By Nicholas G. Miller

Shares of ADC Therapeutics fell after it reported the death of two patients in a late-stage trial for treating an aggressive cancer that starts in white blood cells.

The stock fell 7.6% to $4.25 in premarket trading on Wednesday after closing Tuesday having more than doubled its value this year.

The company's phase 3 study evaluated the safety and efficacy of Zynlonta in combination with glofitamab, which is sold by Roche's Genentech as Columvi, to treat patients with diffuse large B-cell lymphoma that hasn't responded to treatment or had returned.

ADC Therapeutics said the results showed that, among the 49 efficacy-evaluable patients, the drug combination resulted in 89.8% of patients seeing a reduction in their cancer and 77.6% of patients had no signs of cancer after treatment, also known as a complete response.

Two patients in the study experienced Grade 5 adverse events, the highest severity level which refers to an event that is fatal. The deaths occurred during complete response, the company said.

ADC Therapeutics said that one death was treatment-related according to the investigator.

However, the company said the study showed strong efficacy and said the drug combination was generally well-tolerated with a manageable safety profile.

Write to Nicholas G. Miller at nicholas.miller@wsj.com.

(END) Dow Jones Newswires

December 03, 2025 08:32 ET (13:32 GMT)

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