Structured myeloid cells and anti-angiogenic therapy in alveolar soft part sarcoma

Activity of Pazopanib and Trabectedin in Advanced Alveolar Soft Part Sarcoma

BACKGROUND

Alveolar soft part sarcoma (ASPS) is an exceedingly rare and orphan disease, without active drugs approved in the front line. Pazopanib and trabectedin are licensed for sarcoma treatment from second-line, but very little and contradictory data are available on their activity in ASPS. Lacking ongoing and/or planned clinical trials, we conducted a multi-institutional study involving the reference sites for sarcoma in Europe, U.S., and Japan, within the World Sarcoma Network, to investigate the efficacy of pazopanib and trabectedin.

MATERIALS AND METHODS

From May 2007, 14 of the 27 centers that were asked to retrospectively review their databases had identified 44 advanced ASPS patients treated with pazopanib and/or trabectedin. Response was evaluated by Response Evaluation Criteria in Solid Tumors 1.1. Progression-free survival (PFS) and overall survival (OS) were computed by Kaplan-Meier method.

RESULTS

Among 30 patients who received pazopanib, 18 were pretreated (13 with other antiangiogenics). Response was evaluable in 29/30 patients. Best responses were 1 complete response, 7 partial response (PR), 17 stable disease (SD), and 4 progressions. At a 19-month median follow-up, median PFS was 13.6 months (range: 1.6-32.2+), with 59% of patients progression-free at 1 year. Median OS was not reached.Among 23 patients treated with trabectedin, all were pretreated and evaluable for response. Best responses were 1 PR, 13 SD, and 9 progressions. At a 27-month median follow-up, median PFS was 3.7 months (range: 0.7-109), with 13% of patients progression-free at 1 year. Median OS was 9.1 months.

CONCLUSION

The value of pazopanib in advanced ASPS is confirmed, with durable responses, whereas the value of trabectedin appears limited. These results are relevant to defining the best approach to advanced ASPS.

IMPLICATIONS FOR PRACTICE

This retrospective study, conducted among the world reference centers for treatment of sarcoma, confirms the value of pazopanib in patients with advanced alveolar soft part sarcoma (ASPS), with dimensional and durable responses, whereas trabectedin shows a limited activity. Alveolar soft part sarcoma is resistant to conventional cytotoxic chemotherapy. Pazopanib and trabectedin are licensed for treatment of sarcoma from second line; in the lack of prospective clinical trials, these results are relevant to defining ASPS best management and strongly support initiatives aimed at obtaining the approval of pazopanib in the front line of the disease.

Frequent expression of human leukocyte antigen class I and the status of intratumoral immune cells in alveolar soft part sarcoma

The prognosis of alveolar soft part sarcoma is poor, despite the slow growth of the tumor. A number of cases with spontaneous regression of this rare tumor have been reported. Although the mechanisms underlying spontaneous regression remain uncertain, local immune reaction may be a possible contributing factor. Immunohistochemical expression of human leukocyte antigen (HLA) class I, cluster of differentiation (CD) 3, CD4, CD8, CD20, CD45, CD56, CD68, CD138 and CD163 were assessed in a series of 10 alveolar soft part sarcomas, and the expression profiles were associated with patients' clinicopathological parameters. Expression of HLA class I was observed in almost all the tumor cells of all cases. CD8(+) cells were identified in all tumors with varying densities. Moderate infiltration of CD8(+) cells was detected in three patients; one of these patients survived with long-term tumor remission. Infiltration of CD10(+), CD20(+), CD56(+) or CD138(+) cells was not revealed in all tumors. Moderate-diffuse infiltration of CD163(+) cells was observed in all tumors. To the best of our knowledge, the present study represents the first report of intratumoral immune cells in alveolar soft part sarcoma. Frequent expression of HLA class I in tumor cells was observed. CD8(+) cells were identified at various densities and CD163(+) cells were observed in alveolar soft part sarcoma. Moderate infiltration of CD8(+) cells in patients with a good prognosis may indicate the antitumor effects of immune cells in alveolar soft part sarcoma.

Biologic Activity of Autologous, Granulocyte-Macrophage Colony-Stimulating Factor Secreting Alveolar Soft-Part Sarcoma and Clear Cell Sarcoma Vaccines

PURPOSE

Alveolar soft-part sarcoma (ASPS) and clear cell sarcoma (CCS) are rare mesenchymal malignancies driven by chromosomal translocations that activate members of the microphthalmia transcription factor (MITF) family. However, in contrast to malignant melanoma, little is known about their immunogenicity. To learn more about the host response to ASPS and CCS, we conducted a phase I clinical trial of vaccination with irradiated, autologous sarcoma cells engineered by adenoviral-mediated gene transfer to secrete granulocyte-macrophage colony-stimulating factor (GM-CSF).

EXPERIMENTAL DESIGN

Metastatic tumors from ASPS and CCS patients were resected, processed to single-cell suspensions, transduced with a replication-defective adenoviral vector encoding GM-CSF, and irradiated. Immunizations were administered subcutaneously and intradermally weekly three times and then every other week.

RESULTS

Vaccines were successfully manufactured for 11 of the 12 enrolled patients. Eleven subjects received from three to 13 immunizations. Toxicities were restricted to grade 1-2 skin reactions at inoculation sites. Vaccination elicited local dendritic cell infiltrates and stimulated T cell-mediated delayed-type hypersensitivity reactions to irradiated, autologous tumor cells. Antibody responses to tissue-type plasminogen activator (tTPA) and angiopoietins-1/2 were detected. Tumor biopsies showed programmed death-1 (PD-1)-positive CD8(+) T cells in association with PD ligand-1 (PD-L1)-expressing sarcoma cells. No tumor regressions were observed.

CONCLUSIONS

Vaccination with irradiated, GM-CSF-secreting autologous sarcoma cell vaccines is feasible, safe, and biologically active. Concurrent targeting of angiogenic cytokines and antagonism of the PD-1-negative regulatory pathway might intensify immune-mediated tumor destruction.

Modulation of the myeloid compartment of the immune system by angiogenic- and kinase inhibitor-targeted anti-cancer therapies

Targeted therapies were rationally designed to inhibit molecular pathways in tumor cells critically involved in growth and survival; however, many drugs used in targeted therapies may affect the immune system. In addition, selected conventional chemotherapeutic agents have also been reported to be endowed with direct or indirect effects on immunity, for instance via immunogenic death of tumors. Thus, cancer therapies may have off-target effects, some of which are directed to the immune system. Here, we will review some of these effects in specific therapeutic approaches. We will examine the modulation of the immune contexture in human sarcoma and melanoma induced by anti-angiogenic therapies and by BRAF inhibitors, respectively. We will then discuss how the anti-tumor agent trabectedin is selectively cytotoxic to cells of the monocytic-macrophage lineage and how these immune-related effects can be part of the response to treatment.