Obstacles to Biosimilar Acceptance and Uptake in Oncology: A Review.

Importance: Biosimilar drugs provide cost-effective yet clinically indistinguishable replications of target drugs. During initial development, this class of biologic medicines was expected to revolutionize pharmaceutical markets; however, following US Food and Drug Administration approval of the first biosimilar drug in 2015, the commercialization of biosimilars has been limited. The lack of biosimilar use may be especially salient in oncology, given that biosimilar distribution in this particularly high-cost area of medicine would bring savings on the order of many billions of dollars. Observations: While researchers have focused on salient economic barriers to biosimilar uptake in the US, the present review provides insight regarding noneconomic barriers. This review discusses psychological, attitudinal, and educational factors among both health care professionals and payers in the US that may play a role in slowing biosimilar uptake. More specifically, these factors include a lack of health care professional education, concerns of safety and efficacy, and overly complex product naming systems. Conclusions and Relevance: The pathway to biosimilar use has been obstructed by economic elements as well as attitudinal and psychological factors. For biosimilar drugs to achieve their potential in decreasing treatment costs and thus increasing patient access, it will be essential for both economic and noneconomic factors to be identified and systematically addressed.

Monitoring plasma voriconazole levels may be necessary to avoid subtherapeutic levels in hematopoietic stem cell transplant recipients.

BACKGROUND: Low voriconazole levels have been associated with a higher failure rate in patients with confirmed fungal infections. METHODS: Steady-state plasma trough voriconazole levels were measured after at least 5 days of therapy in 87 patients with hematologic malignancies on 201 separate occasions (1-5 levels per patient; median, 2). Most patients (90%) had undergone allogeneic hematopoietic stem cell transplantation. The daily voriconazole dose, administered in 2 divided doses, was 200 mg (n = 4), 400 mg (n = 151), 500 mg (n = 20), 600 mg (n = 18), and 800 mg (n = 8); corresponding to 2.0-16.3 (median, 5.4) mg/kg. Plasma voriconazole levels were 0-12.5 microg/mL (median, 1.2). Voriconazole was undetectable (<0.2 mug/mL) in 15%. RESULTS: The correlation between dose and levels was weak (r = 0.14; P = .045). The median absolute daily drug dose (400 mg) was identical in groups of patients with levels of 0, 0.2 to 0.5, >0.5 to 2.0, >2.0 to 5.0, and >5.0. Whereas the daily drug dose in mg/kg was significantly higher when the levels were >5.0 microg/mL, there was no consistent relation between dose and level below that threshold. In adult patients getting standard doses of voriconazole orally, the drug levels are highly variable. Based on limited available data, between a quarter and two-thirds of these levels could potentially be associated with a lower likelihood of response or a higher likelihood of failure. CONCLUSIONS: Future voriconazole studies should incorporate prospective therapeutic drug monitoring and consideration should be given to checking levels in patients receiving the drug for confirmed, life-threatening fungal infections.