PREVLAR: Phase 2a Randomized Trial to Assess the Safety and Efficacy of RRx-001 in the Attenuation of Oral Mucositis in Patients Receiving Head and Neck Chemoradiotherapy

PURPOSE

No Food and Drug Administration-approved intervention exists for oral mucositis (OM) from chemoradiotherapy (CRT) used to treat head and neck cancers. RRx-001 is a hypoxia-activated, cysteine-directed molecule that affects key pathways involved in OM pathogenesis. This phase 2a, multi-institutional trial was designed to assess the safety and feasibility of 3 schedules of a fixed concentration of RRx-001; a standard-of-care arm was included to identify potential signals of efficacy for further study.

METHODS AND MATERIALS

This study enrolled patients with oral cavity and oropharynx squamous cell carcinoma receiving definitive or postoperative cisplatin-based CRT. Patients were randomized into 4 cohorts. In arms 1 to 3, RRx-001 was coinfused with patients' blood at differing intervals. Arm 4 was a control cohort of patients treated with CRT alone. Trained evaluators assessed OM using a standardized data collection instrument twice weekly during treatment and then until resolution. OM severity was scored centrally using World Health Organization criteria. Safety outcomes were assessed using National Cancer Institute - Common Terminology Criteriav4 benchmarks. Long-term tumor response was defined by Response evaluation criteria in solid tumors v1.1 criteria.

RESULTS

Fifty-three patients were enrolled, with 46 and 45 individuals contributing safety and efficacy data, respectively. There were no severe adverse events attributed to the study drug. Across all 3 active arms, the study drug was infused fully per protocol in 86% of patients. All 3 RRx-001 treatment cohorts appeared to demonstrate a similar or lower OM duration relative to control; arm 1 had the lowest median duration of severe oral mucositis (SOM), 8.5 days versus 24 days in controls among patients who developed at least 1 day of SOM. There were no locoregional failures in any patient.

CONCLUSIONS

Our results support the safety and feasibility of RRx-001 as an intervention to mitigate SOM. Additional studies are planned to confirm its efficacy.

Phase 2 pilot trial of RRx-001 as an anti-mucositis agent in patients with head and neck cancer treated with chemoradiation (PREVLAR)

6078

Background: Severe oral mucositis (SOM) is a dose limiting toxicity during radiotherapy and cisplatin for head and neck cancers. The aim of this 4-arm randomized controlled pilot trial was to evaluate the efficacy of different schedules of a novel radioprotectant, RRx-001 versus standard-of-care (SOC), to reduce duration, time to onset and incidence of SOM in patients received cisplatin-based chemoradiotherapy (CRT) for oral cavity or oropharyngeal cancer (OCC). Methods: Patients with locally advanced OCC treated with definitive or postoperative CRT were randomized to receive RRx-001 by 15-minute intravenous infusion in one of three different schedules versus none. The days and severity of mucositis were prospectively evaluated. Oral mucositis was assessed weekly during and after CRT as well as 28 days after completion. The pre-specified efficacy endpoints were duration of grade 3-4 SOM, resolution of SOM, time to onset of SOM and incidence of SOM. Results: A total of 53 patients were enrolled between June 2018 and July 2019 across 11 institutions. Forty-five (out of 53) patients received study drug and were efficacy evaluable. RRx-001 were well tolerated with no associated serious adverse events. All RRx-001 arms numerically outperformed SOC on the pre-specified efficacy measures, and the greatest effect estimate was observed on Arm 1 (RRx-001 pretreatment only + CRT). The following endpoints favored treatment with RRx-001. Median SOM duration by treatment was 22 and 40 days for Arm 1 and SOC respectively. Time to onset of SOM was by 38 days (Arm 1) vs. 26 days (SOC). On Arm 1, 83% of patients had SOM resolution vs 60% on SOC). Gastrostomy requirement was reduced by 45%. No patients on Arm 1 developed grade 4 mucositis vs 30% developed grade 4 mucositis on the SOC arm. Furthermore, the incidence of oropharyngeal dysphagia, which can substantially impair nutrition, was reduced by treatment with RRx-001, occurring at 50% vs 70% for Arm 1 vs SOC respectively. Treatment with RRx-001 resulted in highly significant decrease in the duration of SOM through 60 Gy with a median SOM of 1 day vs 17 days for Arm 1 vs SOC respectively (Wilcoxon rank-sum test p < 0.001). Median cumulative cisplatin dose was significantly greater for RRx-001 Arm 1 than SOC (557.4 mg vs. 438 mg, Wilcoxon p = 0.025). Conclusions: Compared with SOC, SOM among RRx-001-treated patients given 3 different treatment schedules was less severe, of shorter duration, demonstrated delayed time to onset and resolved earlier. Overall, the incidence, duration and severity of SOM and dysphagia was reduced. The safety profile of RRx-001 was similar to SOC. These results will inform the design of a Phase 3 pivotal study of RRx-001 in the prevention of SOM in at-risk cancer patients. Clinical trial information: NCT03515538.

Results of a randomized, open-label, multicenter trial to assess the safety, dose, and schedule ofRRx-001(001) in reducing incidence, severity and duration of severe oral mucositis (SOM) inpatients receiving concomitant chemoradiation (CRT) for advanced head and neck cancer (HNC)

12081

Background: SOM occurs in 70% of patients receiving CRT for HNC with consequent pain, treatment interruptions and increased costs of care. Supraphysiologic levels of oxidative stress are key SOM initiators. 001 activates nuclear factor erythroid related factor 2 (Nrf2) increasing expression of multiple antioxidant genes including superoxide dismutase glutathione peroxidase and glutathione S-transferase. This trial examined the effect of dose and schedule on safety and efficacy of 001. Primary efficacy endpoint was duration of SOM (WHO criteria assessed); secondary endpoints included time to onset, incidence grade 4 through 60Gy and 70Gy. Methods: Locally advanced HNC treated with definitive or postoperative CRT (cisplatin + RT) received one of 3 001 schedules: (ARM1) 2 doses/wk for 2 weeks (prior to) CRT. ARMS 2, 3: prior to + 2 doses or 6 doses with CRT respectively or standard of care (SOC). Results: 53 patients randomized, 45 evaluable. Benefit trends for endpoints were consistent across all 3 001 arms with greatest effect size in pre-treatment only, ARM1. Compared to SOC, 001 reduced duration of SOM by 45% (40 vs 22 days). Through 60Gy and 70Gy a reduction of 95% and 79% in duration SOM was also observed (17 vs 1 day, and 23 vs 5 days) respectively. No patients in ARM1 developed grade 4, (0% vs SOC 30%). Side effects were comparable to SOC. Conclusions: In this small, open label trial, 001 demonstrated a favorable risk-benefit profile supported by reductions in overall SOM duration including through 60Gy and 70Gy with no grade ARM1 was most effective suggesting short periods of Nrf2 activation before CRT oxidative stress generation may increase the threshold and buffering capacity of upregulated antioxidants. Larger, blinded trials, confirming the observed dose, schedule and treatment effects are warranted. Clinical trial information: NCT03515538 .

Phase IIb, Randomized, Double-Blind Trial of GC4419 Versus Placebo to Reduce Severe Oral Mucositis Due to Concurrent Radiotherapy and Cisplatin For Head and Neck Cancer

PURPOSE

Oral mucositis (OM) remains a common, debilitating toxicity of radiation therapy (RT) for head and neck cancer. The goal of this phase IIb, multi-institutional, randomized, double-blind trial was to compare the efficacy and safety of GC4419, a superoxide dismutase mimetic, with placebo to reduce the duration, incidence, and severity of severe OM (SOM).

PATIENTS AND METHODS

A total of 223 patients (from 44 institutions) with locally advanced oral cavity or oropharynx cancer planned to be treated with definitive or postoperative intensity-modulated RT (IMRT; 60 to 72 Gy [≥ 50 Gy to two or more oral sites]) plus cisplatin (weekly or every 3 weeks) were randomly assigned to receive 30 mg (n = 73) or 90 mg (n = 76) of GC4419 or to receive placebo (n = 74) by 60-minute intravenous administration before each IMRT fraction. WHO grade of OM was assessed biweekly during IMRT and then weekly for up to 8 weeks after IMRT. The primary endpoint was duration of SOM tested for each active dose level versus placebo (intent-to-treat population, two-sided α of .05). The National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.03, was used for adverse event grading.

RESULTS

Baseline patient and tumor characteristics as well as treatment delivery were balanced. With 90 mg GC4419 versus placebo, SOM duration was significantly reduced (P = .024; median, 1.5 v 19 days). SOM incidence (43% v 65%; P = .009) and severity (grade 4 incidence, 16% v 30%; P = .045) also were improved. Intermediate improvements were seen with the 30-mg dose. Safety was comparable across arms, with no significant GC4419-specific toxicity nor increase of known toxicities of IMRT plus cisplatin. The 2-year follow-up for tumor outcomes is ongoing.

CONCLUSION

GC4419 at a dose of 90 mg produced a significant, clinically meaningful reduction of SOM duration, incidence, and severity with acceptable safety. A phase III trial (ROMAN; ClinicalTrials.gov identifier: NCT03689712) has begun.

Radiation-related arterial disease

Arterial occlusive disease has been recognized in association with radiation arteriopathy and, rarely, with spontaneous arterial disruption. This association results from the greater role of radiation therapy in the current management of malignant diseases coupled with longer patient survival and the lengthy latency period between radiation and clinical manifestations of radiation arteriopathy. Experience with six patients having radiation-associated arterial disease was retrospectively reviewed. There were four men and two women, with a mean age of 51 years (range, 36-74). Arteries exposed to radiation include two carotids, three subclavians, one coronary, and one femoral. The time from radiation therapy until clinical arterial disease was a mean of 14.3 years (range, 4-30). Operative repairs with polytetrafluoroethylene and saphenous vein bypass grafts were performed in four patients, stent placement in one patient, and one patient had spontaneous carotid disruption that ultimately was treated with ligation. In conclusion, elective bypass can be performed safely and successfully for arterial occlusive disease in a previously irradiated artery. In contrast, life-threatening arterial disruption secondary to radiation arteriopathy usually requires concomitant exposure to a source of bacterial contamination, and ligation may be the best choice to prevent recurrent hemorrhage.

Radiation-Related Arterial Disease

Arterial occlusive disease has been recognized in association with radiation arteriopathy and, rarely, with spontaneous arterial disruption. This association results from the greater role of radiation therapy in the current management of malignant diseases coupled with longer patient survival and the lengthy latency period between radiation and clinical manifestations of radiation arteriopathy. Experience with six patients having radiation-associated arterial disease was retrospectively reviewed. There were four men and two women, with a mean age of 51 years (range, 36–74). Arteries exposed to radiation include two carotids, three subclavians, one coronary, and one femoral. The time from radiation therapy until clinical arterial disease was a mean of 14.3 years (range, 4–30). Operative repairs with polytetrafluoroethylene and saphenous vein bypass grafts were performed in four patients, stent placement in one patient, and one patient had spontaneous carotid disruption that ultimately was treated with ligation. In conclusion, elective bypass can be performed safely and successfully for aterial occlusive disease in a previously irradiated artery. In contrast, life-threatening arterial disruption secondary to radiation arteriopathy usually requires concomitant exposure to a source of bacterial contamination, and ligation may be the best choice to prevent recurrent hemorrhage.