<p class="prntac"><i>AMT-116 is a potential first-in-class CD44v9-directed Topoisomerase I inhibitor-based ADC </i></p>  <p class="prntac"><i>AMT-116 demonstrated a favorable safety profile, with manageable hematologic and Gastrointestinal toxicities </i></p>  <p class="prntac"><i>Promising efficacies were observed in patients with heavily pretreated EGFR Wild-type NSCLC and other advanced solid tumors without CD44v9 pre-selection</i></p>  <p><span class="legendSpanClass"><span class="xn-location">SHANGHAI</span></span>, <span class="legendSpanClass"><span class="xn-chron">Oct. 17, 2025</span></span> /PRNewswire/ -- Multitude Therapeutics, Inc., a clinical-stage company focused on the development of antibody-drug-conjugate (ADC) drugs, today announced initial data from its ongoing phase I/II open-label, multicenter dose escalation and expansion study evaluating AMT-116, a CD44v9-directed ADC, in patients with EGFR wild-type NSCLC and other advanced solid tumors. The data are being presented on <span class="xn-chron">October 17th</span> at the 2025 European Society for Medical Oncology (ESMO) Annual Meeting being held in <span class="xn-location">Berlin, Germany</span>.</p>  <p>Phase I/II clinical trials are being conducted across <span class="xn-location">Australia</span>, US and <span class="xn-location">China</span>. This first-in-human study will evaluate the Maximum Tolerated Dose (MTD) / the Recommended Phase II Dose (RP2D), safety, tolerability, anti-tumor activity, pharmacokinetics, pharmacodynamics and immunogenicity of AMT-116, in patients with advanced solid tumors. The Phase Ia portion will determine the recommended doses for expansion, and the Phase Ib/II portion will focus on further characterizing safety and efficacy in select tumor types.</p>  <p>As of <span class="xn-chron">July 17th, 2025</span>, safety data are available for 164 patients who have received AMT-116 once every two weeks (Q2W) at doses ranging from 1.5 to 5.0 mg/kg. Primary tumor types are NSCLC, NPC (nasopharyngeal carcinoma), anal carcinoma and salivary gland cancer. In heavily pretreated EGFR Wild-type NSCLC patients, with prior lines of therapy ranging from 1-5, promising efficacy was observed regardless CD44v9 expression status. The overall response rate (ORR) was 40% (6/15), and the disease control rate (DCR) was 93% (14/15), in EGFR Wild-type NSCLC at dose levels <u>&gt;</u>3 mg/kg. Among five EGFR Wild-type NSCLC patients at 5.0 mg/kg, ORR was 80% (4/5) and DCR was 100% (5/5). Preliminary antitumor activity was also observed in patients with NPC, anal carcinoma and salivary gland cancer at <u>&gt;</u>3mg/kg, with ORRs of 50% (3/6), 60% (3/5) and 33% (2/6), respectively. Antitumor activity was observed across patients with varying levels of CD44v9 expression. The safety profile of AMT-116 was consistent with that of other Topoisomerase I inhibitor-based ADCs, with manageable hematologic toxicities as the most common treatment-related adverse events. Only low-grade and infrequent mucosal and skin toxicities were observed, demonstrating a favorable tolerability profile.</p>  <p>&quot;We are excited by the impressive and durable efficacy shown in the early results of AMT-116, especially in unselected heavily pretreated EGFR Wild-type NSCLC and several other advanced solid tumors. The efficacies of AMT-116 observed so far are consistent with its broad tumor expression profile observed in preclinical studies, while the greatly reduced mucosal and skin toxicities reflect the desired outcome of a carefully selected linker-payload platform aimed at mitigating potential on-target toxicities from normal tissue expression. With these encouraging results, we are further expanding the clinically efficacious dose levels of 4 mg/kg Q2W and 5 mg/kg Q2W cohorts in select tumor types to explore the full potential of this novel ADC for greater patient benefit in NSCLC and beyond,&quot; said Dr. <span class="xn-person">Shu-Hui Liu</span>, co-founder and CSO of Multitude Therapeutics.</p>  <p>Mini Oral Presentation Details:</p>  <p><b>Title:</b>&nbsp;Updated ongoing Phase I/II clinical trial results of AMT-116, a first-in-class anti-CD44v9 antibody-drug conjugate (ADC), in patients with advanced solid tumors<br /><b>Mini Oral Session Title:</b> Developmental therapeutics<br /><b>Date and Time</b>: <span class="xn-chron">October 17th</span> ??<span class="xn-chron">04:05 PM</span><br /><b>Location:</b> Heidelberg Auditorium - Hall 6.2<br /><b>Presentation number:</b> 922MO</p>  <p><b>About AMT-116<br /></b>AMT-116, a CD44v9 ADC, is composed of a proprietary antibody with high CD44v9 binding affinity, a hydrolysable linker, and a belotecan derivative payload (a novel and clinically validated topoisomerase-1 inhibitor, named KL610023, collaborating with Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd. (6990.HK)). CD44v9 is involved in broad biological pathways and has an implicated role in cancer stem cells. The target is a highly abundant protein and is overexpressed broadly in solid tumors with a restrictive normal tissue expression. AMT-116 has a drug-to-antibody ratio of 7-8. AMT-116 is being evaluated in a phase I/II study in patients with EGFR Wild-type NSCLC and other advanced solid tumors. Additional information on the <span class="xn-location">Australia</span>/US Phase I (NCT05725291) and China Phase I/II (NCT06782334) trials can be found at <a href="https://clinicaltrials.gov/" target="_blank" rel="nofollow" style="color: #0000FF">clinicaltrials.gov</a>.&nbsp;</p>  <p><b>About Multitude Therapeutics<br /></b>Multitude Therapeutics is a clinical-stage company focused on the development of ADC drugs. Multitude Therapeutics has two technology platforms: MabArray?™? an antibody platform for discovering novel cell surface tumor antigens to identify first-in-class targets, and T1000- exatecan ??a new linker-payload technology for developing ADCs, which allows ADCs prepared with this platform to achieve a better balance of the bystander effect, efficacy, and safety. The combination of MabArray??and T1000-exatecan generates significant synergistic effects, enabling Multitude Therapeutics to build an ADC &quot;atlas&quot; that is expected to treat malignant tumors with high unmet medical needs and achieve higher and more durable responses.</p>  <p>Based on the above technology platforms, Multitude Therapeutics currently has several ADCs in development, including three potential first-in-class target ADCs. Moreover, several ADCs, including all-new target ADCs, have entered the clinical stage, where they have demonstrated promising safety and efficacy and provided preliminary validation of the company's platform technology. For further information, please visit <a href="http://www.multitudetherapeutics.info/" target="_blank" rel="nofollow" style="color: #0000FF">www.multitudetherapeutics.info</a></p>