* Reduction in disability progression and brain lesions
* White blood cells fall, but infections similar to placebo
* Merck to file oral MS drug cladribine in mid-2009
* Shares up 2 pct
(Adds shares, comment from Merck pharmaceuticals head)
By Ben Hirschler
LONDON, April 30 (Reuters) - Multiple sclerosis sufferers taking Merck KGaA’s (MRCG.DE) oral drug cladribine are less likely to become disabled and brain scans show the medicine cuts the risk of damaging lesions, researchers said on Thursday.
New clinical study results show the drug also causes a reduction in white blood cells, but the overall rate and incidence of infections is similar to placebo. The German drugmaker, which presented detail from a Phase III clinical trial at a medical meeting in Seattle, is leading the race to develop the first multiple sclerosis drug that can be taken orally, rather than by injection or infusion.
Merck, whose shares rose 2 percent in early trade on the news, reiterated that it planned to submit its cladribine tablets for U.S. and European approval in mid-2009.
Cladribine, like a rival oral drug called FTY720 from Swiss drugmaker Novartis AG NOVN.VX, appears more effective than current leading treatments.
But both experimental drugs have serious side effects because they interfere with the body’s immune system. As a result, the companies must persuade physicians and investors that the balance of risk and benefit stacks up.
Elmar Schnee, member of the Merck executive board responsible for pharmaceuticals, said he did not see any limitations for the use of the drug in patients with relapsing remitting MS, based on the study results.
“We are very encouraged by this positive side-effect profile, leading to a good efficacy risk balance for patients eagerly awaiting a short-course oral treatment,” he told Reuters.
Lead investigator Dr. Gavin Giovannoni of Barts and The London School of Medicine and Dentistry said cladribine had achieved all its primary and secondary endpoints in the study.
Merck had already said in January that patients on low-dose cladribine enjoyed a 58 percent relative reduction in annualised relapse rates compared to placebo, but full details were held back for the American Academy of Neurology meeting in Seattle.
Significantly, cladribine led to a more than 30 percent reduction in the risk of disability progression and there were also sustained reductions in brain lesions, as measured by magnetic resonance imaging (MRI).
In addition, there was a significant increase in the proportion of patients who remained relapse-free.
The overall incidence of adverse side effects was comparable to that seen in patients on placebo, but lymphopenia, or abnormally low white blood cell levels, occurred in 22 percent of those on low-dose cladribine and in 31 percent of high-dose patients.
The rate of infections in patients treated with cladribine was similar to placebo, although herpes zoster skin infections were reported in 2.3 percent of treated patients.
As previously announced, there were four cases of cancer among people taking cladribine. Researchers said they comprised one each of cervical, melanoma, ovarian and pancreatic cancer.
Novartis gave an update on its MS drug FTY720 on Wednesday. [ID:nLT735142] (Editing by Simon Jessop)