KEY POINTS:
A recent Herald report mentioned an exciting development in the research of a vaccine to prevent rheumatoid arthritis.
Unfortunately, unless there is a change in Pharmac policy, this will not be available in New Zealand for many years after it becomes standard practice elsewhere in the world.
Rheumatoid arthritis is not only a painful disease - it can cause crippling deformities which often require numerous orthopaedic procedures to correct, including joint replacements. However, the outlook has been better over the past 10 years, with newer medicines which are collectively known as "biological agents" being subsidised.
These were initially used for children with rheumatoid arthritis after public pressure, and later extended to adult rheumatoid arthritis as an equity issue, well after being funded in Britain and Australia.
The initial drug used for children was Enbrel and the drug subsidised for adults was Humira. These drugs block a chemical substance called TNF alpha which is responsible for inflammation, thinning of the cartilage coating the ends of the bones in the joints, and an increase in the body cells which cause joint damage by eating away the bones themselves.
By causing a significant reduction in the joint destruction which promotes the disability and deformity characteristic of rheumatoid arthritis, these TNF alpha inhibitors have revolutionised the treatment of rheumatoid arthritis. But unfortunately their manufacture requires an expensive process involving micro-organisms.
Because of the expense, this means that they are used only when other disease-modifying anti-rheumatic drugs, when used in combination, have not provided benefit, which is a socially responsible use of the pharmaceutical budget.
Not so socially responsible is the attitude of Pharmac to the subsidy of alternative agents in the minority of patients with rheumatoid arthritis who do not respond to the TNF alpha inhibitors.
Overseas, such patients would have either an alternative from the same class of agents or, perhaps more logically, another biological agent which acts by a different mechanism, and which has been shown in trials to be equally effective.
Such an agent is MabThera, which has an interesting pedigree.
Rheumatoid arthritis inflammatory tissue contains an excess of white cells which modulate the immune system, called B lymphocytes.
A malignant excess of these lymphocytes in the normal population can lead to a condition called lymphoma, for which MabThera (also called rituximab), has been shown to be very effective.
At a time when most rheumatologists were focusing their research on the related T lymphocyte, an English researcher, Jo Edwards, was doing trials using rituximab to deplete the B cells in patients with rheumatoid arthritis.
A course of MabThera involves giving the medicine intravenously with a further dose given two weeks later.
These trials have also been done at Middlemore with patients who had failed Methotrexate, the current standard medication for rheumatoid arthritis, and to everyone's delight when the code was broken it was revealed that the patients receiving MabThera had up to 10 months of pain-free remission from their arthritis.
No pain, no swelling, no tenderness, and when these symptoms and signs returned a second course of MabThera was equally effective.
International rheumatology experts are now talking of remission rates of 50 per cent with these biological agents, whose expense relates to the complexity of manufacture.
By remission we mean no inflammation, minimal pain and absence of the destruction which in the past would mean that patients would require up to 15 joint replacements, with all the costs associated with these procedures, including time off work.
But at least patients with rheumatoid arthritis have access to one biological agent whereas patients with the related and equally devastating arthritic conditions, psoriatic arthritis and ankylosing spondylitis, have no access to these TNF alpha blocking drugs despite international experience of the effectiveness of Humira and related drugs.
The evidence has been sufficiently convincing for this medication to have been subsidised in Britain and Australia for years, and for the New Zealand Pharmacology and Therapeutics Committee to have given it a moderate to high rating for funding.
Despite this recommendation to Pharmac the drugs have not been funded and no reason for this inequitable decision has been given.
Unlike your report of a vaccine which might offer hope of significant benefits with rheumatoid arthritis and related conditions in five years, these biological drugs are medicines which could revolutionise the treatment of these diseases today.
* Associate Professor Peter Gow is a rheumatologist at Counties Manukau DHB where he is involved in clinical research trials of Humira and MabThera in patients with rheumatoid arthritis.
