Topline results were announced from the phase 3 SURE 2 trial of sulopenem (Iterum Therapeutics) for the treatment of complicated urinary tract infection (cUTI).

Sulopenem is a novel penem antibiotic that has shown in vitro activity against a wide variety of Gram-negative, Gram-positive and anaerobic bacteria resistant to other antibiotics. The multicenter, double-blind SURE 2 trial compared the efficacy and safety of sulopenem to ertapenem in 1395 adult patients with cUTI. 

Patients were randomized to receive either sulopenem intravenously (IV) once daily for at least 5 days followed by oral sulopenem twice daily to complete 7-10 days of treatment, or ertapenem IV once daily for at least 5 days followed by ciprofloxacin or amoxicillin-clavulanate twice daily. The primary end point was overall clinical and microbiologic response on day 21 in the micro-modified intention to treat population (mITT) using a 10% noninferiority margin.

Findings showed that the trial failed to demonstrate noninferiority, with a responder rate of 67.8% for sulopenem at the test of cure visit compared with 73.9% for ertapenem (difference of -6.1%; [95% CI, -12.0, -0.1]). “The difference in response rates was driven almost entirely by higher rates of asymptomatic bacteriuria on sulopenem relative to ertapenem, only evident at the test of cure visit; the rates of patients receiving additional antibiotics or with residual cUTI symptoms were similar,” the Company reported.

Both treatment arms demonstrated similar clinical responses at the test of cure visit in the mITT patient population (sulopenem vs ertapenem: 2.0%; 95% CI, -1.5, 5.4) and Clinically Evaluable patient population (sulopenem vs ertapenem: 0.4%; 95% CI, -2.6, 3.5). Moreover, the overall response at day 10 (secondary end point) was found to be similar between sulopenem (86.7%) and ertapenem (88.9%).

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“We are very disappointed by the outcome in the cUTI study, although sulopenem was well tolerated and demonstrated a safety profile consistent with previous studies and the penem class in general,” said Corey Fishman, Chief Executive Officer of Iterum Therapeutics. 

In December 2019, the Company  announced that sulopenem failed to achieve noninferiority to ertapenem for the treatment of complicated intra-abdominal infections in the phase 3 SURE 3 trial.

For more information visit iterumtx.com.