The roughly 8% of Canadian diabetics
who were using the inhaled insulin Exubera got an unpleasant
surprise on October 18 when its maker pulled the drug
for financial reasons. The puffer worked as well as
injections but was slow to catch on with MDs and patients.
But other alternatives to injected
insulin, from pills to patches, are appearing on the
market and in development for physicians and their patients
to choose from. "We're like mechanics and we need to
have toolboxes full of tools," says Dr J Robin Conway,
director of the Diabetes Clinic in Smiths Falls, ON.
"The more tools we have, the better results we can get."
"Diabetes is a progressive disease,"
he adds. "Over time everybody is going to have to be
treated with insulin." Type I diabetics rely heavily
on it, needing both a constant, basal amount in their
system, and a quick fix or bolus to be taken with meals
to deal with the mealtime sugar hike. In type II diabetes,
it comes in handy when other methods, like diet, exercise
or oral meds, aren't enough to control blood sugar.
And the most readily available way to get that insulin
is through injection. But, as Dr Conway notes, "Patients
sometimes don't want to take the needle."
Here is the lowdown on the latest
insulin alternatives available now — and coming
soon to your toolbox.
ON
THE MARKET
Pens The popular pen-sized devices are a light,
easy-to-use alternative to syringes. "And they have
very fine tips coated with Teflon, so they don't hurt,"
Dr Conway adds. The pens are filled with an insulin
cartridge and a dose is dialled in by turning the bottom
of the pen. The tip of the pen — the actual needle
— goes just under the skin when the release mechanism
is pressed. Both the cartridge and the needle are disposable.
Pumps Several models of
the pump are available and are about the size of a pager.
They're made up of an insulin reservoir, a battery-operated
pump and a computer chip that controls dosage. The pump
is linked via a thin plastic tube to a cannula —
a soft type of needle that gets inserted under the skin,
usually on the abdomen. Tubes can be disconnected for
showering, and the cannula, which remains stuck to the
skin, is changed every two days.
The system offers a constant stream
of basal insulin and can be adjusted to give a bolus
jolt at mealtime. Abscess formation or skin infections
have been known to happen with the pump, but using skin
cleansers and changing the injection site regularly
helps combat these problems.
Insulin jet These needle-free
'syringes' with disposable nozzles use pressure to shoot
insulin through the skin. The syringe is filled with
the required dose from an insulin vial and the insulin
gets delivered with one easy push of the button.
IN
THE PIPELINE
Inhalers "Technically, this is a bolus insulin
only, but in experimental studies, people who used inhaled
insulin had improved fasting glucose as well," says
Dr Conway.
The decision to pull the plug on
Exubera was an economic one — the device was more
expensive than pens and syringes, and there were simply
not enough takers. But other companies are hard at work
on their own puffers, using either liquid or powder
insulin. Generex's Oral-lyn, with its liquid insulin
inhaler that gets sprayed into the mouth, is currently
in late stage clinical trials, as is Novo Nordisk's
AERx, which is expected to hit the market within a couple
of years.
A couple of concerns with this
method are the waste of insulin — since only a
fraction of the inhaled insulin makes it to the bloodstream
— and the unknown longterm effect on the lungs.
The concept is good, but the devices need a little fine-tuning,
says Dr Conway.
Pills "You can't eat insulin,"
says Dr Conway. "It gets broken down by the GI tract."
So scientists are working on ways to circumvent that
— with promising results. The latest buzz, out
of Syracuse University, is that insulin, when attached
to vitamin B12, can travel safely through the GI and
make it to the bloodstream.
Their study, appearing in December's
ChemMedChem, says the basal insulin delivered
this way can last in the rats' system for up to eight
hours. But human trials are still a long way off. "I
don't think the pill would be coming to market for another
decade," says Dr Conway.
Transdermal Scientists are
working on patches using electrical currents, ultrasound
waves or chemicals to deliver insulin through the skin,
but they won't be out for a while yet.
Nasal spray Intranasal insulin
has also been tried, but has so far shown poor absorption
and caused nasal irritation.
But Dr Conway is optimistic. "We
will have other technologies," he predicts. "New devices
are being developed, which will improve convenience
and lower costs."
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