Tetraphase falls on Phase III cUTI miss

Tetraphase Pharmaceuticals Inc. (NASDAQ:TTPH) lost $3.28 (60%) to $2.15 on Wednesday after reporting that IV eravacycline (TP-434) missed the co-primary endpoints in the Phase III IGNITE3 trial to treat complicated urinary tract infections (cUTIs). The company announced the news after market close on Tuesday.

On the 1,205-patient trial's co-primary endpoints, eravacycline failed to achieve non-inferiority to ertapenem in responder rate as measured by a combination of clinical cure and microbiological success in the microbiological intent-to-treat (MITT) population at both the end-of-IV treatment visit (84.8% vs. 94.8%) and the test-of-cure (TOC) visit 5-10 days after the end of therapy (68.5% vs. 74.9%). Tetraphase said it is currently analyzing the data and will provide an update on next steps for eravacycline to treat cUTIs at a later date.

Patients received once-daily 1.5 mg/kg IV eravacycline or 1 g IV ertapenem for a minimum of five days, after which patients were eligible to transition to an approved oral therapy.

In 2015, IV-to-oral dosing of eravacycline missed the FDA- and EMA-defined primary endpoints of non-inferiority to levofloxacin in the Phase III IGNITE2 trial to treat cUTIs (see BioCentury Extra, Sept. 8, 2015).

The broad-spectrum fluorocycline antibiotic is under FDA and EMA review to treat complicated intra-abdominal infections (cIAIs). On a conference call to discuss the data, Tetraphase said it does not expect the IGNITE3 data to have any "read-through" to the cIAI indication.