Proteostasis Therapeutics Announces FDA Grants Orphan Drug Designation for PTI-428 in Cystic Fibrosis

Cambridge, Massachusetts, UNITED STATES

CAMBRIDGE, Mass., March 14, 2018 (GLOBE NEWSWIRE) -- Proteostasis Therapeutics, Inc. (NASDAQ:PTI), a clinical stage biopharmaceutical company dedicated to the discovery and development of groundbreaking therapies to treat cystic fibrosis (CF) and other diseases caused by dysfunctional protein processing, today announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation for PTI-428, the Company’s cystic fibrosis transmembrane conductance regulator (CFTR) amplifier drug candidate. 

“This is the second important regulatory designation PTI-428 has been granted from the FDA this week, highlighting our amplifier’s potential to provide clinical benefit in the treatment of CF,” said Meenu Chhabra, president and chief executive officer of Proteostasis Therapeutics."

The FDA Office of Orphan Products Development grants Orphan Drug Designation to novel drugs or biologics that are intended for the treatment of rare diseases or conditions affecting fewer than 200,000 patients in the United States. The designation allows the sponsor of the drug to be eligible for various incentives, including a seven-year period of U.S. marketing exclusivity upon regulatory approval of the drug, as well as tax credits for clinical research costs, annual grant funding, clinical trial design assistance, and the waiver of Prescription Drug User Fee Act (PDUFA) filing fees.

About PTI-428

PTI-428 is an investigational CFTR amplifier in development for the treatment of CF in patients who are homozygous for the F508del mutation in the CFTR gene as an add-on therapy to approved CFTR modulators or as part of PTI’s proprietary triple combination regimen that includes PTI-808, a potentiator, and PTI-801, a corrector. PTI-428 has been shown to work early during CFTR biogenesis to increase levels of newly synthesized CFTR protein, suggesting potential therapeutic benefits in combination with CFTR correctors and potentiators. In addition to Orphan Drug Designation, PTI-428 has been granted Breakthrough Therapy Designation as well as Fast Track Designation from the FDA.

In December, Proteostasis announced the results from a Phase 2, randomized, placebo controlled study of PTI-428, in 24 CF subjects on background Orkambi therapy which showed that treatment with PTI-428 led to mean absolute improvement in percent predicted forced expiratory volume in 1 second (ppFEV1) of 5.2 percentage points from baseline through Day 28 compared to placebo (p<0.05).

Proteostasis plans to initiate a triple combination CF Study of PTI-428 with PTI-801, its third generation corrector, and PTI-808, its potentiator, in the second quarter of 2018, with preliminary results anticipated in the second half of 2018. The Company is also planning an additional study of PTI-428 in CF Subjects on Symdeko™, with initial data anticipated in early 2019.

About Proteostasis Therapeutics, Inc.

Proteostasis Therapeutics, Inc. is a clinical stage biopharmaceutical company developing small molecule therapeutics to treat cystic fibrosis (CF) and other diseases caused by dysfunctional protein processing. Headquartered in Cambridge, MA, the Proteostasis Therapeutics team focuses on identifying therapies that restore protein function. In addition to its multiple programs in cystic fibrosis, Proteostasis Therapeutics has formed a collaboration with Astellas Pharma, Inc. to research and identify therapies targeting the Unfolded Protein Response (UPR) pathway.

Safe Harbor

To the extent that statements in this release are not historical facts, they are forward-looking statements reflecting the current beliefs and expectations of management made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.  Words such as “aim,” “may,” “will,” “expect,” “anticipate,” “estimate,” “intend,” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements.  Examples of forward-looking statements made in this release include, without limitation, statements regarding the benefits of Orphan Drug designation and the expected timing of the initiation of, patient enrollment in, data from, and the completion of, our clinical studies and cohorts for PTI-428, PTI-801, PTI-808 and our double and triple combination therapy candidates.   Forward-looking statements made in this release involve substantial risks and uncertainties that could cause actual results to differ materially from those expressed or implied by the forward-looking statements, and we, therefore cannot assure you that our plans, intentions, expectations or strategies will be attained or achieved.  Such risks and uncertainties include, without limitation, the possibility final or future results from our drug candidate trials (including, without limitation, longer duration studies) do not achieve positive results or are materially and negatively different from or not indicative of the preliminary results reported by the Company (noting that these results are based on a small number of patients and small data set), uncertainties inherent in the execution and completion of clinical trials (including, without limitation, the possibility FDA requires us to run cohorts sequentially or conduct additional cohorts or pre-clinical or clinical studies), in the enrollment of CF patients in our clinical trials, in the timing of availability of trial data, in the results of the clinical trials, in possible adverse events from our trials, in the actions of regulatory agencies, in endorsement, if any, by therapeutic development arms of CF patient advocacy groups, and in the possibility that we do not maintain Orphan Drug status and therefore lose the benefits thereof, and those set forth in our Quarterly Report on Form 10-Q for fiscal quarter ended September 30, 2017 and our other SEC filings.  We assume no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Orkambi® and Symdeko™ are trademarks of Vertex Pharmaceuticals Incorporated.


David Pitts
Argot Partners

David Rosen
Argot Partners