AMR Investing: The $100 Trillion Biotech Crisis

The market has completely abandoned antibiotics. Abandoned sectors are where the asymmetric returns live.

Antimicrobial resistance killed 1.27 million people directly in 2019, as documented in The Lancet’s global burden study. The O’Neill Report, commissioned by the UK government, projects that AMR will kill 10 million people annually by 2050 at a cumulative economic cost of $100 trillion. To put that in perspective: AMR would surpass cancer as a cause of death. The World Health Organization calls it a top-10 global health threat. And yet the public biotech companies developing novel antibiotics and antifungals have a combined market cap of under $100 million. The market has priced the entire sector at zero. When the market prices something at zero and it turns out to be worth something, the returns are not 20% or 50%. They are 10x.

The problem is not the science. The antibiotic pipeline has produced genuinely novel mechanisms: phage therapies that use viruses to kill bacteria without triggering resistance, monoclonal antibodies that neutralize bacterial toxins rather than the bacteria itself, CRISPR-based antimicrobials that selectively kill resistant strains while sparing the microbiome, and siderophore-antibiotic conjugates that use Trojan horse delivery through bacterial iron uptake systems. The problem is the business model. Antibiotics are taken for 7 to 14 days. Oncology drugs are taken for years. A novel antibiotic that cures a carbapenem-resistant infection and saves a patient’s life generates a few thousand dollars in hospital revenue. An oncology drug that extends survival by three months generates $150,000 annually per patient. The economics are inverted. The better the antibiotic works, the less it is used because stewardship programs restrict novel antibiotics to prevent resistance from developing. The revenue curve on a successful antibiotic actually goes down over time. No other sector in biotech has a business model where success means lower sales.

The result is a market failure of historic proportions. Roughly 80% of large pharmaceutical companies have exited antibiotics research and development since 2000. Novartis left. AstraZeneca left. Sanofi left. Bristol Myers Squibb left. Only GSK, Merck, and Pfizer maintain limited programs. The AMR Action Fund, a $1 billion industry-backed initiative involving more than 20 pharmaceutical companies, aims to bring two to four new antibiotics to patients by 2030. That is the entire goal for a crisis projected to kill 10 million people annually: two to four drugs over a decade. The rest of the pipeline consists of small-cap biotechs that most institutional investors cannot buy because the market caps are too small for their minimum position sizes. This is precisely the opposite of the platform biotech investing framework, where large-cap companies with validated technology platforms and recurring revenue command multi-billion-dollar valuations.

The cautionary tale every AMR investor needs to understand is Achaogen. Achaogen received FDA approval for plazomicin in June 2018, a novel aminoglycoside for carbapenem-resistant Enterobacteriaceae infections. The drug addressed exactly the kind of resistant pathogen the WHO prioritizes. Achaogen reported $800,000 in total sales for all of 2018. Nine months after approval, the company filed for bankruptcy. The assets were sold at auction for $16 million to Cipla, a fraction of the hundreds of millions invested in development. The post-mortem analysis identified three failures: plazomicin was an aminoglycoside in a market that dislikes aminoglycosides due to renal toxicity, US microbiology guidelines made using the drug logistically difficult, and the patient population for the specific resistant pathogen was too small at the time. But Achaogen was not alone. Nabriva Therapeutics, Melinta Therapeutics, and Tetraphase Pharmaceuticals all filed for bankruptcy despite having FDA-approved antibiotics. The common thread: FDA approval does not equal commercial viability in antibiotics. The hospital reimbursement model is the bottleneck, not the regulatory pathway.

This is where the policy catalysts enter the picture. The PASTEUR Act, reintroduced in Congress in February 2026 with bipartisan support, proposes a subscription model for antibiotic purchasing. Under the PASTEUR Act, the federal government would sign contracts with antibiotic developers, paying a fixed annual fee for access to novel antimicrobials regardless of how many doses are used. This decouples revenue from volume. The United Kingdom has already piloted this model through the NHS, paying 10 million pounds annually per antibiotic developer. If the PASTEUR Act passes, it fundamentally rewrites the antibiotic revenue model. The GAIN Act already provides five years of additional market exclusivity plus priority review for Qualified Infectious Disease Products, known as QIDPs. BARDA, the Biomedical Advanced Research and Development Authority, has committed billions in non-dilutive funding to AMR countermeasures. The CARB-X partnership, funded by BARDA and the Wellcome Trust, has deployed over $455 million to early-stage antibiotic development.

The investable universe is small, as it should be for a sector priced at zero. Spero Therapeutics (SPRO), at $73 million market cap and $1.23 per share, has tebipenem HBr, an oral carbapenem antibiotic partnered with GSK. The drug is the first oral carbapenem for complicated urinary tract infections and received FDA approval in late 2025 with a commercial launch expected by end of 2026 through GSK’s infectious disease sales force. GSK is one of the few large pharma companies still committed to anti-infectives. The partnership structure means SPRO receives milestone payments and royalties without funding its own commercial infrastructure. The key risk is that tebipenem, like plazomicin before it, faces the same hospital reimbursement headwinds regardless of who sells it.

Iterum Therapeutics (ITRM) is the cautionary tale playing out in real time. Iterum received FDA approval for Orlynvah (oral sulopenem) in late 2024, the first oral penem antibiotic approved in the United States for uncomplicated urinary tract infections. The company now trades at $0.03 per share with a market cap of approximately $1.6 million. An FDA-approved novel antibiotic with a market cap of $1.6 million. Iterum is Achaogen two years later, and the market is treating it exactly the same way. The drug may have clinical value, but the commercial economics have not changed.

SCYNEXIS (SCYX) represents the antifungal side of the AMR story. The company developed ibrexafungerp, the first new antifungal class approved in over 20 years, with a novel glucan synthase inhibition mechanism that is fungicidal rather than fungistatic. The oral formulation is approved as Brexafemme for vulvovaginal candidiasis, and a liposomal IV formulation is in development for severe hospital-based invasive fungal infections. The company received QIDP designation for SCY-247 in 2026. However, SCYNEXIS has struggled commercially: it wound down its own promotional activities and sought an out-licensing partner for the VVC indication. The hospital IV opportunity is the thesis, but it requires Phase 3 data that is not yet available.

The diagnostics angle is perhaps the most investable AMR thesis for investors who want exposure without betting on antibiotic reimbursement reform. Rapid molecular diagnostics that identify pathogens and resistance profiles in hours instead of days are the enabling technology for the entire AMR response. Current standard-of-care diagnostics take 48 to 72 hours for culture and sensitivity results, during which time patients are on empiric broad-spectrum antibiotics that drive resistance. Companies at the intersection of AMR and diagnostics are building the infrastructure that makes targeted antibiotic therapy possible. The diagnostics piece deserves its own analysis; for now, the key point is that AMR investing does not have to mean buying micro-cap antibiotic developers.

The investment thesis for AMR is straightforward but uncomfortable. This is a policy-driven catalyst play, not a commercial revenue play; the same framework that applies to orphan drug pricing economics where a single policy change can re-rate an entire drug class overnight. This is also the same calculus behind the infectious disease catalyst ranking that structures the sector: the policy catalyst is the thesis, the science is the prerequisite. The companies that generate asymmetric returns will be those that target pathogens with zero treatment options, have non-dilutive BARDA funding extending runway past the policy catalyst timeline, and are positioned for the PASTEUR Act subscription model. Achaogen failed because the reimbursement model was broken. If the PASTEUR Act passes, the model is fixed and the companies that survived to that point capture the value. If it does not pass, these companies go to zero, exactly where the market has already priced them.

The sector is uninvestable for institutional mandates. The total market cap of the AMR pure-play public universe is under $100 million. No fund with a $500 million minimum position size can buy these stocks. That is precisely what makes them interesting for individual investors. The asymmetry comes from being able to take a position that institutions structurally cannot; the same dynamic that creates opportunity in pre-revenue platform biotech investing before the revenue validates the thesis. The risk is total loss, which is exactly what the market is already pricing. Do not allocate more than 1% to 2% of a biotech portfolio to this thesis and only as a policy catalyst call option, not a fundamental value investment. The PASTEUR Act is the catalyst. Everything else is noise.