Gene testing before biologic testing likely to save money

[Guest guest]

Nov 4, 2002

Gene testing before biologic testing likely to save money

New Orleans, LA A flock of posters at the American College of Rheumatology

meeting presented bits of data on genes whose variations affect response to

several biological agents such as those targeting tumor necrosis

factor-alpha (TNF) or interleukin-1. A genetic marker was reported for

response to pulse cyclophosphamide in lupus nephritis, and changes in

genetic expression in response to treatment with disease-modifying

antirheumatoid drugs (DMARDs) were also noted. These data are primarily of

research interest at present, but investigators are beginning to work on

putting genetic profiling tests together into a screening tool, probably a

form of DNA chip, that could provide a " pharmacogenetic profile " of the

individual patient before treatment. Such a profile would predict which

drugs the patient is likely or unlikely to respond to and might also be

useful for monitoring response to therapy. The new biologicals cost $10 000

to $20 000 per year, and avoiding giving them to patients who are

genetically unable to respond could save major amounts of healthcare dollars

as well as sparing patients the expense and unnecessary risk of side effects

of treatment with a drug from which no benefit can be reasonable expected.

Dr Alan Brennan (University of Sheffield, UK) predicted that pretreatment

phamacogenetic testing before treating patients with the IL-1 receptor

antagonist anakinra and treating only those who carry the IL-1A+4845 allele

known to be associated with treatment response would reduce costs during

next 3 months by 35% (from $3745 to $2421) [1]. Pretreatment testing would

also reduce the cost per responder achieved at 3 months by 17% (from $7842

to $6513).

" [The] application of genotyping technology to improve the benefit/risk

ratio of treatment for individuals with a known clinical disease holds great

potential for decreasing healthcare cost while improving outcomes by

improving the effectiveness of prescription drug use, " Brennan said.

The study model used data from studies of responders and nonresponders

treated with anakinra (annual drug cost: $15 056), etanercept

($16 986/year), infliximab ($20 589/year), or conventional maintenance

therapy ($500/year). The model treatment pathway said that after 6 months of

therapy, response was evaluated using ACR20 criteria. " Responders " continued

treatment and were assumed to experience an improvement in HAQ scores over

the previous 6 months. " Nonresponders " in the model withdrew and tried the

next treatment in the sequence, much as rheumatoid arthritis (RA) patients

are switched to a different therapy if the first 1 is not sufficiently

effective.

Brennan's model also assumed that phamacogenetic testing would cost $200.

Conversations with industry scientists working on commercialization of such

tests suggest that the real-world cost is unlikely to be less than $500.

Janis

Cited source

1. Brennan A. Methods to analyse the economic benefits of a pharmacogenetic

(PGt) test to predict response to biologic therapy in RA, and to prioritise

future research. The American College of Rheumatology meeting [abstract

145]. 2002. Available at: http://www.rheumatology.org.