Azitra expands ATR-04 trial to rash from KRAS and MEK inhibitors

Azitra, Inc. (NYSE American: AZTR) said it has amended its ongoing Phase 1/2 clinical trial of ATR04-484 to expand patient eligibility to include people with rash associated with KRAS and MEK inhibitors. The company announced the change in a press release dated October 29, 2026, filed as Exhibit 99.1 to a Form 8-K.

The protocol changes

The expanded eligibility also covers people with neurofibromatosis type 1, known as NF1, who have rash associated with MEK inhibitors. The amendments shorten the required washout periods for antibiotics and steroids. Together, the company says, the changes broaden the potential treatment opportunities for ATR-04 beyond its initial focus on rash linked to epidermal growth factor receptor inhibitors, known as EGFRi, and it expects the additional modifications to facilitate patient recruitment.

The multicenter, randomized, double-blind, vehicle-controlled Phase 1/2 study, registered as NCT06830863, is evaluating the safety, tolerability, bioavailability, pharmacodynamics and preliminary efficacy of topical ATR04-484. The amendments follow the company's recent announcement that the study's safety review committee recommended proceeding to Cohort 2 after reviewing available safety data from Cohort 1.

Chief Executive Officer Francisco Salva called the expansion "a significant step for our ATR-04 program," and said the company is encouraged by the program's progress since the advance to Cohort 2.

The market the company cites

The release says KRAS and MEK inhibitors are precision therapies used to treat various cancers, including non-small cell lung cancer, melanoma, colorectal cancer and ovarian cancer. The company estimates that about 85,000 patients in the United States receive a KRAS or MEK inhibitor each year, and that dermatologic side effects, including skin rash, can substantially impair quality of life and may require dose reductions, treatment interruptions or discontinuation. It adds those patients to the approximately 220,000 patients in the United States who undergo EGFRi treatment each year.

The company and its trial

Azitra describes itself as a clinical-stage biopharmaceutical company focused on innovative therapies for precision dermatology. Its investigational live biotherapeutic, ATR04-484, is an isolated, naturally derived Staphylococcus epidermidis strain, selected for its preclinical profile of reducing the pro-inflammatory cytokine IL-36γ and Staphylococcus aureus levels. The FDA granted Fast Track designation to ATR04-484 for cancer treatment-associated rash, a condition the company says affects up to 300,000 patients annually in the United States.

Cohort 2 is expected to enroll approximately 24 patients, who will receive once-daily treatment for 28 days. The company's annual report on Form 10-K, filed February 27, 2026, says Azitra has not commenced commercial operations.

Financial position

For 2025 the company reported no revenue, compared with $7,500 in 2024. Research and development expense was $4.8 million in 2025 and $4.7 million in 2024. The net loss was $11.0 million in 2025, against $9.0 million in 2024. Cash from operations was negative $11.2 million in 2025 and negative $10.2 million in 2024.

Year-end cash and cash equivalents were $2.1 million at the end of 2025, according to a quarterly report filed August 12, 2026, and $4.6 million at the end of 2024. The company reported cash and cash equivalents of $6.7 million at June 30, 2026.

What comes next

The release reports no efficacy data. The study is Phase 1/2, and the safety committee's recommendation to proceed rested on safety data from Cohort 1 only. The company's own risk list says results from Cohort 1 may not be predictive of Cohort 2 or later-stage trials. Adding KRAS and MEK inhibitor patients widens the population, and the company warns that the expanded populations may present different safety or efficacy profiles and that the amendments may not speed enrollment. The patient counts are the company's estimates, and it says its estimation of addressable markets may be inaccurate. Cohort 2 is about 24 patients. The company also lists the risks that it may fail to raise funding in time and that more effective competing treatments may emerge. Cash and cash equivalents were $6.7 million at June 30, 2026, against cash used in operations of $11.2 million in 2025.

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