Desperate dieters may find that a new anti-obesity treatment is not to be sniffed at.
Desperate dieters may find that a new anti-obesity treatment is not to be sniffed at. US company Nastech Pharmaceutical claims to have got promising results from the first round of clinical trials on its nasal spray to help treat obesity.
Nastech designed the spray to deliver a hormone called PYY 3-36 to the bloodstream. The hormone is released from the gastrointestinal tract after eating to tell the brain when the body is no longer hungry. In clinical trials, volunteers took daily doses of either a placebo or the PYY 3-36 nasal spray one hour before each meal. During an eight day trial, subjects were given no dietary instructions to reduce food intake and did not exercise or even leave the clinical study centre.
Nastech researchers claim that the nasal spray caused a ’significant, sustained caloric reduction’ and that those who cut their calorie intake during a meal that followed the treatment did not then compensate at subsequent meals by eating more. The downside of the nasal spray appears to be that 11 per cent of the PYY doses administered caused nausea.
Stephen Bloom from Imperial College London led the team that originally identified PYY 3-36 as an important factor in generating satiety ( Chem. Br., November 2002, p15). At the time, Bloom said that the discovery that PYY 3-36 suppresses appetite could be of ’huge benefit to those struggling with weight problems’.
Bloom is unsurprised that the spray could cause nausea: ’High blood levels [of PYY] produce more than satiety, ie nausea,’ he told Chemistry World. However, he said that ’PYY has its effects on appetite for many hours (long after nausea has worn off) and is thus a useful way of regulating appetite’.
Bloom considers that by finding a way of administering PYY without the need for injection, Nastech has made a ’significant contribution to the art. The nausea is a problem but it affects only a few volunteers and ways round it are likely to be found. Meanwhile, it is potentially a very useful way of losing weight’.
However, Nature published a letter from 43 leading researchers questioning the efficacy of PYY 3-36 after Nastech’s data were released. Bloom has responded in the same issue (8 July, 2004), but this is clearly controversial.