Cue Biopharma, Inc.

Item 7.01. Regulation FD Disclosure. On September 20, 2026, Cue Biopharma, Inc. (the “Company”) issued a press release announcing positive topline results from a Phase 2 clinical trial of CUE-221 in Chronic Spontaneous Urticaria, or CSU, as discussed in Item 8.01 of this Current Report on Form 8-K. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K. The Company is hosting a conference call and live webcast to discuss the clinical data on September 21, 2026 at 8:00 a.m. E.T. The Company has made available a slide presentation to accompany the call, a copy of which is being furnished as Exhibit 99.2 to this Current Report on Form 8-K. The information in Item 7.01 of this Current Report on Form 8-K, including Exhibits 99.1 and 99.2 attached hereto, is intended to be furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 8.01. Other Events. Phase 2 Chronic Spontaneous Urticaria Study Topline Results On September 20, 2026, the Company announced positive topline data from a Phase 2 clinical trial of CUE-221 in CSU conducted in China by Genesis Life Sciences, an affiliate of Ascendant Health Ltd. This Phase 2 clinical trial enrolled 145 participants with moderate to severe CSU whose disease remained inadequately controlled despite treatment with H1-antihistamines. The Phase 2 multicenter, randomized, double-blind, placebo and active comparator-controlled study was conducted in China and included a 16-week treatment period with a 20-week follow-up period post-treatment. Patients were randomized in a 2:2:2:1:1 ratio across five treatment groups to either subcutaneously delivered CUE-221 at 4 mg/kg, 2 mg/kg, or 1 mg/kg Q4W, or placebo Q4W, or omalizumab 300 mg Q4W. The primary endpoint was the proportion of patients who achieved HSS7=0 at week 12. A key secondary endpoint assessed complete response, defined as the proportion of patients who achieved UAS7=0 at week 12. The study was designed to test superiority over placebo. Omalizumab was included to enable comparative efficacy without planned statistical testing. The primary endpoint of percentage of patients with HSS7=0 at week 12 was dose-responsive and met at all dose levels. The key secondary endpoint of percentage of patients with UAS7=0 at week 12 was dose responsive and met statistical significance at the 4 mg/kg highest dose level. Primary Endpoint of HSS7=0 at Week 12 CUE-221 (Q4W) Placebo Omalizumab Q4W Q4W 4 mg/kg 2 mg/kg 1 mg/kg (N=18) 300 mg (N=35) (N=36) (N=37) (N=17) Complete Resolution of Hives (HSS7=0) 54% 53% 43% 11% 41% 95% Confidence Interval (37%, 71%) (36%, 70%) (27%, 61%) (1%, 35%) (18%, 67%) P-values (vs. placebo) p < 0.005 p < 0.005 p < 0.05 NA Not Tested P-values based on Fisher’s exact test; Clopper-Pearson 95% confidence interval Key Secondary Endpoint of UAS7=0 at Week 12 CUE-221 (Q4W) Placebo Omalizumab Q4W Q4W 4 mg/kg 2 mg/kg 1 mg/kg N=18 300 mg (N=35) (N=36) (N=37) (N=17) Complete Response (UAS7=0) 46 39% 38% 11% 29% 95% Confidence Interval (29%, 63% (23%, 57%) (23%, 55%) (1%, 35%) (10%, 56%) p<0.05 P-values based on Fisher’s exact test; Clopper-Pearson 95% confidence interval The percentage of participants who achieved HSS7=0 further increased beyond the Week 12 primary endpoint, peaking at Week 22 across all CUE-221 dose groups. After a last dose was administered for all groups at Week 16, clinically meaningful benefit was maintained for up to 12 weeks off treatment (through week 28) at the 4 mg/kg dose level. A higher rate of complete resolution of hives was observed for the 4 mg/kg dose group relative to the lower dose groups and placebo, and post hoc analysis at Week 28 demonstrated a statistically significant difference versus omalizumab (delta = 36%), supporting the premise of fundamental difference between CUE-221 and omalizumab with respect to impacts on disease biology. Complete Resolutions of Hives at Primary Endpoint, Peak Effect, and 12 Weeks Off Drug CUE-221 (Q4W) Placebo Omalizumab CUE 4mg/kg vs. Q4W Q4W Omalizumab Time 4 mg/kg 2mg/kg 1 mg/kg Placebo 300 mg Δ in Percent Week 12 Primary 54% 53% 43% 11% 41% 13 Week 22 Peak Effect 69% 61% 57% 11% 41% 28 Week 28 12 weeks off drug 60% 31% 24% 11% 24% 36 p<0.05 P-values based on Fisher’s exact test Demographics and baseline disease characteristics were generally well balanced across treatment groups. CUE-221 demonstrated a favorable safety profile. There were no treatment-related serious adverse events and no cases of hypersensitivity reactions including anaphylaxis. Injection site reactions (ISR) were infrequent, only one ISR was > grade 1, and none led to study discontinuation. The Company believes these findings support continued clinical development of CUE-221 as a product candidate for CSU and will also continue with plans for development in food allergy. The Company recently submitted an IND to the U.S. Food and Drug Administration (FDA) for food allergy and, subject to the FDA’s review of the sufficiency of the data from the Phase 2 clinical trial of CUE-221 in CSU, the Company intends to initiate a Phase 2 trial of CUE-221 in food allergy and a Phase 2b/3 trial in CSU.