(A-141) Contribution to the Development of the ATC/DDD Classification System from Italian Working Group on DDD: Assigning a Defined Daily Dose (DDD) to Anti-Angiogenic Drugs (ATC S01LA)

Background: The Defined Daily Dose (DDD) is a standardized unit for measuring drug consumption. DDD assignment is carried out by the WHO Collaborating Center of Oslo only upon request. Therefore, not all active substances in the ATC/DDD index have already received a DDD.

Objectives: The Italian working group on DDD (Ita-wg-DDD) was established with the aim of contributing to the development of the ATC/DDD system. Herein, we report on the work of Ita-wg-DDD on the assignment of DDDs to anti-angiogenic ophthalmic drugs (ATC S01LA).

Methods: We identified S01LA drugs currently marketed in Italy without WHO-assigned DDD. WHO guidelines, medicines’ labels, and evidence on real-world utilization were considered for assignment. According to the reporting framework developed by ITA-wg-DDD, reference indication, reference daily dosage (RDD), assignment criteria, calculation formulas were described for each assigned DDD.

Results: Twenty medicinal products packages corresponding to six ATC V codes were identified. For the six substances, the primary indication was age-related macular degeneration. In one case, the DDD matched the RDD (S01LA04 = 0.5 mg); in four cases, the RDD was divided by days of therapy cycle (S01LA05 = 0.06 mg, S01LA06 = 0.64 mg, S01LA08 = 0.04 mg, S01LA09 = 0.21 mg); in one case, RDD was multiplied by a body surface area (1.81 m2) of reference (S01LA01 = 10.8 mg).

Conclusions: Six DDD were assigned to a corresponding number of S01LA drugs. This work will be shared with WHO International Working Group for Drug Statistics Methodology to be considered for inclusion in the ATC/DDD index.