LTX-315

A synthetic nine-residue cationic peptide derived from bovine lactoferricin, injected directly into tumors to lyse cancer cells and release antigens, in Phase 2 testing with pembrolizumab in melanoma and as VP-315 in basal cell carcinoma, with no approval anywhere.

Also referenced as: ruxotemitide, VP-315, Oncopore, LTX315

Also appears in: Immune

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What is LTX-315?

LTX-315 (ruxotemitide; early trade name Oncopore) is a synthetic nine-residue cationic peptide, Lys-Lys-Trp-Trp-Lys-Lys-Trp-Dip-Lys-NH2, in which “Dip” is the non-natural amino acid β,β-diphenylalanine. It was designed by Lytix Biopharma, a Norwegian company spun out of the University of Tromsø, through structure-activity work on bovine lactoferricin, an antimicrobial fragment of the milk protein lactoferrin; the result is an amphipathic, strongly positively charged peptide that disrupts the negatively charged membranes typical of cancer cells while sparing most normal cells at the same concentrations (Haug et al., Journal of Medicinal Chemistry, 2016, 59(7):2918–2927). Because it is membranolytic, hemolytic at higher concentrations and designed for local action, it is not given systemically: it is injected directly into accessible tumors, where it kills cells by necrosis and spills their contents into the surrounding tissue.

LTX-315 is in the clinic rather than the wellness market. Its interest lies in the idea of an “in situ vaccine”: a lytic injection that turns a tumor into a source of its own antigens and danger signals, and so primes a systemic T-cell response that checkpoint inhibitors such as pembrolizumab can then amplify. It does not appear to be a research-market product; the material available outside trials is catalog reagent in milligram quantities for laboratory use.

How it works

• Membrane disruption and mitochondrial injury. LTX-315 permeabilizes the plasma membrane within minutes at high concentration and, at lower concentration, is internalized and accumulates near the mitochondria, depolarizing them and distorting their structure; the cell dies by a caspase-independent necrosis that is partly regulated by BAX and BAK (Eike et al., Oncotarget, 2015, 6(33):34910–34923; Zhou et al., Oncotarget, 2015, 6(29):26599–26614).
• Immunogenic cell death. Dying cells expose calreticulin, release ATP and the nuclear protein HMGB1, and induce a type I interferon response, the four accepted hallmarks of immunogenic cell death; injected tumors in mice develop a transient hemorrhagic necrosis with near-universal HMGB1 release and infiltration by myeloid cells and T lymphocytes (Zhou et al., Cell Death and Disease, 2016, 7(3):e2134).
• Dendritic-cell maturation and T-cell priming. Released antigens and nucleic acids act through Toll-like receptors, and the peptide itself activates TLR7, maturing tumor-infiltrating dendritic cells in a MyD88-dependent way (Li et al., Frontiers in Immunology, 2024, 15:1332922). In B16 melanoma, intratumoral LTX-315 produced complete regression in most animals, and cured mice rejected rechallenge both intradermally and intravenously (Camilio et al., Cancer Immunology, Immunotherapy, 2014, 63(6):601–613).
• Reprogramming of the tumor microenvironment. In mouse tumors, LTX-315 lowers the local abundance of regulatory T cells and myeloid-derived suppressor cells and raises polyfunctional CD8+ T cells; tumors resistant to CTLA-4 blockade regressed, with abscopal effects on uninjected lesions, when LTX-315 was added (Yamazaki et al., Cell Death and Differentiation, 2016, 23(6):1004–1015). Separate work reports that LTX-315 lowers PD-L1 expression in pancreatic cancer cells through the flippase ATP11B (Tang et al., Journal for ImmunoTherapy of Cancer, 2022, 10(3):e004129).

Research status

LTX-315 has more than 15 years of human testing behind it, all in small, open-label studies. No randomized trial has read out, and no regulator has approved it.

Phase 1 (2010–2018). Lytix ran three early studies: a 14-patient dose escalation in transdermally accessible tumors (NCT01058616, January 2010 to January 2013), a 12-patient study combining LTX-315 with the telomerase vaccine GV1001 after curative surgery (NCT01223209), and a multi-arm, multicenter dose-escalation program testing monotherapy and combinations with ipilimumab or pembrolizumab in melanoma, breast cancer, head and neck cancer and lymphoma (NCT01986426, November 2013 to April 2018). The published monotherapy report covers 39 patients with advanced solid tumors. The most common related adverse events were grade 1–2 vascular events, transient hypotension in 46% and flushing in 28%, plus injection-site reactions in 38%; the most common grade 3 toxicity was hypersensitivity or anaphylaxis, in 4 patients (10%). Injected tumors shrank by 30% or more in 29% of patients, 12 of 14 paired biopsies showed increased intralesional CD8+ T cells, and T-cell receptor sequencing found expanded blood clones of which 49% were also present in post-treatment tumor tissue. No partial responses by immune-related response criteria were recorded, though abscopal shrinkage of uninjected lesions was seen (Spicer et al., Clinical Cancer Research, 2021, 27(10):2755–2763). A case report describes a desmoid tumor of the chest wall with enhanced T-lymphocyte infiltration after repeated injections (Jebsen et al., Journal of Medical Case Reports, 2019, 13(1):177).

ATLAS-IT-04 in soft tissue sarcoma with cell therapy (NCT03725605). A single-center Phase 2 pilot at Copenhagen University Hospital (December 28, 2018 to October 11, 2021) treated six heavily pretreated patients with metastatic soft tissue sarcoma, injecting LTX-315 into a lesion that was then resected to grow tumor-infiltrating lymphocytes; four patients went on to adoptive cell therapy. Toxicity was described as expected and manageable, the best response was stable disease lasting 208 days, tumor-reactive T cells were detected in blood, and three patients showed T-cell reactivity against predicted neoantigens (Nielsen et al., Oncoimmunology, 2024, 13(1):2290900).

ATLAS-IT-05 in melanoma refractory to PD-1/PD-L1 therapy (NCT04796194). An open-label, single-arm Phase 2 enrolled 23 patients (November 5, 2021 to primary completion February 3, 2025) with unresectable stage IIIB–IV melanoma that had progressed after anti-PD-1 or anti-PD-L1 therapy, 52.1% of them with three or more prior lines; up to seven intratumoral injections were paired with pembrolizumab every three weeks for up to 24 months. Final results presented at the AACR Annual Meeting 2026 showed, among 22 evaluable patients, an objective response rate of 13.6% by RECIST v1.1, a clinical benefit rate of 40.9%, a median progression-free survival of 6.3 months, and responses lasting beyond 24 months in the responders; the most common treatment-related adverse events were injection-site reactions (95.7%), fatigue (30%), pruritus (26.1%), hypotension (26.1%) and anemia (21.7%), and no adverse event led to discontinuation of pembrolizumab. A pooled analysis of this study with ATLAS-IT-03, a Phase 2 cohort of immunotherapy-naive metastatic triple-negative breast cancer treated with the same combination, was presented at the ASCO Annual Meeting 2026; the sponsor summarized it as showing antitumor activity in both populations, durable responses in PD-1/PD-L1-refractory melanoma, regression of non-injected lesions, and a manageable safety profile, without releasing cohort-level figures for the breast cancer group. Neither dataset has yet appeared in a peer-reviewed journal.

NeoLIPA in neoadjuvant melanoma (NCT06651151). An investigator-initiated, single-arm Phase 2 at Oslo University Hospital, started November 1, 2024 with a planned 27 patients, gives LTX-315 plus pembrolizumab before surgery in resectable stage III/IV melanoma, with pathological complete response as the primary endpoint judged against a prespecified 40% threshold and a 20% historical benchmark for pembrolizumab alone. An interim analysis of the first nine evaluable patients reported an overall pathological response in 88%, a major pathological response in 55% and a complete pathological response in 44%, with no relapses at the time of analysis; enrollment was 85% complete in August 2026. On November 3, 2026, Lytix announced that the study had met its primary endpoint in the evaluable population to date, with no new safety signals, without releasing the exact pathological complete response rate. On August 27, 2026, Lytix reported that at a July 2026 meeting the FDA had raised no objections to a proposed randomized Phase 3 of neoadjuvant ruxotemitide plus pembrolizumab versus pembrolizumab alone in resectable high-risk melanoma, with event-free survival as the primary endpoint, and had confirmed that a single well-controlled trial might support a New Drug Application depending on the totality of the data. That trial had not been registered as of November 2026. Separately, on August 26, 2026, Lytix announced its participation in ALETTA, an investigator-initiated, multi-arm Phase 2 run by the Netherlands Cancer Institute and the European Institute of Oncology that includes a randomized comparison of ipilimumab plus nivolumab with or without ruxotemitide in 47 patients with resectable stage III melanoma and low interferon-gamma signatures.

VP-315 in basal cell carcinoma. On August 7, 2020, Verrica Pharmaceuticals licensed LTX-315 for malignant and pre-malignant dermatologic indications (excluding metastatic melanoma and metastatic Merkel cell carcinoma) and renamed it VP-315. A Phase 2 open-label proof-of-concept study with a safety run-in (NCT05188729) enrolled 92 adults with biopsy-proven basal cell carcinoma between February 1, 2022 and April 15, 2024; Part 1 was a dose-escalation run-in with no serious adverse events, and the protocol was amended in June 2023 to drop a planned Part 3 and expand Part 2. Verrica reported complete histological clearance in about 51% of treated tumors, a reduction in size in every treated tumor (86% overall, and 71% in tumors that still had residual disease), no serious treatment-emergent adverse events, and mostly mild to moderate local reactions; a post-hoc analysis announced in November 2024 calculated a 97% objective response rate. At the Society for Investigative Dermatology meeting in 2026, the company reported a 67% overall size reduction in 14 untreated lesions in nine subjects, with 3 of the 14 clearing histologically, which it presented as a possible abscopal effect. These figures are sponsor-reported from a single-arm study without a placebo or surgical comparator and have not appeared in a peer-reviewed journal. After an End-of-Phase 2 meeting in March 2025, Verrica described FDA alignment on two placebo-controlled Phase 3 studies of roughly 100 subjects each with complete clearance at week 14 as the primary endpoint; neither study had been registered as of November 2026.

Other preclinical directions. Academic groups have reported LTX-315 combined with radiotherapy and NK cells in breast cancer models (Yamazaki et al., Oncoimmunology, 2021, 10(1):1962592), with doxorubicin in triple-negative breast cancer (Camilio et al., Breast Cancer Research, 2019, 21(1):9), with radiofrequency ablation in liver cancer models, and in hydrogel, microgel and nanoparticle depots intended to extend its action or allow systemic delivery. None of these has entered human testing, and a 2025 study reporting broad-spectrum antibacterial activity against multidrug-resistant isolates (Tang et al., Journal of Advanced Research, 2025, 76:715–729) is likewise laboratory work only.

Common dosage forms

• Sterile solution for intratumoral injection (investigational). The trial drug product supplied to oncology sites; it is not formulated for subcutaneous, intramuscular or intravenous use.
• VP-315 intralesional injection (investigational). Verrica’s dermatology presentation of the same peptide for injection into basal cell carcinoma lesions in a clinical setting.

Key considerations

• Regulatory status. The Investigational status reflects completed Phase 1 and Phase 2 programs with no marketing approval in any country. A neoadjuvant melanoma trial met its primary endpoint in November 2026, the FDA has reviewed Phase 3 designs from both Lytix and Verrica, and neither planned Phase 3 trial had been registered as of November 2026.
• Small, uncontrolled evidence. Every clinical result to date comes from open-label, single-arm studies of 6 to 92 patients, and the NeoLIPA result is a comparison against a historical benchmark whose exact rate has not been released. Durable responses and abscopal shrinkage of uninjected lesions are real observations but remain anecdotal until a randomized trial confirms them.
• Local and infusion-like safety signals. Injection-site reactions are nearly universal, transient hypotension and flushing are common within hours of injection, and the Phase 1 program recorded grade 3 hypersensitivity or anaphylaxis in 10% of patients, so dosing has been confined to monitored clinical settings. The peptide is membranolytic by design and hemolytic at higher concentrations, which is why no systemic route has been attempted in humans.
• Naming. LTX-315, ruxotemitide (the International Nonproprietary Name), VP-315 (Verrica’s dermatology code) and Oncopore (an early Lytix trade name) all refer to the same molecule, while LTX-401 is a different Lytix compound, a β2,2-amino acid derivative rather than this peptide. LTX-315 is a de novo design informed by the bovine lactoferricin scaffold, not a fragment of lactoferricin or lactoferrin.
• Not a systemic or self-administered agent. Nothing in the preclinical or clinical record supports injecting LTX-315 anywhere other than into a tumor, and its mechanism (indiscriminate lysis of cells it contacts) makes extrapolation to any wellness or longevity use unfounded.