Our Take
Three separate in vivo CAR-T approaches now have clinical or primate data, but Kelonia's 100% ORR rests on 18 patients with short follow-up; durability claims require Phase II validation before the field declares the model solved.
Why it matters
In vivo CAR-T manufacturing inside the patient's body sidesteps the cost and logistics bottleneck of ex vivo cell engineering. Clinical proof matters now because Lilly's acquisition closes soon and investor confidence in the platform directly affects funding for Strand and Immunocore's competing programs.
Do this week
Immunooncology teams: audit your current CAR-T sourcing agreements (ex vivo vs. manufacturing timeline) and request 24-month cost projections from vendors before Q3 2026 budget locks, so you can model in vivo adoption once Phase II data lands.
Three in vivo CAR-T programs advance at ASCO 2026
Kelonia Therapeutics, acquired by Eli Lilly for up to $7 billion (announced April 2026, closing pending), presented Phase I data for KLN-1010 in multiple myeloma. In the inMMyCAR trial (NCT07075185), all 18 evaluable patients achieved 100% overall response rate (ORR), with all bone marrow samples negative for minimal residual disease (MRD) at one month post-treatment. Six patients with more than four months of follow-up showed four stringent complete responses and two very good partial responses, all MRD-negative. The first treated patient remained in deep MRD-negative response beyond 10 months (company-reported).
KLN-1010 generated sustained CAR-T cell persistence in peripheral blood and bone marrow exceeding typical ex vivo CAR-T therapies. Safety remained manageable: 16 of 18 patients experienced Grade 1-2 cytokine release syndrome (CRS), with one Grade 1 and one Grade 3 immune effector-cell-associated neurotoxicity syndrome (ICANS) event observed.
Strand Therapeutics, which raised $135 million in 2025, debuted preclinical in vivo data using programmable circular RNA (circRNA) packaged in targeted lipid nanoparticles (LNPs). Its approach generated functional CAR-T cells in vivo across humanised mouse models and non-human primates. Strand's lead program, STX-001, already showed preliminary evidence of systemic immune activation and anti-tumor activity in patients with advanced solid tumors progressing on prior therapy. A follow-on candidate, STX-003, targets intravenous delivery with tumor-specific expression control.
Immunocore Holdings presented Phase I/II data for brenetafusp (ImmTAC), its T-cell receptor therapy, in 66 heavily pretreated advanced melanoma patients. Median overall survival was 14.3 months with 87% OS at six months and 57% at 12 months (company-reported). Disease control rate was 52%; overall response rate 12%. The 160 mcg dose is moving into Phase III evaluation combined with Opdivo (nivolumab) against standard Opdivo regimens in first-line advanced melanoma.
Manufacturing CAR-T inside the body removes logistics and cost friction
Ex vivo CAR-T requires leukapheresis, off-site cell engineering, expansion, quality control, and re-infusion, taking 2-4 weeks and costing $375,000+ per patient (industry standard). In vivo approaches inject a genetic instruction or cell therapy directly, allowing patients' own immune cells to become CAR-T cells on-site. The model cuts manufacturing time and eliminates centralized production bottlenecks.
Kelonia's data suggests the in vivo platform can sustain CAR-T persistence longer than ex vivo approaches, a physiological advantage if validated in larger cohorts. However, the 18-patient Kelonia cohort carries short follow-up for myeloma, where relapse can occur months to years after initial remission. Durability remains unproven at Phase II scale.
Three separate companies now have data in hand. Lilly's acquisition of Kelonia signals confidence, but also locks the lead candidate into one pharma house; Strand and Immunocore remain independent or partnered, meaning academic centers and smaller pharmas may have more platform flexibility as programs mature.
Prepare for a shift in CAR-T sourcing and timelines
Oncology procurement teams should request detailed timelines and manufacturing cost estimates from both ex vivo and in vivo vendors over the next six months. If Kelonia Phase II confirms durability and safety, hospital and infusion-center workflows may shift away from leukapheresis-dependent models, reducing need for centralized cell therapy units.
Academic medical centers should clarify IP terms and manufacturing partnerships with Strand and Immunocore now, before Lilly's acquisition closes and Kelonia becomes a proprietary Lilly asset. Cost and access advantages of in vivo platforms only materialize if multiple providers survive to Phase III and commercialization.