Drugs that could target disease in certain ethnic groups are causing controversy
Some diseases are known to affect certain human populations particularly severely. Sickle-cell disease, for example, is more common in African/Caribbean groups; people of South Asian origin are particularly prone to type 2 diabetes.
Although such observations are relatively uncontroversial, the idea that medicines could be targeted at particular ethnic groups is an ethical hot potato.
The difﬁculty is both scientiﬁc and social. For a condition such as sickle-cell disease, the cause of the high incidence is clear – it arises from a mutation in a haemoglobin gene, which has survived because it provides protection against malaria. But for more complicated conditions, the situation is less clear. Do biological or social factors underpin a high incidence of disease? Is heart disease in, say, someone from Denmark the same as that in someone from Bangladesh?
We currently don’t know enough about disease mechanisms to answer such questions conﬁdently. And the concern is that by proposing that genetic factors predispose certain groups to a disease, it may reinforce the idea of genetically distinguishable ‘races’ – something that touches upon a long and disturbing history of discrimination.
On the other hand, if factors speciﬁcally affecting one ethnic group could be identiﬁed, treatment for that group might be improved.
Of central importance is the notion of ‘race’. Crucially, race is a social label, not a scientiﬁc one: it is one way in which society groups people, but it has no underlying scientiﬁc principles. Some people argue that it is useful – races may reﬂect some genetic substructure, including variation that affects health.
In 2005, BiDil became the first prescription drug for the treatment of congestive heart failure specifically in African Americans. African Americans have a high incidence of this condition, which involves the progressive weakening of the heart muscle, and do not respond well to other treatments. Its link to race has been further complicated by its economic backdrop. The drug was initially rejected by the US licensing authorities. After a reanalysis of clinical trial data, it was then ‘reinvented’ as a medicine for African Americans, which provided new patent protection.
Although the clinical trial data suggested that African Americans responded better to BiDil, many argued that this was not due to a genetic predisposition. It has been suggested that the difference in response was merely caused by the fact that the African American patients were ‘more ill’ than people of the same age but different race.
The issue of race-based drugs remains a controversial topic. Race is a crude marker for variation in responses to drugs. It’s possible that the rise of pharmacogenetics will enable a better understanding of how different groups of people have varying responses.