(P 335) OUTCOMES OF TALIMOGENE LAHERPAREPVEC IN SOFT TISSUE SARCOMA

Objective: Talimogene laherparepvec (TVEC), an intralesional therapy to illicit an immunogenic anti-tumor response, has a favorable safety profile in phase II trial and may be an effective second-line therapeutic in sarcoma; however, there is a paucity of data on its therapeutic efficacy.  We present a case series of patients who received TVEC for sarcoma at a high-volume sarcoma center.

Methods: A retrospective review of an institutional database for sarcoma patients who received TVEC between January 2018 and January 2025 was performed. We assessed treatment response, adverse events, duration of therapy, and progression-free survival. Response Evaluation Criteria in Solid Tumors v1.1 was used to assess treatment response. A total of 2-4 ml of intra-tumoral TVEC at 100 million plaque-forming units/ml was administered every 2-3 weeks.

Results: A total of four patients who had prior progression of disease on immune checkpoint inhibitors (ICI) received a median of 9.5 (range, 4-15) doses of TVEC over 26.5 (range, 10-49) weeks. One patient with angiosarcoma had a partial response, with a 79% decrease in lesion size after four treatments (Image 1, Panel A: at initial TVEC injection, Panel B: after 9 weeks at fourth TVEC injection), before having distant disease progression at 10 weeks. One patient with alveolar soft part sarcoma had metastatic disease with a good response to ICI but persistent local disease treated with TVEC. The local disease remained stable during 36 weeks of neoadjuvant therapy, with no evidence of recurrence at 33 weeks post-surgery. Two patients, with undifferentiated pleomorphic sarcoma and dedifferentiated chondrosarcoma, had progression of disease at 8 weeks. Only one patient experienced toxicity, which presented as mild flu-like symptoms hours after an injection. Therapy was held in one patient to allow for healing of an open wound that formed due to tumor necrosis. All patients received ICI in combination with TVEC.

Conclusion: This case series of patients receiving TVEC for sarcoma adds to the literature of intralesional therapies for this rare disease. Our experience suggests that TVEC may be administered safely and may provide local tumor control in select patients who have failed prior therapy with ICI.