1135P - Updated results of a phase II study evaluating accelerator-based boron neutron capture therapy (AB-BNCT) with borofalan(10B) (SPM-011) in recurrent squamous cell carcinoma (R-SCC-HN) and recurrent and locally advanced non-SCC (R/LA-nSCC-HN) of the head and neck

Abstract

BackgroundBNCT is a unique cancer treatment technique in which tumor cells are irradiated from the inside with heavy particles produced by 10B(n,α)7Li nuclear transmutation reaction of boron atom and neutron. A next-generation AB-BNCT system that does not require a nuclear reactor has been developed, and it has become possible to perform BNCT in urban hospitals along with stable supply of borofalan (10B) supported by high 10B concentration technology. MethodsIn this world-first, open-label phase II trial of AB-BNCT, patients (pts) with previously irradiated, platinum-resistant R-SCC-HN or with R/LA-nSCC-HN were administered with borofalan(10B) at 200mg/kg/h intravenously for 2hours, followed by neutron irradiation with continuous infusion at 100mg/kg/h. The irradiated dose for tumor was determined passively as a mucosal maximum dose was given 12Gy-Eq. Primary endpoint was objective response rate (ORR) by central review. Updated efficacy and safety analysis are presented here (data cut off: 5 April 2019). ResultsEight R-SCC-HN and thirteen R/LA-nSCC-HN pts were enrolled. All R-SCC-HN pts had prior radiotherapy with a dose of 65.5Gy (range, 59.4–76.0). The tumor minimum dose was 31.0Gy-Eq (range, 16.1–42.6). ORR for all pts were 71.4%, and CR/PR were 50.0%/25.0% in R-SCC-HN and 7.7%/61.5% in R/LA-nSCC-HN. With a median follow up of 21.3 months (range 9.2–30.6), 1-year PFS by investigator review were 70.6%. Other ecacy data are shown in the table. For adverse event, nausea (81%), dysgeusia (71%), acute parotitis (67%) were observed frequently.Table: 1135PTable: 1135PAll (N=21)R-SCC-HN (N=8)R/LA-nSCC-HN (N=13)Overall response rate, n (%) (95% CI)15 (71.4) (47.8–88.8)6 (75) (34.9–96.8)9 (69.2) (38.6–90.9)Disease control rate, n (%) (95% CI)20 (95.2) (76.2–99.9)7 (87.5) (47.3–99.7)13 (100) (79.4–100)Median progression-free survival, monthsNR10.4NR1-y / 2-y progression-free survival rate, %70.6 / 65.530.0 / 15.092.3 / 92.31-y / 2-y overall survival rate, %94.7 / 85.383.3 / 55.6100 / 100NR, Not reached. ConclusionsThese data suggest that AB-BNCT with borofalan(10B) emerges as a promising treatment option for pts with R –SCC- HN or R/LA-nSCC-HN with no other treatment option. Clinical trial identificationJapicCTI-194640. Legal entity responsible for the studySumitomo Heavy Industries, Ltd, Stella Pharma Corporation. FundingFukushima prefectural subsidy for development and testing of global cutting-edge medical devices. DisclosureK. Hirose: Research grant / Funding (self), Travel / Accommodation / Expenses: Sumitomo Heavy Industries, Ltd; Travel / Accommodation / Expenses: Stella Pharma Corporation. K. Ono: Advisory / Consultancy: Stella Pharma Corporation; Advisory / Consultancy: Sumitomo Heavy Industries, Ltd. Y. Takai: Travel / Accommodation / Expenses: Stella Pharma Corporation; Travel / Accommodation / Expenses: Sumitomo Heavy Industries, Ltd. All other authors have declared no conflicts of interest.