Periodic Treatment with Autologous Erythrocytes Loaded with Dexamethasone 21‐Phosphate for Fistulizing Pediatric Crohn's Disease

Abstract

INTRODUCTION Steroids have been used for the treatment of Crohn's disease (CD) since the 1970s with satisfactory results. Unfortunately, most patients with CD develop a dependency to the treatment, and this means that they cannot taper or rapidly flare (usually within 6 months) after steroid withdrawal (1-3). For this reason and for the consideration that long-term use of steroids can produce a variety of metabolic, endocrine, and growth adverse effects (4), alternative forms of treatment have been experimented with. Nutritional treatment has been widely used, especially in pediatrics, in the acute form of CD, and this treatment can produce mucosal healing. However, there are major problems with compliance, especially in cases of relapse (5). Immunosuppressive agents (for example, azathioprine) are also used to keep remission at bay in steroid-dependent patients or nonresponders in corticosteroid therapy (5-7). In recent years, tumor necrosis factor-α antibodies (Infliximab) have been successfully used in patients with CD resistant to conventional treatment, and it has been shown to be particularly effective in the fistulizing forms of the disease but sometimes can cause severe side effects and infections that force the end of the treatment (5,8-10). To treat steroid-dependent patients who did not respond or reacted to alternative treatments, a new way to deliver steroids was developed (11). It was demonstrated that erythrocytes, because of the ability of their membrane to be opened and resealed, provide an excellent vehicle for the target delivery of drugs. In particular, dexamethasone 21-phosphate (Dex 21P), a nondiffusible pro-drug, can be encapsulated in human erythrocytes where is dephosphorylated to dexamethasone and slowly released into circulation (12,13). The erythrocyte-mediated delivery of this drug was studied in adult patients affected by chronic obstructive pulmonary disease, showing positive results without appearance of side effects (11). We recently published the positive effects of this treatment in patients affected by cystic fibrosis with improvement of their respiratory performance without any side effects even after 15 months of continuous treatment. In these patients, pharmacokinetic analyses have shown that a single administration of drug-loaded erythrocytes (8.9 ± 3.8 mg of Dex-21P) was able to maintain detectable dexamethasone concentrations in the blood for up to 4 weeks (0.02-0.1 nmol/mL plasma) (14). We report the case of a 16-year-old patient affected by fistulizing CD and who was corticodependent who presented severe adverse effects when infliximab was used and who we are currently treating with periodic infusions of autologous erythrocytes loaded with Dex 21P with good results. CASE REPORT Our patient, female, presented at the age of 10 years to another hospital with weight loss, irritability, headache, muscle pain, anorexia, diarrhea, abdominal pain, and low-grade fever. Upper gastrointestinal endoscopy was normal, but colonoscopy revealed aphthous ulcers in the colon and a cobble-stone aspect in the last 20 cm of the terminal ileum. Biopsy results confirmed the diagnosis of an ileo-colic CD. She was treated successfully with prednisolone and mesalazine. Subsequently, she had numerous episodes of relapse that were treated with prednisolone and metronidazole. For the appearance of side effects caused by prolonged use of steroids and the development of a perianal fistula, she was started on nutritional treatment, first with an elemental formula and then with a polymeric one. To keep remission at bay, she needed several courses of nutritional treatment with good compliance. Almost immediate relapse occurred when nutritional therapy was stopped. At the age of 16 years, she presented to our hospital with severe abdominal pain and a history of presence of feces in the urine. An abdominal ultrasound showed a parauterine abscess with a rectovesical fistula and an enterocutaneous fistula from the umbilicus to the terminal ileum. She refused further course of nutritional treatment, and therefore she was treated with prednisolone (60 mg/day) and antibiotics without any result. Afterward, she was treated for 24 weeks with budesonide (9 mg/day) and azathioprine (2 mg/kg/day). Because of almost no response to treatment, she was started on infliximab at the dose of 5 mg/kg. The result was excellent: her enterovesical and enterocutaneous fistula were closed, and the clinical condition improved rapidly after the first infusion. Unfortunately, despite premedication with steroids and antihistaminic, she developed a severe anaphylactic reaction at the beginning of the second infusion and the treatment had to be suspended. Her fistulas reopened, and she continued to have open fistulas despite antibiotic treatments and bowel rest. A new cycle of corticosteroid therapy was administered with slight improvement of her conditions, but her fistulas stayed opened. At this point, we decided to start treatment with periodic infusions of autologous erythrocytes loaded with Dex 21P. We chose a 4 week periodic infusion scheme because previous pharmacokinetic studies show stable drug levels for 4 weeks (14). For the procedure for the encapsulation of Dex 21P, a specially designed "red cell loader" apparatus, as previously described (12), was used. Essential steps of the process involve swelling of the patient's red blood cells in hypotonic solutions, entrapping Dex 21P, resealing of erythrocytes, and their reinfusion into the original donor (13). This procedure is completed in 3 hours at room temperature and under blood-banking conditions. Infusions began in October 2001, and she is continuing to have them every 4 weeks. The enterocutaneous fistula starts closing after every infusion, with stopping of external drainage and seldom reopened few days before the following infusion. After the fourth infusion, her enterovesical fistula closed, and she started having normal urine examinations. The patient, 3 years after beginning the infusions, feels well and is able to conduct a normal life. We used the pediatric Crohn activity index (pCDAI) (15) to evaluate her clinical condition. Her mean pCDAI decreased from 33 (range 25-40) 3 years before the beginning of treatment to 13 (range 10-20) during the 3 years of treatment (Fig. 1). She continues medical treatment with mesalazine 800 mg twice a day and azathioprine at 2 mg/kg per day. She is not showing any signs of common steroids side effects; in particular, she has not had any hematologic and ocular side effects. She never again needed any further corticosteroids treatment, either orally or intravenously. She had a computerized bone mineralometry-dual energy x-ray examination performed at the beginning of treatment that showed a Z-score of -1.3 SD; subsequent examination performed after 24 months did not show any worsening. An upper gastrointestinal endoscopy and a colonoscopy performed 24 months after the beginning of treatment showed endoscopic and histologic remission.FIG. 1: pCDAI 36 months before and 36 months after the beginnig of treatment with autologous erytrocytes loaded with Dex 21P.DISCUSSION One of the major problems in managing inflammatory bowel diseases and in particular CD is maintenance of clinical, biochemical, and histologic remission as long as possible. At the moment, corticosteroids, azathioprine, and other immunosuppressants and infliximab are the available drugs used for this purpose. Unfortunately, the prolonged use of these drugs is harmful. The prolonged use of corticosteroids is associated with the risk of clinically significant adverse effects such as high blood pressure, growth impairment, glucose intolerance, osteopenia and osteoporosis, water retention, and hirsutism (4). Furthermore, adolescent patients do not cope very well with their physical image alteration secondary to prolonged use of steroids. Infliximab is a new, revolutionary treatment, especially in cases of fistulizing CD. Unfortunately, severe side effects have been described (8-10). Diagnosis of CD in our patient was made at 10 years of age, and for 6 years, many kinds of available treatment strategies (mesalazine, prednisone, budesonide, immunosuppressant, nutritional treatment) were tried without obtaining long remission periods. She also underwent Infliximab treatment, but unfortunately, she developed a severe reaction after the first infusion. In a recent paper, we evaluated the safety and the efficacy of the administration of low doses of dexamethasone delivered by autologous erythrocytes in patients affected by cystic fibrosis, and we showed that the procedure was safe with benefits for patients (improvement of respiratory function) and without side effects (14). Analogue results were obtained in adult patients affected by chronic obstructive pulmonary disease (13). On the basis of these encouraging results, we decided to try this form of treatment in patients affected by inflammatory bowel diseases, in particular in those affected by CD, with the purpose of long-term maintenance of remission. We were encouraged to use this treatment in our patient because of a lack of response to other forms of treatment and the impossibility of continuing Infliximab therapy. At the beginning of treatment, she had a pCDAI of 27 and two open fistulas (entero-vesical and entero-cutaneous). Unexpectedly, soon after the first infusion, the entero-cutaneous fistula closed with stopping of the external drainage, whereas the entero-vesical fistula closed definitively. She started having normal urine examinations after the forth infusion. Glucocorticoids are used to interfere with some inflammatory pathways and for this purpose are used in several inflammatory diseases. Nevertheless, the good results of corticosteroids treatment is influenced by several factors. As compared with other conventional steroids used for patients affected by inflammatory bowel disease such as prednisone, methylprednisone, and prednisolone, dexamethasone has fivefold higher anti-inflammatory activity, no mineralocorticoid activity, and a longer half life. Furthermore, our methods of delivering dexamethasone use the ability of erythrocytes to slowly release the drug, assuring a stable, continuous drug level in the blood that can have a therapeutic effect but is not high enough to give side effects. Our patient has been receiving this form of treatment for 3 years and has never presented steroid-related side effects. In particular, she has never had high blood pressure, moon-like face, hypertrichosis, and worsening of her osteopenia. She also reports a sensation of well-being with improvement of her quality of life, and her clinical improvement is also confirmed by the fall of her pCDAI (Fig. 1). In conclusion, our experience demonstrates the efficacy and the safety of prolonged treatment with periodic infusion of autologous erythrocytes loaded with Dex 21P, even in patients with fistulizing CD not responding or intolerant to conventional treatment.