Even after a tumor is surgically removed, a few cancer cells may remain undetected and cause a recurrence. Chinese teams are testing a personalized neoantigen mRNA vaccine made for one patient at a time , with encouraging early signals after pancreatic and other hard-to-treat cancers.
From tumor sample to injection: how a personalized neoantigen mRNA vaccine is made (Joyful Medical illustration)
How It Works: A Precision Wanted Poster for the Immune System
As cancer cells divide, they accumulate genetic mutations. Some mutations produce short abnormal protein fragments that appear only on tumor cells — these tumor-specific markers are called neoantigens .
Scientists encode the instructions for a patient’s own neoantigens into a strand of messenger RNA (mRNA), wrap it in lipid nanoparticles (LNPs), and inject it. The body’s cells translate the mRNA into neoantigen proteins and present them, activating tumor-specific T cells . If any residual cancer cell carrying the same markers reappears, those T cells can recognize and attack it.
Why one vaccine per patient? Even two people with the same cancer carry different mutation patterns, so each vaccine is built from the individual’s own tumor. After sequencing, thousands of candidate mutations remain; machine-learning algorithms select the small number most likely to trigger a strong immune response. In leading international programs, a single vaccine encodes up to 34 neoantigens.
Importantly, this is a therapeutic vaccine for people who already have cancer and have had curative surgery. It is not a preventive shot for healthy people, and it differs from virus-preventing vaccines such as those for HPV or hepatitis B.
Treatment Process: The Key Window Is Before Surgery
1 Pre-surgical evaluation and enrollment
Patients must be assessed and give informed consent before surgery. The vaccine needs fresh tumor tissue; once tissue is formalin-fixed after surgery, some genetic information is lost.
2 Surgery with fresh-tissue collection
During curative surgery — for pancreatic cancer, often a pancreaticoduodenectomy — fresh tumor tissue is collected promptly, along with a blood sample.
3 Sequencing and AI design
Whole-exome and RNA sequencing compares tumor with normal cells to identify tumor-specific mutations, alongside HLA typing. AI ranks the most immunogenic neoantigens.
4 mRNA vaccine manufacturing
The neoantigen instructions are loaded into mRNA lipid nanoparticles to make an individualized injectable. According to industry reports, the custom process takes several weeks.
5 Post-surgical dosing and follow-up
Patients complete standard chemotherapy combined with vaccine injections, with regular follow-up for recurrence and immune response.
Clinical Results: Early Signals From China Phase 1 Studies
XH001 , developed by Beijing-based Xinhe Bio (Stemirna), is among the first personalized mRNA neoantigen vaccines to reach the clinic in China. Its Phase 1 trial began at Peking Union Medical College Hospital and Peking University Cancer Hospital , enrolling patients after curative surgery for pancreatic ductal adenocarcinoma, biliary tract cancer, hepatocellular carcinoma, and gastric adenocarcinoma. A Beijing Daily report carried by the Beijing government portal on August 22, 2026 said XH001 had essentially completed Phase 1 enrollment and moved into dose expansion, was safe and activated tumor-specific immune responses, and that its pancreatic cohort showed recurrence-free survival better than historical controls ; no figures were released (trial ChiCTR2500102611).
At Sir Run Run Shaw Hospital (SRRSH) , academician Cai Xiujun’s team began research in 2023. It has treated 43 patients with pancreatic, liver, or biliary tract cancer; the hospital reports tumor-specific immune responses, lower recurrence risk and longer survival, with findings presented at SITC 2025. A new Phase 1 registered study launched in early August 2026, expanded to six digestive cancers and 18 planned patients; two pancreatic patients had enrolled.
International background: the BioNTech/Roche BNT122 Phase 1 study enrolled 16 patients after pancreatic surgery. At median follow-up 3.2 years, 50% (8/16) mounted strong T-cell responses; median recurrence-free survival was not reached in responders versus 13.4 months of progression-free survival in non-responders (HR 0.14, P=0.007). Reports citing Nature studies describe a 92% reduction in recurrence or death among strong responders and vaccine-induced T cells lasting about 7.7 years.
Stage of evidence The Chinese programs are Phase 1 or investigator-initiated studies with small samples. The pancreatic signal is qualitative (‘better than historical controls’) without randomized comparison or published figures, and it is not confirmed efficacy. No product of this type is approved anywhere in the world.
One Pancreatic Patient’s Journey
In 2023, a patient called Uncle Liu (not his real name) traveled from northeast China to Hangzhou and reached Academician Cai’s team before his operation. He enrolled in the study, underwent a pancreaticoduodenectomy performed by Cai, and his fresh tumor tissue was collected on the spot to build his custom mRNA vaccine.
After surgery he completed standard chemotherapy combined with vaccine doses. He has since recovered well, and recent examinations showed no recurrence. By contrast, another patient who came a month after surgery could not enroll: his tissue had already undergone routine pathology processing.
A practical reminder for families If curative surgery for a digestive cancer is being planned, ask early — before surgery — whether a neoantigen vaccine trial is available. The enrollment window is short.
Safety and Who May Be Eligible
Official Chinese reports describe the vaccine as safe, but detailed adverse-event data have not yet been published. The treatment is positioned as an adjuvant for patients at high risk of recurrence after curative surgery , not as a treatment for large advanced tumors.
Limitations are real: manufacturing takes several weeks at high cost, enrollment must happen before surgery, and not every patient mounts an effective response (about half did so in international data), so non-responders may gain little. Pancreatic cancer is a ‘cold tumor’ with a strongly suppressive microenvironment and a limited supply of high-quality neoantigens — a challenge shared worldwide.
Availability This therapy remains in clinical trials and is not yet widely available. Eligibility and treatment should be decided by licensed physicians under the trial protocol.
Personalized neoantigen mRNA vaccine vs conventional adjuvant chemotherapy
Conditions It Can Treat
• Pancreatic ductal adenocarcinoma
• Biliary tract cancer
• Hepatocellular carcinoma
• Gastric adenocarcinoma
• Esophageal cancer
• Colorectal cancer
• Melanoma (global Phase 3)Want to know if this technology is right for you? Joyful Medical can help organize your medical records, connect you with the Chinese hospitals and specialist teams using this technology, and assess a treatment plan in China. After you submit your case, our coordinator will contact you. Free Case Evaluation