Swiss Spexis AG  has announced a US$2.5m capital commitment to fund a two-part pivotal Phase III study to get market approval for its inhaled cystic fibrosis antibiotic colistimethate sodium.

The cash injection of US$2.5m that was led by SPRIM Global Investments (SGI) is urgently needed to finance US commercialisation of the company’s inhaled macrocyclic antibiotic colistimethate sodium as a treatment for patients with cystic fibrosis (CF) who suffer from infections from the antibiotic-restistant gram-negative pathogen P. aeruginosa, a major cause of opportunistic infections. US commercialisation of colistimethate sodium is estimated to cost about US$90m by analysts and yield peak sales of more than US$300m.

Acording to an ad hoc announcement, the US$2.5m capital commitment will be in the form of US$$1m in secured, interest-bearing debt with partial warrant coverage from SGI and US$1.5m subordinated debt mandatorily converting into equity from institutional investors.

Colistimethate sodium is a polymyxin antibiotic developed by Pari Pharma AG that got EU-approval in February 2021. Spexis aquired the ex-EU commercialisation rights for the antibiotic that effectively fights infections with even multi-resistant gram-negative bacteria from Pari in 2022. Spexis announced to initiate a bipartite pivotal Phase III study in Q3/2023. 

Money for the initiation of the Phase III study’s safety (COPILOT) part starting in Q3/2023 also came from SGI that committed US$4.5m in April 2023. According to Spexis, 38 CF patientis will be enrolled in COPILOT to confirm the twice-daily administration of inhaled colistimethate sodium before initiating the pivotal efficacy study COPA.

Infections with P. aeruginosa are a major contributor to lung disease in people with CF, and P. aeruginosa is considered the key bacterial agent in CF lung disease. It’s been estimated that more than 60% of adults with CF are infected with P. aeruginosa.

Spexis resulted from a reverse merger of Swiss antibiotic specialist Polyphor AG with Boston-based Enbiotix Inc in late 2021. The new company ‘s business focus is on directing macrocyclic antibiotics that target the outer cell membrane of gram-negative bacterial pathogens involved in orphan lung diseases. The company also has a macrocyclic candidate in its pipeline to fight cancer.