The new formulation, which offers a significantly reduced chance of an injection-site reaction, will replace the existing version of Rebif once the anticipated EU approval is granted in the next few months. Although the company was unable to disclose a vast amount of detail regarding the new formulation, Benedicte Bogh, a spokesperson for Merck Serono, did tell in-PharmaTechnologistt.com that the revamped Rebif was formulated without the use of serum.
"Many biotech products use serum to stabilise the protein, but the new Rebif formulation is human serum albumin free," said Bogh. This may have contributed to the products reported improved tolerability and immunogenicity profile, but further details regarding the new formulation were seen as too commercially sensitive to reveal.
The administration regimen for the new Rebif will be the same as the current version, administered three times a week by subcutaneous injection and available in the same strengths and pharmaceutical forms (i.e. 8.8mcg, 22mcg and 44mcg in pre-filled syringes). The shelf-life of the reformulated product is similar to that of the current version, and the company claims that it does not expect any significant price increase, despite the improved profile of the drug.
Although it may only seem a small step, Bogh stresses that the increased tolerability really is "a great technical achievement," with cases of injection-site reactions in MS patients who received the new formulation three times lower than with other treatments. As well as this, a beneficial effect on immunogenicty was reported due to lower levels of antibody production.
In terms of the impact on revenues generated by the revised formulation, Bogh said that the company expects the new version to "support the strong competitive position" that the current form of Rebif enjoys. Rebif is the company's best-selling product, accounting for 58.1 per cent of the firm's product sales and generating sales of $1.45bn (€1.1bn) worldwide over 2006. According to Merck Serono, Rebif is currently the leading treatment for relapsing MS outside the US, though the company is expecting to face increased competition from both existing and new MS treatments.
However, in addition to potentially reinforcing the position of Rebif in the market thanks to the improved formulation, Merck Serono is also in pole position in the race to be the first on the market with an oral MS treatment, the race for which is hotting up as competing companies edge towards late stage clinical trials. The company earlier this year announced that it had completed enrolment in its Phase III trials for Movectro, its proprietary oral formulation of cladribine. Although Novartis is not far behind and planning Phase III trials of its compound FTY720 (fingolimod) and both companies hoping to file in 2009, according to Bogh the company believes it is "on track to be the first on the market with a disease modifying oral treatment for MS".