CMX001 (Brincidofovir)


Brincidofovir (CMX001) Is…


CMX001 appears to be effective against herpesviruses

a ‘novel, oral, broad spectrum lipid acyclic nucleoside’ which inhibits the activity of double-stranded viruses including several herpesviruses as well as adenoviruses and the BKV virus.  An experimental drug derived from antiviral Cidofovir (Vistide)  – which requires a complex  infusion process and frequent blood tests because of the possibility of severe kidney damage, -CMX001 presents the possibility of a safer, more effective, more easily handled drug.

CMX is currently being tested to see if can reduce the rate of infection in transplant patients and as a biological countermeasure against a  terrorist attack involving smallpox.

Increased Safety

Chimerix has modified Vistide so that its more easily taken up into the tissue – thereby eliminating  the need for infusions and  the possibility of kidney damage.  Chimerix’s new ‘packaging’ process is innovative enough for CMX001 to be considered a ‘new chemical entity’ and be protected by patent laws CMX001’s only toxicity worries appear to involve the gastrointestinal system which Chimerix reports are ‘easily monitored and rapidly reversible’.

Increased Effectiveness

Chimerix states CMX001 is not just a little bit more, or even moderately more, but ‘much more potent’ than the original drug (Vistide) in in vitro studies against a wide variety of viruses. A  2012 review named CMX001 as one the ‘ten hot topics’ in antiviral research.


Chimerix announced in March the FDA awarded the drug fast-track status  the prevention of cytomegalovirus infection and was awarded fast-track status for adenovirus infections earlier.  Fast Track status means drugs get priority reviews.

Phase II trials showed CMX001 was well tolerated  and Phase III trials are underway.

Chimerix was incorporated in 2000 and, as of 2013, had 46 employees. In March, 2013 the company filed papers with the Securities and Exchange Commission to go public and is expected to go public soon.  It reportedly hopes to raise in the neighborhood $80 million, most of which will be pumped into CMX001. Chimerix is based in Durham, North Carolina.

Implications for Chronic Fatigue Syndrome

Dr. Peterson’s April 2013 report that 70% of severely ill ME/CFS patients with herpesvirus infections (HHV6, HCMV) improved significantly on Vistide, with many returning to work, suggests CMX001 could be a boon to this subset of patients if approved by the FDA. Given the difficulties it presents in administration Vistide is not used by many ME/CFS physicians, but a safe and effective pill form of Vistide could gain more converts. Given Dr. Peterson’s success with Vistide, FDA approval of CMX001 could be very good news for ME/CFS patients with HHV6, HCMV and/or possibly EBV infections.


Does CMX001 represent a breakthrough in treating herpesvirus infections? Time will tell…..

Chimerix believes its new packaging process will ‘dramatically change the way certain viral diseases are treated. Its website states CMX001 is not just a little bit more, or even moderately more, but ‘much more potent’ than the original drug (Vistide) in in vitro studies against a wide variety of viruses.

Vistide, referred in a tongue in cheek manner on the PR Forums as ‘the Hammer’, was already one of the more effective drugs against herpesviruses. Having this drug available in a safer, more effective form could be a big boon for physicians treating herpesvirus infections.

From Chimerix’s website: 

Based on data obtained to date, CMX001’s profile may allow physicians to treat patients much earlier and more effectively in the disease course, as opposed to many current therapies where the risks of serious and harmful side effects delays treatment.

That makes CMX001 sound almost made to order for herpesvirus infected people with ME/CFS who often need to take large doses of antivirals for long periods of time. Its possible that some ME/CFS patients who can’t tolerate antivirals in the doses needed or don’t respond well to them might very well respond well to CMX001. CMX001’s increased efficacy might also make it more effective at getting at the ‘buried’ herpesviruses infections that often require such long treatment regimes in ME/CFS.….

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