UPDATED: AdverseEvents: New generation of hep C meds bests older therapies in side-effect reports

AdverseEvents' Keith Hoffman

The latest generation of hep C meds came to market with big promises for change. Older therapies were saddled with harmful side effects, while newer, all-oral and interferon-free therapies would result in fewer safety issues for patients.

Companies often make such promises for new generations of meds. While the newer generations don't always live up to their hype, the latest batch of hep C therapies--including Gilead Sciences' ($GILD) Sovaldi and Harvoni--show key safety advantages over older treatments, according to a recent analysis by healthcare informatics firm AdverseEvents.

"Everyone assumes that a newer generation is safe, and oftentimes, it's not. But in this case it's true," Keith Hoffman, vice president of scientific affairs at AdverseEvents, told FiercePharmaMarketing. "Some of the drugs in the older generation of hep C meds are only a couple years old, but we're already seeing an incredible shift in the efficacy and safety of these drugs."

The company looked through the FDA's Adverse Event Reporting System (FAERS) for reports on hep C treatments and used its own algorithms to pinpoint case reports linked to a specific therapy. Sovaldi and Harvoni were linked to fewer serious side effects in postmarketing data. Merck's ($MRK) Victrelis (boceprevir) and Vertex Pharmaceuticals' ($VRTX) Incivek (telaprevir) turned up more cases of serious side effects than Harvoni or Sovaldi, ranging from anemia and rash to anorectal discomfort and influenza-like illness. The firm's analysis of Victrelis found 880 cases of anemia and 198 cases of neutropenia, or low white blood cell count. And its analysis of Incivek showed 5091 cases of fatigue, 4160 cases of nausea, 1360 cases of flu-like illness and 2009 cases of anorectal discomfort.

But it isn't all smooth sailing for Gilead's hep C wunderkinds, as the AdverseEvents report also uncovered some serious side effects linked to the newer meds--Sovaldi in particular. The company's analysis turned up 100 cases of overdose, 49 cases of accidental overdose and 47 cases of increased blood bilirubin, or bile in the blood, for the $84,000-per-treatment course med. None of the other meds in the firm's report showed the blood bilirubin increase, which could be a sign of bigger problems further down the line, Hoffman said.

"I think what the manufacturer would say is, this is being given to some of the worst-off patients, so they'll be having some of those issues. They'll assume it relates to the patient's state already and not the drug-induced effect," he said. "It might not be a true signal yet but it's something to keep our eye on."

And the jury is still out on AbbVie's ($ABBV) Viekira Pak, Hoffman added. AdverseEvents did not analyze the drug in its report because it is still waiting for more postmarketing data on the recently approved med. But the company is not optimistic that Viekira Pak's safety profile will top Harvoni's or Sovaldi's, he said. The drug has four active ingredients and a long list of side effects on its FDA-approved label, including liver inflammation, nausea and rash. And regulators advise against using the med in hep C patients with severe liver impairment and with other major drugs.

"It's very hard to draw postmarketing conclusions yet on Viekira Pak. Most of that relates to the fact that it has four active ingredients and they'll be hitting a lot of different targets. Anytime you have a drug that hits a number of different targets, you increase your potential for side effects. We do not yet have the data to back that up," Hoffman said.

AbbVie told FiercePharmaMarketing in an email that "an analysis of Viekra Pak's implied safety on the sole basis of a partial label reference without noting the medicine's rigorous clinical program is superficial and not clinically relevant," the company said. "Viekira Pak's safety assessment was based on data from the large clinical trial program, and since clinical trials are conducted under varying conditions, adverse reaction rates observed in Viekira Park trials cannot be directly compared to rates in the clinical trials of another drug."

The company will continue to evaulate patient response to Viekira Park through a post-marketing surveillance program, collecting and analyzing safety data for the drug among a broader GT1 patient population, AbbVie said.

Gilead did not respond to FiercePharmaMarketing's requests for comment.

- here's a link to the report (reg. req.)

Special Reports: The new drug approvals of 2014 - Harvoni - Viekira Pak | The new drug approvals of 2013 - Sovaldi - Gilead

Editor's Note: This story was updated with a statement from AbbVie.