AVROBIO Announces First Patient Dosed in Phase 1/2 Trial of Gene Therapy for Cystinosis

CAMBRIDGE, Mass.--(BUSINESS WIRE)-- AVROBIO, Inc. (NASDAQ: AVRO) (the “Company”) today announced that the first patient has been dosed in the Company’s AVR-RD-04 investigational gene therapy program for cystinosis, a devastating lysosomal storage disease, in an ongoing Phase 1/2 clinical trial sponsored by academic collaborators at the University of California San Diego. The gene therapy is derived from the patient’s own hematopoietic stem cells, which are genetically modified to produce functional cystinosin, a crucial protein that patients with cystinosis lack.

The trial will enroll up to six patients with cystinosis, a rare inherited disease caused by a defect in the gene that encodes for cystinosin. The cystinosin protein enables transport of the amino acid cystine out of lysosomes. When it is absent, cystine accumulates and crystalizes, causing progressive damage to the kidneys, liver, muscles, eyes and other organs and tissues. Cystinosis affects both children and adults; they face shortened life spans and often painful symptoms, including muscle wasting, difficulty breathing, blindness and kidney failure.

“Cystinosis is a debilitating and progressive disease, and new treatment options are sorely needed. The current standard of care does not avert deterioration; at best, it can attenuate symptoms. That’s why gene therapy is particularly exciting: It has the potential to change the course of disease -- and the lives of patients -- by addressing the underlying cause of cystinosis,” said Birgitte Volck, MD, PhD, President of Research and Development at AVROBIO. “We believe we can engineer patients’ own stem cells so they sustainably produce the functional protein that is needed to prevent a toxic buildup of cystine and halt progression of the disease. We are so pleased that this investigational gene therapy is now in the clinic in collaboration with Dr. Stephanie Cherqui at UC San Diego.”

The single-arm trial will enroll four adults and a potential follow-on cohort of two adults or adolescents at least 14 years of age who are currently being treated with cysteamine, the standard of care for cystinosis. If started at an early age and taken on a strict dosing schedule, cysteamine can delay kidney failure. However, the treatment regimen is highly burdensome, with side effects that can be severe and unpleasant, and many patients find it difficult to adhere to this treatment regimen. Even if compliance is high, cysteamine therapy cannot prevent kidney failure or avert other complications.

“For people with cystinosis, there are no healthy days. They must take dozens of pills a day, around the clock, just to stay alive. It is a relentless disease and we urgently need new treatments,” said Nancy J. Stack, President of the Cystinosis Research Foundation, which supported development of the gene therapy with more than $5.4 million in grants to Dr. Cherqui’s lab at UC San Diego. “We believe that we are now an important step closer to the potential cure that our community has been working toward for many years.”

The trial’s primary endpoints are safety and tolerability, assessed for up to two years after treatment, as well as efficacy, as assessed by cystine levels in white blood cells. Secondary endpoints to assess efficacy include changes in cystine levels in the blood, intestinal mucosa and skin and cystine crystal counts in the eye and skin. Efficacy will also be evaluated through clinical tests of kidney function, vision, muscle strength, pulmonary function and neurological and psychometric function, as well as through assessments of participants’ quality of life after treatment. The trial is funded by grants to UC San Diego from the California Institute for Regenerative Medicine (CIRM) as well as the Cystinosis Research Foundation.

“This investigational gene therapy starts with the patients’ own stem cells, which are genetically modified so that their daughter cells can produce and deliver functional cystinosin to cells throughout the body. With this approach we aim to prevent the abnormal accumulation of cystine that causes so many devastating complications,” said Stephanie Cherqui, PhD, an Associate Professor of Pediatrics at UC San Diego School of Medicine, and consultant to AVROBIO. “We have been working toward this trial for years and we are grateful for all the support that brought us to this moment.”

About AVR-RD-04

AVR-RD-04 is a lentiviral-based gene therapy designed to potentially halt the progression of cystinosis with a single dose of the patient’s own hematopoietic stem cells. The stem cells are genetically modified so they can produce functional cystinosin with the aim of substantially reducing levels of cystine in cells throughout the patient’s body. Before the infusion of the cells, patients undergo personalized conditioning with busulfan to enable the cells to permanently engraft. The Phase 1/2 clinical trial is being conducted under the name CTNS-RD-04 by AVROBIO’s academic collaborators at the University of California, San Diego.

About Cystinosis

Cystinosis is a rare, inherited lysosomal storage disorder characterized by the accumulation of cystine in all the cells of the body, resulting in serious and potentially fatal damage to multiple organs and tissues and the shortening of patients’ life spans. The kidneys and eyes are especially vulnerable; more than 90% of untreated patients require a kidney transplant before age 20. An estimated 1 in 170,000 people are diagnosed with cystinosis.

About AVROBIO, Inc.

AVROBIO, Inc. is a leading, Phase 2 gene therapy company focused on the development of its investigational gene therapy, AVR-RD-01, in Fabry disease, as well as additional gene therapy programs in other lysosomal storage disorders including Gaucher disease, cystinosis and Pompe disease. The Company’s plato™ platform includes a proprietary vector system, automated cell manufacturing solution and a personalized conditioning regimen deploying state-of-the-art precision dosing. AVROBIO is headquartered in Cambridge, MA and has offices in Toronto, ON. For additional information, visit www.avrobio.com.

Forward-Looking Statements

This press release contains forward-looking statements, including statements made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These statements may be identified by words such as “aims,” “anticipates,” “believes,” “could,” “estimates,” “expects,” “forecasts,” “goal,” “intends,” “may,” “plans,” “possible,” “potential,” “seeks,” “will” and variations of these words or similar expressions that are intended to identify forward-looking statements. These forward-looking statements include, without limitation, statements regarding the therapeutic potential of our product candidates, the design, commencement, enrollment and timing of ongoing or planned clinical trials, including the ongoing Phase 1/2 trial of the Company’s AVR-RD-04 investigational gene therapy, the anticipated benefits of our gene therapy platform, the expected safety profile of our product candidates, timing and likelihood of success of our current or future product candidates, and the market opportunity for our product candidates. Any such statements in this press release that are not statements of historical fact may be deemed to be forward-looking statements. Results in preclinical or early stage clinical trials may not be indicative of results from later stage or larger scale clinical trials and do not ensure regulatory approval. You should not place undue reliance on these statements, or the scientific data presented.

Any forward-looking statements in this press release are based on AVROBIO’s current expectations, estimates and projections about our industry as well as management’s current beliefs and expectations of future events only as of today and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward-looking statements. These risks and uncertainties include, but are not limited to, the risk that any one or more of AVROBIO’s product candidates will not be successfully developed or commercialized, the risk of cessation or delay of any ongoing or planned clinical trials of AVROBIO or our collaborators, the risk that AVROBIO may not realize the intended benefits of our gene therapy platform, including the features of our plato platform, the risk that our product candidates or procedures in connection with the administration thereof will not have the safety or efficacy profile that we anticipate, the risk that prior results, such as signals of safety, activity or durability of effect, observed from preclinical or clinical trials, will not be replicated or will not continue in ongoing or future studies or trials involving AVROBIO’s product candidates, the risk that we will be unable to obtain and maintain regulatory approval for our product candidates, the risk that the size and growth potential of the market for our product candidates will not materialize as expected, risks associated with our dependence on third-party suppliers and manufacturers, risks regarding the accuracy of our estimates of expenses and future revenue, risks relating to our capital requirements and needs for additional financing, and risks relating to our ability to obtain and maintain intellectual property protection for our product candidates. For a discussion of these and other risks and uncertainties, and other important factors, any of which could cause AVROBIO’s actual results to differ materially and adversely from those contained in the forward-looking statements, see the section entitled “Risk Factors” in AVROBIO’s most recent Quarterly Report on Form 10-Q, as well as discussions of potential risks, uncertainties and other important factors in AVROBIO’s subsequent filings with the Securities and Exchange Commission. AVROBIO explicitly disclaims any obligation to update any forward-looking statements except to the extent required by law.

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