A phase II study of oraxol in the treatment of unresectable cutaneous angiosarcoma

11517 Background: Oraxol is a combination of oral paclitaxel and a novel oral P-glycoprotein inhibitor, HM30181A. Cutaneous angiosarcomas are highly aggressive malignant tumors with poor prognosis. Currently there is no FDA-approved treatment. Methods: This is an open label study evaluating the activity, safety and tolerability of Oraxol 205mg/m2 administered orally, once daily, for 3 consecutive days per week. Planned treatment is for 25 weeks. Subjects included in this study had not received prior therapy with a taxane and did not have metastatic disease. Tumour response was evaluated at 6 weekly intervals using RECIST and photography. A Simon two stage design was used. Results: 18 of 24 enrolled patients (pts); male/female 11/7; median age 77 years (range 56-93), were evaluable at time of analysis. Subjects were recruited during an 18 month period, from Aug-2018 to Jan-2020. Best objective response rates were: CR 22% (n = 4), PR 11% (n = 2), SD 67% (n = 12), PD 0%. 42% of pts with SD had durability > 13 weeks (range 13-25). Median PFS was 38 weeks. All pts remain alive at time of reporting. Furthermore, 5 pts (28%) who had inoperable lesions were deemed operable after Oraxol and received surgical resection. Oraxol was generally well tolerated. Most common adverse events (AEs) G>3 were: diarrhea (n = 1), fatigue (n = 3), neutropenia (n = 9), leucopenia (n = 5), lymphopenia (n = 5). Serious AEs were G3 pneumonia in 2 subjects and G4 neutropenia in 2 subjects, one of which was febrile. All events fully resolved. Neuropathy was uncommon: n = 2 (G1 = 1 @ day 10, G2 = 1 @ day 64). Dose reductions were recorded in 7 subjects. 2 subjects discontinued treatment due to AEs; both asymptomatic pneumonitis seen on CT, which recovered after discontinuation. Following the initial positive results, the protocol has been amended to change the maximum recruitment of subjects from 25 to 43. Conclusions: Oraxol provides an orally administered treatment option for angiosarcoma, with a high and durable clinical benefit rate (CR + PR+ long SD). It is generally well tolerated even in an older patient population; particularly with respect to the the low incidence of neuropathy compared to IV paclitaxel. Recruitment is ongoing. Clinical trial information: NCT03544567 . [Table: see text]