ADC Therapeutics SA (NYSE:ADCT) stock is trading lower on Thursday after the company indicated that LOTIS-5 showed elevated serious and Grade 5 adverse events, and it will discuss the benefit-risk profile with the FDA.



<h2>LOTIS-5 Meets Primary Endpoint</h2>



ADC Therapeutics shared topline results from its Phase 3 LOTIS-5 confirmatory study, with ZYNLONTA in combination with rituximab meeting the trial’s primary endpoint of progression-free survival in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL).



The combination also showed no detrimental impact on overall survival while delivering higher complete response rates and longer durations of complete response compared with the control regimen.



Patients treated with ZYNLONTA plus rituximab recorded a median progression-free survival of 6.1 months, compared with 4.7 months for those receiving R-GemOx.



Overall survival results showed no negative effect for the ZYNLONTA-based regimen versus the control arm.



The company noted that the overall survival analysis was influenced by earlier use and a higher rate of switching to new anti-lymphoma treatments among patients in the control group.



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<h2>Response Rates Favor ADC Therapeutics ZYNLONTA Combination</h2>



Additional efficacy measures also favored the investigational combination. The overall response rate reached 58.1% with ZYNLONTA plus rituximab, compared with 45.2% for R-GemOx.



Complete response rates were 39.5% versus 26.7%, respectively.



Patients receiving the ZYNLONTA regimen also experienced longer responses. Median duration of response was 9.2 months, compared with 7.7 months in the control arm.



The median duration of complete response was 16.8 months versus 12.3 months.



Among patients who achieved a complete response, 48.5% remained in complete remission at 24 months, compared with 16.7% in the R-GemOx arm.



<h2>Safety Profile</h2>



Hematologic adverse events were reported more frequently in the control arm, while infections, hepatotoxicity, and edema or effusion occurred more often in the ZYNLONTA arm.



Serious adverse events, treatment discontinuations due to adverse events, and Grade 5 events were higher in the ZYNLONTA group.



ADC Therapeutics noted that most Grade 5 treatment-emergent adverse events in the test arm occurred in patients aged 75 years or older.



“Based on these topline results from LOTIS-5, we look forward to discussing next steps for this combination of ZYNLONTA plus rituximab with the U.S. FDA,” said Mohamed Zaki, Chief Medical Officer of ADC Therapeutics. “We intend to conduct a pre-sBLA meeting in August and are preparing for a planned sBLA submission in the fourth quarter of 2026.”



In addition, the company will continue to evaluate value-maximizing alternatives.



In January, Genmab A/S (NASDAQ:GMAB) released topline results from the Phase 3 EPCORE DLBCL-1 trial of epcoritamab for DLBCL. The study demonstrated an overall survival (OS) of HR: 0.96, which did not reach statistical significance.



ADCT Stock Price Activity: ADC Therapeutics shares were down 49.68% at $1.55 during premarket trading on Thursday, according to Benzinga Pro.



Image via Shutterstock



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ADCT

ADC Therapeutics (ADCT) stock plummeted nearly 50% in premarket trading after its Phase 3 LOTIS-5 trial for ZYNLONTA plus rituximab met the primary endpoint of progression-free survival but revealed elevated serious and Grade 5 adverse events, particularly in patients aged 75+. The company plans to discuss the benefit-risk profile with the FDA and aims for a sub-BLA submission in Q4 2026.

Why Is ADC Therapeutics Stock Falling Thursday?