Advera: Harvoni bests Sovaldi, Viekira Pak in hep C drug safety

Recent reports have shown that Gilead's ($GILD) hep C superstars, Sovaldi and Harvoni, are linked to fewer serious side effects than AbbVie's ($ABBV) rival med Viekira Pak. But Harvoni could take home the prize of being the safest option of the three drugs.

According to a review by healthcare informatics firm Advera Health Analytics, Harvoni turned up fewer serious side effects in postmarketing safety data than its hep C peers. Advera determined this by sifting through the FDA's postmarketing safety reports and gathering data on Harvoni, Sovaldi and Viekira Pak using a reporting odds ratio (ROR), which compares the actual number of side effects reported for a certain med with how many are expected. An ROR above 1.5 flags a potential safety issue or something to keep an eye on. Each side effect is tied to a certain number of cases.

Harvoni had the least reports of serious side effects, tallying 17 side effects with an ROR over 1.5. But the drug was still linked to safety issues in postmarketing data. Within those side effects, Harvoni turned up 615 cases of headache with an ROR of 5.79, 193 cases of insomnia with an ROR of 3.39, and 109 cases of anxiety with an ROR of 1.69.

Sovaldi had 20 side effects with an ROR above 1.5. The drug was linked to 184 cases of anemia with an ROR of 3.41, 170 cases of depression with an ROR of 2.59, 112 cases of overdose with an ROR of 2.6, and 172 cases of rash with an ROR of 2.22. For comparison's sake, Harvoni only had 52 cases of anemia with an ROR of 1.12, and Viekira Pak was linked to 96 cases of anemia with an ROR of 2.11.

Gilead declined to comment to FiercePharma on Advera's findings for Harvoni and Sovaldi.

Viekira Pak was tied to the most safety issues in Advera's report, with 25 side effects with an ROR over 1.5. The drug turned up 344 cases of pruritus, or severe skin itching, with an ROR of 6.14, 331 cases of insomnia with an ROR of 6.14, 415 cases of headache with an ROR of 3.71, and 220 cases of diarrhea with an ROR of 2.18.

One side effect for Viekira Pak that stood out in the report was "drug dose omission," or patients not taking their meds on time, Advera Health Analytics VP of scientific affairs Keith Hoffman told FiercePharma. Drug dose omission turned up 170 cases and an ROR of 5.05, "much higher" than Harvoni or Sovaldi, Hoffman said. For comparison's sake, Harvoni had 35 cases of drug dose omission with an ROR of 0.99, and Sovaldi had 62 cases with an ROR of 1.47.

"This could represent a possible adherence issue associated with real world usage of the medication," Hoffman said. "We look forward to re-assessing these conclusions based on future case reports as these drugs become even more widely prescribed."

Viekira Pak--Courtesy of AbbVie

Advera's findings for Harvoni, Sovaldi and Viekira Pak don't exactly come as a surprise. In May, the company looked at side effect reports for all hep C drugs, including older treatments and next-generation therapies. and saw that Harvoni and Sovaldi showed advantages over older treatments such as Merck's ($MRK) Victrelis and Vertex Pharmaceuticals' ($VRTX) Incivek.

The company left Viekira Pak out of its May analysis because there wasn't enough postmarketing data for the drug at that point. But Advera was "not optimistic" that Viekira Pak's safety profile would top Harvoni's or Sovaldi's, Hoffman said at the time, and the current numbers seem to confirm those predictions.

The latest findings come as AbbVie is facing headwinds regarding Viekira Pak's safety. In October, another Advera report showed that Viekira Pak was riskier than Harvoni to treat hep C. A little less than a week later, the FDA warned that the med and another AbbVie hep C treatment, Technivie, may cause serious liver injury or death in patients with advanced liver disease, and demanded that the company update the drugs' label.

AbbVie did not return FiercePharma's requests for comment by publishing time. But the company has stood by Viekira Pak in the past, telling FiercePharmaMarketing in May that an "analysis of Viekira 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 relevant."

- read the report (reg. req.)

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

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