Efficacy and Safety of Stimulan® for the Treatment of Diabetic Foot Osteomyelitis. The BIG D-FOOT Study

Efficacy and Safety of aBIo- Absorbable Antibiotic Delivery in Calcium Sulphate Granules (Stimulan®) for the Treatment of Osteomyelitis in Patients With Diabetic FOOT: a Randomised, Double Blind, Controlled Clinical Study. The BIG D-FOOT Study

This study is designed as a double-blind, placebo-controlled, parallel series randomized trial aimed at verifying the effiicacy and safety of a local calcium-sulphate bio-absorbable antibiotic delivery (tobramicina+vancomicina) versus placebo (calcium-sulphate matrix without antibiotics) in patients with diabetic foot osteomyelitis treated with surgical procedures.

Osteomyelitis is a severe complication of diabetic foot ulcers, that can occur in nearly 20-60% of patients. Current treatments for diabetic foot osteomyelitis (DFO) include surgical procedures aimed at removing necrotic soft tissue, gengrene and infected bones and systemic antibiotic therapy for at least 4-6 weeks; however in some cases, prolonged antibiotic therapy is not unusual.

Antibiotic therapy can be problematic for several reasons, such as the achievement of appropriate and stable therapeutic concentration at bone level, particularly due to the common presence of concomitant peripheral artery disease, and kidney impairment. In recent years, another important barrier to the treatment of DFO was the increasing incidence of resistant pathogens. On the other hand, surgical options are affected by several side effects, such as alterations of foot biomechanics possibly leading to new ulcers (the so called transfer ulcer), post-surgical infections, ecc. All these factors make the DFO treatment challenging, with a high risk of all-cause mortality and rate of patients requiring major amputations Local bio-absorbable antibiotic delivery can be a valid therapeutic option for DFO treatment. During the last 2 decades, biodegradable carriers have been developed: proteins (collagen, gelatin, thrombin etc.), synthetic polymers, grafts, and substitutes (calcium sulfate or phosphate).

Local antibiotic delivery system has been widely explored to increase the duration of local antibiotic delivery and bone penetration, achieving very high local therapeutical doses (about several times higher than that obtained with systemic antibiotic therapy) with reduced systemic toxicity. Another important advantage of this device is the possibility of using very effective, but highly toxic, antibiotic such as aminoglycosides, often not taken into account for systemic therapies.

Finally, this device can be used as a bone substitute filling the dead space caused by bone resection, thus reducing the incidence of reinfection. Complications of calcium sulfate are negligible and include postoperative drainage and transient hypercalcemia.

There several observational studies and very few randomized trials performed on DFO exploring the efficacy of local bio-absorbable antibiotic delivery and none on Stimulan.

The present study is designed as a double-blind, placebo-controlled, parallel series randomized trial aimed at verifying the effiicacy and safety of a local calcium-sulphate bio-absorbable antibiotic delivery (either with tobramicina or vancomicina) versus placebo (calcium-sulphate matrix without antibiotics) in patients with DFO treated with surgical procedures.

Inclusion Criteria:

• Type 1 or 2 diabetes
• Forefoot osteomyelitis
• Deep tissue infection

Exclusion Criteria:

• Pregnancy
• Severe cognitive impairment
• Creatinine clearance< 30 ml/min