Calla Lily joins $50m Wellcome Leap programme to advance targeted UTI treatment

London-based women’s health company Calla Lily Clinical Care has been selected to join Wellcome Leap’s $50 million Focused Antibiotics programme, supporting the development of more targeted approaches to antibiotic delivery for urinary tract infections (UTIs).

The programme aims to address antimicrobial resistance (AMR) by developing technologies that allow antibiotics to reach the site of infection while reducing unnecessary exposure elsewhere in the body.

Calla Lily will use the programme to evaluate its proprietary Callavid intravaginal drug delivery platform for delivering antibiotics directly through the vaginal wall.

Targeting antibiotics at the site of infection

Antimicrobial resistance is a growing global health challenge, driven in part by the widespread use of antibiotics and the selective pressure this places on bacterial populations.

Wellcome Leap's Focused Antibiotics programme is designed to explore ways of reformulating existing antibiotics so they can be delivered more precisely, potentially reducing their impact on the gut microbiome without compromising efficacy.

The programme estimates that although around 85–90% of infections are localised, almost all antibiotics are currently administered systemically.

UTIs are among the most common bacterial infections affecting women and are a major source of antibiotic prescribing. Calla Lily says women aged between 16 and 54 are prescribed almost 40% more antibiotics than men, potentially increasing their exposure to the downstream effects of systemic antibiotic treatment.

Callavid is designed to deliver medicines locally through the vaginal wall, bypassing gastrointestinal transit and first-pass metabolism. Calla Lily expects the approach could reduce systemic exposure to below 5%.

The company will investigate whether the platform can be adapted to deliver antibiotics directly for the treatment of UTIs.

Developing a targeted delivery platform

Callavid uses a patented, leak-free design similar to a tampon, intended to provide a cleaner and more comfortable method of administering vaginal therapeutics.

The platform is already being evaluated clinically through the NIHR-funded FREEDOM trial, which is investigating the vaginal delivery of progesterone using Callavid.

Initiated in April 2026, the study has passed its safety stopping rule, with 90% of patients having completed their first round of dosing, according to Calla Lily.

The trial is assessing safety, user acceptability and drug absorption, providing clinical data to support the broader development of the delivery platform.

The company says no first-line UTI antibiotic is currently available in a mass-manufactured vaginal formulation. It believes the Focused Antibiotics programme could therefore provide an opportunity to apply its technology to a significant unmet need while contributing to efforts to reduce antibiotic-driven resistance.

Women’s health and antimicrobial resistance

Dr Lara Zibners, Co-founder and Chair of Calla Lily Clinical Care, said the programme highlighted the potential for women's health technologies to address challenges beyond reproductive and fertility care.

She added that Calla Lily was “honoured” to join the Focused Antibiotics programme and explore Callavid in an antibiotic application.

Thang Vo-Ta, Co-founder and CEO of Calla Lily Clinical Care, described the selection as a significant validation of the company's technology and its ambitions for intravaginal drug delivery.

He said the programme would allow Calla Lily to pursue UTI treatment as “one of the most consequential” potential applications for Callavid, while contributing to efforts to tackle antimicrobial resistance.

The project will be led by Dr Serena de Gelidi, Principal Investigator and R&D Manager at Calla Lily Clinical Care. She will be supported by Professor Andrew Lewis, Principal Scientist at the company and a specialist in drug-eluting systems.

A broader application for localised drug delivery

Calla Lily's participation in the Focused Antibiotics programme could provide an important test of whether its intravaginal delivery technology can be applied beyond its initial reproductive health applications.

The company aims to establish Callavid as a platform for intravaginal delivery of medicines and hormones across multiple indications.

By combining localised delivery with reduced systemic exposure, the company hopes its technology could improve treatment tolerability while maintaining therapeutic efficacy.

For Wellcome Leap, the collaboration forms part of a broader effort to develop new approaches to antibiotic treatment and reduce the contribution of antibiotic use to the global AMR crisis.