Precision medicine for
15q11.2 duplication
Longinus Therapeutics is developing a targeted treatment for 15q11.2 BP1-BP2 microduplication — a common, recurrent genetic change affecting families worldwide. Our lead program is a CYFIP1-lowering antisense oligonucleotide (ASO), advanced through a strictly staged, evidence-first plan: confirm the target, then build the drug.
The gap between diagnosis and treatment ends here
Longinus Therapeutics is a Madrid-based precision-medicine biotech founded in 2026 to develop targeted treatments for 15q11.2 BP1-BP2 microduplication. We exist because no one else is building the program — despite a well-understood genetic mechanism, clear preclinical models, and a precedented regulatory path.
The science exists. The CYFIP1 gene is well-characterized. The downstream pathways are druggable. A realistic ASO development timeline is 5–7 years to first patient dosed, 7–9 years to potential approval. What is missing is a focused, well-funded program to make it happen.
We fund the research, own the IP, and are building the data package that can bring a development partner to the table — following the proven rare-disease model: patient-derived science → preclinical data → partnership.
15q11.2 BP1-BP2 Microduplication
What the duplication does to the brain
The 15q11.2 BP1-BP2 microduplication places an extra copy of CYFIP1 in every cell. CYFIP1 overexpression disrupts two core pathways — NMDA receptor suppression and mTOR overdrive — both confirmed in human post-mortem brain tissue. CYFIP1 is dosage-sensitive in both directions: deletion and duplication each cause disease. That defines our therapeutic principle precisely — lower CYFIP1 back toward the normal range, never to zero. Over-suppression would recreate the deletion disorder, so the goal is dosage normalisation, not silencing.
Two design constraints follow, and both shape the program from day one. CYFIP2 selectivity is a hard safety gate: CYFIP1's paralogue CYFIP2 is ~88% identical, and loss of CYFIP2 causes a severe epileptic encephalopathy — so any candidate must lower CYFIP1 while sparing CYFIP2. And because CYFIP1 is broadly expressed in the body but only its brain dosage drives the phenotype, the program is built around CNS-selective (intrathecal) delivery to act where it matters and limit exposure elsewhere.
Six interconnected biological pathways are perturbed by CYFIP1 overexpression — each offers a potential therapeutic handle. Our program targets CYFIP1 itself at the mRNA level via an antisense oligonucleotide, restoring dosage upstream of every downstream pathway shown below.
From design to first patient
Our program follows a strictly staged, evidence-first sequence. Money is committed only after each prior step proves out — so the cheapest experiments answer the make-or-break questions before any expensive work begins. Each phase has a defined exit criterion; if the data does not support advancing, the program stops there.
Spend follows proof
How the program is built
A focused operation with a clear division of labour: patient-derived science to prove the target, regulated execution to build the drug, and a sponsor that funds the work, owns the IP, and sequences the spend.
Patient-derived neurons
Patient iPSC-derived neurons are the human validation model for the program — confirming what is true in patient-specific cells, not only in an animal model. A single characterised cell line is derived once, banked, and shared under controlled agreements with every collaborator.
The science partner
An academic lab with deep expertise in CYFIP1 biology confirms the target in patient cells and validates candidate molecules — the de-risking engine that runs before any expensive regulated work begins.
Regulated execution
A specialist contract research organization designs and screens the ASO candidates, then carries out clinical-grade manufacturing and the safety package for the selected lead. The inventive work is structured so that the resulting intellectual property is owned by Longinus.
The sponsor
Longinus funds the research, owns the IP and the data package, and takes formal responsibility for coordination and the regulatory route — building a de-risked asset designed to be advanced to the wider patient population through a development partner.
How you can help move this forward
Whether you are a family with a diagnosis, a researcher, or a potential pharma partner — there is a concrete role for you.
Families with a Diagnosis
If your child has a confirmed 15q11.2 BP1-BP2 duplication, connect with us. A patient-derived cell line is the foundation of any future treatment, and your experience helps shape what matters most.
Connect with usResearchers
We are seeking academic collaborators for patient iPSC-neuron work, target validation, and ASO screening. Funded sponsored-research agreements available.
CollaboratePartners
We are speaking to mission-aligned partners — patient foundations, philanthropic capital, and biotech operators with rare-disease experience. The program is designed around clear preclinical decision gates, and we are happy to share a detailed development plan under a mutual NDA.
Get in touchGet in touch
Longinus is a small, focused operation. The fastest way to reach us is email — we read everything and respond personally to substantive inquiries. If you are a family with a diagnosis, a researcher with relevant data, an investor with rare-disease conviction, or a clinician fielding a similar case, please write.
If your child has a 15q11.2 BP1-BP2 duplication confirmed by microarray, we want to hear from you. We are building a contact registry and can share what is actionable today versus what is in development. No commitment, no sales pitch.
Write to usPatient iPSC-neuron work, target validation, ASO screening. We have a defined target and a focused budget — collaborations move faster than grants.
Propose a collaborationFor mission-aligned partners — patient foundations, philanthropic capital, biotech operators with rare-disease experience — we are happy to share a detailed development plan and clear preclinical decision gates under a mutual NDA.
Open a conversationIf you are a pediatric neurologist or geneticist who has a 15q11.2 BP1-BP2 carrier on your panel and want to discuss off-label options, biomarker testing, or referral to research, this is the inbox.
Discuss a case