News|Articles|March 12, 2026

INT230-6 Combination Increases Response Rates in Triple-Negative Breast Cancer

Fact checked by: Alex Biese

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Key Takeaways

Pathological complete response at surgery was higher with INT230-6 pre-treatment plus Keynote-522 (5/7; 71.4%) than with Keynote-522 alone (2/6; 33%), with one evaluation pending.
Grade ≥3 adverse events were fewer with INT230-6 plus standard therapy (14 events) versus standard therapy alone (25 events), including fewer immune checkpoint inhibitor–associated severe toxicities.
INVINCIBLE-4 is a multicenter, randomized, open-label, non-comparative, hypothesis-generating phase 2 study in Switzerland and France targeting tumors ≥1.5 cm, planned total enrollment of 61.
INT230-6 combines intratumoral cisplatin and vinblastine with SHAO to enhance intratumoral dispersion and cellular uptake, aiming to limit systemic exposure relative to conventional chemotherapy.
Protocol modifications (lower injection volume, single injection) were implemented to mitigate skin irritation that prompted a September 2025 enrollment pause, while preserving presurgical feasibility.

Preliminary INVINCIBLE-4 study data shows INT230-6 plus standard care may increase pathological complete response rates and improve patient safety.

Preliminary results from the INVINCIBLE-4 study show that 71.4% of patients with triple-negative breast cancer achieved a pathological complete response when receiving the investigational drug INT230-6 before standard treatment.

Intensity Therapeutics, Inc. reported these findings via a news release while announcing a protocol amendment to resume enrollment in the Phase 2 trial. The study, which compares a combination of INT230-6 and standard care against standard care alone, had been paused in September 2025 due to skin irritations. By using a lower drug volume and a single injection, the company aims to continue evaluating how this treatment helps patients with cancer achieve the absence of live tumor cells before undergoing surgery.

Main Data That Support the Findings

Preliminary observations from the 14 patients treated in the study so far indicate that adding INT230-6 to the standard of care (SOC) may improve the likelihood of a pathological complete response (pCR), which is the absence of live cancer in the breast and lymph nodes at the time of surgery. In Cohort A, five out of seven patients (71.4%) who received INT230-6 before starting standard treatment achieved a pCR. In contrast, in Cohort B, which received only the standard of care, two out of six patients (33%) achieved a pCR, with one patient in that group still awaiting evaluation.

The data also suggest a more favorable safety profile for the combination therapy. Patients in Cohort A experienced 44% fewer grade 3 (severe) or higher side effects than those in Cohort B. Achieving a pCR is a significant goal for patients with cancer, as it has been shown to reduce the risk of the disease returning from 50% to 16% over five years.

Trial Details

The INVINCIBLE-4 study is a phase 2, randomized, open-label trial conducted at multiple centers in Switzerland and France. The study is designed to analyze how INT230-6 works when administered before the standard Keynote-522 regimen. This standard treatment is a six-month presurgical process involving the immunotherapy drug Keytruda (pembrolizumab) and several chemotherapy agents, including paclitaxel, carboplatin and either doxorubicin or epirubicin with cyclophosphamide.

The trial specifically enrolls patients with tumor sizes of 1.5 cm or larger. Because these tumors are generally larger on average than those in the Keynote-522 study, the pCR rates are particularly notable. The study is non-comparative and hypothesis-driven, with a primary goal of measuring pCR rates for both the combination and the standard treatment alone. The FDA and the European Medicines Agency recognize pCR as an endpoint that could allow for accelerated or conditional marketing approval for high-risk breast cancers like the triple-negative subtype. Total enrollment for the study is expected to reach 61 patients.

Safety

Safety observations through March 2, 2026 show that INT230-6 plus standard treatment was well-tolerated compared to standard treatment alone. In Cohort A, there were 14 total grade 3 or higher side effects, only one of which was a common immune-related side effect. In Cohort B, there were 25 grade 3 side effects related to the standard of care, including four side effects associated with immune checkpoint inhibitors, three grade 3 and one grade 4 (life-threatening).

The drug INT230-6 is designed for direct injection into the tumor. It contains two potent anti-cancer agents, cisplatin and vinblastine sulfate, combined with a molecule called SHAO that helps the drugs spread through the tumor and enter cancer cells. This method is intended to keep the medication within the tumor, potentially resulting in fewer body-wide side effects than systemic chemotherapy. To address the skin irritations that caused the initial enrollment pause, the new study protocol will use a reduced volume of the drug and a single injection. Data from a 2023 study of INT230-6 alone also showed that skin issues were rare and surgeries were performed without complications.

Reference

“Intensity Therapeutics, Inc. Provides Update on the Phase 2 Presurgical Triple-Negative Breast Cancer INVINCIBLE-4 Study,” news release.

Editor's note: This article is for informational purposes only and is not a substitute for professional medical advice, as your own experience will be unique. Use this article to guide discussions with your oncologist. Content was generated with AI, reviewed by a human editor, but not independently verified by a medical professional.

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