The Efficacy of Orgotein in the Treatment of Acute Toxicity Due to Radiotherapy on Head and Neck Tumors

Phase 1b/2a Trial of the Superoxide Dismutase Mimetic GC4419 to Reduce Chemoradiotherapy-Induced Oral Mucositis in Patients With Oral Cavity or Oropharyngeal Carcinoma

PURPOSE

To assess the safety of the superoxide dismutase mimetic GC4419 in combination with radiation and concurrent cisplatin for patients with oral cavity or oropharyngeal cancer (OCC) and to assess the potential of GC4419 to reduce severe oral mucositis (OM).

PATIENTS AND METHODS

Patients with locally advanced OCC treated with definitive or postoperative intensity modulated radiation therapy (IMRT) plus cisplatin received GC4419 by 60-minute intravenous infusion, ending <60 minutes before IMRT, Monday through Friday for 3 to 7 weeks, in a dose and duration escalation study. Oral mucositis was assessed twice weekly during and weekly after IMRT.

RESULTS

A total of 46 patients received GC4419 in 11 separate dosing and duration cohorts: dose escalation occurred in 5 cohorts receiving 15 to 112 mg/d over 3 weeks (n=20), duration escalation in 3 cohorts receiving 112 mg/d over 4 to 6 weeks (n=12), and then 3 additional cohorts receiving 30 or 90 mg/d over 6 to 7 weeks (n=14). A maximum tolerated dose was not reached. One dose-limiting toxicity (grade 3 gastroenteritis and vomiting with hyponatremia) occurred in each of 2 separate cohorts at 112 mg. Nausea/vomiting and facial paresthesia during infusion seemed to be GC4419 dose-related. Severe OM occurred through 60 Gy in 4 of 14 patients (29%) dosed for 6 to 7 weeks, with median duration of only 2.5 days.

CONCLUSIONS

The safety of GC4419 concurrently with chemoradiation for OCC was acceptable. Toxicities included nausea/vomiting and paresthesia. Doses of 30 and 90 mg/d administered for 7 weeks were selected for further study. In an exploratory analysis, severe OM seemed less frequent and briefer than expected.

Subcutaneous administration of bovine superoxide dismutase protects lungs from radiation-induced lung injury

BACKGROUND

The objective of the present study was to determine whether single administration of the antioxidant enzyme bovine superoxide dismutase (bSOD) after radiation therapy (RT) mitigates development of pulmonary toxicity in rats.

METHODS

Female F344 rats (n = 60) were divided among six experimental groups: (1) RT, single dose of 21 Gy to the right hemithorax; (2) RT + 5 mg/kg bSOD; (3) RT + 15 mg/kg bSOD; (4) No RT; (5) sham RT + 5 mg/kg bSOD; and (6) sham RT + 15 mg/kg bSOD. A single subcutaneous injection of bSOD (5 or 15 mg/kg) was administered 24 h post-radiation. The effects of bSOD on radiation-induced lung injury were assessed by measurement of body weight, breathing frequency, and histopathological changes. Immunohistochemistry was used to evaluate oxidative stress (8-OHdG(+), NOX4(+), nitrotyrosine(+), and 4HNE(+) cells), macrophage activation (ED1(+)), and expression of profibrotic transforming growth factor-β or TGF-β in irradiated tissue.

RESULTS

Radiation led to an increase in all the evaluated parameters. Treatment with 15 mg/kg bSOD significantly decreased levels of all the evaluated parameters including tissue damage and breathing frequency starting 6 weeks post-radiation. Animals treated with 5 mg/kg bSOD trended toward a suppression of radiation-induced lung damage but did not reach statistical significance.

CONCLUSIONS

The single application of bSOD (15 mg/kg) ameliorates radiation-induced lung injury through suppression of reactive oxygen species/reactive nitrogen species or ROS/RNS-dependent tissue damage.

Superoxide dismutase administration, a potential therapy against oxidative stress related diseases: several routes of supplementation and proposal of an original mechanism of action

Oxidative stress, involved in many diseases, is defined as an impaired balance between reactive oxygen species (ROS) production and antioxidant defences. Antioxidant enzymes such as superoxide dismutase (SOD) play a key role in diminishing oxidative stress. Thus, the removal of ROS by exogenous SODs could be an effective preventive strategy against various diseases. The poor bioavailability of exogenous SODs has been criticized. However, improvements in SOD formulation may overcome this limitation and boost interest in its therapeutic properties. Here, we provide a review of animal and human studies about SODs supplementation in order to evaluate their therapeutic value. Protective effects have been observed against irradiation, carcinogenesis, apoptosis and neurodegeneration. SODs administration has also been reported to alleviate inflammatory, infectious, respiratory, metabolic and cardiovascular diseases and genitourinary and fertility disorders, raising the question of its mechanism of action in these diverse situations. Some authors have shown an increase in endogenous antioxidant enzymes after exogenous SODs administration. The induction of endogenous antioxidant defence and, consequently, a decrease in oxidative stress, could explain all the effects observed. Further investigations need to be carried out to test the hypothesis that SODs supplementation acts by inducing an endogenous antioxidant defence.

Systematic review of anti-inflammatory agents for the management of oral mucositis in cancer patients

PURPOSE

The aim of this project was to review the available literature and define clinical practice guidelines for the use of anti-inflammatory agents for the prevention and treatment of oral mucositis in cancer patients.

MATERIALS AND METHODS

A systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology. The body of evidence for use of each intervention, in each cancer treatment setting, was assigned an evidence level. Based on the evidence level, one of the following three guideline determinations was possible: recommendation, suggestion, and no guideline possible.

RESULTS

Forty-one papers were reviewed. There was sufficient evidence to recommend the use of benzydamine mouthwash for the prevention of oral mucositis in head and neck cancer patients receiving moderate-dose radiation therapy (up to 50 Gy), without concomitant chemotherapy. A new suggestion was developed against the use of misoprostol mouthwash for the prevention of oral mucositis in head and neck cancer patients receiving radiation therapy. Positive results were reported for some other anti-inflammatory agents. However, no guidelines were able to be developed for any other agents due to insufficient and/or conflicting evidence.

CONCLUSIONS

The use of anti-inflammatory agents continues to be a promising strategy for the prevention and treatment of oral mucositis. Additional well-designed studies are needed to examine the use of this class of agents for oral mucositis.

Exogenous superoxide dismutase: action on liver oxidative stress in animals with streptozotocin-induced diabetes

Aim. To investigate the effects of exogenous antioxidant copper zinc superoxide dismutase (Cu/Zn SOD) on oxidative stress in the experimental model of diabetes mellitus (DM). Methods. Twenty eight male Wistar rats divided in four groups were used: control (CO), controls treated with SOD (CO + SOD), diabetics (DM), and diabetics treated with SOD (DM + SOD). SOD (orgotein, 13 mg/Kg body weight was administered. DM was induced by a single streptozotocin injection (i.p., 70 mg/kg), and 60 days later, we evaluated liver oxidative stress. Results. Liver lipoperoxidation was increased in the DM group and significantly decreased in the DM + SOD group. Nitrite and nitrate measures were reduced in the DM and increased in the DM + SOD group, while iNOS expression in the DM group was 32% greater than in the CO and 53% greater in the DM + SOD group than in the DM group (P < .01). P65 expression was 37% higher in the DM (P < .05), and there was no significant difference between the DM and DM + SOD groups. Conclusion. SOD treatment reduced liver oxidative stress in diabetic animals, even though it did not change NFκB. SOD also increased NO, probably by the increased dismutation of the superoxide radical. The iNOS expression increase, which became even more evident after SOD administration.

Efficacy of superoxide dismutase mimetic M40403 in attenuating radiation-induced oral mucositis in hamsters

PURPOSE

M40403 is a small-molecule superoxide dismutase mimetic that has shown efficacy in animal model disease states in which superoxide anions are thought to play a key role. Radiation treatment and chemotherapy for cancer generate free oxygen radicals that are hypothesized to trigger unwanted side effects in healthy tissue. For some patients undergoing these antineoplastic treatments, one of the most prevalent side effects is oral mucositis, which is a painful, often dose-limiting condition. Preclinical and clinical studies of this condition have shown the positive effect of treatment with compounds that decrease free oxygen radicals. This study investigated the efficacy M40403 in a clinically relevant hamster model of acute, radiation-induced oral mucositis.

METHODS

Oral mucositis was induced in hamsters by irradiation of the cheek pouch. The ability of i.p. administered M40403 to decrease the duration and severity of oral mucositis was assessed after treatment at different doses and dosing schedules. Oral mucositis was scored using the WHO grading scale.

RESULTS

Compared with placebo-treated animals, those irradiated on day 0 and treated twice daily with 30 mg/kg M40403 had significantly less severe and shorter duration mucositis over a range of treatment schedules, including from days -1 to 3, day 0 to 3, and day 0 alone. Similar efficacy was achieved at doses of 10 and 3 mg/kg twice daily on days -1 to 3.

CONCLUSIONS

These results implicate free oxygen radicals in the onset of oral mucositis and also provide the basis for further development of M40403 in the prevention of this condition in at-risk cancer patients.

Anti-inflammatory agents in the management of alimentary mucositis

BACKGROUND

Alimentary mucositis is a significant complication of cancer therapy, with important clinical and economic implications.

MATERIALS AND METHODS

In June 2005, the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society for Oral Oncology conducted an evidence-based review of the literature on alimentary mucositis. The goal of this literature review was to update previously published guidelines for the management of mucositis.

RESULTS

This article reports the findings of the subgroup charged with reviewing the literature related to anti-inflammatory interventions. Considerable preclinical and clinical evidence suggests that the use of anti-inflammatory agents may be a promising approach to reduce the severity of mucositis. However, there was not enough evidence to support any new guidelines advocating the use of any specific anti-inflammatory intervention.

CONCLUSION

Thus, there is a need for well-designed clinical trials evaluating the use of anti-inflammatory agents in the management of mucositis.

Superoxide dismutase prevents development of adenocarcinoma in a rat model of Barrett's esophagus

AIM

To test whether antioxidant treatment could prevent the progression of Barrett's esophagus to adenocarcinoma.

METHODS

In a rat model of gastroduodenoesophageal reflux by esophagojejunal anastomosis with gastric preservation, groups of 6-10 rats were randomized to receive treatment with superoxide dismutase (SOD) or vehicle and followed up for 4 mo. Rat's esophagus was assessed by histological analysis, superoxide anion and peroxinitrite generation, SOD levels and DNA oxidative damage.

RESULTS

All rats undergoing esophagojejunostomy developed extensive esophageal mucosal ulceration and inflammation by mo 4. The process was associated with a progressive presence of intestinal metaplasia beyond the anastomotic area (9% 1st mo and 50% 4th mo) (94% at the anastomotic level) and adenocarcinoma (11% 1st mo and 60% 4th mo). These changes were associated with superoxide anion and peroxinitrite mucosal generation, an early and significant increase of DNA oxidative damage and a significant decrease in SOD levels (P<0.05). Exogenous administration of SOD decreased mucosal superoxide levels, increased mucosal SOD levels and reduced the risk of developing intestinal metaplasia beyond the anastomotic area (odds ratio = 0.326; 95%CI: 0.108-0.981; P = 0.046), and esophageal adenocarcinoma (odds ratio = 0.243; 95%CI: 0.073-0.804; P = 0.021).

CONCLUSION

Superoxide dismutase prevents the progression of esophagitis to Barrett's esophagus and adenocarcinoma in this rat model of gastrointestinal reflux, supporting a role of antioxidants in the chemoprevention of esophageal adenocarcinoma.

Efficacy of orgotein in prevention of late side effects of pelvic irradiation: a randomized study

PURPOSE

To study whether orgotein is effective in preventing late radiation-induced effects.

METHODS AND MATERIALS

Patients >18 years old who were diagnosed with rectal cancer, had an indication for pelvic irradiation (RT) after surgery, and complied with the selection criteria were randomly assigned at the end of RT to receive orgotein for 7 weeks or no treatment (control). The Radiation Therapy Oncology Group toxicity scale was used to evaluate the RT-induced side effects for up to 2 years. Interruptions due to toxicity, concomitant medication, and non-RT adverse events were also recorded.

RESULTS

A total of 100 patients were included, with 50 in each group. The groups were comparable in terms of the demographic and baseline characteristics. The orgotein group had statistically significant less late toxicity than the control group (p = 0.036) and nontreated patients had a 66% greater chance of developing late toxicity at 2 years. Grouping toxicity as nonrelevant (Radiation Therapy Oncology Group Grade 0-1) and relevant (Grade 2 or worse), patients given orgotein had a lower incidence of late relevant toxicity than did controls, with statistical significance reached at all follow-up visits. After 2 years, patients not treated with orgotein had, in general, a 37% greater chance of developing late relevant toxicity; this risk was 26% when referring specifically to GI toxicity. No adverse events attributable to orgotein were recorded at any time during the study.

CONCLUSION

Orgotein is a safe treatment that significantly prevents the overall occurrence of late toxicity, with toxicity reduction particularly evident in the lower GI tract.