LONDON – Natural product specialist Neem Biotech Ltd. is spinning out a new company to develop synthetic analogues of ajoene, the chemical that gives garlic its anti-infective properties.

Those compounds are progressing in preclinical development in the treatment of lung infections in cystic fibrosis and in chronic wound infections, with both on track to enter clinical trials in 2020.

That will require a cash infusion, and in combination with establishing a separate anti-infectives business, Neem is now looking for new investors, launching its search at the J.P. Morgan Healthcare Conference in San Francisco last month.

Neem's products are inhibitors of quorum sensing, the communications system used by pathogenic bacteria to synchronize expression of virulence factors that are involved in colonization and the formation of biofilms.

"We are pitching ourselves as a company that is developing non-traditional solutions for antimicrobial resistance," said Graham Dixon, CEO. "Our contribution is pursuing first-in-class molecules that inhibit bacterial virulence," he told BioWorld.

Building on studies showing crude garlic extract inhibits Pseudomonas aeruginosa, Michael Givskov, one of Neem's scientific advisors, was responsible for identifying ajoene as the source of that effect.

In in vitro studies, administering ajoene in combination with the antibiotic tobramycin killed biofilms and reactivated the immune system to fight the infection.

Givskov subsequently elucidated the mechanism of action, showing ajoene inhibits a number of genes that are controlled by quorum sensing.

Using the quorum sensing system to control expression of virulence factors allows P. aeruginosa to operate in stealth mode until it reaches a certain density. When activated, the coordinated release of virulence factors leads to tissue damage and the destruction of neutrophils and macrophages, dampening of the host immune defense.

In addition to blocking the immune system response, virulence factors released as a result of quorum sensing create a barrier that antibiotics cannot penetrate. Tobramycin can kill bacteria on the surface of biofilms, but it cannot eradicate them completely.

Inhibiting quorum sensing does not remove P. aeruginosa's ability to form biofilms, but the films are more fragile and more sensitive to antibiotics. That gives Neem's products the potential to decrease the use of conventional antibiotics and slow the development of antimicrobial resistance.

"Traditional antibiotics kill bacteria by interfering with primary metabolism. Because of that, there is high pressure to generate resistance," said Dixon. "We are not targeting essential genes and our products don't kill bacteria, so we don't expect to create the same pressure for them to develop resistance."

While Neem's synthetic ajoene compounds inhibit only a few genes, the virulence factors they express are critical to the infection process. "We know they hit well upstream in quorum sensing, and they hit both gram-negative and gram-positive bacteria, which is important in wound and respiratory infections," Dixon said. Other companies are pursuing quorum sensing, but they are targeting different stages of the pathway.

Upcoming trials

The coexistence of different bacteria in respiratory diseases and chronic wound infections is one reason for choosing cystic fibrosis and infected venous leg ulcers as the first two indications. Another is that ajoene is a sulfur-rich molecule that is not orally available, leading Abertillary, Wales-based Neem to concentrate on topical and inhaled products.

The lead program, NX-AS-911, will enter a 400-patient clinical trial in wound biofilm disruption, in 2020, overseen by Neem's medical advisor, Keith Harding, who is director of the Welsh Wound Innovation Center.

"We chose venous ulcers because, of the whole group of patients with chronic wound infections, these are the most homogeneous," said Dixon.

Control of infection is key to managing hard-to-heal wounds. In preclinical studies of wounds co-infected with P. aeruginosa and Staphylococcus aureus, NX-AS-911 has been shown to inhibit biofilm formation and eradicate existing biofilms, encouraging wound closure.

As an orphan disease, Neem expects to do a much smaller, 50-patient trial of NX-AS-401 in cystic fibrosis. The product will be administered as an adjunctive treatment to antibiotics, with the aim of showing an improvement in forced expiratory volume.

Despite the approval of disease-modifying drugs that modulate the mutated cystic fibrosis transmembrane conductance regulator (CFTR) gene, new treatments are needed, Dixon said.

"These [CFTR modulators] help, but the belief in the community is that patients will still get chronic infections and will still need antibiotics. There is quite a lot of interest in [NX-AS-401] because we are coming at it from a different direction. The evidence is, it can prevent the development of biofilms and also alter the nature of existing biofilms," he said.

Having begun life in 1998 as a natural products contract research organization (CRO), Neem has built significant expertise in the medicinal chemistry of natural products, and in bacterial virulence and biofilms.

To generate further compounds, it is now applying that expertise in screening chemical libraries for novel quorum sensing inhibitors. One objective is to find orally available molecules.

To date, Neem has been financed through its CRO work and by the Zaluvida Foundation, a Malaysian and Singaporean family office that operates through a holding company in Switzerland.

"Clinical trials are not cheap and we are now starting to look for further funding. We are in the process of discussing this with family offices and other strategic investors who are interested in early stage products," said Dixon. The aim is to develop compounds to phase IIa and then find corporate partners to take them forward.

The increasing focus on antimicrobial resistance and the regulatory and other incentives that are being put in place to promote development of new anti-infectives provides the rationale for forming a quorum sensing inhibitor specialist.

"Neem is a center of excellence in antivirulence research. But because of its age it is not the most attractive for further investment, so we are creating a separate company to specialize in antimicrobial resistance," Dixon said.