Pfizer has announced the results of the Phase III ECHELON-3 clinical trial, indicating that the antibody-drug conjugate (ADC) ADCETRIS (brentuximab vedotin) regimen improved overall survival (OS) in patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL).

The double-blind, randomised, multicentre trial is assessing ADCETRIS in combination with lenalidomide and rituximab versus lenalidomide and rituximab plus placebo in 230 adult patients with relapsed/refractory DLBCL, regardless of CD30 expression.

Enrolled across trial sites in North America, Europe and Asia-Pacific, these subjects should have received two or more lines of therapy previously and are not eligible for stem cell transplant or CAR-T therapy to be part of the trial.

OS in the intent to treat population was the primary endpoint while key secondary endpoints were progression free survival (PFS) and overall response rate (ORR).

According to the trial data, treatment with the ADCETRIS regimen demonstrated a statistically significant and clinically meaningful improvement in OS versus placebo.

Positive outcomes were also observed in secondary endpoints such as PFS and ORR.

ADCETRIS’ safety and tolerability profile in the trial was in line with prior data.

It targets CD30-positive tumour cells, releasing the cytotoxic agent monomethyl auristatin E upon internalisation.

The drug is already approved as a standard of care in certain lymphoma indications and has been administered to more than 55,000 patients in the US since its first approval in 2011.

Pfizer plans to submit the trial data to the US Food and Drug Administration to potentially support a regulatory filing in the country.

Pfizer Oncology chief development officer Roger Dansey said: “This is the third Phase III study in a type of lymphoma to demonstrate an overall survival benefit for an ADCETRIS combination. Based on the strong results from ECHELON-3, we’re excited that ADCETRIS could address an area of high unmet need in patients with relapsed or refractory DLBCL irrespective of CD30 expression.

“The results are particularly encouraging because the study evaluated heavily pretreated patients, including some who received prior CAR-T therapy.”

The latest development comes after the company reported top-line data from the Phase III RENOIR trial of its respiratory syncytial virus (RSV) vaccine, ABRYSVO, for RSV-linked lower respiratory tract disease.