French pharmaceutical group Sanofi reported a plunge in second-quarter profit on Thursday and lowered its year-end forecast, pushing the shares down 6.29 percent. But the company said it expected a return to growth in the second half of the year, and highlighted the unfavourable comparative effect of the ending of some patent rights. Net profit in the second quarter fell by 61.5 percent to 444 million euros ($675 million) and sales fell by 9.8 percent to 8.0 billion euros. This reflected mainly the end of exclusive patents rights to some products -- a so-called cliff effect -- and to exceptional items in Brazil. The net profit on activities, which Sanofi uses as its main performance indicator, fell by 23.4 percent in the quarter from the equivalent figure last year to 1.48 billion euros, disappointing analysts. Sanofi said that as a consequence it was downgrading its target for net earnings per share this year to a fall of 7.0-10.0 percent at constant exchange rates from previous guidance of zero change to a fall of 5.0 percent. The price of shares in the group was showing a fall of 6.29 percent to 75.13 euros in mid-morning trading. The overall French market as measured by the CAC 40 index was showing a gain of 0.20 percent. At brokers Aurel BGC, analyst Tangi Le Liboux commented that the figure amounted to \"a big setback in the second quarter\". The chief executive of Sanofi, Chris Viehbacher, said that conditions in the second quarter had been very difficult but also noted that this would be the last quarter of comparison with a high level of profits last year, because of the effects of expiring exclusive patent rights. However, the fundamental position of the group was just as strong as last year and the group was progressing well on many fronts, notably on research and development and on emerging markets, he said. The group had also suffered from problems in Brazil where it had to manage unduly high stocks of generic drugs. This hit sales to the extent of 122 million euros and had added a provision of 79 million euros.