Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.


LeukoScan (Australian Radioisotopes)
3 mL vials containing 0.31 mg powder for reconstitution
Approved indication: diagnosis of osteomyelitis

Prompt treatment of osteomyelitis may prevent bone necrosis. Early diagnosisis therefore important, but the infection may not show up on a plain X-ray. A technetium (99mTc) bone scan will detect most cases, but sometimes cannot distinguish infection from other causes of inflammation. Using sulesomab may overcome this problem.

Sulesomab is a monoclonal antibody which binds to antigens on the surface of neutrophils. If it is labelled with 99mTc it will reveal areas where there is intense inflammation. In vitro studies suggest that labelled sulesomab binds more avidly to activated granulocytes.

After the sulesomab and the 99mTc are mixed they are given by intravenous injection. Imaging can take place between one and eight hours after the injection. Most of the dose is renally excreted, with 41% of the radioactivity appearing in the urine within 24 hours of the dose.

Sulesomab has been studied in 122 patients with diabetes who were thought to have osteomyelitis secondary to foot ulcers. The performance of the scan was assessed by bone biopsy. The scan detected 74 of the 81 patients with osteomyelitis and excluded it in 23 of the 41 patients who did not have osteomyelitis. Sulesomab therefore has a sensitivity of 91% and a specificity of 56%. The sensitivity compares favourably with the technique of using radio labelled white blood cells, which has a sensitivity of 79%. Sulesomab imaging has slightly greater accuracy(81% versus 75%) and the results are likely to influence the patients' management.1

Leucocyte numbers fall after the injection, but usually recover within 10 days. Other reported adverse effects include eosinophilia and rashes. The production of sulesomab involves mice, but no anti-mouse antibody reactions occurred in the trial.

Sulesomab is safer and easier to use than radio labelled white blood cells, so it is being studied in other conditions, such as inflammatory bowel disease, where the detection of inflammation is important.

References

  1. Harwood SJ, Valdivia S, Hung G-L, Quenzer RW. Use of sulesomab, a radio labeled antibody fragment, to detect osteomyelitis in diabetic patients with foot ulcers by leukoscintigraphy. Clin Infect Dis1999;28:1200-5.