August 7, 2015
By Alex Keown, BioSpace.com Breaking News Staff
CAMBRIDGE, Mass. – Shares of Biogen, Inc. stock dropped more than 5 percent after Dutch doctors published a report in the “The New England Journal of Medicine” saying more cases of brain infections may occur in patients taking drugs similar to the company’s top multiple sclerosis treatment.
Shares dropped to $316.60 per share by the end of trading Thursday.
In their report the doctors noted that patients who take dimethyl fumarate, which Biogen markets as Tecfidera, are at “risk for opportunistic infections, ” including progress multifocal leukoencephalopathy (PML), which may initially present as new or worsening weakness in the body. The Dutch physicians who sent the letters said a 23-year-old patient was being treated with dimethyl fumarate to treat psoriasis who then mysteriously developed varicella–zoster virus, which the physicians said may have been triggered by the regiment of dimethyl fumarate.
“Further studies concerning safety monitoring and new methods for identification of patients at risk are therefore urgently needed,” the doctors who sent the letters said.
On Nov. 25, 2014, the FDA announced a patient taking Tecfidera for multiple sclerosis died of PML. The woman had been on a Tecfidera regimen for four years.
“Prior to developing PML, the patient had a very low number of lymphocytes, a type of white blood cell, in her blood. Reduced lymphocyte counts can weaken the immune system, which increases the risk for PML. It is unknown whether the low lymphocyte count contributed to the development of PML in the patient, or if low lymphocyte counts are a risk factor for PML development in Tecfidera-treated patients,” the FDA said.
Following last year’s death of the patient taking Tecfidera, Biogen included a label warning that PML is a risk factor.
In April, Dutch physicians published a study in the New England Journal of Medicine outlining the death of a patient who had been taking dimethyl fumarate for the treatment of psoriasis. The 64-year-old patient developed progressive apraxia (speech problems), and was eventually diagnosed with treatment-related PML, although the initial diagnosis was atypical ischemic stroke. The medications the patient took were put together at a compounding pharmacy, not by Biogen. Responding to a BioSpace inquiry, Biogen spokewoman, Catherine Falcetti, said comparing the risks of a pharmacy-mixed drug to Tecfidera is not scientifically appropriate. The compound pharmacy drug is basically unregulated and varies from Tecfidera on the amount, specific formulation, doses and specifics of the active substances, she said.
Tecfidera sales are predicted to reach $3.6 billion this year and $5.2 billion by 2020, Bloomberg said. About 155,000 patients have been treated with Tecfidera worldwide, Bloomberg said.
Tecfidera is not the only drug linked to PML. Novartis AG ’s Gilenya, also used to treat multiple sclerosis, has also been linked to as many as two cases of brain infection, the FDA said. Bloomberg notes that Gilenya is not a dimethyl fumarate like Tecfidera.
