ABSTRACT:The bioavailability and metabolism of cyclosporine A (CsA) capsules were compared with two bioequivalent (Food and Drug Administration approved) preparations in rats. Two groups of WistarKyoto rats were given 10 mg/kg q.

e23559 Background: Radiation therapy is an essential backbone of the management of patients (pts.) with soft tissue sarcoma (STS) as part of a multimodal curative or palliative treatment. Concurrent external-beam radiation therapy (EBRT) and chemotherapy with doxorubicin (doxo) and ifosfamide (ifo) may be indicated as well, but is associated with relevant toxicity. Gemcitabine (gem) is a known radiosensitizer and has shown activity in STS. The purpose of this study was to evaluate the efficacy and toxicity of concurrent EBRT and gemcitabine. Methods: A single center, retrospective analysis of 12 patients (pts) with STS treated with concurrent EBRT and gemcitabine from Nov 2017 to Dez 2019 in a neoadjuvant (6 pts) or palliative setting (6 pts). Gemcitabine (gem) was administered with 150-300mg/m2 once weekly for the duration of the EBRT (50 Gy in 25 fractions over 5 weeks). In the neoadjuvant treated group, 4 pts had undifferentiated pleomorphic sarcoma (UPS) G3, 1 leiomyosarcoma (LMS) G2 and 1 retroperitoneal G1 liposarcoma (LPS). The pts. were either not eligible for a neoadjuvant systemic treatment with doxo/ifo or received the EBRT/gem treatment in addition to it. Results: 5/6 pts. with neoadjuvant EBRT/gem had R0 resection and 1/6pt. R1. The IUCC stage was IIIB in 5/6 pts and IB in 1/6 pt. The tumor regression grade (TRG) was > 99% in 3/4 pts. with UPS G3 (75%) and 80% in 1/4 pt. with UPS G3. The TRG for the G2 LMS and for the G1 LPS was 20%. All pts treated in palliative setting had high grade sarcoma and responded to the treatment with partial remission, the 6 months’ local control rate was 83% (5/6 pts) for symptomatic fast growing lesions, 1/6 pt. being in PR at 4 months follow up. The combination treatment was well tolerated with reversible skin toxicity CTCAE grade I. As expected transient thrombocytopenia was observed without limiting effect on the planned EBRT. Conclusions: The combination therapy of EBRT and gemcitabine as sensitizer in pts. with STS is feasible und well tolerated. The treatment is an option for patients not eligible for neoadjuvant systemic treatment with doxo/ifo and in the palliative setting as well. It might be more potent than radiation only in achieving tumor regression and local control for high grade STS.