Recommendations regarding subcutaneous administration of bortezomib caution to ensure medication is delivered into adipose tissue and not muscle, which is dependent on site selection. Several factors, such as skin thickness and subcutaneous fat, appropriate skinfold technique prior to injection, injection angle, and needle length, play a role in site selection. Nursing management suggestions note that sites should be rotated using common subcutaneous site selection, which include the abdomen, the upper arm, and the upper outer aspects of the thighs; however, it should be noted that upper arm sites were not included in pharmacokinetic studies for subcutaneous bortezomib, and thus efficacy and safety at this injection site remain uncertain. Guidance provided was also specific to adult male and female patients, with no recommendations for pediatric adipose tissue composition. [1]
The phase 3 study for bortezomib did not evaluate subcutaneous administration into the arm, and pharmacokinetic data from administration into the abdomen and thigh cannot be extrapolated to this site of administration. For this reason, an observational survey published in 2015 explored oncology nurses’ opinions regarding subcutaneous bortezomib administration. A 44-question electronic survey was developed, and a total of 43 nurses from 17 clinics in 12 states recorded responses. A total of 98%, 19%, and 53% of nurses reported using the abdomen, thigh, and arm, respectively, for administration of subcutaneous bortezomib. The abdomen and arm were preferred by 88% and 12% of respondents, respectively, which was primarily due less irritation/pain (n= 17, 40%), the presence of more tissue/larger area (n= 15, 35%), ease of access (n= 11, 26%), and patient preference (n= 4, 9%). A total of 72% of nurses believed that patients preferred receiving injections in the abdomen compared to 28% who believed patients preferred injections in the arm. Of note, the abdomen (76%) and arm (24%) were preferred in nonprivate facilities compared to all respondents indicating a preference for abdominal injections in private/somewhat private facilities (p= 0.02). [2]
A 2015 brief communication explored the incidence and severity of injection site reactions (ISRs) following subcutaneous bortezomib administration in 22 Japanese patients with multiple myeloma (age range 46 to 80). Bortezomib, administered subcutaneously at a concentration of 1.3 mg/m², was injected into the upper arm, with the injection sites rotated alternately between the arms. The injections were given at a ~30° angle, and reactions were graded based on the National Cancer Institute Common Toxicity Criteria version 4.0. Out of the 197 total injections administered, grade 1 ISRs occurred in only 3 patients (13.6%), representing 3.0% of the total injections, while no grade 2 or higher ISRs were observed. Grade 0 reactions, such as mild redness, warmth, or itching, were noted after 24.9% of the injections. Importantly, none of the patients with grade 1 ISRs required treatment. Comparison to previous research showed that the incidence of ISRs in this cohort was lower than other documented frequencies, particularly when contrasted with thigh or abdomen administration as demonstrated in a previous report. Additionally, some patients who previously experienced frequent ISRs from abdominal injections encountered no reactions when injections were shifted to the upper arm. The acceptability of the upper arm as an alternative site was further supported by the study’s observation that only 2 of 10 patients with a low BMI (<20.0) experienced injection-site reactions, suggesting that upper arm administration offers a viable option even for patients with less adipose tissue. [3]