How lizard spit aids diabetes

A drug that enables Type 2 diabetics to produce more insulin and lose weight opens a whole new chapter in diabetic management

A year ago, when 58-year-old retiree B S Wig, saw the scales tip at 149 kg, he was dismayed. He was diabetic and also increasingly obese. His blood sugar hit a dismal 350 mg/dl after meals. The normal should be under 140 mg/dl. ''I had become weak and refused to socialise. My life had gone haywire,'' says Wig. Till he was put on to a new drug, which not only reduced his weight to a healthy 118 kg, but his sugar levels to normal. ''I can now be dated,'' he says happily.
    Wig is lucky. Most diabetics have difficult lives, with an unending cycle of ill health, weakness and obesity as the pancreas produce little or no insulin, the hormone that converts glucose to energy. Plus, diabetic drugs usually make the patient obese, which adds to the risk of high BP, heart problems and strokes. So it's essential to have drugs which control sugar levels and reduce weight.
    And that's what a new injectable drug, Byetta, does, say experts. It's made from the saliva of the Gila monster, a venomous lizard found in Southwest America. It's the first in a new range of anti-diabetic medicines and is FDAapproved. However, it can be used only on Type 2 diabetics.
    It came to India exactly a year back and now, experts can quantify its success. By 2009, an upgraded version may be available.
    Unlike Type 1 diabetes where there's no insulin secretion, in Type 2, insulin production from the beta cells of the pancreas isn't sufficient. And for Byetta to work, viable beta cells are needed, says Dr Ambrish Mithal, senior endocrinologist, Apollo Hospital, Delhi.
    It works in three ways: It signals the pancreas to make the right amount of insulin after a meal; stops the liver from making too much glucose when the body does not need it, reduces appetite and the amount of food eaten and slows the rate at which glucose leaves the stomach.
    Type 2 diabetics form 90% of the estimated 40 million diabetic cases in India. Almost 80% of them are obese, says Mithal. Adds Dr Pradeep Talwalkar, professor, diabetology, Raheja Hospital, Mumbai. ''It suppresses rise in sugar levels by suppressing glucogon, a hormone which has the opposite effect of insulin.''
    ''Byetta'' says Mithal, ''can produce nausea and vomiting in some patients. It is a niche drug, not for all diabetics, but is a good choice for those who need to lose weight with high post-meal blood sugar rises that remain uncontrolled even on oral medicines.''
    ''Byetta also carries a lower risk than insulin of causing hypoglycaemia, a dangerous condition where the patient can lose consciousness and slip into coma as insulin drops to very low levels,'' says Talwalkar.
    Wig's case is an ideal example. ''I was not judicious about my medicines and kept oscillating between oral medicines and insulin. Meanwhile, my weight and sugar levels went for a toss till I started taking Byetta,'' he says.
    It's important for obese diabetics to lose weight, says Chennai-based Dr A Ramachandran, president, India Diabetics Research Foundation, as obesity makes them resistant to diabetic treatment. ''It is, in fact, an analog for hormones which produce insulin called incretin.'' A weight reduction of 5-6 kg a year is good, says Mithal. Byetta is normally given with oral medicines.
    But it's expensive — around Rs 7,500 monthly. Rimi Dasgupta, a 41-year-old diabetic, who lost 12 kg and with sugar levels which came down to 140 mg/dl from 390 mg/dl, says, ''It's easy to inject, but I don't know how long I can take it as it's expensive. I hope to continue it for a year.''
    Byetta comes in a prefilled injection pen which uses a small needle. This pen contains pre-measured doses, so the patient doesn't have to adjust the dose. It's injected twice daily before morning and evening meals.
    Generally, the patient is started off on a dose of 5 micrograms (mcg) twice a day for at least 30 days, but this could be increased to 10 mcg based on individual results. In clinical trials, it was found that on an average, patients lost five pounds in 30 weeks. However, Byetta cannot be used simply for weight reduction.
    Though there are other new medicines which stimulate the pancreas to make insulin without producing hypoglycaemia such as Januvia and Glavus, says Ramachandran, these don't make a patient lose weight.
    Byetta could just be that shot that makes a difference.