NextCure, Inc.

Item 7.01 Regulation FD Disclosure On June 1, 2026, NextCure, Inc. (“Company”) issued a press release announcing the presentation of a poster containing Phase 1 dose escalation data for its investigational drug candidate SIM0505, such presentation occurring at the American Society for Clinical Oncology 2026 conference (“ASCO 2026”) in Chicago, IL, on June 1, 2026. A copy of the Company press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K, and a copy of the ASCO 2026 poster is furnished as Exhibit 99.2 to this Current Report on Form 8-K. On June 1, 2026, Company updated its corporate presentation to reflect pipeline updates and interim phase 1 data from its ongoing clinical trial for SIM0505. Beginning on June 1, 2026, Company will be engaging with members of the investment community, which may reference these presentation materials. A copy of the Company presentation materials is furnished as Exhibit 99.3 to this Current Report on Form 8-K. The information contained in this Item 7.01, including Exhibits 99.1, 99.2, and 99.3, shall not be deemed to be “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 into any of the Company’s filings under the Exchange Act or the Securities Act, regardless of any general incorporation language in such filing.

Item 8.01 Other Events On June 1, 2026, Company announced data from its Phase 1 dose escalation study (NCT06792552) evaluating SIM0505 in a multicenter, first in human global study in patients with advanced solid tumors. The reported data were from 59 cancer patients applying a data cutoff of April 07, 2026. Patients in the U.S. (n=25) and China (n=34) received SIM0505 at doses ranging from 1.6 mg/kg to 9.6 mg/kg and were enrolled without preselection for CDH6 expression. SIM0505 efficacy data for gynecologic cancer patients (consisting of ovarian cancer patients and uterine serous carcinoma (“USC”) patients) in dose cohorts in the range of 4.8 - 8.0 mg/kg and who have had a minimum 12 weeks of follow-up as of the April 7, 2026 data cut off (n=20) are reported in the table below. All percentages reflect objective response rate (“ORR”) as determined using best response according to RECIST v1.1 criteria. Patient Group ORR* All gynecologic patients (n=20) 55% (11/20) • Ovarian cancer (n=17) 52.9% (9/17) • USC (n=3) 66.7% (2/3) *Reported for patients within therapeutic SIM0505 dose cohorts of 4.8 - 8.0 mg/kg who had a minimum 12 weeks of follow-up at the April 7, 2026 data cut-off, and were determined by best response according to RECIST 1.1 criteria. Of the nine (9) ovarian patients with PR, there was one unconfirmed PR and one PR pending confirmation at next follow-up scan. SIM0505 safety data for all patients (n=59) were as follows. No primary prophylaxis for hematological toxicities was used. The observed Grade 1 and Grade 2 treatment emergent adverse events (“TEAEs”) were predominantly hematological, nausea and vomiting. TEAEs leading to dose reduction (n=12) were predominantly hematological (4.8 - 9.6 mg/kg) and the majority occurring at 8.0 mg/kg, with nonhematological events including fatigue, dyspnoea, and nausea/vomiting (n=1 each). Observed Grade 3 and 4 TEAEs were predominantly hematological and manageable without primary prophylaxis for hematological toxicities. Treatment related adverse events (“TRAEs”) requiring dose discontinuation (n=3) were Grade 2 interstitial lung disease (“ILD”) and Grade 3 fungal pneumonia (both at 6.4 mg/kg), and Grade 4 thrombocytopenia (at 9.6 mg/kg). Adverse Events of Special Interest (“AESI”) were pneumonitis (n=1, Grade 1 at 5.6 mg/kg), and ILD (n=1, Grade 2 at 6.4 mg/kg). Patient demographics data for all patients (n=59) were as reported in the table below: All Patients Baseline Characteristics (n=59) Age, years: median (range) 58 (42-78) Sex, %: Male/Female 3.4%/96.6% Race, n (%) Asian 34 (57.6%) Black or African American 3 (5.1%) White 20 (33.9%) Other 2 (3.4%) Tumor Type, n (%) Ovarian 46 (78.0%) USC/other endometrial 10 (16.9%) Renal cell carcinoma (RCC) 3 (5.1%) ECOG performance status, n (%) 0 16 (27.1%) 1 43 (72.9%) Prior systemic anti-cancer regimen: median (range) 5 (1-12) On June 1, 2026, Company announced that it believes that its existing cash, cash equivalents and marketable securities will be sufficient to fund its planned operations into the first quarter of 2027. Company based this estimate on assumptions that may prove to be incorrect, and it could exhaust its available capital resources sooner than it currently expects.