A Phase 1-2 Trial of Concurrent Radiation Therapy, Cisplatin and BMX-001 in Locally Advanced Head and Neck Cancer

Abstract

<h3>Purpose/Objective(s)</h3> Prevention/mitigation of oral mucositis (OM) and xerostomia are challenges to the use of chemoradiation (CRT) for advanced head and neck squamous ca (HNSCC). MnTnBuOE-2-PyP5⁺(BMX-001) is a lipophilic manganese metalloporphyrin superoxide dismutase mimic that protects against radiation and chemotherapy induced OM in orthotopic animal tumor models. This study objective was to determine the toxicity profile of BMX-001 given during CRT for locally advanced HNSCC and to measure the incidence of severe (CTCAE v 4.03 grade 3-4) OM and xerostomia. <h3>Materials/Methods</h3> Multi-center prospective phase 1-2 open label trial for patients with AJCC 7 stage III/IVB HNSCC undergoing concurrent RT/cisplatin, curative (70 Gy) or post-op (60-66 Gy). BMX-001 was administered subcutaneously 2x/week during CRT with an initial loading dose given up to 4 days prior to the start of CRT. Two additional doses of BMX-001 were given in the first week post-CRT. A 3+3 design was used. BMX-001 dose levels were 1: 7 mg load/3.5 mg maintenance; 2: 14 mg load/ 7mg maintenance; 3: 28 mg load/ 14 mg maintenance. Level 3 was expanded to assess phase 2 endpoints. Co-primary endpoints: toxicity of BMX-001 and the incidence of severe (grade 3-4) OM. OM was evaluated 2x/week during CRT and then weekly for 4 additional weeks. Secondary endpoints: median duration and time to onset of grade 3-4 OM, grade ≥2 xerostomia 1- and 6-months post-CRT, and progression-free survival (PFS). <h3>Results</h3> A total of 29 patients (M:F = 25:4) were enrolled from 5/2017-12/2019. Primary sites: p16+ oropharynx 25 (86%), nasopharynx (1), hard palate (1), unknown primary (2). Median age: 62 yo (IQR:56-67). Dose levels were 1 (3); 2 (3); dose 3 (23). Median RT dose: 70 Gy (IQR 70-70). 79.3% of subjects received > 200mg/m² of CDDP. All subjects on levels 1 and 2 received all BMX-001 as prescribed by protocol. Level 3, 19/23 (83%) received all doses of BMX-001. All patients had a grade 1 injection site reaction. There were 2 (7%) mild AEs related to QT interval prolongation and 3 serious adverse events (SAE) categorized as possibly related to BMX-001: hypotension, fever with pancytopenia, and hyponatremia. Other SAEs (n = 19) were judged to be expected due to the nature of the disease or treatment with CRT. Incidence of severe OM was 41% (median duration 25 days, IQR 25-47). Median time to onset of severe OM was 43 (IQR 34-52) days; 83.3% cases of severe OM resolved by 5 weeks post-CRT. Incidence of grade ≥ 2 xerostomia was 18%, 8%, and 9% at 1, 6, and 12 months respectively post-CRT. Mean unstimulated whole saliva production was 0.69 ml/min at baseline and 0.29 ml/min at 1 yr. Mean stimulated whole saliva production was 1.38 ml/min at baseline and 0.72ml/min at 1 yr. Median follow up was 20 mo. 1 yr PFS was 96.6%. <h3>Conclusion</h3> CRT and 2x/week BMX-001 was safe in HNSCC at the highest dose tested. Promising rates of severe OM and xerostomia justify further investigation in HNSCC patients receiving CRT.