Proteostasis Therapeutics Regulatory Update Following Scientific Advice Meeting with MHRA

Proteostasis Therapeutics, Inc. (NASDAQ:PTI), a clinical stage biopharmaceutical company dedicated to the discovery and development of groundbreaking therapies to treat cystic fibrosis (CF), today announced a regulatory update following the completion of a scientific advice meeting with the Medicines and Healthcare Products Regulatory Agency (MHRA), UK, regarding its two pivotal studies, MORE and CHOICES.

BOSTON, Jan. 13, 2020 /PRNewswire/ -- Proteostasis Therapeutics, Inc., (NASDAQ:PTI), a clinical stage biopharmaceutical company dedicated to the discovery and development of groundbreaking therapies to treat cystic fibrosis (CF), today announced a regulatory update following the completion of a scientific advice meeting with the Medicines and Healthcare Products Regulatory Agency (MHRA), UK, regarding its two pivotal studies, MORE and CHOICES.

Both studies are designed to explore the potential of Proteostasis’ proprietary cystic fibrosis transmembrane conductance regulator (CFTR) modulator combinations that include dirocaftor, posenacaftor and nesolicaftor, a CFTR potentiator, corrector and amplifier, respectively. The MHRA’s scientific advice outlined a clear path forward toward the initiation and execution of the proposed two-pronged Phase 3 program, including establishment of a common safety database to support the safety profile of the proprietary combination, all toward the goal of supporting a Marketing Authorization Application for dirocaftor, posenacaftor and nesolicaftor. Both trials are expected to begin in 2020 and can run concurrently, building on the safety and efficacy database Proteostasis has established to date in over 300 patients with CF. The Company will continue to seek additional advice from other major regulatory agencies throughout 2020.

“CF is a heterogenous disease whose limited CFTR treatment options leave a significant portion of patients with little or no benefit. This is underscored by what we have demonstrated in our own data, including Phase 2 results comparable to the recently approved CFTR modulator triple combinations, despite a higher disease burden study population, and based on our own market research, where physicians report 1 in 3 patients either discontinuing triple combination treatment for poor tolerability or achieving suboptimal benefit. Our goal is to change this by delivering more choices to patients to better reflect an individualized treatment approach and provide to each patient with CFTR modulators that lead to highest benefit,” said Meenu Chhabra, President and Chief Executive Officer of Proteostasis Therapeutics.

Ms. Chhabra continued: “We value the opportunity to engage with regulators who recognize this challenge, and we are pleased that the Company’s preclinical and clinical programs were in line with MHRA expectations for the conduct of our pivotal program. The Proteostasis team continues to work closely with European Medicines Agency and other regulators toward finalizing the details of this program and, with positive outcomes, to work toward ensuring its support for the registration for dirocaftor, posenacaftor and nesolicaftor.”

The CHOICES trial (Crossover trial based on Human Organoid Individual response in CF - Efficacy Study) is designed to be the first ever personalized medicine-based study in CF. CHOICES seeks to translate promising responses from an ex vivo organoids study of PTI modulators in rare CF mutations that is part of a pan-European strategic initiative, known as HIT-CF (Human Individualized Therapy of CF), whose goal is to accelerate the development of, and access to, personalized therapies for CF patients. The MORE trial (Modulator Options to RestorE CFTR study) is designed as a global, Phase 3, randomized, placebo-controlled study in CF subjects with the common F508del homozygous mutation, and will seek to confirm the positive efficacy and tolerability results from a recently completed Phase 2 study of the Proteostasis CFTR modulator triple combination.

About Dirocaftor, Posenacaftor and Nesolicaftor

Nesolicaftor (PTI-428) is an investigational CFTR amplifier in development for the treatment of CF in patients with at least one F508del mutation in the CFTR gene, as part of PTI’s proprietary triple combination regimen that includes dirocaftor (PTI-808), a novel potentiator, and posencaftor (PTI-801), a third-generation CFTR corrector. Posencaftor received Fast Track Designation from the U.S. Food and Drug Administration (FDA). In May 2019, nesolicaftor received Orphan Drug Designation (ODD) from the European Commission (EC). In addition to ODD from the EC, nesolicaftor has ODD, Breakthrough Therapy Designation and Fast Track Designation from the FDA.

About Proteostasis Therapeutics, Inc.

Proteostasis Therapeutics, Inc. is a clinical stage biopharmaceutical company developing small molecule therapeutics to treat cystic fibrosis and other diseases caused by dysfunctional protein processing. Headquartered in Boston, MA, the Proteostasis Therapeutics team focuses on identifying therapies that restore protein function. For more information, visit

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 potential of our proprietary combination therapies for the treatment of CF, the potential benefit to patients of our proprietary combination therapies, expected timing of patient enrollment in our clinical studies and cohorts for our clinical programs, including our planned Phase 3 programs and initiation of registrational or pivotal studies. 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 that FDA or other regulatory agency comments delay, change or do not permit trial commencement, or intended label, or the FDA or other regulatory agency 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 a competitive clinical environment, 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 the endorsement, if any, by therapeutic development arms of CF patient advocacy groups (and the maintenance thereof), and those set forth in our Annual Report on Form 10-K for the year ended December 31, 2018, our Quarterly Report on Form 10-Q for the quarter ended September 30, 2019 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.


David Pitts / Claudia Styslinger
Argot Partners
212.600.1902 /

David Rosen
Argot Partners

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SOURCE Proteostasis Therapeutics, Inc.

Company Codes: NASDAQ-NMS:PTI