By Michael Meyer, USPTO-Registered Patent Attorney | Chemistry Degree, UNO | J.D., Creighton University | Updated February 2026

Patent Law in Biotechnology: Myriad, Mayo & What's Still Patentable (2026)

Biotechnology sits at the intersection of cutting-edge science and some of the most legally contentious areas of patent law. Supreme Court decisions over the past 15 years have fundamentally reshaped what can and cannot be patented in the life sciences — from genes and diagnostic methods to CRISPR gene editing tools and engineered antibodies.

For researchers, biotech companies, and university tech transfer offices, understanding these legal boundaries is essential. Filing a patent application on a naturally occurring gene sequence will fail. Filing on a synthetically created cDNA sequence or a CRISPR-modified organism may succeed — but only if the claims are drafted with the post-Myriad, post-Mayo framework in mind.

This guide explains what changed, what's still patentable in biotechnology, and how claim drafting strategy determines whether your biotech invention survives § 101 examination.

Table of Contents

1. The Biotech Patent Landscape: What Changed
2. Myriad Genetics: Genomic DNA vs. cDNA
3. Mayo v. Prometheus: The Diagnostic Method Problem
4. What IS Patentable in Biotechnology?
5. What Is NOT Patentable in Biotechnology?
6. CRISPR and Gene Editing: Patent Eligibility and Ownership
7. Antibodies and Biologics: Patenting Engineered Proteins
8. Stem Cells and Cell Lines: Patent-Eligibility Challenges
9. Claim Drafting Strategy for Biotech Patents
10. Frequently Asked Questions

1. The Biotech Patent Landscape: What Changed

Before 2012, biotechnology patents were granted broadly on naturally occurring genes, diagnostic correlations, and personalized medicine methods based on natural biological relationships. Those patents are no longer valid.

Two Supreme Court cases fundamentally changed biotechnology patent law:

Mayo Collaborative Services v. Prometheus Laboratories (2012)

Held that diagnostic methods based on natural correlations (measuring a biomarker and correlating it to a disease state or drug efficacy) are not patent-eligible if the additional steps are "well-understood, routine, and conventional" in the field. This decision invalidated thousands of diagnostic method patents and created ongoing § 101 challenges for personalized medicine.

Association for Molecular Pathology v. Myriad Genetics (2013)

Held that naturally occurring genomic DNA sequences are not patentable even when isolated from the body, but that synthetically created cDNA (complementary DNA) — which does not occur in nature — remains patent-eligible. This eliminated gene patents covering natural sequences like the BRCA1 and BRCA2 genes.

Together, these cases established the "markedly different from nature" standard — a biotech invention is patent-eligible only if it has been meaningfully transformed or engineered beyond what exists naturally.

2. Myriad Genetics: Genomic DNA vs. cDNA

The Myriad decision is the most important biotech patent case in U.S. history. Myriad Genetics held patents on isolated BRCA1 and BRCA2 gene sequences — mutations in these genes are associated with significantly increased breast and ovarian cancer risk. Myriad's patents effectively prevented other laboratories from offering BRCA genetic testing, giving Myriad a monopoly on a critical diagnostic test.

The Supreme Court's Holding

In a unanimous decision, the Court held:

• Genomic DNA (gDNA) is NOT patentable — even when isolated and purified from the human genome. A naturally occurring DNA sequence is a product of nature. Isolating it does not make it patent-eligible.
• Complementary DNA (cDNA) IS patentable — cDNA is synthetically created by reverse-transcribing mRNA. It contains only the exons (protein-coding sequences) and does not include introns. Because cDNA does not exist in this form in nature, it is sufficiently "markedly different" to qualify as patent-eligible.

What This Means for Biotech Researchers

The key test post-Myriad: Is the claimed molecule meaningfully different in structure or function from what exists in nature? If yes, it may be patent-eligible. If it's merely isolated or purified, it is not.

3. Mayo v. Prometheus: The Diagnostic Method Problem

The Mayo decision created a different but equally significant problem for biotechnology patents — it made diagnostic method patents extremely difficult to obtain and enforce.

The Case

Prometheus Laboratories held patents on a method for optimizing the dosage of thiopurine drugs used to treat autoimmune diseases. The method involved:

1. Administering a thiopurine drug to a patient
2. Measuring the concentration of drug metabolites in the patient's blood
3. Comparing the measured level to a threshold indicating whether the dosage should be increased or decreased

The Supreme Court invalidated the patent, holding that the method was directed to a natural law — the relationship between metabolite levels and drug efficacy — and that the additional steps (administering the drug, measuring, and comparing) were "well-understood, routine, and conventional" in the medical field. The patent did not add "significantly more" than the natural law itself.

The Mayo Two-Step Test

The Court established a two-step framework (later extended to all § 101 cases in Alice Corp. v. CLS Bank) for evaluating patent eligibility:

1. Step 1: Is the claim directed to a law of nature, natural phenomenon, or abstract idea?
2. Step 2: If yes, do the additional elements in the claim amount to "significantly more" than the exception itself?

For biotech diagnostic methods, this test is devastating. Most diagnostic methods are based on natural correlations (biomarker X correlates with disease Y), and the measurement steps are typically standard lab techniques. As a result, many diagnostic claims fail at Step 2.

What Mayo Means for Biotech Inventors

Diagnostic method patents are now very difficult to obtain unless the claims include:

• A novel, non-obvious biomarker that was not previously known to correlate with the disease
• An unconventional measurement technique that is not routine in the field
• A treatment step that goes beyond merely observing and applying the natural correlation

Even with these elements, § 101 rejections are common, and many biotech diagnostic patents granted before Mayo have been invalidated in litigation. See our full guide to Alice and patent eligibility for more on the two-step test.

4. What IS Patentable in Biotechnology?

Despite Myriad and Mayo, many categories of biotechnology inventions remain patent-eligible if properly claimed:

Synthetically Created or Engineered Molecules

• cDNA sequences (as held in Myriad)
• Synthetic genes with optimized codons for expression in specific host organisms
• Engineered proteins with modified amino acid sequences that do not exist in nature
• Chimeric antibodies combining human and non-human sequences
• Fusion proteins created by joining two or more naturally occurring protein sequences

Novel Compositions and Formulations

• Drug-antibody conjugates (ADCs) linking a therapeutic agent to a targeting antibody
• Novel pharmaceutical formulations with improved stability, bioavailability, or delivery characteristics
• Nanoparticle delivery systems for biologics

Genetically Modified Organisms

• Transgenic plants and animals with inserted genes conferring new traits
• Engineered microorganisms producing novel compounds or performing novel functions (e.g., bacteria engineered to synthesize biofuels)
• CRISPR-modified organisms (with careful claim drafting to avoid § 101 issues)

Methods of Making or Using Biotech Products

• Novel methods of producing recombinant proteins with improved yield or purity
• Gene therapy methods using engineered vectors
• Cell culture techniques producing enhanced or modified cell lines

The common thread: the invention must involve human intervention that creates something markedly different from what exists in nature.

5. What Is NOT Patentable in Biotechnology?

The following categories face § 101 patent-eligibility challenges and are difficult or impossible to patent post-Myriad and post-Mayo:

Naturally Occurring Molecules

• Genomic DNA sequences as they exist in nature (per Myriad)
• Naturally occurring proteins, peptides, or antibodies isolated from human or animal sources
• Natural metabolites or biomarkers discovered to correlate with disease

Diagnostic Correlations Based on Natural Laws

• Methods claiming only the observation that biomarker X correlates with disease Y
• Diagnostic methods using routine measurement techniques to apply a natural correlation (per Mayo)
• Personalized medicine methods selecting treatment based on genetic variants unless the selection method itself is novel and non-routine

Abstract Data Analysis

• Bioinformatics methods that merely analyze genetic data using conventional computational techniques
• Claims directed to correlating genotype with phenotype without a concrete application beyond the correlation itself

6. CRISPR and Gene Editing: Patent Eligibility and Ownership

CRISPR-Cas9 gene editing has been one of the most significant biotechnology breakthroughs of the 21st century — and one of the most contentious areas of patent law, both in terms of eligibility and ownership.

Patent Eligibility of CRISPR Inventions

CRISPR itself is a naturally occurring bacterial immune system. However, the engineered CRISPR-Cas9 systems used in gene editing are patent-eligible because they are:

• Synthetically created guide RNAs designed to target specific DNA sequences
• Modified Cas9 proteins with altered specificity or reduced off-target effects
• CRISPR delivery systems (viral vectors, nanoparticles) engineered for use in mammalian cells
• Methods of using CRISPR to edit specific genes in specific cell types

Claims directed to the naturally occurring CRISPR-Cas system as it exists in bacteria would fail under Myriad. Claims directed to engineered components or specific applications survive.

The CRISPR Patent Wars

The Broad Institute (MIT/Harvard) and UC Berkeley have been litigating over CRISPR patent ownership since 2014 in one of the most expensive interference proceedings in USPTO history. The core dispute: who invented the use of CRISPR-Cas9 in eukaryotic cells first?

As of 2026, both parties hold patents in different jurisdictions with different scopes. Companies commercializing CRISPR often license from both to avoid infringement risk.

7. Antibodies and Biologics: Patenting Engineered Proteins

Antibody therapeutics represent a multi-billion-dollar segment of the biotech industry. Patent protection for antibodies depends on whether the antibody is naturally occurring or engineered.

What's Patentable

• Humanized or chimeric antibodies — Antibodies engineered to combine human constant regions with non-human variable regions are patent-eligible as compositions of matter
• Fully human monoclonal antibodies produced through recombinant methods with specific binding characteristics not found in nature
• Antibody fragments (Fab, scFv) engineered for specific therapeutic applications
• Bispecific antibodies binding two different antigens simultaneously
• Antibody-drug conjugates (ADCs) linking antibodies to cytotoxic agents

What's Challenging

Antibodies that exist naturally in humans or animals — even if discovered through novel screening techniques — face eligibility challenges under Myriad. The claim must emphasize what makes the antibody structurally or functionally different from natural antibodies.

8. Stem Cells and Cell Lines: Patent-Eligibility Challenges

Stem cell patents face unique challenges due to their origin from natural human cells.

What's Patentable

• Induced pluripotent stem cells (iPSCs) — created by reprogramming adult cells, these are patent-eligible as engineered cell lines
• Differentiated cells produced through novel protocols — methods of directing stem cells to specific cell types can be patented
• Genetically modified stem cell lines — stem cells engineered to express specific genes or knockout specific pathways

What's Challenging

• Embryonic stem cell lines isolated directly from embryos without modification face eligibility challenges as naturally occurring
• Methods of isolating or culturing stem cells using conventional techniques are difficult to patent post-Mayo if they simply apply well-understood methods

9. Claim Drafting Strategy for Biotech Patents

Post-Myriad and post-Mayo, biotech patent claim drafting requires careful strategic choices to survive § 101 examination:

Emphasize Structural Differences

For composition of matter patents, the specification and claims should explicitly describe how the claimed molecule is structurally different from any naturally occurring counterpart. Include sequence comparisons, structural data, and functional assays demonstrating the difference.

Avoid "Isolated" or "Purified" Language Alone

Post-Myriad, claiming a molecule as merely "isolated" or "purified" is insufficient. The claims must recite structural modifications, synthetic origin, or functional characteristics that do not exist in nature.

For Diagnostic Methods, Add Concrete Application Steps

To survive Mayo, diagnostic method claims should include treatment steps, novel measurement techniques, or specific clinical decision algorithms that go beyond simply observing and applying a natural correlation.

Use the Specification to Establish Non-Obviousness

The Mayo framework turns on whether additional claim elements are "well-understood, routine, and conventional." The specification should describe technical challenges overcome, unexpected results achieved, and why the claimed method was not obvious to skilled practitioners.

Consider Method Claims in Addition to Composition Claims

For engineered biologics, file both composition claims (covering the molecule itself) and method claims (covering how it's made or used). If composition claims face § 101 challenges, method claims may survive.

10. Frequently Asked Questions

Can you patent genes after the Myriad decision?

You cannot patent naturally occurring genomic DNA sequences as they exist in the human genome, even if isolated and purified. However, you can patent synthetically created cDNA (complementary DNA) that does not include introns, synthetic genes with optimized codon usage, or engineered gene sequences that are structurally different from natural sequences. The key test is whether the claimed DNA is "markedly different" from what exists in nature.

What is the difference between genomic DNA and cDNA for patent purposes?

Genomic DNA (gDNA) includes both exons (coding sequences) and introns (non-coding sequences) exactly as they exist in the genome. It is not patentable because it is a naturally occurring product. Complementary DNA (cDNA) is created in the lab by reverse-transcribing mRNA and contains only exons with no introns. Because this structure does not exist in nature, cDNA is patent-eligible under Myriad.

Can you patent CRISPR gene editing methods?

Yes — methods of using engineered CRISPR-Cas9 systems to edit specific genes in specific cell types are patent-eligible. Engineered guide RNAs, modified Cas9 proteins, and delivery systems for CRISPR components are also patentable. However, claims directed to the naturally occurring bacterial CRISPR system would not be patent-eligible. The invention must involve human engineering that creates something different from what exists in nature.

Are diagnostic method patents still possible after Mayo?

Diagnostic method patents are significantly more difficult to obtain post-Mayo but not impossible. To survive § 101 examination, diagnostic claims must include elements that amount to "significantly more" than simply observing and applying a natural correlation. This can include novel biomarkers, unconventional measurement techniques, treatment steps, or specific clinical decision algorithms that are not routine in the field. Many diagnostic patents granted before Mayo have been invalidated in litigation.

Can you patent antibodies?

Yes, but the antibody must be structurally or functionally different from naturally occurring antibodies. Humanized antibodies, chimeric antibodies, antibody fragments, bispecific antibodies, and antibody-drug conjugates are all patent-eligible as engineered molecules. Naturally occurring antibodies isolated from human serum would likely not be patent-eligible under Myriad's "markedly different" standard.

What is the "markedly different" standard in biotech patents?

The "markedly different" standard comes from the Myriad decision and asks whether the claimed invention has characteristics that are meaningfully different from anything found in nature. For molecules, this typically means structural differences (different sequence, different folding, different functional groups). For methods, it means the process creates something or achieves a result that does not occur naturally. Mere isolation, purification, or discovery of a natural product or correlation is not enough.

How does Michael Meyer's chemistry background help with biotech patents?

Biotechnology patent prosecution requires understanding both the legal framework (Myriad, Mayo, § 101 eligibility) and the underlying science (molecular biology, protein structure, genetic engineering). A patent attorney with a chemistry degree can evaluate whether a biotech invention is likely to survive eligibility challenges, draft claims that emphasize structural differences from natural products, and argue non-obviousness based on technical challenges in the field — all of which are critical for biotech patent success.

Warning & Disclaimer: The pages, articles, and comments on michaelmeyerlaw.com do not constitute legal advice, nor do they create any attorney-client relationship. The articles published express the personal opinions and views of the author as of the time of publication.