Tissue Sarcomas Expressing NY-ESO-1

PURPOSE

CMB305 is a heterologous prime-boost vaccination regimen created to prime NY-ESO-1-specific CD8 T-cell populations and then activate the immune response with a potent TLR-4 agonist. This open-label randomized phase II trial was designed to investigate the efficacy and safety of adding the CMB305 regimen to atezolizumab (anti-programmed death ligand-1 therapy) in comparison with atezolizumab alone in patients with synovial sarcoma or myxoid liposarcoma.

PATIENTS AND METHODS

Patients with locally advanced, relapsed, or metastatic synovial sarcoma or myxoid liposarcoma (any grade) were randomly assigned to receive CMB305 with atezolizumab (experimental arm) or atezolizumab alone (control arm). The primary end points were progression-free survival (PFS) and overall survival (OS) analyzed using the Kaplan-Meier method. Safety and immune responses were assessed.

RESULTS

A total of 89 patients were enrolled; 55.1% had received ≥ 2 prior lines of chemotherapy. Median PFS was 2.6 months and 1.6 months in the combination and control arms, respectively (hazard ratio, 0.9; 95% CI, 0.6 to 1.3). Median OS was 18 months in both treatment arms. Patients treated with combination therapy had a significantly higher rate of treatment-induced NY-ESO-1-specific T cells (P = .01) and NY-ESO-1-specific antibody responses (P < .0001). In a post hoc analysis of all dosed patients, OS was longer (36 months) in the subset who developed anti-NY-ESO-1 T-cell immune response (hazard ratio, 0.3; P = .02).

CONCLUSION

Although the combination of CMB305 and atezolizumab did not result in significant increases in PFS or OS compared with atezolizumab alone, some patients demonstrated evidence of an anti-NY-ESO-1 immune response and appeared to fare better by imaging than those without such an immune response. Combining prime-boost vaccines such as CMB305 with anti-programmed death ligand-1 therapies merits further evaluation in other clinical contexts.

Targeting cancer testis antigens in synovial sarcoma

Synovial sarcoma (SS) is a rare cancer that disproportionately affects children and young adults. Cancer testis antigens (CTAs) are proteins that are expressed early in embryonic development, but generally not expressed in normal tissue. They are aberrantly expressed in many different cancer types and are an attractive therapeutic target for immunotherapies. CTAs are expressed at high levels in SS. This high level of CTA expression makes SS an ideal cancer for treatment strategies aimed at harnessing the immune system to recognize aberrant CTA expression and fight against the cancer. Pivotal clinical trials are now underway, with the potential to dramatically alter the landscape of SS management and treatment from current standards of care. In this review, we describe the rationale for targeting CTAs in SS with a focus on NY-ESO-1 and MAGE-A4, the current state of vaccine and T-cell receptor-based therapies, and consider emerging opportunities for future development.

IL-15 mediated expansion of rare durable memory T cells following adoptive cellular therapy

Background

Synovial sarcoma (SS) and myxoid/round cell liposarcoma (MRCL) are ideal solid tumors for the development of adoptive cellular therapy (ACT) targeting NY-ESO-1, as a high frequency of tumors homogeneously express this cancer-testes antigen. Data from early phase clinical trials have shown antitumor activity after the adoptive transfer of NY-ESO-1–specific T cells. In these studies, persistence of NY-ESO-1 specific T cells is highly correlated with response to ACT, but patients often continue to have detectable transferred cells in their peripheral blood following progression.

Method

We performed a phase I clinical trial evaluating the safety of NY-ESO-1–specific endogenous T cells (ETC) following cyclophosphamide conditioning. Peripheral blood mononuclear cells (PBMCs) from treated patients were evaluated by flow cytometry and gene expression analysis as well as through ex vivo culture assays with and without IL-15.

Results

Four patients were treated in a cohort using ETC targeting NY-ESO-1 following cyclophosphamide conditioning. Treatment was well tolerated without significant toxicity, but all patients ultimately had disease progression. In two of four patients, we obtained post-treatment tumor tissue and in both, NY-ESO-1 antigen was retained despite clear detectable persisting NY-ESO-1–specific T cells in the peripheral blood. Despite a memory phenotype, these persisting cells lacked markers of proliferation or activation. However, in ex vivo culture assays, they could be induced to proliferate and kill tumor using IL-15. These results were also seen in PBMCs from two patients who received gene-engineered T-cell receptor–based products at other centers.

Conclusions

ETC targeting NY-ESO-1 with single-agent cyclophosphamide alone conditioning was well tolerated in patients with SS and those with MRCL. IL-15 can induce proliferation and activity in persisting NY-ESO-1–specific T cells even in patients with disease progression following ACT. These results support future work evaluating whether IL-15 could be incorporated into ACT trials post-infusion or at the time of progression.

Clinical outcomes of patients with advanced synovial sarcoma or myxoid/round cell liposarcoma treated at major cancer centers in the United States

BACKGROUND

Outcomes data regarding advanced synovial sarcoma (SS) and myxoid/round cell liposarcoma (MRCL) are limited, consisting primarily of retrospective series and post hoc analyses of clinical trials.

METHODS

In this multi-center retrospective study, data were abstracted from the medical records of 350 patients from nine sarcoma centers throughout the United States and combined into a registry. Patients with advanced/unresectable or metastatic SS (n = 249) or MRCL (n = 101) who received first-line systemic anticancer therapy and had records of tumor imaging were included. Overall survival (OS), time to next treatment, time to distant metastasis, and progression-free survival (PFS) were evaluated using the Kaplan-Meier method and Cox regression.

RESULTS

At start of first-line systemic anticancer therapy, 92.4% of patients with SS and 91.1% of patients with MRCL had metastatic lesions. However, 74.7% of patients with SS and 72.3% of patients with MRCL had ≥2 lines of systemic therapy. Median OS and median PFS from first-line therapy for SS was 24.7 months (95% CI, 20.9-29.4) and 7.5 months, respectively (95% CI, 6.4-8.4). Median OS and median PFS from start of first-line therapy for MRCL was 29.9 months (95% CI, 27-44.6) and 8.9 months (95% CI 4.5-12.0).

CONCLUSIONS

To the best of our knowledge, this is the largest retrospective study of patients with SS and MRCL. It provides an analysis of real-world clinical outcomes among patients treated at major sarcoma cancer centers and could inform treatment decisions and design of clinical trials. In general, the survival outcomes for this selected population appear more favorable than in published literature.