LTX-315

LTX-315 is a short, positively charged, amphipathic peptide that disrupts membranes. In cancer-cell studies it accumulated in mitochondria, halted cellular respiration, collapsed the mitochondrial membrane potential and released mitochondrial proteins into the cell; cells lacking the proteins BAX and BAK, or stripped of their mitochondria, were harder to kill¹. Cells destroyed this way die by necrosis, bursting and spilling tumor antigens and danger signals, which is thought to explain the immune-stimulating effects seen in preclinical models^2,4.

In patients, biopsies taken after injection showed tumor necrosis and more CD8+ killer T cells, and expanded T-cell clones appeared in the blood, about half of them also found in post-treatment tumor biopsies².

All human data come from early, uncontrolled trials. In a Phase 1 study of 39 patients with injectable advanced solid tumors, injected lesions shrank by at least 30% in 29% of patients and CD8+ T cells rose in 12 of 14 biopsied tumors, but no formal partial responses were recorded².

In a Phase 2 melanoma study with pembrolizumab, in people whose disease had progressed on PD-1 or PD-L1 drugs, 3 of 22 patients analyzed had partial responses and none had complete responses³. Under the code VP-315⁴, the peptide was injected into basal cell carcinomas in a 92-person open-label study; 41 of 77 first target lesions showed no remaining tumor on histology when surgically removed, with no control group⁵. A neoadjuvant melanoma trial, with treatment before surgery, is recruiting⁶.

LTX-315 is not approved by the FDA or by any other regulator found; it is available only inside clinical trials.

In the Phase 1 trial, the most common treatment-related effects were transient low blood pressure (46% of patients), injection-site reactions (38%) and flushing (28%); the most common severe events were hypersensitivity reactions or anaphylaxis, in 10%². In the basal cell carcinoma study, local skin reactions dominated, including redness, hardening, swelling, erosion and necrosis at the injection site; one of 92 participants had a serious adverse event⁵.

1. Zhou et al., Oncotarget 2015PubMed
2. Spicer et al., Clin Cancer Res 2021PubMed
3. ClinicalTrials.gov: NCT04796194ClinicalTrials.gov
4. Kepp et al., J Immunother Cancer 2026PubMed
5. ClinicalTrials.gov: NCT05188729ClinicalTrials.gov
6. ClinicalTrials.gov: NCT06651151ClinicalTrials.gov