Dose Rounding of Cytotoxic Drugs and Monoclonal Antibodies

Marc Geirnaert, BSc Pharm
Director of Provincial Oncology Drug Program
CancerCare Manitoba
Winnipeg, Manitoba, Canada

Christan M. Thomas, PharmD BCOP
Clinical Content Specialist
Truven Health Analytics, an IBM Company
Denver, CO

Given the high cost of antineoplastic agents and monoclonal anti- bodies, many institutions have adopted dose-rounding policies in order to minimize waste—both financial and physical—while still providing optimal patient care.

Several studies have addressed the cost-effectiveness and feasibility of dose rounding for specific agents. For example, a 2013 retrospective study by Patel and Le examined the feasibility of rounding rituximab to the nearest vial size. Authors determined that 99% of the 2,028 reviewed orders fell within 10% dose deviation, and 66.1% fell within 5% if rounded to the nearest 100 mg vial.¹

Winger and colleagues also looked at potential cost savings that could be achieved by rounding seven biologic agents during a 3-month period.² In total, 126 orders for these agents were processed during the study period. Even when the cost of nonad- herence to rounding practices was included, the actual cost savings was $15,922 out of a potential reported savings of $24,434.²

A third example of dose rounding came from Francis and colleagues in 2015.3 The authors selected three agents—bevaci- zumab, trastuzumab, and cetuximab—to target and compared the cost of prescribed doses to the cost of theoretically rounded doses (5% or 10%) if a decrease in the number of vials was expected.3 The authors reported that of 425 doses, 51 would have qualified for rounding at a 5% dose reduction, which translated to a potential cost savings of $60,648. At the 10% threshold, 24 doses qualified for dose rounding, which translated to a potential cost savings of
$112,585.³

With the widespread interest in this topic and its potential impact on practice in mind, the Hematology/Oncology Pharmacy Association (HOPA) recently released a draft position statement on dose rounding. Six recommendations were established:

1. Based on the limited published data, HOPA recommends that monoclonal antibodies and other biologic agents currently available be dose rounded to the nearest vial size within 10% of the prescribed dose.
2. For monoclonal antibodies with a cytotoxic constituent, HOPA favors using the dose-rounding recommendation applied to cytotoxic agents.
3. HOPA recommends that traditional cytotoxic agents be considered independently for dose rounding within 10% of the prescribed dose.
4. On the basis of the inference that dose rounding will influence clinical safety or effectiveness, HOPA supports the use of the same threshold for dose rounding of anticancer drugs as for palliative and curative therapy.
5. When oral chemotherapy is supplied in more than one strength of capsule or tablet, it is recommended that one strength be used and that the final dose be rounded to avoid confusion for the patient and to eliminate the possibility of multiple copayments.
6. Institutions should develop policies through interdisciplinary efforts, which can be endorsed by a policy-managing body such as a pharmacy and therapeutics committee or an oncology subcommittee. The policy should describe which cytotoxic and monoclonal antibody classes are subject to dose rounding, rounding limits for each class, the process for rounding ordered doses, documentation of such changes, and any applicable exceptions such as drugs supplied in multidose vials or circumstances where prescribers should be consulted before any rounding is done by the pharmacist.

The draft position statement is an excellent resource (and publication of the final position statement is planned for April 2017), but HOPA recommends that each institution develop its own dose-rounding policy addressing both monoclonal antibodies and cytotoxic drugs

References

1. Patel S, Le A. Rounding rituximab dose to nearest vial size. J Oncol Pharm Pract. 2013 Sep;19(3):218-21.

2. Winger BJ, Clements EA, DeYoung JL, et al. Cost savings from dose rounding of biologic anticancer agents in adults. J Oncol Pharm Pract. 2011 Sep;17(3):246-51.

3. Francis SM, Heyliger A, Miyares MA, et al. Potential cost savings associated with dose rounding antineoplastic monoclonal agents. J Oncol Pharm Pract. 2015 Aug;21(4):280-4.