Roche, a leader in research-focused healthcare, announced that in the IMvigor 210 study, the investigational cancer immunotherapy atezolizumab (MPDL3280A; anti-PDL1) shrank tumours (objective response rate, ORR, the primary end point of this phase II study) in people with locally advanced or metastatic urothelial bladder cancer (UBC) who had progressed on initial treatment (second-line or later).

High amounts of PD-L1 (Programmed Death Ligand-1) expression by a person’s cancer correlated with increased response to the medicine. Adverse events were consistent with what has been previously observed for atezolizumab.

“We are encouraged by the number of people who responded to atezolizumab and maintained their response during the study because minimal progress has been made in advanced bladder cancer for nearly 30 years,” said Sandra Horning, M.D., chief medical officer and head of global product development. “We plan to present results at an upcoming medical meeting and will discuss next steps with health authorities to bring a new treatment option to patients as soon as possible.”  

Last year, the US Food and Drug Administration (FDA) granted Breakthrough Therapy designation for atezolizumab in people whose metastatic bladder cancer expressed PD-L1. This designation is designed to expedite the development and review of medicines intended to treat serious diseases.

IMvigor 210 is an open-label, multicenter, single-arm phase II study that evaluated the safety and efficacy of atezolizumab in people with locally advanced or metastatic UBC, regardless of PD-L1 expression. People in the study were enrolled into one of two cohorts. Cohort 1 consisted of people who had received no prior therapies for locally advanced or metastatic UBC, but who were ineligible for first-line cisplatin-based therapy; results from this cohort are not yet mature. Cohort 2, for which results were announced, included people whose disease progressed during or following previous treatment with a platinum-based chemotherapy regimen (second-line or later). People received a 1200-milligram intravenous dose of atezolizumab on day one of 21-day cycles until progressive disease (Cohort 1) or loss of clinical benefit (Cohort 2). The primary endpoint of the study was ORR. Secondary endpoints included duration of response (DoR), overall survival (OS), progression-free survival (PFS) and safety. PD-L1 expression was assessed using an investigational immunohistochemistry (IHC) test being developed by Roche Diagnostics.

In addition to the IMvigor 210 study, Roche has an ongoing randomised phase III study, IMvigor 211, comparing atezolizumab with standard-of-care chemotherapy in people who have relapsed UBC, and a planned phase III study, IMvigor 010, that will evaluate atezolizumab compared with observation in people with early-stage muscle-invasive bladder cancer who are selected for PD-L1 expression and are at risk for recurrence (adjuvant). All studies include the evaluation of a companion test developed by Roche Diagnostics to determine PD-L1 status.

Metastatic urothelial bladder cancer is associated with a poor prognosis and limited treatment options. It is a disease that has seen no major advancements for nearly 30 years. Bladder cancer is the ninth most common cancer worldwide, with 430,000 new cases diagnosed in 2012, and it results in approximately 145,000 deaths globally each year. Men are three times more likely to suffer from bladder cancer compared with women and it is also three times more common in developed countries than in less developed countries.

Atezolizumab (also known as MPDL3280A; anti-PDL1) is an investigational monoclonal antibody designed to interfere with a protein called PD-L1. Atezolizumab is designed to target PD-L1 expressed on tumour cells and tumour-infiltrating immune cells, preventing it from binding to PD-1 and B7-1 on the surface of T cells. By inhibiting PD-L1, atezolizumab may enable the activation of T cells.

All studies of atezolizumab include the evaluation of an investigational IHC test that uses the antibody SP142 to measure PD-L1 expression on both tumour cells and infiltrating immune cells. The goal of PD-L1 as a biomarker is to identify those people most likely to benefit when treated with atezolizumab alone, and to determine which people may benefit most from a combination of atezolizumab and another medicine. There are 11 ongoing or planned phase III studies of atezolizumab across certain kinds of lung, kidney, breast and bladder cancer.