The most commonly reported adverse reaction associated with the use of besilesomab is the development of Human Anti-Mouse Antibodies (HAMA) after a single administration FDA Label. Patients who have developed HAMA may potentially have a higher risk for hypersensitivity reactions. Screening for possible previous exposure to murine monoclonal antibodies and tests for the presence of HAMA in prospective patients should be made prior to administrating besilesomab FDA Label. Moreover, because the incidence of developing HAMA appears to be dose related with besilesomab, the recommended dosage is restricted to no more than 250 micrograms of antibody per injection T132. Patients who are HAMA positive are consequently contraindicated from using besilesomab FDA Label.

Hypersensitivity to besilesomab or to any other murine antibodies or to any of the excipients associated with the active besilesomab radio-diagnostic agent is subsequently a contraindication FDA Label.

Some patients have also reported hypotension as a common adverse reaction FDA Label.

As exposure to ionizing radiation is linked with cancer induction and a potential for developing hereditary defects, the use of radio-diagnostic besilesomab in pregnant women is considered a formal contraindication FDA Label. If in doubt about a woman's potential pregnancy, alternative techniques to not using ionizing radiation should be considered and/or offered instead to the patient FDA Label.

Moreover, although it is not known if besilesomab is excreted in human milk, the potential risk to a breast-fed child cannot be excluded FDA Label. Furthermore, while consideration should be given to the possibility of perhaps delaying the administration of radionuclide agents until the mother has ceased breastfeeding or perhaps certainly choosing alternative radoopharmaceuticals with more appropriate secretion activity, if the use of besilesomab is absolutely necessary then the mother's breastfeeding should be stopped for three days and any expressed feeds during that time discarded FDA Label. The time period of three days corresponds to 10 half-lives of technetium (Tc99m)(60 hours) FDA Label. At that time, the remaining activity represents about 1/1000 of the initial activity in the body FDA Label.

In general, close contact with infants and pregnant women should be restricted for patients who have been administered besilesomab during the first 12 hours after the injection FDA Label.

Since besilesomab contains sorbitol, patients having any rare hereditary conditions of fructose intolerance should not be administered this medicine FDA Label.

Because no sufficient data regarding the safety and efficacy of using besilesomab in children below the age of 18 years exists, the use of besilesomab in this patient population is not recommended ^L1711.

Even though data regarding the repeated dosing of besilesomab is extremely limited, the use of besilesomab should only be used once in a patient's lifetime FDA Label.

Other medicines that can inhibit inflammation or affect the hematopoietic system (like antibiotics and corticosteroids) can lead to false negative results. Such agents should therefore not be administered together with, or a short time before the injection of besilesomab FDA Label.

Preclinical data obtained with the non-radioactive compound revealed no special hazard for humans based on conventional studies of safety pharmacology, single-dose and repeated dose toxicity, although antimurine antibodies were found in all dose groups (including controls) in a repeated-dose study in monkeys FDA Label. Genotoxicity studies conducted to test for potentially genotoxic impurities were also negative. Long-term carcinogenicity studies and toxicity to reproduction have not yet been carried out FDA Label.