Table 1 – Proposed criteria for evaluation of orphan drugs and corresponding potential parameters

Rarity

1:2,000 - 1:20,000 or COMP figures > 3 in 10,000 (11%)

1:20,000 - 1:200,000 or COMP figures 1–3 in 10,000 (51%)

Less than 1:200,000 or COMP figures less than 1 in 10,000 (38%)

Level of research undertaken

Literature review

Building on previous existing knowledge

“Blue-sky” – starting research & development programme in an unknown area

Level of uncertainty of effectiveness

Immature, but promising data

Appropriate surrogate end-points

Robust clinical end-points

Manufacturing complexity

Not complex – small molecule / classic galenic form

Moderately complex

Highly complex biological and galenic form

Follow up measures (additional benefits and associated costs)

Moderate to none

Designed to answer specific, defined, delineated question

Safety and efficacy studies + size and duration of study

Characteristics without direct cost impact

Disease severity

Morbidity

Mortality / severe invalidity in adulthood

Mortality / severe invalidity as infant

Available alternatives / unmet medical need

Alternatives with similar characteristics

Alternatives – but offering strong innovation to the disease treatment

No alternative

Level of impact on condition / disease modification

Low

Medium

Strong

Use in unique indication or not

Existing orphan or non-orphan indications for the same molecule*

Potential for multiple indications

Unique indication – no other use possible