Roche's polatuzumab vedotin combination meets main goal in trial of previously treated aggressive lymphoma

Roche's Genentech unit said Phase II results presented at the American Society of Hematology (ASH) annual meeting on Sunday showed that its experimental anti-CD79b antibody drug conjugate polatuzumab vedotin in combination with bendamustine plus Rituxan (rituximab) significantly improved complete response rates in patients with diffuse large B-cell lymphoma (DLBCL), compared to bendamustine plus Rituxan alone. "As many as 40 percent of people with diffuse large B-cell lymphoma do not respond to initial therapy or experience the return of their disease, at which point their treatment options are limited and the prognosis is very poor," noted chief medical officer and head of global product development Sandra Horning, adding that the "efficacy observed for polatuzumab vedotin in this study supports its potential as a new treatment option" for this patient population. 

The Phase Ib/II GO29365 trial assessed polatuzumab vedotin in combination with Rituxan or Roche's Gazyva (obinutuzumab) plus bendamustine in relapsed or refractory follicular lymphoma or DLBCL. The Phase II stage of the trial randomised 80 patients with heavily pre-treated relapsed or refractory DLBCL to receive bendamustine plus Rituxan, or bendamustine plus Rituxan together with polatuzumab vedotin. According to the drugmaker, the primary endpoint was complete response at the end of treatment, as measured by positron emission tomography and assessed by an independent review committee (IRC), while secondary goals included objective response by investigator assessment and best objective response at the end of treatment by investigator and IRC assessment. 

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Results demonstrated that the addition of polatuzumab vedotin to bendamustine plus Rituxan increased complete response rates from 15 percent to 40 percent at the end of treatment. Genentech said the benefit observed was consistent across secondary endpoints, while exploratory endpoints also improved with the addition of polatuzumab vedotin. Specifically, patients treated with polatuzumab vedotin achieved a median overall survival (OS) of 11.8 months, versus 4.7 months for those on bendamustine plus Rituxan alone. Further, polatuzumab vedotin was associated with a median progression-free survival (PFS) of 6.7 months, compared with 2 months for bendamustine plus Rituxan alone, while duration of response was 8.8 months versus 3.7 months, respectively. Roche said there were no unexpected safety signals observed with polatuzumab vedotin. 

"These results exceeded our expectations both for the complete response rate, because this is a heavily pre-treated population, and also that we were able to detect an overall survival benefit of this magnitude," Horning remarked.

The company noted that based on results from the trial, polatuzumab vedotin was recently granted a breakthrough therapy designation by the FDA, as well as a PRIME designation by the European Medicines Agency, for the treatment of patients with relapsed or refractory DLBCL. 

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