ROMAN: Reduction in oral mucositis with avasopasem manganese (GC4419)–Phase III trial in patients receiving chemoradiotherapy for locally advanced, nonmetastatic head and neck cancer

TPS6596

Background: Approximately 70% of patients receiving intensity-modulated radiotherapy (IMRT) plus cisplatin for locally advanced head and neck cancer (HNC) develop SOM, defined as WHO Grade 3 or 4, which limits patients' ability to eat solids (Gr 3) or liquids (Gr 4, requiring enteral nutrition). An RT-induced burst of superoxide initiates oral mucositis (OM) development. GC4419, a superoxide dismutase mimetic, interrupts this process by converting superoxide to H2O2. It showed promising reduction of SOM in a published open-label Phase 1b/2a trial (IJROBP 1 Feb 2018). In a subsequent randomized, double-blind placebo-controlled trial in 223 patients receiving IMRT/cisplatin for HNC (ASCO 2018), 90 mg of GC4419 administered M-F prior to IMRT demonstrated statistically significant reduction in SOM duration (p=0.024, median 1.5 days @ 90 mg vs. 19 days placebo) and meaningful reductions @ 90 mg in SOM incidence (43% vs. 65%) and severity (incidence of Grade 4, 16% vs. 30%). The safety results were acceptable and consistent with the known toxicities of IMRT/cisplatin. Methods: 335 patients at multiple centers in the U.S. and Canada with locally-advanced, nonmetastatic head and neck cancer (oral cavity/oropharyngeal) receiving 70 Gy IMRT (>50 Gy to > 2 oral sites) plus cisplatin (40 mg/m2 qwk x 6-7, or 100 mg/m2 q3wk x 3) are being randomized (double-blinded) 3:2 to 90 mg of GC4419 or placebo, M-F before each RT fraction. Enrollment is stratified by cisplatin schedule and treatment setting (definitive vs. post-op). OM by the WHO scale will be assessed twice weekly during RT & weekly for 2 weeks post RT. The primary efficacy endpoint is incidence of SOM through the end of IMRT. Secondary efficacy endpoints include severity (incidence of Grade 4 OM through the end of IMRT), & days of SOM (days from first to last SOM for all patients, with patients never developing SOM having 0 days of SOM by definition). Days of SOM for the subset developing SOM will be analyzed descriptively. Patients will be followed for one year post IMRT for tumor progression/recurrence and for two years for survival. Clinical trial information: NCT03689712 .

Roman: Reduction in oral mucositis with avasopasem manganese (GC4419)—Phase 3 trial in patients receiving chemoradiotherapy for locally-advanced, non-metastatic head and neck cancer

TPS6096

Background: Approximately 70% of patients receiving intensity-modulated radiotherapy (IMRT) plus cisplatin for locally advanced head and neck cancer (HNC) develop SOM, defined as WHO Grade 3 or 4, which limits patients' ability to eat solids (Gr 3) or liquids (Gr 4, requiring enteral nutrition). An RT-induced burst of superoxide initiates oral mucositis (OM) development. GC4419, a superoxide dismutase mimetic, interrupts this process by converting superoxide to H2O2. It showed promising reduction of SOM in a published open-label Phase 1b/2a trial (IJROBP 1 Feb 2018). In a subsequent randomized, double-blind placebo-controlled trial in 223 patients receiving IMRT/cisplatin for HNC (ASCO 2018), 90 mg of GC4419 administered M-F prior to IMRT demonstrated statistically significant reduction in SOM duration (p=0.024, median 1.5 days @ 90 mg vs 19 days placebo) and meaningful reductions @ 90 mg in SOM incidence (43% vs 65%) and severity (incidence of Grade 4, 16% vs 30%). The safety profile was acceptable and consistent with the known toxicities of IMRT/cisplatin. Methods: 335 patients at multiple centers in the U.S. and Canada with locally-advanced, nonmetastatic head and neck cancer (oral cavity/oropharyngeal) receiving 70 Gy IMRT (>50 Gy to > 2 oral sites) plus cisplatin (40 mg/m2 qwk x 6-7, or 100 mg/m2 q3wk x 3) are being randomized (double-blinded) 3:2 to 90 mg of GC4419 or placebo, M-F before each RT fraction. Enrollment is stratified by cisplatin schedule and treatment setting (definitive vs post-op). OM by the WHO scale will be assessed twice weekly during RT & weekly for 2 weeks post RT. The primary efficacy endpoint is incidence of SOM through the end of IMRT. Secondary efficacy endpoints include severity (incidence of Grade 4 OM through the end of IMRT), & days of SOM (days from first to last SOM for all patients, with patients never developing SOM having 0 days of SOM by definition). Days of SOM for the subset developing SOM will be analyzed descriptively. Patients will be followed for one year post IMRT for tumor progression/recurrence and for two years for survival. Supported by Galera Therapeutics, Inc. Clinical trial information: NCT03689712.

CLO19-037: Reducing the Duration, Incidence and Severity of Mucosal Injury Due to Cancer Radiation therapy (RT); Positive Randomized Phase 2b Trial Results With GC4419 (Avasopasem Manganese), a Small Molecule Superoxide (SO) Dismutase (SOD) Mimetic

Introduction: RT-induced SO contributes to initiation of mucosal injury; eg, oral mucositis (OM) and esophagitis. GC4419 specifically mimics SOD’s dismutation of SO to hydrogen peroxide (H2O2), interdicting OM initiation. GC4419 reduced RT-severe OM (SOM) in a hamster cheek pouch model, and protected mucosa and other normal tissues from radiation-induced injury in other animal models. In a published phase 1b/2a open-label trial (Anderson et al, IJROBP, 1 Feb 2018), GC4419 attenuated SOM in patients (Pts) receiving intensity-modulated RT (IMRT) plus concurrent cisplatin (CDDP) for locally advanced head & neck cancer (HNC). Objectives: Determine whether GC4419 reduces duration, incidence, & severity of SOM. Methods: Pts with locally advanced oral cavity or oropharyngeal cancer; definitive or postoperative intensity-modulated (IM)RT (approximately 70 Gy [>50 Gy to > 2 oral sites]) plus CDDP (weekly or q3wk) were randomized (stratification: tumor HPV status, CDDP schedule) to 30 or 90 mg of GC4419, or placebo (PBO), 60-minute IV infusion, M–F, ending <60 minutes before IMRT delivered in 35 fractions over 7 weeks. WHO grade OM was assessed by trained evaluators biw during IMRT & qwk for up to 8 wks after IMRT. Primary endpoint: duration of SOM. Efficacy was tested for each active dose vs PBO (ITT population) by a sequential, conditional approach (2-sided alpha, 0.05). Results: 223 pts (44 sites): 90 mg (n=76), 30 mg (n=73), or PBO (n=74). Baseline patient and tumor characteristics and treatment delivery were balanced. Efficacy: At 90 mg GC4419 vs PBO, duration of SOM was significantly reduced (median, 1.5 vs 19 d; P=.024). SOM incidence (43% vs 65%; P=.009), and grade 4 incidence (16% vs 30%; P=.045) also improved. There were intermediate improvements with 30 mg. Safety was comparable across arms; no significant GC4419-specific toxicity; other known toxicities of IMRT/CDDP were not increased. Conclusions: GC4419 demonstrated a significant, clinically meaningful reduction of SOM duration, and dose-dependent improvements in other SOM parameters, with acceptable safety. A confirmatory phase 3 trial (NCT03689712) is in progress. Clinical trials to reduce RT-related esophagitis are also planned.