Biotech & drug discovery · Kidney gene therapy
Nephrogen
A five person New York company engineering a way to get genetic medicine into the kidney, run by a computational biologist who carries the disease he is trying to cure. Everything it has built so far sits in the preclinical stage.
Second place, and a volunteer
In late October 2025, twenty startups pitched on the Disrupt stage in San Francisco for the Startup Battlefield Cup. A hybrid electric vehicle for moving shipping containers won. The runner up was a biotech with five employees whose founder told the room he intends to enroll himself in his own clinical trial.
Demetri Maxim has autosomal dominant polycystic kidney disease. He inherited it from his mother, whose kidneys failed when he was seven. She spent two years on dialysis, four sessions a week, before a transplant. Asked by TechCrunch what the disease feels like now, Maxim gave an answer that is not a pitch: back pain, hospital visits, and a drug that mostly makes him urinate.
The drug is tolvaptan, sold as JYNARQUE. In its own federal contractor profile Nephrogen describes it as the only FDA approved drug for the condition, priced at about $13,000 for a 28 day supply and taken twice daily for decades to get the full effect. That is a company statement, not an independent price check, but it frames what a cure would be worth.
The organ everyone skipped
Gene therapy has worked in the eye, the liver and skeletal muscle. The kidney has been left behind, and the reason is not the editing tools. It is the courier. Adeno associated virus, or AAV, is the standard vehicle, and the serotypes with real human safety records, AAV9 among them, have long been considered poor at reaching kidney tubules. Companies working on hard organs usually answer that by engineering new capsids, which restarts the safety question from zero.
Nephrogen went the other way. In a preprint posted to Research Square in October 2025, the company and its academic collaborators reported that by tuning promoter, cargo, genome configuration, dose and route of administration, plain AAV9 transduced 40 to 60 percent of kidney tubules in mice. The team also reported transduction in a live human kidney using ex vivo normothermic perfusion, the technique used to keep donor organs viable outside the body.
The authors state the implication in the paper itself. Their result argues that better kidney targeting does not require a novel capsid, which is close to the opposite of the story most delivery startups tell.
A long apprenticeship
Maxim has been working on this since he was fourteen. At seventeen he was profiled by the PKD Foundation as a two time Maine State Science Fair winner, a patent holder, and an aspiring Olympic alpine skier for Cyprus, where he holds dual citizenship. He is a descendant of Hiram Maxim, who built the first portable automatic machine gun, and the lesson he says he took from his ancestor is about abandoning approaches that stop working.
He trained at Stanford in the Division of Nephrology under Vivek Bhalla, Avnesh Thakor and the AAV researcher Mark Kay, and worked in George Church’s lab at Harvard Medical School and with Terry Watnick at an NIH funded polycystic kidney disease center. Bhalla is listed as chief medical advisor on the company website and as a co-founder on the TechCrunch Battlefield page. Church advised the company from 2020 to 2024 according to the website, and a May 2026 journal disclosure states he receives compensation from Nephrogen.
The name is older than the current company. A 2018 Stanford student venture spotlight described Nephrogen as a medical device company building a rapid biomarker test for organ rejection, and the patent from that era, US 10,908,156, was filed in 2015 and granted in 2021. CB Insights still lists the founding year as 2015. Y Combinator lists 2022, a Summer 2020 batch, and Maxim dates incorporation to 2022. All three can be true of the same person. They are not true of the same company.
What has been paid for so far
In 2023 Nephrogen won the $200,000 grand prize in 2048 Ventures’ Spring biotech pitch competition. That September the NIH awarded it a Small Business Technology Transfer Phase I grant of $325,000 through NIDDK, with Maxim as principal investigator, for CRISPR-Cas editing as a genetic cure for ADPKD. The award ran to August 31, 2025. No Phase II award appears in the record.
In July 2025 a Delaware vehicle named Allometric Nephrogen Seed Jun 2025 filed a Form D reporting $309,000 raised from eleven investors. In November 2025 the Czech fund ZAKA VC was named as an investor in a closed $2 million pre-seed. Nephrogen has said it is raising $4 million more and expects clinical studies in 2027.
What is proven, and what is still claimed
| Evidence | What the record shows | Source type |
|---|---|---|
| NIH STTR Phase I | 1R41DK138689-01, NIDDK, $325,000, awarded Sep 19, 2023, ended Aug 31, 2025. PI: Demetrios S. Maxim. Grant abstract states ADPKD affects 650,000 Americans; company materials say 600,000. No Phase II award on record as of Sep 22, 2026. | Public record |
| Peer reviewed publication | One. EditABLE, a web tool that picks CRISPR editors and guide RNAs, in Genome Biology, May 11, 2026, demonstrated on the ADPKD mutation landscape. Software, not a therapy. | Public record |
| Kidney delivery data | Preprint, Research Square, Oct 24, 2025, 23 authors across Nephrogen, Stanford, UCSF, Yale, Harvard and Santiago de Compostela. Reports 40 to 60 percent of mouse kidney tubules transduced with systemic AAV9-Cbh-mCherry-WPRE, plus transduction in ex vivo perfused human kidney. Not peer reviewed. | Public record |
| The 100 times claim | Maxim told TechCrunch the delivery mechanism is 100 times more efficient than FDA approved vehicles. The preprint reports transduction percentages and states no 100 times figure. The two have not been reconciled in public. | Claim beyond the paper |
| Clinical trials | None. A ClinicalTrials.gov query for Nephrogen returned zero studies on Sep 22, 2026. The company has said it expects studies to begin in 2027. | Not found |
| FDA status | No 510(k), no PMA, and no orphan drug or rare pediatric disease designation found. A designation buys fee relief and exclusivity on approval, not evidence that a therapy works, and Nephrogen does not appear to hold one. | Not found |
| Pharma funding | Y Combinator’s listing claims non-dilutive funding from seven pharmaceutical companies including Merck KGaA, Novartis and Bristol Myers Squibb. Maxim told ITKeyMedia the company collaborates with six. No amounts or partner confirmations found. | Company-stated |
Read plainly: the delivery result is the asset, and it is one unrefereed preprint old. The single peer reviewed paper is a software tool. There is no candidate drug in the public record, no IND, no trial, and no FDA designation. What Nephrogen has is a specific, checkable claim about an already approved capsid, made with named academic co-authors who have reputations to lose. That is a better position than most preclinical startups occupy, and it is still a long way from a patient.
What to watch
- Peer review of the October 2025 AAV preprint, which would move the central claim into the refereed record.
- A registered trial, or an IND disclosure. The company points at 2027.
- A follow on NIH award. The Phase I STTR ended in August 2025 with no Phase II filed.
- Named pharma partners. Seven are claimed, none confirmed by the partners.
- A Form D from Nephrogen itself. Every filing that mentions the company so far was made by someone else.
In their words
“You get a lot of back pain. You have to go to the hospital a lot. You are on this drug that’s supposed to slow the progression, but it doesn’t really do anything. Just makes you pee all the time.”
Demetri Maxim, founder and CEO, to TechCrunch, October 2025 · Independent
“Since our incorporation in 2022, we’ve been collecting data about drug delivery. We have our PoC, as we’ve tested our delivery on mice, reaching 40-60% delivery rate, which is among the highest in the industry. We’ve also tested on monkeys and even unhealthy human kidneys removed from bodies.”
Demetri Maxim to ITKeyMedia, November 2025 · Interview
“These findings challenge the prevailing assumption that enhanced kidney tropism requires engineered or re-targeted capsids.”
Garcia and colleagues, Research Square preprint, October 24, 2025 · Preprint
“Nephrogen stands out through exceptional founder-market fit and a first-in-class approach that has the potential to redefine how kidney and pancreatic diseases are treated.”
Ján Kasper, co-founder and managing partner, ZAKA VC, quoted by ITKeyMedia, November 2025 · Investor
“I was originally hesitant to open up about my disease because I thought that it would influence some people’s perceptions of me, but recently I’ve started talking about it pretty openly because I want to connect with others who have the disease so we can work together to find a cure.”
Demetri Maxim, age 17, PKD Foundation, 2016 · Patient organization
Related companies
Sources
- Public recordNIH RePORTER 1R41DK138689-01, CRISPR-Cas Editing as a Genetic Cure for Autosomal Dominant Polycystic Kidney Disease
- Public recordDesigning genome editing experiments with EditABLE, PMID 42108472
- Public recordIntegrated AAV optimization enables efficient gene delivery to kidney in murine and human tissue, PMID 41282112
- Public recordForm D, Allometric Nephrogen Seed Jun 2025 a Series of CGF2021 LLC, CIK 0002077358
- Public recordClinicalTrials.gov query for Nephrogen, zero studies returned
- IndependentBiotech Nephrogen combines AI and gene therapy to reverse kidney disease, by Marina Temkin
- IndependentAnd the winner of Startup Battlefield at Disrupt 2025 is: Glid
- InterviewZAKA VC backs Nephrogen’s kidney-focused gene therapy platform, by Kostiantyn Tupikov
- IndependentYoung scientist on mission to find alternative to his own transplant
- IndependentCongrats to the winners of the Spring 2023 Biotech Pitch Competition
- IndependentNephrogen company profile, founding year and funding total
- CompanyNephrogen website, mission, team and advisors
- CompanyNephrogen company listing, founders and pharma funding claim
- CompanyNephrogen Inc SBIR awardee profile, tolvaptan pricing and indication
Profile researched and written by Healthcare Discovery. Last updated September 29, 2026.
