Tetraphase’s eravacycline misses endpoints in phase 3 flop

It has been a bumpy ride for eravacycline, which failed a phase 3 trial in complicated urinary tract infections back in 2015. (Ahmad Ardity)

Tetraphase Pharma, which is working on antibiotics to take on multidrug-resistant infections, has hit a late-stage snag: Its lead candidate, eravacycline, failed to best Merck’s ertapenem in the treatment of complicated urinary tract infections (cUTI).

The phase 3 trial, dubbed Ignite 3, involved 1,205 patients who received at least a five-day course of eravacycline or Merck’s ertapenem, a carbapenem antibiotic marketed as Invanz.

While Tetraphase’s candidate was safe and well tolerated, it did not meet its co-primary efficacy endpoints, namely responder rate, a combination measure of clinical cure and microbiological success, recorded at the end of treatment and at a test-of-cure visit, the company said in a statement Tuesday.

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The news sent Tetraphase’s shares plummeting nearly 60% in after-hours trading. And this isn’t eravacycline’s first speed bump: The candidate previously failed a phase 3 cUTI trial back in 2015, which saw the company's shares nose-dive by 80%.

“We are surprised and obviously very disappointed that the IGNITE3 trial did not achieve its co-primary endpoints and are fully analyzing the data to understand this outcome,” said Guy Macdonald, president and CEO of Tetraphase, in the statement. “Independent of this outcome, we continue to move forward with our registration strategy for eravacycline in complicated intra-abdominal infections (cIAI).”

Just last month, the Watertown, Massachusetts-based company filed an NDA for eravacycline for the treatment of cIAI, based on positive data from a pair of phase 3 trials. But it hasn’t all been smooth sailing in this indication either; the company’s shares dropped 24% in May 2016 on the news that its route to approval would be delayed by an FDA request for more data.