New Microbiology Data from Paratek Pharmaceuticals Show Omadacycline Effective Against Most Common Skin Infections and Pathogens, Including MRSA

- Microbiology analysis and full results of Phase 3 OASIS study presented at ECCMID 2017

- Data on utility in geographic regions also presented

VIENNA, Austria, April 24, 2017 (GLOBE NEWSWIRE) -- Paratek Pharmaceuticals, Inc. (Nasdaq:PRTK) announced today that an analysis of microbiology data from its Phase 3 study of omadacycline in acute skin infections found that once-daily treatment with IV-to-oral omadacycline is effective in treating the most frequently isolated bacterial pathogens associated with skin infections, including methicillin-resistant Staphylococcus aureus (MRSA). These findings were presented for the first time at the annual meeting of the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID 2017) in Vienna, Austria.

Paratek also presented full clinical efficacy, safety and tolerability results from the study, which is known as OASIS (Omadacycline Acute Skin and Skin Structure Infections Study). The full results demonstrate the efficacy and safety of omadacycline compared to linezolid in acute bacterial skin and skin structure infections (ABSSSI).

“With this new microbiology analysis, we further increase the body of evidence regarding the utility of omadacycline against serious community-acquired infections and pathogens with known resistance patterns, including MRSA,” said Evan Loh, M.D., President, Chief Operating Officer and Chief Medical Officer, Paratek.  “These results, coupled with the recently announced positive topline results of our Phase 3 registration study in community-acquired bacterial pneumonia, continue to bolster our confidence in omadacycline and its potential to address the significant health challenge of antibiotic resistance.”

Analyses by Infection Type and Pathogen in the OASIS Study
OASIS was a global Phase 3 randomized, double-blind, multi-center study comparing the safety and efficacy of IV-to-oral once-daily omadacycline with twice-daily linezolid over a 7-to-14-day course of therapy in 645 treated adult patients with ABSSSI. To analyze clinical success per infection type, the modified intent-to-treat (mITT) population included randomized subjects without a sole Gram-negative pathogen at screening (n=627). Among this population, infection type broke down as follows: 33% wound infection; 38% cellulitis/erysipelas; and 29% major abscess. At Post Therapy Evaluation (PTE, 7 – 14 days after the last day of treatment), once-daily omadacycline was effective across all infection types studied. Compared to twice-daily linezolid, efficacy for once-daily omadacycline was comparable in wound infection (81% vs 81%), cellulitis/erysipelas (91% vs 85%), and major abscess (85% vs 85%).

Further analysis of the micro-mITT population, which included patients with at least one Gram-positive pathogen at screening (n=455), showed that the most common pathogen was Staphylococcus aureus (68% overall, 61% MSSA and 39% MRSA) followed by Streptococcus anginosus (19%) with mixed Gram-positive and Gram-negative infections in 15% of the patients. Overall clinical success at PTE in this group was 83% for omadacycline vs 83% for linezolid (MSSA 84% vs 82%; MRSA 83% vs 86%, S. anginosus 75% vs 70%, mixed infections 81% vs 76%).

OASIS Full Results
The full results of OASIS presented today at ECCMID expanded on the positive topline results first announced in June 2016. Omadacycline met the U.S. Food and Drug Administration-specified primary efficacy endpoint of early clinical response (ECR) and the two European Medicines Agency-specified co-primary efficacy endpoints for post-treatment evaluation (PTE). In the study, the ECR in the modified Intent to Treat (mITT) population for the omadacycline and linezolid treatment arms was 84.8% compared to 85.5%, respectively.

At PTE in the mITT and the clinically evaluable (CE) populations, omadacycline achieved the primary efficacy endpoint of statistical non-inferiority (10% margin) compared to linezolid. In the mITT population at PTE, clinical success rates for the omadacycline and linezolid treatment arms were 86.1% and 83.6%, respectively. In the CE population at PTE, clinical success rates for the omadacycline and linezolid treatment arms were 96.3% and 93.5%, respectively. 

Additional OASIS Sub-Analyses Expands Body of Evidence for Omadacycline
Additional presentations at ECCMID highlighted the efficacy of omadacycline in ABSSSI across geographic regions and demonstrated that omadacycline reduces skin lesion size and local signs of ABSSSI.

  • Regional distribution of infection type remained consistent across OASIS study locations in North America, Latin America, Eastern Europe and Western Europe, with aureus emerging as the most prevalent. Clinical success at PTE among the mITT population (n=627) for omadacycline vs linezolid was 80.7% vs 80.2% in North America; 100% vs 94% in Eastern Europe and 82.6% vs 76.2% in Western Europe; Latin America was not included in the evaluation because of a limited sample size (< 5 subjects per treatment group).
  • Further analysis of OASIS demonstrated treatment of ABSSSI with omadacycline or linezolid led to similar and rapid reductions in lesion size and local signs of infection. In the mITT population, median baseline lesion area was 299.5 cm2 (OMC) and 315.0 cm2 (LZD) at initial evaluation. Infection presence and severity was similar for both treatment groups at baseline. Reduction in lesion area of > 50% was seen on day two for both omadacycline and linezolid-treated patients (14% vs 11%). A 99% reduction was reported for both therapies at PTE.

About Acute Bacterial Skin and Skin Structure Infections (ABSSSIs)
Acute bacterial skin and skin structure infections are responsible for more than 750,000 hospitalizations per year (latest data available, 2011), representing a 17.3% increase in hospitalized ABSSSI patients from 2005 to 2011.

About Paratek Pharmaceuticals, Inc.
Paratek Pharmaceuticals, Inc. is a biopharmaceutical company focused on the development and commercialization of innovative therapies based upon its expertise in novel tetracycline chemistry. Paratek's lead product candidate, omadacycline, is the first in a new class of tetracyclines known as aminomethylcyclines, with broad-spectrum activity against Gram-positive, Gram-negative and atypical bacteria. Omadacycline is a new, once-daily oral and intravenous broad spectrum antibiotic being developed for use as empiric monotherapy for patients suffering from serious community-acquired bacterial infections, such as acute bacterial skin and skin structure infections, community-acquired bacterial pneumonia, urinary tract infections, and other community-acquired bacterial infections, particularly when antibiotic resistance is of concern to prescribing physicians. Omadacycline has been granted Qualified Infectious Disease Product designation and Fast Track status by the U.S. Food and Drug Administration for the target indications.

In June 2016, Paratek announced positive efficacy data in a Phase 3 registration study in acute bacterial skin and skin structure infections (ABSSSI) demonstrating the efficacy, general safety and tolerability of intravenous (IV) to once-daily oral omadacycline compared to linezolid. In April 2017, Paratek announced positive efficacy data in a Phase 3 registration study in community-acquired bacterial pneumonia (CABP) demonstrating the efficacy, general safety and tolerability of IV to once-daily oral omadacycline compared to moxifloxacin. A Phase 3 registration study in ABSSSI comparing once-daily oral-only dosing of omadacycline to twice-daily oral-only dosing of linezolid was initiated in August 2016. Top-line data from this study are expected as early as the end of June. The Company plans to submit its new drug application (NDA) in the U.S. as early as the first quarter of 2018 with an EMA submission later in 2018.

In addition to its Phase 3 program for omadacycline, a Phase 1B study in uncomplicated urinary tract infections (UTI) was initiated in May 2016 and positive top-line PK proof-of-principle data was reported in November 2016. The Company plans to begin enrolling patients in a proof-of-concept Phase 2 study of omadacycline in acute pyelonephritis, the most common subset of complicated urinary tract infections, as early as December 2017.

In October 2016, Paratek announced a research agreement with the U.S. Department of Defense to explore the utility of omadacycline against pathogenic agents causing infectious diseases of public health and biodefense importance including plague and anthrax.

Paratek's second Phase 3 product candidate, sarecycline, is a well-tolerated, once-daily oral, narrow spectrum tetracycline-derived antibiotic with potent anti-inflammatory properties for the potential treatment of acne and rosacea in the community setting. Allergan owns the U.S. rights for the development and commercialization of sarecycline. Paratek retains all ex-U.S. rights. Allergan and Paratek reported positive results from two identical Phase 3 registration studies of sarecycline for the treatment of moderate to severe acne vulgaris in March 2017. Allergan has publicly announced plans to submit an NDA in the U.S. in the second half of 2017. 

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Forward-Looking Statements
This press release contains forward-looking statements including statements related to our overall strategy, product candidates, clinical studies, prospects and expected results, including statements about the timing of advancing omadacycline and otherwise preparing for clinical studies, the timing of enrollment in our clinical studies and of our reporting of the results of such studies, the potential for omadacycline to serve as an empiric monotherapy treatment option for patients suffering from ABSSSI, CABP, UTI, and other bacterial infections when resistance is of concern, the prospect of omadacycline providing broad-spectrum activity, and our ability to obtain regulatory approval of omadacycline. All statements, other than statements of historical facts, included in this press release are forward-looking statements, and are identified by words such as "advancing," "believe," "expect," "well positioned," "look forward," "anticipated," "continued," and other words and terms of similar meaning. These forward-looking statements are based upon our current expectations and involve substantial risks and uncertainties. We may not actually achieve the plans, carry out the intentions or meet the expectations or projections disclosed in our forward-looking statements and you should not place undue reliance on these forward-looking statements. Our actual results and the timing of events could differ materially from those included in such forward-looking statements as a result of these risks and uncertainties. These and other risk factors are discussed under "Risk Factors" and elsewhere in our Annual Report on Form 10-K for the year ended December 31, 2016, and our other filings with the Securities and Exchange Commission. We expressly disclaim any obligation or undertaking to update or revise any forward-looking statements contained herein.

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