Use of immunotherapy with check point inhibitors in soft tissue sarcoma: Analysis from single institution.

person Pranali Santhoshini Pachika University of Louisville, Louisville, KY info_outline Pranali Santhoshini Pachika, Shreyas Kalantri, Rohit Kumar

Authors person Pranali Santhoshini Pachika University of Louisville, Louisville, KY info_outline Pranali Santhoshini Pachika, Shreyas Kalantri, Rohit Kumar Organizations University of Louisville, Louisville, KY, James Graham Brown Cancer Center, University of Louisville, Louisville, KY Abstract Disclosures Research Funding No funding sources reported Background: Traditional treatments for soft tissue sarcomas include surgery, chemotherapy, and radiation. Effectiveness of Check point inhibitors for sarcoma has been unsatisfactory thus far. Major clinical trials PEMBROSARC and SARC028 revealed median PFS of 2 and 4.5 months, respectively. The FDA has approved three immunotherapy (IO) therapies for sarcoma. Atezolizumab was approved for alveolar soft part sarcoma. Dostarlimab is approved for sarcoma with DNA mismatch repair deficiency (dMMR), Sarcoma patients with high microsatellite instability (MSI-H), dMMR, or tumor mutational burden can receive pembrolizumab. A single-institution analysis of soft tissue sarcoma patients with IO is presented in this paper. Methods: All soft tissue sarcoma patients who have received IO from January 2021 to now have been included. At our institute, a total of seven patients received IO for soft tissue sarcoma. Observations were made regarding their fundamental characteristics and the progression free survival (PFS). The data was not statistically examined due to the small sample size and the heterogeneity of the data. Results: 2 of 7 trial patients were lost to follow-up. Recurrent autoimmune hepatitis terminated IO for another patient. Most of the patients are elderly with the median age of 78. Given their comorbidities and age, IO was chosen as the first line for 5 patients. Median PFS was 5.8 months. High PDL1 ( > / = 5%) patients had a median PFS of 5.6 months, while low PDL1 patients had 4.5 months. However, one patient with low PDL1 had PFS of 7 months. 5/7 patients didn’t have IO related side effects. Two patients developed Autoimmune (AI) hepatitis. Conclusions: The limited sample size prevented definitive conclusions from being drawn. Despite the unsatisfactory outcomes, it is worth mentioning that IO provided a certain degree of PFS in older patients with comorbidities who are not suitable candidates for chemotherapy. Based on limited data, patients with high PDL1 status appear to benefit more. IO alone has not shown promising results. In clinical trials, IO is being tested with chemotherapy and Tyrosine kinase inhibitors. The findings from these trials will provide valuable insights into the potential benefits of combination therapy. Age Sex Type of sarcoma Immunotherapy Line of therapy TMB PDL1 Prior lines of therapy Progression free survival in months 86 M Myxofibrosarcoma Pembrolizumab 1 - 5% 0 5 64 M Myxofibrosarcoma Pembrolizumab 2 5 0% 1(Adriamycin+ifosfamide+ Mesna) 7 76 F Leiomyosarcoma Pembrolizumab 2 1 0% 2(Doxorubicin/dacarbazine and Gemzar/docetaxel) 2 86 F Myxoid spindle cell Pembrolizumab 0 2 5% 0 10 77 F Liposarcoma Ipilimumab/Nivolumab 0 1 0% 0 Patient lost follow up after 1 month 85 M Myxofibrosarcoma Nivolumab Stopped after 4 cycles because of recurrent AI hepatitis 0 3 100% 0 5 74 F Liposarcoma Ipilimumab/Nivolumab 0 1 1% 0 Patient lost to follow up after 1 cycle