Interim analysis of a randomized trial of radiation therapy of rectal cancer with/without WR-2721

Amifostine-Loaded Nanocarrier Traverses the Blood-Brain Barrier and Prevents Radiation-Induced Brain Injury

Radiation-induced brain injury (RIBI) is a severe, irreversible, or even life-threatening cerebral complication of radiotherapy in patients with head and neck tumors, and there is no satisfying prevention and effective treatment available for these patients. Amifostine (AMF) is a well-known free radical scavenger with demonstrated effectiveness in preventing radiation-induced toxicity. However, the limited permeability of AMF across the blood-brain barrier (BBB) when administered intravenously reduces the effectiveness of AMF in preventing RIBI. Herein, we construct a nanoparticle (NP) platform for BBB delivery of AMF. AMF is conjugated with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-n-[poly(ethylene glycol)]-hydroxy succinamide [DSPE-PEG-NHS, PEG M 2000], and the product is DSPE-PEG-AMF. Then, the nanoparticles (DAPP NPs) were formed by self-assembly of poly(lactic-co-glycolic acid) (PLGA), DSPE-PEG-AMF, and polysorbate 80 (PS 80). PEG shields the nanoparticles from blood clearance by the reticuloendothelial system and lengthens the drug circulation time. PS 80 is used to encapsulate nanoparticles for medication delivery to the brain. The results of our study showed that DAPP NPs were able to effectively penetrate the blood-brain barrier (BBB) in healthy C57BL/6 mice. Furthermore, in a well-established mouse model of X-knife-induced brain injury, treatment with DAPP NPs (corresponding to 250 mg/kg AMF) was found to significantly reduce the volume of brain necrosis compared to mice treated with AMF (250 mg/kg). Importantly, the use of DAPP NPs was also shown to significantly mitigate the effects of radiation-induced neuronal damage and glial activation. This work presents a convenient brain-targeted AMF delivery system to achieve effective radioprotection for the brain, providing a promising strategy with tremendous clinical translation potential.

Use of Amifostine for Cytoprotection during Radiation Therapy: A Review

BACKGROUND

Radiation therapy is a cornerstone of the therapeutic modalities used in modern oncology. However, it is sometimes limited in its ability to achieve optimal tumor control by radiation-induced normal tissue toxicity. In delivering radiation therapy, a balance must be achieved between maximizing the dose to the tumor and minimizing any injury to the normal tissues. Amifostine was the first Food and Drug Administration (FDA)-approved clinical radiation protector intended to reduce the impact of radiation on normal tissue, lessening its toxicity and potentially allowing for increased tumor dose/control. Despite being FDA-approved almost 20 years ago, Amifostine has yet to achieve widespread clinical use.

SUMMARY

A thorough review of Amifostine's development, mechanism of action, and current clinical status were conducted. A brief history of Amifostine is given, from its development at Walter Reid Institute of Research to its approval for clinical use. The mechanism of action of Amifostine is explored. The results of a complete literature review of all prospective randomized trials to date involving the use of Amifostine in radiation therapy are presented. The results are arranged by treatment site and salient findings discussed. Side effects and complications to consider in using Amifostine are reviewed. Key Messages: Amifostine has been explored as a radiation protectant in most radiation treatment sites. Studies have demonstrated efficacy of Amifostine in all treatment sites reviewed, but results are heterogeneous. The heterogeneity of studies looking at Amifostine as a clinical radiation protectant has precluded a definitive answer on its efficacy. Complicating its clinical use is its toxicity and delivery requirements. Amifostine has largely fallen out of use with the advent of intensity modulated radiation therapy (IMRT). However, side effects with IMRT remain a challenge and concern. The use of Amifostine in the IMRT era has been poorly explored and is worthy of future study.

Amifostine- and chemoradiotherapy-related esophagitis in small cell lung cancer: a single institutional series and literature update

Objectives

Concurrent chemoradiotherapy is considered a standard option for patients with stage 3 small cell lung carcinoma. A 25% risk of acute esophagitis is experienced by patients as a result of the volume of esophagus encompassed within a conformal radiotherapy technique. We reviewed our institutional experience administering the radioprotectant amifostine prior to daily radiotherapy to determine its effects on the onset of esophagitis.

Materials and methods

From 2005 to 2016, 49 patients diagnosed with stage 3 small cell lung carcinoma received concurrent chemoradiotherapy. Chemotherapy (CT) consisted of cisplatin and etoposide with radiotherapy (RT) encompassing CT-identified gross tumor volume. In 32 patients (group 1), amifostine was delivered (500 mg subcutaneously divided in two injections) prior to the second daily RT fraction. The remaining 17 patients (group 2) did not receive amifostine due to choice or drug intolerance.

Results

Metrics of esophagitis included weight loss and opiate requirement during treatment. About 31% of group 1 required opiates at a median RT dose of 3300 cGy, and 41% of group 2 required opiates at a median dose of 2250 cGy. The dose of radiotherapy delivered to 50% of the esophageal volume for group 1 was significantly greater than that in group 2 (3000 cGy vs 576 cGy).

Conclusion

In this modern retrospective series of thoracic chemoradiotherapy in the treatment of stage 3 small cell lung cancer, amifostine that was delivered subcutaneously postponed the onset of esophagitis.

Radioprotective effect of calcium channel blockers against late rectal bleeding in prostate cancer

OBJECTIVE

This study was done to assess the impact of clinical factors and in particular the use of drugs for concomitant illnesses on late radiation-induced rectal bleeding in patients with prostate cancer.

MATERIALS AND METHODS

Patients with histologically proven prostate adenocarcinoma treated with radical radiotherapy and followed up for at least 6 months were selected. The correlation between late rectal bleeding and a number of factors was investigated by univariate and multivariate analysis.

RESULTS

A total of 278 patients who underwent radiotherapy at our institution between October 2002 and May 2011 were selected. At univariate analysis, delivery of radiation doses higher than 70 Gy and use of angiotensin-converting enzyme inhibitors were associated with a higher incidence of rectal bleeding. Conversely, patients who used calcium channel blockers had a lower risk (3-year rectal bleeding-free survival 89.8 versus 66.5 %, p = 0.043). At multivariate analysis, use of calcium channel blockers was found to have a protective effect with a hazard ratio of 0.3 (95 % CI 0.12-0.96). Delivery of higher radiation doses was associated with an increased risk of rectal bleeding (hazard ratio 3.02, 95 % CI 1.23-7.38).

CONCLUSIONS

Use of calcium channel blockers during and after radiotherapy treatment might have a protective effect against late rectal bleeding. If these results are reconfirmed by larger clinical series, calcium channel blockers may be tested as radioprotector agents in clinical trials.

Effect of amifostine on survival among patients treated with radiotherapy: a meta-analysis of individual patient data

PURPOSE

Controversy exists regarding whether or not amifostine might reduce the efficacy of cancer treatment. The aim of this meta-analysis was to evaluate the impact of amifostine on overall survival (OS) and progression-free survival (PFS) in patients treated with radiotherapy or chemoradiotherapy.

MATERIAL AND METHODS

Updated data from individual patients with non-small-cell lung cancer, head and neck squamous cell carcinoma, and pelvic cancer treated with radiotherapy or chemoradiotherapy and randomly assigned to amifostine or not were included. The primary end point was OS.

RESULTS

Twenty-two randomized trials (2279 patients) were potentially eligible. Data were available for 16 trials (1554 patients), but four trials (435 patients) were excluded after data checking. Ultimately 12 trials and 1119 patients were analyzed. A total of 431 patients were treated with radiotherapy alone (three trials), and 688 patients were treated with chemoradiotherapy (nine trials). Thirty-three percent of patients had lung cancers, 65% had head and neck cancers, and 2% had pelvic carcinomas. Ninety-one percent of patients had locally advanced disease (early stage, 9%). Median follow-up was 5.2 years. The hazard ratio (HR) of death was 0.98 (95% CI, 0.84 to 1.14; P = .78). On the basis of 11 trials (1091 patients), the HR of progression, relapse, or death was 1.05 (95% CI, 0.90 to 1.22; P = .53). The tests for heterogeneity were not significant (P ≥ .73), and there was no significant variation of treatment effect according to sex, age, tumor site, stage, histology, locoregional treatment, or type of administration for either end point.

CONCLUSION

Amifostine did not reduce OS and PFS in patients treated with radiotherapy or chemoradiotherapy.

Randomized phase II exploratory study of prophylactic amifostine in cancer patients who receive radical radiotherapy to the pelvis

BACKGROUND

This study aimed to investigate the efficacy of prophylactic amifostine in reducing the risk of severe radiation colitis in cancer patients receiving radical radiotherapy to the pelvis.

METHODS

Patients with pelvic tumours referred for radical radiotherapy who consented participation in this trial, were randomly assigned to receive daily amifostine (A) (subcutaneously, 500 mg flat dose) before radiotherapy or radiotherapy alone (R). Sigmoidoscopy and blinded biopsies were scheduled to conduct prior to initiation and following completion of radiotherapy and again 6 to 9 months later. Radiation colitis was assessed by clinical, endoscopic and histolopathological criteria.

RESULTS

A total 44 patients were enrolled in this trial, the majority with rectal (20 patients) and cervical cancer (12 patients) and were assigned 23 in R arm and 21 in the A arm. In total 119 sigmoidoscopies were performed and 18 patients (18/44, 40.9%) were diagnosed with radiation colitis (15 grade 1 and 2, and 3 grade 3 and 4). Of them, 6 patients belonged to the A group (6/21, 28.6%) and 12 to the R group (12/23, 52.2%). Acute and grade IV radiation colitis was only developed in four patients (17.4%) in the R group. Amifostine side effects were mild. Amifostine treated patients were less likely to develop histologically detectable mucosal lesions, which indicate protection from acute mucosal injury.

CONCLUSIONS

Amifostine given subcutaneously can lower the risk of acute severe radiation colitis in patients who receive radical radiotherapy to pelvic tumors.

The role of amifostine on late normal tissue damage induced by pelvic radiotherapy with concomitant gemcitabine: an in vivo study

In this in vivo study, we aimed to assess the radioprotective effect of amifostine on late normal tissue damage induced by gemcitabine concomitant with pelvic radiotherapy by histopathological and quantitative methods. Fifty-six male Wistar albino rats were randomly divided into seven experimental groups as follows: (I) gemcitabine, (II) radiation + gemcitabine, (III) radiation + gemcitabine + amifostine, (IV) radiation + amifostine, (V) sham radiation, (VI) amifostine, (VII) radiation. Irradiation was given to pelvic region with a dose of 25 Gy in 5 fractions. Amifostine was given for 30 min; gemcitabine was administered 24 h before the first fraction of radiotherapy. All animals were killed at the end of 4th month. Pathological examination was performed and the tissue collagen content was measured in bladder and rectal tissues. Fifty-one animals that were alive at the end of the follow-up period were analyzed. Thirty-five animals (68.6%) revealed grades I-III late effect in histopathological examination. We observed grade III colitis in 1 animal (radiation + gemcitabine) and bladder fibrosis in 4 animals (radiation and radiation + gemcitabine groups). There was no significant difference between any groups for bladder cystitis and fibrosis by Kruskal-Wallis method. Colitis was seen significantly lower in the radiation + gemcitabine + amifostine group (P = 0.0005). The collagen contents in the bladder and rectum of radiation and radiation + gemcitabine groups were markedly increased as compared to the sham group. This effect was reversed in the groups which received amifostine in addition to radiation and radiation + gemcitabine groups, but this difference was not significant. This study demonstrated that amifostine may have a beneficial effect in limiting rectal colitis from the radiosensitizing effect of gemcitabine.

Cytoprotective efficacy of amifostine against radiation- induced rectal toxicity: objective and subjective grading scales for radiomucositis

Curative radiation therapy of pelvic malignancies, frequently results in dose-limiting toxicities such as serous, mucoid, or more rarely, bloody diarrhea. Several studies have evaluated the cytoprotective effects of amifostine in preventing rectal mucositis associated with radiation treatment. We searched Medline for published comparative studies that evaluated the use of amifostine to reduce radiation-induced toxicity associated with pelvic irradiation. In ten studies there was an evidence-based cytoprotection (P<0.05) by amifostine. Although results are variable, current evidence suggests that amifostine may have a radioprotective effect in the rectal mucosa, particularly when administered intrarectally. Significant improvements were seen in both symptomatic and objective (rectosigmoidoscopy) end points. There is a need to conduct well-designed clinical trials with sufficient numbers of participants to confirm these findings together with a cost-benefit study. Objective measurements using rectosigmoidoscopy are superior to subjective measures such as WHO or RTOG/EORTC toxicity grading scales.

Intrarectal amifostine during external beam radiation therapy for prostate cancer produces significant improvements in Quality of Life measured by EPIC score

PURPOSE

To test whether intrarectal amifostine limits symptoms of radiation proctitis, measured by using the Radiation Therapy Oncology Group (RTOG) gastrointestinal (GI) toxicity score and the Expanded Prostate Cancer Index Composite (EPIC) score.

METHODS AND MATERIALS

Patients with localized prostate cancer received amifostine as a rectal suspension 30-45 minutes before daily three-dimensional conformal radiation therapy. The first 18 patients received 1 g of amifostine, and the next 12 patients received 2 g. Toxicity was assessed at baseline, during treatment, and at follow-up visits by using RTOG grading and the EPIC Quality of Life (QoL) 50-item questionnaire. The Bowel Function subset of the bowel domain (EPIC-BF), which targets symptom severity, and the Bowel Bother subset of the bowel domain (EPIC-BB), which assesses QoL, were evaluated and compared with the RTOG GI toxicity score.

RESULTS

Median follow-up was 30 months (range, 18-36 months). Overall, EPIC-BF and EPIC-BB scores both tracked closely with the RTOG GI toxicity score. Seven weeks after the start of radiation therapy, the incidence of RTOG Grade 2 toxicity was 33% in the 1-g group (6/18 patients) compared with 0% (0/12 patients) in the 2-g group and tended toward statistical significance (p = 0.06). A significant difference between amifostine groups was observed using the EPIC-BF score at 7 weeks (p = 0.04). A difference in EPIC-BB scores between dose groups was evident at 7 weeks (p = 0.07) and was significant at 12 months (p = 0.04).

CONCLUSIONS

Higher doses of amifostine produced significant improvements in acute and late bowel QoL (up to 1 year after therapy), measured using the EPIC score.

Intrarectal amifostine suspension may protect against acute proctitis during radiation therapy for prostate cancer: a pilot study

PURPOSE

Our goal was to test the ability of intrarectal amifostine to limit symptoms of radiation proctitis.

METHODS AND MATERIALS

The first 18 patients received 1 g of intrarectal amifostine suspension placed 30-45 min before each radiation treatment. The following 12 patients received 2 g of amifostine. Total dose prescribed ranged from 66 to 76 Gy. All patients were treated with three-dimensional conformal radiation therapy. The suspension remained intrarectal during treatment and was expelled after treatment. For gastrointestinal symptoms, during treatment and follow-up, all patients had a Radiation Therapy Oncology Group (RTOG) grade recorded.

RESULTS

Median follow-up was 18 months (range, 6-24 months). With 2 g vs. 1 g amifostine, there was a nearly significant decrease in RTOG Grade 2 acute rectal toxicity. Seven weeks after the start of radiation therapy, the incidence of Grade 2 toxicity was 33% in the 1-g group (6/18) compared with 0% (0/12) in the 2-g group (p=0.06). No Grade 3 toxicity or greater occurred in this study.

CONCLUSION

This trial suggests greater rectal radioprotection from acute effects with 2 g vs. 1 g amifostine suspension. Further studies should be conducted in populations at higher risk for developing symptomatic acute and late proctitis.

Amifostine reduces side effects and improves complete response rate during radiotherapy: Results of a meta-analysis

PURPOSE

To evaluate the efficacy of amifostine in diminishing radiotherapy side effects and whether or not it protects the tumor.

METHODS AND MATERIALS

We performed a systematic review and meta-analysis of 14 included randomized controlled trials, comprising 1451 patients, comparing the use of radiotherapy vs. radiotherapy plus amifostine for cancer treatment.

RESULTS

The use of amifostine significantly reduced the risk of developing mucositis (odds ratio [OR], 0.37; 95% confidence interval [CI], 0.29-0.48; p < 0.00001), esophagitis (OR, 0.38; CI, 0.26-0.54; p < 0.00001), acute xerostomia (OR, 0.24; CI, 0.15-0.36; p < 0.00001), late xerostomia (OR, 0.33; CI, 0.21-0.51; p < 0.00001), dysphagia (OR, 0.26; CI, 0.07-0.92; p = 0.04), acute pneumonitis (OR, 0.15; CI, 0.07-0.31; p < 0.00001) and cystitis (OR, 0.17; CI, 0.09-0.32; p < 0.00001). There was no difference in overall response rate between the groups. However, complete response rate was superior for patients using amifostine (OR, 1.81; CI, 1.10-2.96; p = 0.02).

CONCLUSIONS

This systematic review shows that amifostine significantly reduces the side effects of radiation therapy. The efficacy of radiotherapy was not itself affected by the use of this drug and patients receiving amifostine were able to achieve higher rates of complete response.

A phase III randomized, placebo-controlled, double-blind study of misoprostol rectal suppositories to prevent acute radiation proctitis in patients with prostate cancer

PURPOSE

Acute radiation proctitis is the most relevant complication of pelvic radiation and is still mainly treated supportively. Considering the negative impact of acute proctitis symptoms on patients' daily activities and the potential relationship between the severity of acute radiation injury and late damage, misoprostol was tested in the prevention of acute radiation-induced proctitis.

METHODS AND MATERIALS

A total of 100 patients who underwent radiotherapy for prostate cancer were entered into this phase III randomized, placebo-controlled, double-blind study with misoprostol or placebo suppositories. Radiation-induced toxicity was evaluated weekly during radiotherapy using the Common Toxicity Criteria.

RESULTS

Between the placebo and the misoprostol groups, no significant differences in proctitis symptoms occurred: 76% of patients in each group had Grade 1 toxicity, and 26% in the placebo group and 36% in the misoprostol group had Grade 2 toxicity. No differences were found in onset or symptom duration. Comparing the peak incidence of patients' toxicity symptoms, significantly more patients experienced rectal bleeding in the misoprostol group (p = 0.03).

CONCLUSION

Misoprostol given as a once-daily suppository did not decrease the incidence and severity of radiation-induced acute proctitis and may increase the incidence of acute bleeding.

Phase II multicenter randomized study of amifostine for prevention of acute radiation rectal toxicity: topical intrarectal versus subcutaneous application

PURPOSE

To investigate the cytoprotective effect of subcutaneous vs. intrarectal administration of amifostine against acute radiation toxicity.

METHODS AND MATERIALS

Patients were randomized to receive amifostine either intrarectally (Group A, n = 27) or a 500-mg flat dose subcutaneously (Group B, n = 26) before irradiation. Therapy was delivered using a four-field technique with three-dimensional conformal planning. In Group A, 1,500 mg of amifostine was administered intrarectally as an aqueous solution in 40 mL of enema. Two different toxicity scales were used: the European Organization for Research and Treatment of Cancer/Radiation Therapy Oncology Group (RTOG) rectal and urologic toxicity criteria and the Subjective-RectoSigmoid scale based on the endoscopic terminology of the World Organization for Digestive Endoscopy. Objective measurements with rectosigmoidoscopy were performed at baseline and 1-2 days after radiotherapy completion. The area under the curve for the time course of mucositis (RTOG criteria) during irradiation represented the mucositis index.

RESULTS

Intrarectal amifostine was feasible and well tolerated without any systemic or local side effects. According to the RTOG toxicity scale, Group A had superior results with a significantly lower incidence of Grades I-II rectal radiation morbidity (11% vs. 42%, p = 0.04) but inferior results concerning urinary toxicity (48% vs. 15%, p = 0.03). The mean rectal mucositis index and Subjective-RectoSigmoid score were significantly lower in Group A (0.44 vs. 2.45 [p = 0.015] and 3.9 vs. 6.0 [p = 0.01], respectively), and the mean urinary mucositis index was lower in Group B (2.39 vs. 0.34, p < 0.028).

CONCLUSIONS

Intrarectal administration of amifostine (1,500 mg) seemed to have a cytoprotective efficacy in acute radiation rectal mucositis but was inferior to subcutaneous administration in terms of urinary toxicity. Additional randomized studies are needed for definitive decisions concerning the cytoprotection of pelvic irradiated areas.

Impact on cytoprotective efficacy of intermediate interval between amifostine administration and radiotherapy: a retrospective analysis

PURPOSE

To evaluate the cytoprotective impact of the interval between amifostine administration and radiotherapy (RT).

METHODS AND MATERIALS

In a nonrandomized study, we reviewed the records of 177 patients with tumors localized in the pelvis (prostate, bladder, or gynecologic cancer), upper abdomen (pancreas, stomach, kidney), thorax (lung and breast cancer), head and neck (nasopharynx), soft tissue (sarcomas), and central nervous system. The patient records were stratified according to whether the patients had undergone RT either 25-40 min (Group 1, 96 subjects) or 10-15 min (Group 2, 81 subjects) after i.v. amifostine administration. The mean toxicity score was the mean value of recorded acute radiation toxicity. The mean interruption time was the mean value of the recorded interruption time due to radiation toxicity.

RESULTS

A significantly reduced severity of symptoms related to oral (p = 0.023), esophageal (p = 0.05) and rectal (p = 0.015) mucosa was noted in Group 2. A statistically significant reduction in the mean toxicity score (p <0.001) and mean interruption time (p = 0.001) was observed in Group 2 vs. Group 1. In terms of the incidence of radiation-induced dermatitis and alopecia, multivariate logistic analysis revealed only the total dose (p = 0.018) and the amifostine-RT interval (p = 0.002) as independent factors.

CONCLUSION

A significantly better cytoprotective effect of amifostine against radiation-induced mucositis, dermatitis, and alopecia was noted if RT was administered no later than 15 min after i.v. amifostine infusion. The results presented here need additional investigation with randomized prospective trials.

Clinical practice guidelines for the prevention and treatment of cancer therapy-induced oral and gastrointestinal mucositis

BACKGROUND

Oral and gastrointestinal (GI) mucositis can affect up to 100% of patients undergoing high-dose chemotherapy and hematopoietic stem cell transplantation, 80% of patients with malignancies of the head and neck receiving radiotherapy, and a wide range of patients receiving chemotherapy. Alimentary track mucositis increases mortality and morbidity and contributes to rising health care costs. Consequently, the Multinational Association of Supportive Care in Cancer and the International Society for Oral Oncology assembled an expert panel to evaluate the literature and to create evidence-based guidelines for preventing, evaluating, and treating mucositis.

METHODS

Thirty-six panelists reviewed literature published between January 1966 and May 2002. An initial meeting in January 2002 produced a preliminary draft of guidelines that was reviewed at a second meeting the same year. Thereafter, a writing committee produced a report on mucositis pathogenesis, epidemiology, and scoring (also included in this issue), as well as clinical practice guidelines.

RESULTS

Panelists created recommendations from higher levels of evidence and suggestions when evidence was of a lower level and there was a consensus regarding the interpretation of the evidence by the panel. Panelists identified gaps in evidence that made it impossible to recommend or not recommend use of specific agents.

CONCLUSIONS

Oral/GI mucositis is a common side effect of many anticancer therapies. Evidence-based clinical practice guidelines are presented as a benchmark for clinicians to use for routine care of appropriate patients and as a springboard to challenge clinical investigators to conduct high-quality trials geared toward areas in which data are either lacking or conflicting.

Amifostine: is there evidence of tumor protection?

A large body of experimental evidence suggests that amifostine (Ethyol, WR-2721; MedImmune, Inc, Gaithersburg, MD) is a selective cytoprotector of normal tissues. Nevertheless, several experimental studies, most of which were conducted in the early 1980s, suggest that amifostine may protect tumor tissues, although to a much lower degree than its protective effect on normal tissues. Based on a critical literature review, we conclude that any experimental evidence suggesting tumor protection is weak. The effects of anesthesia and hypotension on normal and tumor tissue oxygenation status of animals, the consequences of such events on amifostine activity, and the impact of this complex situation on host immunity and radiotherapy efficacy in the experimental setting do not reliably simulate the clinical setting. Analyses of radiobiologic and histologic results of the Canine Sarcoma Study show that, if any conclusion is to be made, amifostine protected normal tissues and preserved (or even enhanced) the antitumor activity of radiotherapy. The Ormaplatin Study clearly showed a 10-fold decreased concentration of platinum in tumor compared with normal tissues, and does not therefore support evidence of lack of amifostine selectivity. Finally, not one clinical study suggests tumor protection with amifostine. On the contrary, the majority of clinical data strongly suggest that patients who receive amifostine with radiotherapy and/or chemotherapy do better than controls. Rather than organizing large-scale, randomized clinical trials to exclude tumor protection by amifostine, it seems more useful to design trials that would measure amifostine benefits in terms of improved quality of life, tumor control, and survival rates in patients being treated with standard or novel chemotherapy/radiotherapy regimens.

Protective effect of amifostine during fractionated radiotherapy in patients with pelvic carcinomas: results of a randomized trial

PURPOSE

To evaluate whether pretreatment with amifostine can reduce treatment-induced toxicity in patients with pelvic malignancies undergoing radiotherapy (RT).

METHODS AND MATERIALS

A total of 205 patients with pelvic malignancies (rectal, 32; bladder, 47; prostate, 40; gynecologic, 86) were randomized to receive RT (Group 1, n = 95) or RT plus amifostine (Group 2, n = 110). The patient characteristics for both treatment groups were well balanced. Amifostine was administered at 340 mg/m(2) i.v., 15 min before RT, with standard antiemetics 30 min before. All patients received conventional RT, radical (65-70 Gy) or postoperative (50 Gy), with 45 Gy given to the whole pelvis at daily fractions of 1.8-2.0 Gy, 5 d/wk. Skin, bowel, bladder, and hematologic toxicities were evaluated according to the Radiation Therapy Oncology Group/European Organization Research and Treatment of Cancer scoring system.

RESULTS

A significant reduction occurred in acute Grade 2-3 bladder and lower GI tract toxicities in the amifostine group (p <0.05, Weeks 3-7). With a median follow-up of 12 months, few late Grade 2-3 effects were observed in either group. No statistically significant difference between the two groups was observed in terms of response 6 weeks after RT completion (complete response plus partial response, 96.8% in the control and 98.3% in the amifostine arm). Amifostine was well tolerated, with only moderate hypotension occurring in 2 patients and moderate nausea in 1 patient.

CONCLUSIONS

The results of this randomized trial support the role of amifostine in reducing acute radiation-related toxicity of the bladder and lower GI tract in patients with pelvic malignancies, without evidence of tumor protection.

Amifostine in clinical oncology: current use and future applications

Amifostine (Ethyol), an inorganic thiophosphate, is a selective broad-spectrum cytoprotector of normal tissues that provides cytoprotection against ionizing radiation and chemotherapeutic agents, thus preserving the efficacy of radiotherapy and chemotherapy. This review summarizes the preclinical data and clinical experience with amifostine, and provides insight into future clinical directions. Amifostine, an inactive pro-drug, is transformed to an active thiol after dephosphorylation by alkaline phosphatase found in the normal endothelium. The absence of alkaline phosphatase in the tumoral endothelium and stromal components, and the hypovascularity and acidity of the tumor environment, may explain its cytoprotective selectivity. The cytoprotective mechanism of amifostine is complicated, involving free radical scavenging, DNA protection and repair acceleration, and induction of cellular hypoxia. Intravenous administration of amifostine 740-900 mg/m(2) before chemotherapy and 250-350 mg/m(2) before each radiotherapy fraction are widely used regimens. The US Food and Drug Administration has approved the use of amifostine as a cytoprotector for cisplatin chemotherapy and for radiation-induced xerostomia. Ongoing trials are being conducted to determine the efficacy of amifostine in reducing radiation-induced mucositis and other toxicities. Novel schedules and routes of administration are under investigation, and may further simplify the use of amifostine and considerably broaden its applications.

Rationale for a phase I/II radiation dose-escalation study with concurrent amifostine (Ethyol) and infusional 5-FU chemotherapy for preoperative treatment of unresectable or locally recurrent rectal carcinoma

Rectal adenocarcinoma almost invariably requires extirpative surgery to be cured. Although radiation therapy and concurrent chemotherapy often will elicit dramatic responses, the treatment morbidity limits the tolerable dose of radiation to about 45 to 50 Gy. Strategies to reduce procto/enteritis may permit higher doses of radiation to be delivered. This report reviews a recently activated radiation dose-escalation study that combines the radioprotector amifostine (Ethyol, WR-2721) with 3-dimensionally planned radiation therapy and concurrent infusional 5-fluorouracil chemotherapy.

Randomized phase III trial of radiation treatment +/- amifostine in patients with advanced-stage lung cancer

PURPOSE

This multicenter trial investigated whether daily pretreatment with amifostine (A) could reduce the incidence of acute and late lung toxicity and esophagitis without affecting antitumor efficacy of radiation in advanced lung cancer.

PATIENTS AND METHODS

Radiotherapy (XRT) patients (n = 146) received a daily fraction of 2 Gy/5 days/week to a total of 55-60 Gy +/- amifostine 340 mg/m(2) administered daily 15 min before irradiation. Acute and late toxicities were graded from 0 to 4 according to the Radiation Therapy Oncology Group/European Organization for the Research and Treatment of Cancer system.

RESULTS

Ninety-seven patients were evaluated 2 months post-XRT for the incidence of pneumonitis; 43% (23/53) of patients in the XRT arm and 9% (4/44) in the A + XRT arm experienced > or = Grade 2 pneumonitis (p < 0.001) [corrected]. Forty-nine percent (26/53) of patients in the XRT arm and 16% (7/44) in the A+XRT arm demonstrated changes representative of > or = Grade 2 lung damage (p < 0.001). At 6 months, fibrosis was present in 53% (19/36) receiving XRT vs. 28% (9/32) receiving A+XRT (p < 0.05). Incidence of esophagitis > or = Grade 2 during Week 4 was 42% (31/73) in the XRT arm vs. 4% (3/73) in the A+XRT arm (p < 0.001). Among 97 patients evaluable for response 2 months after XRT, complete or partial response was present in 76% (40/53) of patients in the XRT arm and 75% (33/44) in the A+XRT arm (p = 1.0).

CONCLUSION

Amifostine reduces the incidence of pneumonitis, lung fibrosis, and esophagitis in radiotherapy patients with lung cancer without compromising antitumor efficacy.

Radiation, radicals, and images

Nitroxide stable free radicals exhibit varied chemical and biological properties. Their biological applications have been greatly expanded over the past few years. Not only have they been shown to exhibit potent antioxidant and radioprotective properties, but also they can serve as in vivo functional imaging probes that non-invasively report on the oxygen status and redox properties of tissue, which may have utility in clinical biomedical research.

Subcutaneous administration of amifostine during fractionated radiotherapy: a randomized phase II study

PURPOSE

Amifostine (WR-2721) is an important cytoprotective agent. Although intravenous administration is the standard route, pharmacokinetic studies have shown acceptable plasma levels of the active metabolite of amifostine (WR-1605) after subcutaneous administration. The subcutaneous route, due to its simplicity, presents multiple advantages over the intravenous route when amifostine is used during fractionated radiotherapy.

PATIENTS AND METHODS

Sixty patients with thoracic, 40 with head and neck, and 40 with pelvic tumors who were undergoing radical radiotherapy were enrolled onto a randomized phase II trial to assess the feasibility, tolerance, and cytoprotective efficacy of amifostine administered subcutaneously. A flat dose of amifostine 500 mg, diluted in 2.5 mL of normal saline, was injected subcutaneously 20 minutes before each radiotherapy fraction.

RESULTS

The subcutaneous amifostine regimen was well tolerated by 85% of patients. In approximately 5% of patients, amifostine therapy was interrupted due to cumulative asthenia, and in 10%, due to a fever/rash reaction. Hypotension was never noted, whereas nausea was frequent. A significant reduction of pharyngeal, esophageal, and rectal mucositis was noted in the amifostine arm (P <.04). The delays in radiotherapy because of grade 3 mucositis were significantly longer in the group of patients treated with radiotherapy alone (P <.04). Amifostine significantly reduced the incidence of acute perineal skin and bladder toxicity (P <.0006).

CONCLUSION

Subcutaneous administration of amifostine is well tolerated, effectively reduces radiotherapy's early toxicity, and prevents delays in radiotherapy. The subcutaneous route is much simpler and saves time compared with the intravenous route of administration and can be safely and effectively applied in the daily, busy radiotherapy practice.

Innovative treatment strategies in locally advanced and/or unresectable non-small cell lung cancer

BACKGROUND

While small improvements in outcome have occurred for patients with locally advanced non-small cell lung cancer (NSCLC), 5-year survival results remain low, ranging from 5% to 20%. Distant metastases and local-regional progression remain significant patterns of failure.

METHODS

Trials investigating innovative treatment strategies for patients with locally advanced and/or unresectable NSCLC are reviewed, including altered radiation fractionation schema, conformal 3-dimensional radiotherapy, and combined chemoradiotherapy regimens.

RESULTS

Whereas hyperfractionated radiation therapy (HFRT) alone does not appear to be beneficial, combined HFRT and chemotherapy appears promising in several trials. Patients treated with accelerated RT compared with standard RT have an improved survival. As higher radiation doses appear to enhance local tumor control, strategies involving 3-dimensional conformal radiotherapy merit further investigation. RT plus chemotherapy is superior to RT alone, albeit with greater toxicity. Amifostine is currently being investigated as a radioprotector. The optimal chemotherapy agents and their integration with radiotherapy are the subject of randomized trials.

CONCLUSIONS

Ongoing investigations are warranted to combat both local-regional and systemic failures for patients with locally advanced NSCLC. Treatment strategies need to consider not only the traditional endpoints of survival and local control, but also quality of life.

The lazaroid U74389G protects normal brain from stereotactic radiosurgery-induced radiation injury

PURPOSE

To test an established model of stereotactic radiosurgery-induced radiation injury with pretreatments of either methylprednisolone or the lazaroid U74389G.

METHODS AND MATERIALS

Nine cats received stereotactic radiosurgery with a linear accelerator using and animal radiosurgery device. Each received a dose of 125.0 Gy prescribed to the 84% isodose shell to the anterior limb of the right internal capsule. One animal received no pretreatment, two received citrate vehicle, three received 30 mg/kg of methylprednisolone, and three received 5 mg/kg of U74389G. After irradiation, the animals had frequent neurologic examinations, and neurologic deficits developed in all of them. Six months after the radiation treatment, the animals were anesthetized, and had gadolinium-enhanced magnetic resonance (MR) scans, followed by Evans blue dye perfusion, euthanasia, and brain fixation.

RESULTS

Magnetic resonance scans revealed a decrease in the size of the lesions from a mean volume of 0.45 +/- 0.06 cm(3) in the control, vehicle-treated, and methylpredniosolone-treated animals to 0.22 +/- 0.14 cm(3) in the U74389G-treated group. The scans also suggested the absence of necrosis and ventricular dilatation in the lazaroid-treated group. Gross pathology revealed that lesions produced in the untreated, vehicle-treated, and methylprednisolone-treated cats were similar and were characterized by a peripheral zone of Evans blue dye staining with a central zone of a mature coagulative necrosis and focal hemorrhage. However, in the U74389G-treated animals, the lesions were found to have an area of Evans blue dye staining, but lacked discrete areas of necrosis and hemorrhage.

CONCLUSION

These results suggest that the lazaroid U74389G protects the normal brain from radiation injury produced by stereotactic radiosurgery.

Cardioprotective potency of the radical scavenger S-2-(3 aminopropylamino) ethylphosphorothioic acid in the post-ischaemic rat heart

S-2-(3 aminopropylamino) ethylphosphorothioic acid (WR-2721) shown to surpass radical scavenging thiols in their radioprotective efficacy in cancer-type diseases has been tested for its protective potential in the reperfused heart. We investigated the radical scavenger properties of the compound in a radical generating system in vitro as well as in isolated rat hearts subjected to 30 min ischaemia and 30 min reperfusion with the electron-paramagnetic resonance spin trap technique. The action on high-energy phosphates is observed by means of phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy while its influence on left ventricular systolic segmental length change (SSLC) during 60 min reperfusion following 60 min regional ischaemia was assessed with a fibreoptic system in anaesthetized open-chest rats. WR-2721 (0.1 mM) reduced the vascular concentration of radical adduct in isolated hearts by up to 78% (275 +/- 84% of pre-ischaemic baseline values vs 1260 +/- 413%, p < 0.05) between 5 and 12.5 min reperfusion. This was accompanied by a reduction of the left ventricular end diastolic pressure to pre-ischaemic values at 30 min of reperfusion (9 +/- 6 mmHg vs 42 +/- 8 mmHg in the absence of WR-2721, p < 0.02). An accelerated recovery of creatine phosphate levels (78 +/- 5% of pre-ischaemia values vs 41 +/- 5% within 60 min reperfusion: p < 0.05) was observed under similar conditions with NMR-spectroscopy, although the post-ischaemic tissue content of adenosine triphosphate was not affected.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiation treatment for rectal cancer

Radiation treatment is widely used in the management of adenocarcinomas of the rectum, either alone or more frequently as part of multimodality treatment protocols. External beam radiation is capable of eradicating about one-third of bulky but mobile primary rectal cancers and is an alternative to be considered when standard surgery is not possible. Endorectal irradiation, either alone or combined with external beam treatment, has proved highly effective for selected superficial cancers of the distal rectum. Irradiation alone or in conjunction with cytotoxic chemotherapy appears to reduce the risk of tumor progression at the primary site or in regional lymph nodes when combined with local surgical excisions that preserve anorectal function. The treatment of recurrent and metastatic cancer frequently provides palliation, although cure by irradiation is rare.

Radiation-induced lymphoid tumors and radiation lethality are inhibited by combined treatment with small doses of zinc aspartate and WR 2721

Combined small doses of zinc aspartate and WR 2721 provided additive protection against radiation lethality in mice. Survival obtained with a small dose of WR 2721 which was ineffective alone could be enhanced to 83% by combining the drug with zinc aspartate, which on its own also displayed no effect. The survival of 25% provided by a higher dose of WR 2721 was increased significantly by adding zinc aspartate. Additivity was also tested in a model of radiation carcinogenesis. For this purpose, lethality and occurrence of lymphoid tumors induced by fractionated total-body irradiation were studied in C57B1/6 mice treated with zinc aspartate and WR 2721. In order to reveal additive effects, both agents were used at sub-optimal dosages. In mice subjected to 5 daily exposures of 1.9 Gy, the combination of zinc aspartate and WR 2721 was effective and enhanced the survival to 83% as compared with 25% afforded by WR 2721 alone (p < 0.005). Similarly, histological assessment of organ involvement with lymphoma revealed that zinc aspartate and WR 2721 alone did not bring about a significant reduction of lymphoma incidence. On the other hand, the combined agents diminished organ involvement with lymphoma to 9.1% as against 90% in the controls (p < 0.0005) and 62.5% with WR 2721 alone (p < 0.025). Thus, combined treatment with zinc aspartate and WR 2721 also inhibited radiation-induced lymphoid tumors.

Topical application of WR-2721 to prevent radiation-induced proctosigmoiditis. A phase I/II trial

Patients undergoing x-ray therapy to the pelvis have intestinal symptoms proportional to the volume treated and the dose delivered. WR-2721, S-2 (3-aminopropylaminoethyl) phosphorothioic acid, is an organic thiophosphate compound that selectively protects normal tissues against radiation effects. A Phase I/II study was done to test the ability of topical application of WR-2721 to protect the mucosa of the rectosigmoid from radiation damage. Thirty-one patients were enrolled in this study, of which, seven were control subjects. Twenty-four patients received WR-2721 daily, in enema form, 45 minutes before treatment. The patients were assigned by groups of three to receive increasing doses of WR-2721 beginning with 100 mg/enema to 450 mg/enema. Rectal mucosal biopsies were obtained within the treated field before, during, and at the end of therapy. The degree of damage to the rectal mucosa was scored on the basis of a 0 to 4 scale (with 0, least damage to 4, most damage) as determined by the percentage of damaged mucosal crypt glands. The patients' symptoms were recorded once a week during the entire course of therapy. The biopsy scores of the control group were slightly higher than those of the treatment groups; however, this difference did not appear to be significant. In the treated groups, there was a slight decrease in the biopsy scores with increasing doses of WR-2721, but this trend was not sustained. There were no differences among any of the groups in the symptoms experienced during the course of therapy. This study showed that WR-2721 could be administered safely in enema form in doses ranging from 100 to 450 mg/enema, but this drug did not protect the rectosigmoid mucosa from radiation damage at the doses administered.