Cardiff-based biotech secures backing from the Development Bank of Wales, DEBRA Research, EB Research Partnership and founding investors to progress MP5219 towards the clinic

Cardiff, Wales — Mariposa Therapeutics (“Mariposa” or the “Company”), a clinical-stage rare disease company developing a potential first disease-modifying therapy for Epidermolysis Bullosa Simplex (EBS), today announced the close of a £750,000 seed financing round.

The round was led by the Development Bank of Wales, which has invested from the Wales Technology Seed Fund, with co-investments from DEBRA Research GmbH, the EB Research Partnership (EBRP) and the Company’s Founders.

EBRP has been an investor in Mariposa since the Company’s earliest days. Its renewed participation in this round represents a third consecutive investment and reflects continued confidence in both the science underpinning MP5219 and the team advancing it. As one of the world’s foremost EB-focused research funding organisations, EBRP’s ongoing commitment is a meaningful endorsement of Mariposa’s programme.

Targeting the Root Cause of EBS
EBS is a chronic, painful and potentially life-limiting genetic condition that causes the skin to blister and tear with even the mildest friction or heat. It is estimated to affect approximately 1 in 125,000 people across the US and Europe and more than 500,000 people worldwide. EBS accounts for roughly 70% of all Epidermolysis Bullosa cases globally, yet no approved treatment addresses the underlying cause of the disease.

MP5219 works by activating the expression of keratin 17 and other inducible keratins, restoring skin integrity and preventing blister formation. This mechanism has the potential to transform the lives of children and adults living with EBS—enabling normal mobility, extending life expectancy and offering the prospect of a life free from constant pain. The potential addressable market for a disease-modifying therapy, based on currently diagnosed patients with access to treatment centres, is estimated at approximately £1 billion.

Use of Proceeds
Mariposa will deploy the seed funding to advance pre-clinical development of MP5219, including further studies, engagement with regulatory authorities and securing scientific advice in preparation for clinical development. MP5219 is expected to qualify for orphan drug designation, a regulatory status that confers significant benefits including reduced regulatory fees, tax credits for clinical trials and extended market exclusivity.

Building a Welsh Science Base
With Cardiff-based Dr Lucy Sykes as Chief Scientific Officer, Mariposa intends to establish a dedicated research facility with laboratory space in Cardiff in 2026, following its next funding round. The Company also plans to recruit scientific staff in Wales to support formulation development and future manufacturing activities, creating high-value jobs and building long-term capabilities in the Welsh life sciences sector.

 
Stakeholder Commentary
Dr David Howat, Chief Executive Officer of Mariposa Therapeutics, said: “EBS is a devastating condition with no current disease-modifying treatment options. With this funding we can take MP5219 through pre-clinical development and build the foundations for clinical testing. We are committed to developing Mariposa as a Welsh company, and our longer-term vision is to establish a dedicated science base in Cardiff, creating high-value jobs and capabilities to support the next stages of development.”

Thomas Hafner, Founder of Mariposa Therapeutics, said: “We founded Mariposa because we believe that people living with EBS deserve more than symptom management—they deserve a real treatment. The quality of this investor syndicate speaks for itself: a national development bank, two of the world’s leading EB research charities and our founding group, all aligned behind a single mission. When organisations whose sole purpose is to find treatments for EB choose to invest alongside you, it tells you something important about where the science stands. We are grateful for the confidence of every investor in this round and deeply motivated by the responsibility that comes with it.”

Dr Martin Steiner, Managing Director at DEBRA Research GmbH, commented: “Our investment in Mariposa exemplifies how impact capital can accelerate the translation of cutting-edge science into real hope for patients. EBS accounts for roughly 70% of all EB cases worldwide, yet there are still no treatments that address the root cause of the disease. We are excited to support the development of MP5219, which has the potential to become the first disease-modifying therapy for EBS, and to help bring it into the clinic.”

Michael Hund, Chief Executive Officer of the EB Research Partnership, said: “EBRP has supported Mariposa since its earliest days because the science behind MP5219 represents one of the most compelling approaches we have seen to addressing the root cause of EBS. This is our third consecutive investment in the Company, and our continued participation reflects our conviction that this programme has genuine potential to change lives. We look forward to seeing MP5219 progress towards the clinic.”

Harry George, Investment Executive at the Development Bank of Wales, said: “This is an opportunity for an early-stage investment in a solution to a rare disease, which has the potential to achieve orphan drug status. Our investment provides the foundation for Mariposa to progress towards further funding that will drive the clinical development of a life-changing treatment. The backing of DEBRA and EBRP is a strong endorsement of the company’s potential and reflects our commitment to working with co-investors to increase the flow of funding into Wales.”

 
About Mariposa Therapeutics
Mariposa Therapeutics is a Cardiff-based biotechnology company focused on developing MP5219, a potential first-in-class, first disease-modifying therapy for Epidermolysis Bullosa Simplex. Founded by Thomas Hafner, the Company’s management team is led by CEO Dr David Howat, who brings decades of experience as Chief Development Officer across multiple drug development programmes, and Chief Scientific Officer Dr Lucy Sykes. Mariposa is supported by a strong board of directors and a syndicate of mission-aligned investors.

About the Development Bank of Wales
The Development Bank of Wales is a public finance institution wholly owned by the Welsh Government. It provides loans and equity for Welsh businesses, people and communities. With £2 billion in funds under management and a portfolio of more than 3,600 small business customers, the Development Bank is a cornerstone investor in the Welsh economy. During 2024/25, £152 million in debt and equity funding helped 502 businesses to create and safeguard 6,185 jobs across Wales, with £8.2 million directed to 34 early-stage tech ventures.

About DEBRA Research GmbH
DEBRA Research GmbH is a specialist rare disease impact investor focused on accelerating therapies for Epidermolysis Bullosa. Through its investment activities, DEBRA Research translates philanthropic capital into clinical-stage programmes with the potential to deliver meaningful improvements for EB patients worldwide.

About the EB Research Partnership
The EB Research Partnership (EBRP) is the world's largest non-profit organisation dedicated to funding the most promising research toward treatments and cures for all forms of Epidermolysis Bullosa. Founded by a dedicated group of parents along with Jill and Eddie Vedder, EBRP has raised more than $80 million to fund over 200 projects in 20 countries through its award-winning venture philanthropy model. EBRP has been an early and consistent supporter of the Mariposa programme, investing across three consecutive rounds.

 
Media Contact
Mariposa Therapeutics
Dr David Howat
dhowat@mariposa.health
+44 2922550650