COMPANY PROFILE / iPS CELLS & REGENERATIVE MEDICINE
Prime Medicine
A company that rewrites DNA without cutting it, and has now moved prime editing into clinical trials for an inherited liver disease
Prime Medicine is a genome editing company, not an iPS cell company. It aims to use "prime editing" in medicine: rather than cutting both strands of DNA, the tool nicks a single strand and rewrites it to a chosen sequence. At the end of 2025 it had 146 employees. It is a listed clinical-stage developer, but its only revenue is collaboration income, and it held just US$95.1 million in cash and investments at the end of June 2026. Its 10-K states that there is substantial doubt about its ability to continue as a going concern. This profile sets out what it is developing, whom it works with, how far it has got and what remains unconfirmed, using only the company's statutory filings and official materials.
- Prime Medicine in 30 seconds, and where it stands in iPS cells and regenerative medicine
- The logo and how the name is written
- Where the company sits in iPS cells and regenerative medicine
- Scale
- Resources committed to iPS cells and regenerative medicine
- Track record so far
- Plans ahead
- What the company is aiming for in iPS cells and regenerative medicine
- Partnership map for iPS cells and regenerative medicine
- Technology, products and services on offer
- The risks this company carries
- Glossary, references and claim-to-source audit
1. Prime Medicine in 30 seconds, and where it stands in iPS cells and regenerative medicine
Massachusetts, U.S.60 First Street
(mainly in vivo)Plans to reach the liver with lipid nanoparticles (LNPs)
Regenerative medicine companies fall broadly into two camps: those that make cells and those that rewrite genes directly. Prime Medicine belongs to the second camp, and its main candidates edit a patient's own liver cells inside the body Sourced. It does, however, also have a candidate (PM359) in which a patient's own blood stem cells are edited outside the body and returned, and the company describes this as the first prime-editing therapy ever given to humans. Its early data cover only two patients, and in May 2025 the company changed course so that it would "not take this programme forward on its own" Sourced. Every data set here is an early result from a handful of patients and is no guarantee of a therapeutic effect.
2. The logo and how the name is written
A note on names: the legal entity is Prime Medicine, Inc., a Delaware corporation. "PM359", "PM577a" and "PM647" are development code names, not the names of approved drugs. The 10-K calls one candidate "PM577" and the August 2026 10-Q calls it "PM577a", but both refer to the same Wilson disease candidate. Beam Therapeutics is a separate company co-founded by one of Prime Medicine's founders (David Liu), and this article treats it as a distinct legal entity.
Official site: https://primemedicine.com/3. Where the company sits in iPS cells and regenerative medicine
In conventional CRISPR approaches, an enzyme such as Cas9 cuts both strands of the DNA. The 10-K explains that such cuts can lead to unintended insertions and deletions (indels) and to chromosomal rearrangements Sourced. Prime Medicine's answer is prime editing, which does not involve a double-strand cut. For the types of editing tool and how safety is assessed, see our explainers on genome editing and on off-target effects and safety assessment.
4. Scale
This is a clinical-stage biotech, so the figures to watch are R&D spending and cash on hand rather than sales Sourced. Amounts are in US dollars.
| Metric (US$ thousand) | FY2024 (year to December 2024) | FY2025 (year to December 2025) | January to June 2026 |
|---|---|---|---|
| Revenue (collaboration and licence income) | 2,983 | 4,632 | 2,010 |
| Research and development expense | 155,289 | 160,636 | 67,502 |
| Net loss | (195,882) | (201,142) | (91,231) |
| Capital expenditure (purchase of property and equipment) | 7,294 | 4,531 | 260 |
| Item | Detail | As of |
|---|---|---|
| Cash and investments (cash and short-term investments) | US$177.7 million (excluding restricted cash) | 31 December 2025 |
| Cash and investments (cash and short-term investments) | US$95.1 million | 30 June 2026 |
| Funding outlook (company) | The company expects its cash to last into 2027 | 10-K and 10-Q |
| Employees | 146 (119 in R&D, 27 in administration; 63 hold an MD or PhD) | 31 December 2025 |
| Accumulated deficit | US$979.6 million | 30 June 2026 |
Both the 10-K and the 10-Q state that there is substantial doubt about the company's ability to continue as a going concern Sourced. The company plans to rely on further financing, including sales of shares, but says itself that it cannot guarantee it will raise the money. Its revenue is collaboration income alone; it has no product sales.
5. Resources committed to iPS cells and regenerative medicine
We give amounts only where they have been disclosed, and write "not confirmed" where they have not.
| Type of resource | Detail | Category |
|---|---|---|
| People | 146 employees (end of December 2025): 119 in R&D and 63 with an MD or PhD. A workforce reduction of about 25% was announced in May 2025 | Sourced |
| Research and manufacturing sites | Cambridge (60 First Street, about 149,000 square feet, leased to February 2034) and Watertown (500 Arsenal Street, about 48,500 square feet, to August 2028). It has built its own animal facility (vivarium) | Sourced |
| Money: R&D expense | US$160.6 million in FY2025 (up US$5.3 million on the prior year). US$67.5 million in January to June 2026 | Sourced |
| Money: capital expenditure | Purchases of property and equipment were US$4.5 million in 2025 and US$7.3 million in 2024 | Sourced |
| Manufacturing | No commercial-scale production capability. For clinical supply it uses outside contract manufacturing and testing organisations together with its own cGMP manufacturing and testing (for some core technologies) | Sourced |
| In-licensing from outside | Prime-editing patents licensed from the Broad Institute (September 2019, since amended). It has committed to donate US$5.0 million a year for 14 years to the Broad Institute and Harvard University (from 2021) | Sourced |
| Outside investments and acquisitions | The 10-K lists no investments in or acquisitions of start-ups. With Beam Therapeutics it exchanged shares in 2019 (Beam received about US$5.0 million worth; Prime received 1,608,337 shares) | Sourced |
| Public and non-profit funding | Up to US$15.0 million (2024) and up to US$24.0 million (2025) from the Cystic Fibrosis Foundation. The 10-K lists no government grants or public funding related to iPS cells | Sourced |
| Universities and research institutions | It licenses patents jointly owned by the Broad Institute, MIT, Harvard University, Princeton University and the University of California | Sourced |
According to the 10-K, the company intends to reuse a common LNP composition and a common editing-enzyme design across several programmes, cutting the toxicology and chemistry, manufacturing and controls (CMC) work involved Sourced. Much of the clinical manufacturing is done by outside contract manufacturers, so the quality and supply of lipid raw materials, mRNA and guide RNA (pegRNA) could set the pace of development. The suppliers of these materials are not disclosed, so this article cannot confirm which materials come from whom Not yet confirmed.
6. Track record so far
The timeline is limited to what we could confirm in statutory filings and press releases.
| When | What happened | Why it matters |
|---|---|---|
| September 2019 | Founded. Licence agreement with the Broad Institute and collaboration agreement with Beam Therapeutics | Licensed in the prime-editing patents and laid the foundation for development |
| July 2020 | Began operations | The 10-K states that it was founded in September 2019 and began operations in July 2020 |
| February 2021 | Commitment to donate US$5.0 million a year for 14 years to the Broad Institute and Harvard University | Locks in the relationship with the patent source for the long term |
| January 2024 | Agreement with the Cystic Fibrosis Foundation (up to US$15.0 million) | Funding for cystic fibrosis |
| September 2024 | Collaboration and licence agreement with a Bristol Myers Squibb subsidiary. Upfront payment of US$55.0 million and equity investment of US$55.0 million | Covers therapies in which T cells are edited outside the body |
| October 2024 | Phase 1/2 trial of PM359 started (start date on ClinicalTrials.gov) | The first trial of prime editing in humans |
| March to April 2025 | Announced development in alpha-1 antitrypsin deficiency (AATD). Beam filed for arbitration | A dispute over the scope of the collaboration agreement |
| May 2025 | Published early data from the first PM359 patient. The same day, announced a restructuring that deprioritised PM359, a workforce reduction of about 25% and a change of CEO | Results and retrenchment came on the same day. The company described 20% as the lower bound of expected clinical benefit (a single patient's figure) |
| July to August 2025 | The Cystic Fibrosis Foundation added up to US$24.0 million. In August, data from the second PM359 patient | Foundation money keeps the cystic fibrosis work going |
| June 2026 | Clinical trial application (CTA) for PM577a cleared in New Zealand. FDA granted PM359 RMAT designation | The first clinical-trial clearance for in vivo prime editing |
| July 2026 | FDA cleared the IND for PM577a. On 6 July, final arbitration award (PM647 falls within the company's rights) | Enrolment in the U.S. becomes possible, and the arbitration uncertainty is removed |
7. Plans ahead
The Phase 1/2 trial of PM577a enrols adults and adolescents with Wilson disease who carry the H1069Q variant, and its primary endpoint is safety and tolerability (through week 48). Efficacy is assessed only as a secondary measure, and initial data are expected in 2027 Not yet confirmed.
None of the following is stated in the primary sources Not yet confirmed.
When the PM647 trial will start; when PM359 might be approved; manufacturing scale and the names of the contract manufacturers for each programme; the expected price; and the sales structure if approved. This article does not assert timing such as "approval will come at X".
8. What the company is aiming for in iPS cells and regenerative medicine
This chapter includes points the company does not state directly. We set out inferences that can be read from the primary sources, together with the grounds for each.
| What can be read from the sources | Primary-source basis | Category |
|---|---|---|
| The centre of gravity of the business has shifted from editing cells outside the body to in vivo treatment of the liver | In May 2025 the company announced that it would deprioritise PM359 and concentrate internal resources on Wilson disease and AATD (Form 8-K) | Inference |
| A strategy of reusing a common LNP and a common editing enzyme to add programmes | The 10-K describes shared toxicology and CMC with a common LNP and editing enzyme, and says it is considering a comprehensive IND strategy for Wilson disease | Inference |
| PM359 is positioned not as a programme to commercialise alone but as one to partner or otherwise leverage externally | In May 2025 the company said it would seek to continue it externally; the 2026 10-Q says it continues discussions with the FDA toward a BLA submission. The final policy is unclear | Inference |
| It is discussed under regenerative medicine because a therapy that edits a patient's own blood stem cells outside the body and returns them was the first to enter humans | The 10-K states that PM359 is for patients undergoing autologous hematopoietic stem cell transplantation. It mentions no use of iPS cells | Sourced |
| 2027 is a year for early data, not a year for approval | The 10-K and 10-Q give 2027 for initial clinical data. The BLA for PM359 is at the planning stage | Inference |
On the same day, 19 May 2025, the company announced both good data from the first PM359 patient and the deprioritisation of that programme with a workforce cut of about 25% Sourced. The company explained that results and retrenchment came together in order "to withstand the current market environment" and "to focus on the liver and externally funded programmes". From this we read the company as having concluded that an autologous cell therapy for a blood disease that serves only a few patients cannot be carried to the end on its own funds. On the other hand, it received RMAT designation from the FDA in June 2026 and plans a BLA submission, so its policy may have changed Not yet confirmed.
9. Partnership map for iPS cells and regenerative medicine
10. Technology, products and services on offer
There are no products yet. What the company offers is a treatment mechanism (a platform) and the development candidates built on it Sourced.
| Programme / technology | Target | Mechanism | Stage (as of August 2026) |
|---|---|---|---|
| PM577a | Wilson disease (H1069Q variant of the ATP7B gene) | Prime editing inside the body, delivered to liver cells by LNP | FDA cleared the IND. Phase 1/2 trial starting (in development) |
| PM647 | Alpha-1 antitrypsin deficiency (SERPINA1 gene) | Corrects the Z-AAT variant using the same liver-directed LNP | IND/CTA to be filed (Q3 2026) |
| Cystic fibrosis programme | Variants in the CFTR gene | Delivered to airway epithelial cells in the lung by LNP or AAV | Lead optimisation (preclinical) |
| PM359 | Chronic granulomatous disease (the NCF1 ΔGT variant) | Patient's own blood stem cells are edited outside the body and returned | Phase 1/2 trial (NCT06559176). The company said it would not advance it alone (May 2025); a BLA is planned |
| Joint programme with BMS | T-cell therapy (CAR-T) | BMS holds the licence; T cells are edited outside the body | Joint research stage |
What is prime editing?
A modified Cas9 "nickase" (an enzyme that cuts only one strand of DNA) is fused to a reverse transcriptase, and a guide molecule called a pegRNA carries a template from which the new sequence is written into the target site. Because it does not cut both strands, the company says unintended insertions and deletions (indels) are less likely to occur Sourced. This is, however, the company's account based on preclinical data, and long-term safety in humans has yet to be established in future trials.
Three materials make up this therapy: (1) mRNA encoding the editing enzyme, (2) the pegRNA (a long RNA whose chemical-modification design decides its quality) and (3) the lipid nanoparticle that delivers them to liver cells. The 10-K explains that the company has optimised a "common LNP" for the liver and addresses new variants simply by swapping the mRNA and pegRNA Sourced. On the materials side, what probably matters most is lipid purity and lot-to-lot reproducibility, RNA synthesis quality and impurity control, and uniform particle size with stability in freezing and storage Not yet confirmed. The company has not disclosed its control values for these, so this paragraph is a general discussion of materials.
11. The risks this company carries
| Risk | Details | Category |
|---|---|---|
| Funding | Substantial doubt about its ability to continue as a going concern. Cash and investments were US$95.1 million at the end of June 2026, expected to last into 2027 | Sourced |
| Early clinical stage | The in vivo programmes are still at the entrance to Phase 1/2. The PM359 data cover only two patients, with short follow-up | Sourced |
| Expansion beyond the liver | The lung programme (cystic fibrosis) is at lead optimisation, with both LNP and AAV being studied in parallel | Sourced |
| Uncertainty in delivery (LNP) | The 10-K states that clinical evidence for delivering large RNAs such as editing tools by LNP is limited, and that LNPs may cause liver toxicity and other effects | Sourced |
| Reliance on patents and licences | The core technology is in-licensed from the Broad Institute and others. The institute has rights that include securing certain targets for itself | Sourced |
| Dispute with a partner | The arbitration with Beam was decided in the company's favour in July 2026, and each side's remaining claims were dismissed. The effect on future dealings is unclear | Sourced |
| PM359 policy | After saying it would not advance the programme itself, the company now plans a BLA submission. How it will finally proceed is not settled | Not yet confirmed |
| People and organisation | A workforce cut of about 25% and a change of CEO in 2025. Continuity of development depends on funding and execution | Inference |
12. Glossary
- Prime editing
- Genome editing that nicks one strand of DNA, rather than cutting both, and rewrites the sequence according to a template.
- pegRNA
- The RNA that guides prime editing. It carries both the target location and the template for the new sequence to be written.
- Nickase
- A Cas9 modified so that it nicks only one of the two DNA strands.
- In vivo / ex vivo
- In vivo means editing directly inside the body; ex vivo means taking cells out of the body, editing them and returning them.
- LNP (lipid nanoparticle)
- A tiny lipid particle that wraps mRNA and similar cargo and delivers it to cells. It tends to accumulate in the liver.
- AAV
- Adeno-associated virus, used as a vector to carry genes into cells.
- Chronic granulomatous disease (CGD)
- A rare inherited disease in which white blood cells have a congenitally weak ability to kill microbes, leading to repeated infections.
- Wilson disease
- An inherited disease in which the body cannot excrete copper properly, so copper accumulates in the liver and brain.
- IND / CTA
- Applications filed with regulators to begin a clinical trial. In the U.S. it is an IND; in Europe, the U.K. and elsewhere it is a CTA.
- RMAT
- Regenerative Medicine Advanced Therapy. An FDA designation for regenerative medicine products aimed at serious diseases, which brings advantages in advice and review.
- BLA
- Biologics License Application. The filing made in the U.S. to seek approval of a cell or gene therapy.
- Going concern
- The assumption that a company can keep operating. Where there is substantial doubt, it is disclosed in a note to the financial statements.
13. References
- Prime Medicine Form 10-K for the year ended December 2025 (filed with the U.S. SEC on 3 March 2026). Business description, pipeline, collaboration agreements, headcount, facilities, finances, going-concern doubt and risks. https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm
- Prime Medicine Form 10-Q for the quarter ended 30 June 2026 (filed with the U.S. SEC on 6 August 2026). Clinical trial clearance for PM577a, RMAT designation and BLA plan for PM359, cash balance and the outcome of the arbitration. https://www.sec.gov/Archives/edgar/data/1894562/000162828026053883/prme-20260630.htm
- Prime Medicine Form 8-K, Exhibit 99.1 (19 May 2025). Early data from the first PM359 patient. https://www.sec.gov/Archives/edgar/data/1894562/000119312525122156/d863812dex991.htm
- Prime Medicine Form 8-K, Exhibit 99.2 (19 May 2025). Announcement of the restructuring, the workforce reduction of about 25% and the change of CEO. https://www.sec.gov/Archives/edgar/data/1894562/000119312525122156/d863812dex992.htm
- Prime Medicine Form 8-K, Exhibit 99.1 (7 August 2025, second-quarter 2025 results). Data from the second PM359 patient. https://www.sec.gov/Archives/edgar/data/1894562/000162828025038617/q220258-kex991xpressrelease.htm
- Prime Medicine Form 8-K (filed 8 July 2026; dated 6 July). Final arbitration award in the dispute with Beam Therapeutics. https://www.sec.gov/Archives/edgar/data/1894562/000162828026047590/prme-20260706.htm
- U.S. National Library of Medicine ClinicalTrials.gov NCT06559176 (PM359, Phase 1/2 trial in chronic granulomatous disease). https://clinicaltrials.gov/study/NCT06559176
- U.S. National Library of Medicine ClinicalTrials.gov NCT07748403 (PM577a, Phase 1/2 trial in Wilson disease). https://clinicaltrials.gov/study/NCT07748403
- Prime Medicine Official website (used to check the logo and company overview). https://primemedicine.com/
14. Claim-to-source audit
| Claim in the article | Category | Source |
|---|---|---|
| Legal name (Prime Medicine, Inc.), head office address and Nasdaq listing | Sourced | Reference 1 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm |
| Founded in September 2019 and began operations in July 2020 | Sourced | Reference 1 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm |
| 146 employees (119 in R&D, 27 in administration, 63 with an MD or PhD) | Sourced | Reference 1 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm |
| R&D expense, net loss, revenue and capital expenditure (FY2024 and FY2025) | Sourced | Reference 1 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm |
| R&D expense, revenue and net loss for January to June 2026, cash and investments of US$95.1 million, accumulated deficit | Sourced | Reference 2 https://www.sec.gov/Archives/edgar/data/1894562/000162828026053883/prme-20260630.htm |
| Substantial doubt about going concern, and the cash outlook into 2027 | Sourced | References 1 and 2 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm https://www.sec.gov/Archives/edgar/data/1894562/000162828026053883/prme-20260630.htm |
| Floor area and lease terms of the facilities (Cambridge and Watertown) | Sourced | Reference 1 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm |
| Description of manufacturing (no commercial-scale capacity; contract manufacturers plus in-house cGMP) | Sourced | Reference 1 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm |
| Licence from the Broad Institute and the commitment to donate US$5.0 million a year | Sourced | Reference 1 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm |
| Agreement with BMS (US$55.0 million upfront, US$55.0 million equity, total milestones above US$3.5 billion) | Sourced | Reference 1 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm |
| Agreements with the Cystic Fibrosis Foundation in 2024 and 2025 | Sourced | Reference 1 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm |
| The 2019 collaboration agreement with Beam and the exchange of shares | Sourced | Reference 1 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm |
| The course of the arbitration with Beam and the final award of 6 July 2026 | Sourced | References 2 and 6 https://www.sec.gov/Archives/edgar/data/1894562/000162828026053883/prme-20260630.htm https://www.sec.gov/Archives/edgar/data/1894562/000162828026047590/prme-20260706.htm |
| Data from the first PM359 patient (DHR-positive neutrophils 58% on day 15 and 66% on day 30) | Sourced | Reference 3 https://www.sec.gov/Archives/edgar/data/1894562/000119312525122156/d863812dex991.htm |
| Data from the second PM359 patient, and the policy of not advancing it alone | Sourced | Reference 5 https://www.sec.gov/Archives/edgar/data/1894562/000162828025038617/q220258-kex991xpressrelease.htm |
| The May 2025 restructuring, the workforce reduction of about 25% and the change of CEO | Sourced | Reference 4 https://www.sec.gov/Archives/edgar/data/1894562/000119312525122156/d863812dex992.htm |
| Outline of the PM359 trial (Phase 1/2, population, endpoints, start date) | Sourced | Reference 7 https://clinicaltrials.gov/study/NCT06559176 |
| RMAT designation for PM359 (June 2026) and the BLA plan (first half of 2027) | Sourced | Reference 2 https://www.sec.gov/Archives/edgar/data/1894562/000162828026053883/prme-20260630.htm |
| CTA clearance for PM577a (June 2026) and FDA IND clearance (July 2026) | Sourced | Reference 2 https://www.sec.gov/Archives/edgar/data/1894562/000162828026053883/prme-20260630.htm |
| Outline of the PM577a trial (Phase 1/2, primary endpoint safety, planned enrolment 42) | Sourced | References 1 and 8 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm https://clinicaltrials.gov/study/NCT07748403 |
| Planned IND/CTA filing for PM647 (Q3 2026) and initial data in 2027 | Sourced | References 1 and 2 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm https://www.sec.gov/Archives/edgar/data/1894562/000162828026053883/prme-20260630.htm |
| The cystic fibrosis programme being at lead optimisation | Sourced | Reference 1 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm |
| How prime editing works, and the company's account of how it differs from conventional CRISPR approaches | Sourced | Reference 1 https://www.sec.gov/Archives/edgar/data/1894562/000162828026013569/prme-20251231.htm |
| Use of iPS cells | Not yet confirmed | Not mentioned in the 10-K. This article does not assert that there is none either |
| Start date of the PM647 trial, manufacturing scale, names of contract manufacturers, price and approval timing | Not yet confirmed | Not stated in the primary sources. This article does not estimate them |
| The reading that the centre of gravity has shifted to in vivo liver treatment | Inference | This article's interpretation of the May 2025 restructuring announcement |
| The reading that the strategy reuses a common LNP and editing enzyme | Inference | This article's interpretation of the 10-K statements (shared toxicology and CMC) |
| The reading that PM359 is a candidate for partnering or external leverage | Inference | This article's interpretation of the difference between the May 2025 announcement and the 2026 10-Q |
| The reading that 2027 is a year for early data, not for approval | Inference | This article's interpretation of the timing given for clinical data |
| The risk that the workforce cut and leadership change could affect continuity of development | Inference | This article's own interpretation |
| Materials challenges around LNPs, RNA and lipids | Not yet confirmed | A general discussion in this article. The company has not disclosed its control values |
Last updated 1 October 2026 / Troy Technical
Every figure in this article comes from the statutory filings Prime Medicine has made with the U.S. Securities and Exchange Commission (SEC), the company's press releases and ClinicalTrials.gov. No research-firm estimates or press-based figures have been used. Passages marked "Inference" are this article's interpretation of the primary sources, not statements made by the company. This article does not recommend any particular treatment and is not medical advice.