SHELTON, Conn., July 15, 2026
Intensity Therapeutics, Inc. has restarted patient treatment in its Phase 2 INVINCIBLE-4 clinical trial evaluating INT230-6 for patients with early-stage operable triple-negative breast cancer (TNBC). The first patients have now been dosed in Switzerland, marking a significant milestone for the company’s clinical development program after regulatory approval of an amended study protocol. The randomized, open-label, multicenter study will evaluate INT230-6 administered before standard-of-care (SOC) neoadjuvant immunochemotherapy compared with SOC alone, with the primary goal of improving pathological complete response (pCR) rates in one of the most aggressive forms of breast cancer. The study restart follows protocol modifications designed to optimize treatment delivery and patient safety while continuing to investigate the investigational therapy’s potential to enhance anti-tumor immune responses.
Phase 2 Trial Resumes with Optimized Treatment Protocol
The INVINCIBLE-4 Study (NCT06358573) is designed to evaluate the clinical activity, safety, and tolerability of INT230-6 in patients with operable triple-negative breast cancer before surgery. Under the amended protocol, participants are randomized to receive a single dose of INT230-6 followed by standard-of-care therapy, consisting of pembrolizumab, anthracyclines, carboplatin, cyclophosphamide, and paclitaxel, or standard-of-care treatment alone. Enrollment resumed after investigators addressed skin irritation observed during the initial phase by lowering the drug-to-tumor volume ratio and adopting a single intratumoral injection strategy. Prior to the enrollment pause, 14 patients had participated in the study, with preliminary findings indicating that patients receiving INT230-6 before standard therapy experienced fewer Grade 3 or higher adverse events and fewer immune-related adverse events than those receiving SOC alone. The revised study is expected to enroll 47 additional patients across Switzerland and France, further evaluating whether the investigational treatment can significantly improve pathological complete response while maintaining a favorable safety profile.
INT230-6 Aims to Improve Outcomes in Aggressive Breast Cancer
INT230-6 is Intensity Therapeutics’ lead investigational intratumoral therapy developed using its proprietary DfuseRx™ technology platform. The formulation combines the well-established anticancer agents cisplatin and vinblastine sulfate with a proprietary diffusion enhancer that promotes deep penetration of the drugs throughout the tumor while limiting systemic exposure. Beyond directly destroying tumor cells, the therapy is designed to stimulate a broader anti-cancer immune response by releasing tumor-specific neoantigens capable of activating the immune system. This dual mechanism may help overcome one of the major limitations of existing treatments for triple-negative breast cancer, a subtype accounting for approximately 11–17% of breast cancer diagnoses and associated with limited targeted treatment options, higher recurrence rates, and poorer clinical outcomes. Standard neoadjuvant immunochemotherapy currently achieves approximately 63% pathological complete response rates while producing significant treatment-related toxicity, highlighting the need for safer and more effective therapeutic strategies.
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Clinical Development Advances Precision Oncology Innovation
The resumption of the INVINCIBLE-4 Phase 2 study reinforces Intensity Therapeutics’ commitment to advancing innovative intratumoral cancer therapies capable of transforming treatment for aggressive solid tumors. Positive early safety observations combined with the amended dosing strategy provide renewed momentum for evaluating whether INT230-6 can improve surgical outcomes, reduce severe treatment-related toxicity, and potentially extend long-term event-free survival for patients with triple-negative breast cancer. As enrollment expands across Europe, the study is expected to generate important clinical evidence supporting the development of a novel immunologically active therapeutic approach that may complement existing immunochemotherapy regimens and contribute to the future evolution of precision oncology and breast cancer treatment.
Source: Intensity Therapeutics press release
