“In the five years covered by this report, we have had just 12 antibiotics approved, with only one of these – Cefiderocol – able to target all the pathogens deemed critical by WHO,” explains Dr Gigante. “And there are only 27 more currently under development in phase 1 to 3 clinical trials, with little innovation. Only four of the 27 have new mechanisms of action, and most are not new drug classes, but evolution of existing classes.”
Currently, one antibiotic, Solithroymcin – to be used to treat community acquired pneumonia and other infections – is at the ‘new drug application’ stage (passed through clinical trials and awaiting market authorisation) and a further seven products are in phase 3 trials having their efficacy assessed. Dr Gigante explains, that, since failures are possible even in phase 3 trials, it is difficult to predict if and when a market authorisation will be granted for these drugs.
According to recent estimates almost 5 million deaths are already associated each year due to antimicrobial resistance (AMR). However, the true burden of resistance could be even greater. Furthermore, AMR disproportionately affects poor individuals who have little access to second line, more expensive antibiotics that could work when first-line drugs fail.
Antimicrobials are not as lucrative a prospect as other treatments for pharmaceutical companies, because they are mostly short-term treatments and antibiotic stewardship programmes are aimed at conserving or ‘saving’ any such new drugs until they are desperately needed. And they are just as likely to fail during the research and development process as any other drug for other conditions, yet offer a fraction of the revenue returns compared with, for example, cancer and cardiology drugs. As a result of these and other factors, the research and development process for new antibiotics is challenging and poorly funded. The last novel antibiotic class was discovered in the 1980s, and the first antibiotic from this class, daptomycin, reached the market in 2003.
Silent pandemic of antibiotic resistance
Resistance to antimicrobials develops because of overuse and improper use, such as people not completing their full course of antibiotics or because of the wrong antibiotic being prescribed – or, in some countries, antibiotics being used widely without prescriptions. The global trend of inappropriate use of antibiotics is demonstrated by the time it takes for resistance to develop to new antibiotics – for antibiotics launched between 1930 and 1950 the average time to develop resistance was 11 years; for antibiotics launched between the 1970 to 2000 it was just 2-3 years.
This silent pandemic of antibiotic resistance continues to grow worldwide. Experts repeatedly warn of a ‘doomsday scenario’ in which routine medical procedures – for example antibiotic prophylaxis in cancer or other disease care – would no longer be effective, and untold numbers of people could die
from what were previously simple, treatable infections.
One example of a drug-resistance mechanism experts are worried about is New Delhi metallobeta-lactamase 1 (NDM-1). Bacteria which contain the gene to produce this enzyme can break down (and are therefore resistant to) a wide-range of carbapenem antibiotics – considered part of the last line of defence in antibiotic treatments where other antimicrobials have failed. The most common bacteria that make this enzyme are Escherichia coli and Klebsiella pneumoniae, but the gene for NDM-1 can spread from one strain of bacteria to another. Prevalence of NDM-1 containing bacteria continues to grow worldwide.
Dr Gigante says: “There is a major gap regarding products addressing multi-drug resistant (MDR) pathogens such as Acinetobacter baumannii and Pseudomonas aeruginosa (just one agent authorised against all the critical pathogens and few in the pipeline). Very few agents target metallo-β-lactamases, which continue to grow in prevalence. Few new innovative antibiotics are expected in the coming years. We have no silver bullets.”
She adds: “The rapid increase of multidrug-resistant infections worldwide is concerning. Time is running out for us to bring new antibiotics to market and combat this urgent threat to public health. Without immediate action, we risk returning to a pre-antibiotic era where common infections become deadly.”
She concludes: “While we face significant challenges in the fight against antimicrobial resistance, research and development efforts are underway to discover and develop new and hopefully innovative antimicrobial agents, and we have seen promising results in recent years. With increased investment and collabo-
ration across sectors, we can make progress in the fight against antimicrobial resistance and ensure that patients have an equitable and global access to effective treatments for drug-resistant bacterial infections.”