# Intero Biosystems replaces animal drug tests with lab-grown guts > A Denver startup is selling mini human intestines to drugmakers, offering an alternative to animal testing that better predicts how drugs will work in people. - Title: Intero Biosystems replaces animal drug tests with lab-grown… - Summary: A Denver startup is selling mini human intestines to drugmakers, offering an alternative to animal testing that better predicts how drugs will work in… - Keywords: intero biosystems, organoids, drug testing, animal testing alternatives, pharmaceutical, biotech, denver, fda, technology, startups, Intero, Biosystems - Source: TechCrunch — https://techcrunch.com/2026/10/14/intero-biosystems-wants-drugmakers-to-test-on-mini-human-intestines-not-animals - Author: Kate Park - Published: 2026-10-14T23:00:00+00:00 - Read time: 2 min - Topics: intero biosystems, organoids, drug testing, animal testing alternatives, pharmaceutical, biotech, denver, fda, technology, startups ## Why animal testing fails drugmakers Most drugs fail clinical trials because differences between animal species and humans mean results don't translate. Intero Biosystems is developing a better model using lab-grown human intestinal tissue. ## What makes Intero's organoids different Intero's organoids contain multiple cell and tissue types found in the human intestine, unlike simpler models that replicate only part of the gut.Co-founder and CTO Madeline Eiken said this makes them more human-relevant for testing. ## The core problem Intero solves Most drugs fail clinical trials, and Madeline Eiken, co-founder and CTO, said the reason is clear: we are neither mice nor flat layers of cells. > Most drugs fail clinical trials, and I think it's pretty easy to appreciate that we are neither mice nor flat layers of cells. ## How Intero ships its product Intero's flagship product, GastroScreen, is a human intestinal organoid model about one millimeter across. The company ships roughly one hundred at a time in a tube to pharmaceutical, biotech, food, and chemical companies. > We're literally shipping mini living organs in the mail to people. ## What customers can do with organoids Customers use organoids as healthy intestinal models or induce disease-like conditions to test how tissue responds to different compounds. Intero also sells nutrient mixes, chemicals for experiments, and runs custom studies for clients. ## Intero's business so far Founded in two thousand twenty-four, Intero has seven employees and just under ten customers after raising two point three million dollars in a pre-seed round last year. ## FDA pushes alternatives to animal testing In April of last year, the U.S. Food and Drug Administration laid out plans to reduce reliance on animal testing in drug development, promoting organoids, organs-on-chips, and AI-based computational models as potential alternatives. ## New FDA guidance on non-animal testing In March of this year, the FDA issued draft guidance outlining how drug developers should validate new approach methodologies, or NAMs, which are non-animal testing methods. ## Why pharma companies are now interested Changes in U.S.law allowing drug developers to use non-animal testing methods in some cases have made pharmaceutical companies more willing to explore organoid technology. ## How Intero differs from competitors Intero's GastroScreen is derived from induced pluripotent stem cells, adult cells reprogrammed to become almost any cell type and generated from a blood sample. ## Intero's validation progress Intero is in the second stage of a three-stage validation process.It has shown GastroScreen contains key tissues of the human gut and now tests well-known drugs with documented effects in humans. ## Intero's next steps and ambitions Intero can currently make a few thousand organoids at a time and is working to automate manufacturing to produce hundreds of thousands per batch. ## Key takeaway Intero Biosystems, a Denver-based startup, is selling lab-grown human intestinal organoids to pharmaceutical companies as an alternative to animal testing, with regulatory changes now encouraging the shift.