A Tale of Drug Company Collaboration on a Rare Disease

The PML Consortium formed among several pharmaceutical companies to prevent and treat a rare disease that emerged among patients taking immunomodulatory drugs. It could offer a model for finding solutions for adverse drug reactions.

Pharmaceutical companies compete, but sometimes collaboration is important, too. A new commentary in Advances in Therapy highlights how a consortium formed (and then disbanded) to address a rare disease that appears as a severe reaction to immunomodulatory therapies.

Progressive multifocal leukoencephalopathy (PML) is a possibly fatal inflammation of the white matter in the brain caused by the JC virus, and occurs in patients who already have weakened immune systems. As PML emerged in the mid-2000s, multiple drug companies formed the PML Consortium to find ways to prevent or treat this disease.

The authors explain that while PML was long recognized as a risk for patients with HIV, it emerged among patients with multiple sclerosis as they began to take natalizumab, then among more patients taking other new immunomodulatory drugs. The PML Consortium’s first members were Roche, Elan, and Biogen Idec; later, Pfizer, Takeda, MedImmune, and Bristol-Myers signed on to share information and collaborate in other ways.

The authors state that the PML Consortium not only succeeded, but it is also a model for other joint efforts to address adverse reactions to new drug classes.

Among the consortium activities outlined in the commentary:

  • Members developed a research program to expand knowledge of PML, which featured a scientific advisory board and invested more than $5 million in 17 grants.
  • The group addressed clinical issues, such as drug candidates for prophylaxis and identified T-cell deficiencies as a risk factor for PML.
  • The consortium identified key research questions, including where the JC virus is harbored, why does the virus cross the blood-brain barrier, what factors restrict virus replication or, conversely, how does the virus suppress antiviral signals?
  • Members worked to raise awareness of PML across the scientific community, to reduce misinformation, and to engage regulators in the United States, Canada, and Europe.

Since 2009, the authors wrote, “The ability to stratify PML risk improved, enhanced risk management plans were implemented, and increased awareness helped support earlier intervention.”

In this manner, the group reduced the need for urgency for a breakthrough to treat PML, but in doing so, this also limited the group’s ability to sustain research efforts. The board disbanded the consortium “after 8 years of intense collaboration.”

The authors state that board members and scientific advisory board members see the consortium as a model worth repeating, particularly when new drug classes produce adverse events. “It allows researchers from across sectors to work together in ways they could not otherwise,” they wrote. “Furthermore, this model has value because it enables more effective use of resources,” which brings progress more quickly than would occur otherwise.


Peterson IS, Iverson Wo, Kasaian MT, Liu M. The progressive multifocal leukoencephalopathy consortium as a model for advancing research and dialogue on rare severe adverse drug reactions [published online February 13, 2019]. Adv Ther. doi:org/10.1007/s12325-019-0886-2.

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