Genzyme Corp’s woes have continued with the news that the company is stopping development of a compound that would have replaced Renvela, its next-generation version of Renagel, for the control of serum phosphorus in patients with chronic kidney disease.

The US firm reported results of a Phase II/III study of its advanced phosphate binder (APB), noting that the trial met its primary endpoint, which was to show that it lowered phosphate levels effectively compared to placebo. However, the APB did not show a significant improvement compared to Renvela (sevelamer carbonate) and Genzyme will not pursue further clinical development as it was seeking to develop a product “with higher potency that would more effectively bind phosphate, while maintaining all the benefits of Renvela”.

In the trial, which enrolled 349 adult haemodialysis patients with hyperphosphatemia, both Renvela and the APB both effectively lowered phosphorus levels. Genzyme added that adverse events associated with both compounds were mild in nature, the most frequent being gastrointestinal disorders.

Analysts are saying that this is a major blow for Genzyme, which booked third-quarter sales of $181.7 million for Renvela and Renagel. Christopher Raymond at Robert W Baird issued a note arguing that "this is a very significant negative in our view” because of the Renagel/Renvela patent expiry looming in 2014. “This programme was seen as the primary vehicle to extend Genzyme's $850-million renal franchise," he adds.

The news comes just days after the US Food and Drug Administration issued a warning about possible foreign particle contamination (with steel and rubber) in five of the company’s products, including Cerezyme (imiglucerase) for Gaucher disease and Fabrazyme (agalsidase beta) for Fabry disease. The contaminated drugs were manufactured at Genzyme’s Allston Landing, Boston facility which was temporarily shut down in June after a bioreactor was contaminated with a virus, affecting production of Cerezyme and Fabrazyme.

One bit of good news for Genzyme came with positive Phase III data on mipomersen, co-developed with Isis Pharmaceuticals for high-risk cardiovascular patients, which has shown the drug can reduce LDL cholesterol levels by 25%. For more details, see today’s PharmaTimes Clinical News.