Chimerix scores promising antiviral data from a controversy-fueled PhIII pilot

Chimerix CEO Michelle Berrey

Chimerix reports that its pilot Phase III study of the powerful antiviral brincidofovir has posted promising preliminary data, cutting the risk of death from lethal adenovirus infections by as much as half or more.

The Durham, NC-based biotech ($CMRX) spread the word that the mortality rate for 48 evaluable patients taking the treatment in an open-label study was 35%, while historic rates would suggest a rate closer to 80%. And CEO Michelle Berrey says that the company has also made some significant progress toward a planned pivotal follow-up, raising awareness of the treatment in key centers that will play a big role in late-stage development work.

One of the patient success stories for this study was reported for young Josh Hardy, who was declared to be recovering soon after he was treated in the pilot back in March. After Chimerix earlier rejected Hardy's parents' plea for the compassionate use of the treatment outside of a clinical trial, the pair took to the Internet and quickly drummed up a storm of controversy over the company's contention that it couldn't afford to provide the drug for all the compassionate use requests it was receiving. 

Social media enthusiasts, as well as a big crowd who watch cable news shows religiously, made their feelings known in an unprecedented popular assault on the executives who run the biotech, a small company that was frequently branded as an unfeeling pharma operation. Then CEO Ken Moch said at the time that the company had come up with the pilot study compromise --"here's what we were trying to accomplish during the entire time"--and was out the door of the company soon after.

As a public relations exercise, the pilot worked well, with the anger dissipating as soon as Hardy was treated. As a drug development strategy, Berrey says the pilot has been a big help for Chimerix. In addition to the positive survival trend, a majority of subjects with compromised immune systems also "had suppression or clearance of adenovirus from the blood."

Of the 26 patients with at least two months of follow-up, 14 of 23 patients with viremia--virus in the blood--achieved undetectable virus levels and 12 patients died.

Over half of the patients in the study "were hematopoeitic cell transplant recipients with disseminated disease, but solid organ transplant recipients and patients undergoing chemotherapy were also enrolled. Over one-third of the subjects (10 of 26) had a second active infection with another DNA virus in addition to adenovirus, including BK (27%), cytomegalovirus (19%) and Epstein Barr Virus (8%). As of the data cut, 61 percent (15 of 23) of subjects had undetectable adenovirus viral loads and 35 percent had died (9 of 26)."

When the company started talks with the FDA about the pilot, says Berrey, regulators suggested that it could be limited to 20 patients. A few days later, the number suggested by the FDA swelled to 100. The FDA's main concern was patient access, says the CEO, summing up the agency's view as: "Let's make sure you don't end up in the same media storm." 

For Chimerix, it was important to channel demand for the antiviral into a study rather than simply handle all emergency situations on a case-by-case compassionate use basis. And that strategy has now been extended to Ebola, where the biotech and the agency have been hammering out a new study after the antiviral was reportedly provided to a patient in Dallas.

Studies, she says, are much more helpful in developing this treatment. 

"The first patient at each site has been eye opening for many of these centers," says Berrey. Without any effective remedy before, physicians hadn't been aggressive about diagnosing adenovirus infections. Now, with the pilot study raising the profile of brincidofovir, she expects that the Phase III will help spur earlier diagnoses--which should lead to even better outcomes ahead.

Brincidofovir is a lipid-conjugated version of cidofovir specifically designed to amp up the antiviral impact with a pill while sparing kidneys from a toxic threat. Its ability to get into cells more effectively than cidofovir has vastly improved its punch against all 5 DNA viral infections. And Berrey says that all the data gathered so far suggest that the treatment is not a threat to patients.

Wende Hutton, a general partner at Canaan and until recently a board member at Chimerix, told FierceBiotech earlier that the Chimerix experience had prompted her to suggest social media training for all of the biotech execs she works with.

- here's the release 

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