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pharmafile | November 3, 2008 | News story | Sales and Marketing | Acomplia, Sanofi
Acomplia's EU suspension dispels illusion of blockbuster future
The EMEA has suspended Acomplia due to the risk of serious psychiatric disorders. The anti-obesity agent had been promised a sure success by numerous analysts, as it addressed indications beyond obesity. However, Acomplia failed to win approval in the US, and just two years after the EU approval its sales have been completely halted, leaving the potentially vast anti-obesity market bare again.
Over a year after the FDA concluded that Acomplia's benefits did not outweigh its risks (June 2007), the EMEA's Committee for Medicinal Products for Human Use (CHMP) has come to the same conclusion, forcing Sanofi-Aventis to withdraw the drug. Under the suspension, Sanofi can still continue the phase III research, and if additional supportive data are available in the future, the agent may reappear on the market.
However, such an outcome is very unlikely given the current post-marketing experience, which indicates that serious psychiatric disorders may be more common than in the clinical trials used in the initial assessment of the medicine. As for the US, Sanofi is planning to reapply to the FDA in 2009 Q4, but for a diabetes indication this time. This may be a strategic move to avoid the non-reimbursement of obesity drugs as lifestyle agents. However, the current regulatory climate in the US is very conservative, and growing more so. It is therefore hard to visualise a drug with known serious adverse effects successfully reaching the US market.
The CHMP confirmed that there is an approximate doubling of the risk of psychiatric disorders in obese or overweight patients taking Acomplia (rimonabant) compared to those taking placebo. Even in pre-marketing studies with rimonabant, depression and other psychiatric side effects were the biggest concern. The clinical trials excluding patients with depression alarmed opinion leaders and physicians with their rate of depressed mood disorders. The side effects profile limited the patient potential of rimonabant dramatically, since a lot of the obese patients tend to have an inclination to depression.
Moreover, it appears that the effectiveness of Acomplia in clinical practice is more limited than was expected on the basis of the trials, because available data indicate that patients generally take Acomplia only for a short period. As previously highlighted in Datamonitor research, the main reason behind low compliance is the non-reimbursement of obesity medication in most of the major markets. Together with the concerns raised by Acomplia's safety profile, this low level of compliance led Datamonitor to believe that the drug would not become a blockbuster, in contradiction to the many forecasts predicting success. At one point, Sanofi forecasted the annual sales of the agent to be over $3 billion – now it is clear that even if Acomplia returns to the market, these expectations will not be realised.
The recent discontinuation of Merck & Co's taranabant, another CB1 endocannabinoid receptor modulator, due to psychiatric side effects, further darkens the shadows around the development of this class of agents (including Pfizer's otenabant, currently in phase III development) for the treatment of obesity, a highly prevalent condition presenting high unmet needs.
The number of available drugs in each of the seven major markets is marginally low. Most of the markets have only Xenical (orlistat) and Reductil (sibutramine) approved for treatment of obesity. Orlistat is preferred to sibutramine in all countries, due to its good safety profile, but is plagued with poor tolerability, which makes special patient education regarding the optimal use of the drug crucial. Sibutramine is not popular with physicians due to its side effects, particularly the raising of blood pressure. Since a lot of obese people develop hypertension, a large proportion of obese population has to be screened out of treatment with sibutramine. The compound also does not boast high efficacy.
Apart from concerns specific to each of the available drugs, a major issue is the efficacy of the agents being far below the patients' expectations. The high cost together with the lack of reimbursement, poor safety/tolerability, and low efficacy compared to expectations lead to poor compliance and high discontinuation rates, significantly limiting the size of the anti-obesity market and minimising the prospects of novel agents. This in turn leads to low interest in obesity R&D, which has been demonstrated by Pfizer announcing its exit from the heart and obesity development arena for more lucrative areas. The vicious circle results in obesity remaining the blind spot of pharmaceutical progress.
Related research
Commercial and Pipeline Perspectives: Obesity – Lack of Reimbursement Limits Market Potential
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