Bavarian Nordic has again delayed the release of data from a phase 3 trial of Prostvac. Top-line data on the Bristol-Myers Squibb-partnered prostate cancer vaccine are now due to drop in the fourth quarter, with the delayed third interim analysis penciled in for September.
The timing means Bavarian Nordic is still on course to deliver data in 2017. But the data are due to arrive later in the year than was forecast 6 months ago. Over that period, the forecast has gone from 2017 to the second half of 2017 to the fourth quarter of 2017. The timing of the third interim analysis has slipped in lockstep with the final data date, with the latest news shunting the review from the middle of this year to September.
Bavarian Nordic’s forecasts for the date of the third interim review and top-line data are tied to the rate at which patients in the trial are dying. The interim review will happen when 427 patients have died. And the final analysis will begin once about another 100 patients have died.
A lot is resting on the data. If Bavarian Nordic bucks the trend in cancer vaccines by delivering positive data, Bristol-Myers may pay $80 million to license Prostvac. The option fee will increase if the study's median overall survival benefit bests that seen in a previous phase 2 trial.
Bavarian Nordic penned that deal more than 2 years ago. Since then, the forecast date on which Bristol-Myers will have the data to make its decision has slipped, adding to the string of delays that blighted the early years of the study.
When Bavarian Nordic initiated the trial late in 2011, it predicted it would take up to 2 years to fully enroll the study. After making progressively more downbeat statements about the status of the study, Bavarian Nordic replaced the head of its cancer vaccine unit, added interim analyses to the trial design and revealed a “more arduous regulatory process than anticipated” had delayed initiation of sites.
The objective shifted to getting the study fully enrolled in the first half of 2014. That delayed target proved to be overly ambitious. The last patient ultimately came into the trial in December 2014.
Since then, the delays have continued. In January, Bavarian Nordic said top-line data were due in the second half of 2017. Previous forecasts suggested the data could arrive earlier in the year. The January update also said the third interim analysis would occur in the middle of 2017. Speculation prior to the clarification tipped the analysis to happen in the first quarter.
Now the mid-2017 target for the third interim analysis has slipped too. The latest forecast has the monitoring committee performing the analysis in September.
When Bavarian Nordic CEO Paul Chaplin disclosed the January delay he called the trends behind the news “great news” for patients. Chaplin assumed that position because the delay stemmed from the fact the trial will end when 534 participants have died. A slower rate of deaths is clearly good news for patients. But it is unclear whether the rate is slower than expected in the treatment arm, placebo cohort or across both groups.
That will become clear when Bavarian Nordic belatedly posts data from the trial.