Lytix Biopharma Reports Promising Phase II Data for Ruxotemitide in Advanced Melanoma and Triple-Negative Breast Cancer
Key Insights
Lytix Biopharma (search) presented pooled Phase II data showing antitumor activity of intratumoral ruxotemitide combined with pembrolizumab in heavily pretreated patients with advanced melanoma and metastatic triple-negative breast cancer.
The study demonstrated durable responses in melanoma patients who had progressed after prior anti-PD-1 (search)/PD-L1 (search) therapy, with systemic activity observed including tumor regression in non-injected lesions.
The combination therapy showed a manageable safety profile consistent with known effects of intratumoral immunotherapy and pembrolizumab.
Lytix Biopharma (search) ASA announced promising Phase II results for its lead intratumoral oncolytic peptide ruxotemitide (LTX-315) in combination with pembrolizumab, demonstrating antitumor activity in two challenging patient populations with limited therapeutic options. The data was presented at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago.
Clinical Efficacy in Hard-to-Treat Populations
The pooled analysis from two open-label Phase II studies evaluated intratumoral ruxotemitide plus pembrolizumab in patients with advanced melanoma who had progressed following prior anti-PD-1 (search)/PD-L1 (search) therapy and in patients with metastatic triple-negative breast cancer (TNBC). Key efficacy observations included antitumor activity in heavily pretreated patients across both cancer types.
"The pooled Phase II data show that intratumoral ruxotemitide in combination with pembrolizumab was generally manageable and demonstrated antitumor activity in two difficult-to-treat patient populations," said Prof. Aurélien Marabelle of Gustave Roussy, France, who presented the poster. Prof. Marabelle is a senior clinical investigator in cancer immunotherapy with dedicated expertise in intratumoral treatment approaches and serves on the Board of Directors of the Society for Immunotherapy of Cancer (SITC).
Durable Responses and Systemic Activity
The study demonstrated durable responses in melanoma patients despite their prior PD-1 (search)/PD-L1 (search)-refractory disease status. Notably, systemic activity was observed, including tumor regression in non-injected lesions, supporting ruxotemitide's potential to induce broader immune activation following local intratumoral administration.
"The observation of durable responses in melanoma, disease stabilization across both studies and activity in non-injected lesions supports further clinical evaluation of this intratumoral immunotherapy approach, including in earlier treatment settings," Prof. Marabelle added.
Safety Profile and Mechanism of Action
The safety profile observed across the studies was broadly consistent with the known effects of intratumoral immunotherapy and pembrolizumab, with the combination proving manageable. Ruxotemitide is designed as a first-in-class oncolytic peptide for intratumoral administration that disrupts tumor cells locally, leading to the release of tumor antigens and danger-associated molecular signals that may activate systemic antitumor immune responses.
This mechanism has the potential to convert immunologically "cold" tumors into "hot" tumors and enhance responses to checkpoint inhibitor therapies, addressing a key challenge in immuno-oncology.
Future Clinical Development Strategy
"These Phase II data represent an important step in building the clinical rationale for ruxotemitide as a differentiated intratumoral immunotherapy," said Øystein Rekdal, Chief Executive Officer of Lytix Biopharma (search). "Our ambition is to use local tumor destruction to initiate broader systemic antitumor immunity and thereby improve the depth and durability of responses to checkpoint inhibition."
The company plans to advance ruxotemitide into earlier treatment settings, where immune activation may have the greatest potential to change patient outcomes. Lytix will also present final Phase II results from its ATLAS-IT-05 study of ruxotemitide in combination with pembrolizumab at the AACR Annual Meeting 2026 in San Diego, with the poster to be presented by melanoma immunotherapy expert Dr. Adi Diab of Cleveland Clinic.
The Oslo-based clinical-stage biotech company has developed a highly differentiated oncolytic molecule platform based on host-defense peptide-derived molecules, with a pipeline designed to work across multiple cancer indications and treatment settings, both as monotherapy and in combination therapy.