Why does the WHO say too few new antibiotics are being developed?
Because the pipeline is short on genuine innovation. In its 2024 report, the WHO found that of 32 antibiotics in development against its priority bacteria, only 12 can be considered innovative, and just 4 of those 12 are active against at least one “critical” pathogen, the highest-risk category.
The headline number looks better than the reality. The count of antibacterial agents in clinical development rose from 80 in 2021 to 97 in 2023. But given how long development takes and how often drugs fail, that is still too few, and most of the candidates are not new enough to get ahead of resistance.
This connects to themes from the penicillin podcast about the search for new antibiotics: the systematic screening that followed penicillin’s success has become much harder to repeat.
What the data show:
- Pipeline size: 97 antibacterial agents in clinical development in 2023, up from 80 in 2021
- Innovation gap: Only 12 of the 32 antibiotics targeting priority pathogens are innovative, and only 4 of those work against a critical pathogen
- Recent approvals: Since July 2017, 13 new antibiotics have been authorized, but only 2 belong to a new chemical class
- Missing products: Gaps remain in treatments for children, oral options for outpatients, and agents against rising drug resistance
- Non-traditional agents: Bacteriophages, antibodies, anti-virulence, immune-modulating, and microbiome-modulating agents are increasingly being explored as complements and alternatives to antibiotics
Dr. Kumar’s Take
The WHO’s assessment is sobering. Despite decades of warnings about antibiotic resistance, drug development has not kept pace, and even when new antibiotics are approved, the WHO says they are not reaching the patients who need them in countries of all income levels. In the decades after penicillin, screening programs produced one new drug class after another. Of the 13 antibiotics approved since mid-2017, only 2 belong to a new class. The growth of non-traditional approaches, such as bacteriophages and microbiome-based treatments, is the most hopeful part of the report.
Historical Context
The WHO first released this pipeline report in 2017. It measures whether research is aimed at the drug-resistant bacteria listed in the WHO bacterial priority pathogen list, updated in 2024, which ranks them as critical, high, or medium priority. Resistance is driven largely by the misuse and overuse of antimicrobials, yet many people worldwide still lack access to essential antimicrobial medicines.
What the Research Shows
Limited Innovation in the Pipeline Only 12 of the 32 antibiotics being developed against priority pathogens count as innovative. Of the 13 antibiotics approved since mid-2017, only 2 represent a new chemical class, which reflects how hard it is to find new antibacterials that are both effective and safe for humans.
Thin Coverage of Critical Pathogens Just 4 of the innovative candidates are active against at least one critical-priority pathogen. The preclinical pipeline continues to focus on Gram-negative bacteria that resist last-resort antibiotics and can pass resistance genes to other bacteria.
Non-Traditional Agents Three non-traditional agents have been authorized, all fecal-based products that restore gut bacteria to prevent recurrent Clostridioides difficile infection after antibiotic treatment in adults. The WHO notes that studying and regulating these newer kinds of products is not straightforward.
Diagnostics and Narrow-Spectrum Drugs The shift toward agents that target a single pathogen appears to have plateaued. Those drugs depend on fast, affordable diagnostic tests to confirm which bacteria are causing an infection.
Access The WHO stresses that new antibacterials must be matched by efforts to make them available equitably, particularly in low- and middle-income countries, and calls for greater transparency in the pipeline to encourage collaboration and funding.
Practical Takeaways
- The pipeline is growing but not innovating enough: More candidates do not mean more new classes of drugs.
- The most dangerous bacteria are the least covered: Only 4 innovative candidates target a critical pathogen.
- New approaches are emerging: Phages, antibodies, and microbiome therapies are being explored alongside antibiotics.
- Access matters as much as discovery: New drugs help only if patients can get them.
Related Studies and Research
- Penicillin: The Accidental Discovery That Changed Medicine and Won a War
- Global Burden of Bacterial Antimicrobial Resistance
- Current Status of Clinical Trials for Phage Therapy
FAQs
What are the main problems with the current antibacterial pipeline?
Too few candidates overall given how often drugs fail, too little innovation (12 of 32 priority-targeted antibiotics), and gaps in products for children, oral outpatient options, and agents against rising resistance.
How many new antibiotics have been approved recently?
Since July 1, 2017, 13 new antibiotics have received marketing authorization, but only 2 represent a new chemical class.
Are there alternatives to traditional antibiotics in development?
Yes. Bacteriophages, antibodies, anti-virulence agents, immune-modulating agents, and microbiome-modulating agents are increasingly being explored. Three fecal-based microbiome products have been authorized to prevent recurrent C. difficile infection.
What does the WHO recommend?
More innovation, easier pathways to study non-traditional agents, affordable rapid diagnostics, greater pipeline transparency, and equitable access to new antibacterials, especially in low- and middle-income countries.
Bottom Line
The WHO’s 2024 report shows a pipeline that is growing in numbers, from 80 to 97 clinical candidates, but falling short on innovation: only 12 of 32 antibiotics aimed at priority bacteria are innovative, and just 4 target a critical pathogen. Non-traditional approaches offer some hope, but new drugs must also reach the patients who need them.
