Proteostasis Presents New Data Demonstrating Potential For Genotype-Agnostic And Combination Therapies For People With Cystic Fibrosis

Data Presented at 13th Annual ECFS Basic Science Conference on Novel Therapies Targeting Cystic Fibrosis

Cambridge, Mass., March 30, 2016 – Proteostasis Therapeutics, Inc. (NASDAQ: PTI), a biopharmaceutical company developing small molecule therapeutics to treat diseases caused by dysfunctional protein processing, such as cystic fibrosis (CF), today announced new preclinical data on the company’s first-in-class genotype-agnostic amplifier and novel corrector at the 13th Annual European Cystic Fibrosis Society (ECFS) Basic Science Conference near Pisa, Italy from March 30-April 2. The company will hold a conference call and webcast today at 4:00 p.m. ET to discuss the data being presented at the conference and the company’s outlook for 2016.

“We are strongly encouraged by our early findings and the potential implications for improving the lives of people with cystic fibrosis,” said Meenu Chhabra, President and Chief Executive Officer of Proteostasis Therapeutics. "Patients treated with currently available therapies still struggle to achieve full lung function, while many are not receiving treatment at all due to rare mutations of the disease. The results from our preclinical studies show the potential of our CFTR amplifier to restore lung function to near-normal levels not only in patients with the most common gene mutation found in cystic fibrosis, but across multiple gene mutations.”

In the company’s poster presentation, “Characterization of CFTR amplifiers, mutation-agnostic modulators that increase protein levels and complement other CF therapeutic modalities,” company researchers describe a new class of modulator – an amplifier – which increases the levels of immature CFTR protein available for other modulators, such as correctors and potentiators, to act upon.

The study found that amplifiers

• increase CFTR immature protein and stabilize CFTR mRNA;

• increase substrate for additional modulators;

• work across CFTR genotypes; and,

• demonstrate activity in non-lung tissues and in vivo.

The early findings suggest the potential for the novel class of amplifiers to enhance CFTR translation efficiency across CFTR mutations and be used in combinations to boost the activity of additional modulators in treating CF.

In a second poster presentation, company scientists have identified a novel corrector with properties that differentiate it from clinical-stage correctors such as lumacaftor or VX-661. The study, “A novel corrector for F508del-CFTR that complements existing CFTR modulators in vitro,” demonstrated that exposure to Proteostasis Therapeutics’ corrector significantly increases the proportion of mature CFTR protein. Moreover, in vitro CFTR function is increased accordingly when the company’s corrector is dosed with other modulators, including lumacaftor, potentiators and its amplifier.

"We believe we have the potential to dramatically improve therapeutic outcomes for patients with cystic fibrosis," said Po-Shun Lee, M.D., Executive Vice President and Chief Medical Officer of Proteostasis Therapeutics. “The data not only validate the use of our novel CFTR amplifiers in combination with existing therapies such as Orkambi and Kalydeco, but they also represent an important early milestone in developing a new and possibly game-changing triple combination therapy for those living with the disease.”

Following is a schedule of the company’s poster presentations and conference call:

Poster Presentations

Thursday, March 31
Time: 2:30-3:30 p.m. CEST
Title: Characterization of CFTR amplifiers, mutation-agnostic modulators that increase protein levels and complement other CF therapeutic modalities

Friday, April 1
Time: 6:30-7:30 p.m. CEST
Title: A novel corrector for F508del-CFTR that complements existing CFTR modulators in vitro

Conference Call and Webcast

Wednesday, March 30
Time: 4:00 p.m. ET
The conference call can be accessed by dialing 1-877-626-4740 (toll-free domestic) or 1-281-973-6278 (international) and referring to conference ID 78792593. A live webcast and accompanying slide presentation will be available on the Event Calendar page in the Investors & Media section of the company’s website, A replay of the webcast will be available on the company’s website shortly after the conclusion of the conference call.

About Cystic Fibrosis

Cystic fibrosis (CF) is a life threatening, progressive genetic disease affecting an estimated 70,000-100,000 people worldwide. The disease is caused by defects in the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which acts as a passageway to promote the transport of salt and water to tissues such as the lungs, skin and pancreas. The defect disrupts healthy ion flow and causes a buildup of thick mucus and bacteria in several organs, resulting in persistent lung infections and the inability for the body to break down food and absorb vital nutrients. While advancements in research and treatments have extended the life expectancy for those living with the disease, CF remains a serious, life-limiting condition with no known cure.

About Proteostasis Therapeutics

Proteostasis Therapeutics, Inc. is a biopharmaceutical company dedicated to the discovery of groundbreaking therapies to treat diseases caused by dysfunctional protein processing, such as cystic fibrosis (CF). Headquartered in Cambridge, MA, the Proteostasis Therapeutics team focuses on the proteostasis network and identifying therapies that modulate the proteostasis imbalance in cells and restore protein function. The company is currently enrolling eligible adults with CF to participate in its Phase 1 clinical trial of PTI-428, a unique modulator called an amplifier, that when used in combination with existing treatments and therapies has shown a consistent positive effect on CFTR protein activity in pre-clinical studies. In addition to its multiple programs in CF, the company has formed collaborations with Biogen to research and identify therapeutic candidates for neurodegenerative disease and with Astellas Pharma, Inc. to research and identify therapies targeting the Unfolded Protein Response (UPR) pathway. For more information visit

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