Paratek Pharmaceuticals, Inc. (Nasdaq: PRTK), a commercial-stage biopharmaceutical company focused on the development and commercialization of innovative therapeutics, announced the outcome of its two exploratory Phase 2 clinical studies evaluating the efficacy and safety of its once-daily oral and intravenous (IV) modernized tetracycline omadacycline in patients with two common forms of urinary tract infections (UTI).
Both studies were adaptive studies which included multiple dosage regimens of omadacycline with the objective to identify a dose regimen for further investigation that would be clinically and microbiologically effective in each of the UTI indications to be studied.
The first Phase 2 study, conducted in the U.S., was designed to evaluate the efficacy, safety, tolerability and pharmacokinetics of oral-only omadacycline compared to an oral-only regimen of nitrofurantoin in female patients with cystitis, or uncomplicated urinary tract infections (uUTI). In the study, 225 subjects were randomized to receive one of four omadacycline dosing regimens or nitrofurantoin.
The second Phase 2 study, conducted globally, was designed to evaluate the efficacy, safety, tolerability and pharmacokinetics of once-daily IV or IV-to-oral omadacycline compared to a once-daily regimen of IV-to-oral levofloxacin, in patients with acute pyelonephritis, a common clinical subset of complicated UTI (cUTI). In the study, 201 patients were randomized into four omadacycline dosing regimens or levofloxacin.
In both studies, omadacycline showed generally comparable levels of clinical success to either nitrofurantoin or levofloxacin, as determined by the investigator’s assessment of clinical response at the post-treatment evaluation. However, the microbiological responses were generally lower than the comparators. Consistent with safety results from previously completed pivotal Phase 3 clinical trials, omadacycline was generally safe and well-tolerated in both studies.
Due to the exploratory intent and small numbers of subjects enrolled in each dose in these phase 2 studies, the Company has identified dose regimens that require additional investigation before determining any future development plans for these indications. Additional analyses are ongoing including pathogen-specific level efficacy and relationships of both clinical and microbiological responses to urinary pharmacokinetic data. The Company plans on presenting data from both studies at a future medical conference.
“We are pleased with the innovative design and high-quality conduct of these exploratory Phase 2 adaptive studies, providing data that has both identified potential dose regimens for future investigation and ruled out ineffective ones.” said Evan Loh, M.D., CEO of Paratek. “Beyond these top-line data, we have more data to evaluate from these studies in order to determine the best path forward for omadacycline in UTI. We are grateful to the patients, principal investigators, clinical site staffs, our CRO and vendor partners, and the Paratek clinical development team who participated in and enabled these studies to be executed in a timely and professional manner.”