US FDA scientists are concerned that data submitted in support of Y-mAbs' Therapuetics ( NASDAQ: YMAB ) Biologics License Application for its neuroblastoma therapy omburtamab does not provide substantial evidence of efficacy.
In briefing documents posted Wednesday in advance of an agency advisory committee meeting on Friday, the scientists identified three key issues.
Y-mAbs ( YMAB ) submitted data from just a single center, single arm trial for its BLA.
FDA researchers said that the external control population is inappropriate as a comparator due to substantial differences between the study and control populations. They noted that multimodality treatment in the treatment arm was more intensive than in the control population, which was based on data from a childhood cancer registry.
Second, the FDA conducted additional analyses to examine bias and results found that differences in survival cannot be reliably attributed to omburtamab.
Finally, the application does not include reliable response rate data to provide supportive evidence of the treatment effect of omburtamab. The agency added that objective response rate data was not collected in the trial.
"The complex review issues described above result in a large degree of uncertainty regarding whether the observed differences in overall survival between the single-arm Study 03-133 and external control populations are due to I-omburtamab or whether they are due to differences in other anticancer treatments, supportive care regimens, unknown differences between the two populations, or a combination of these factors," the researchers wrote.
Y-mAbs ( YMAB ) has had a long road trying to get omburtamab approved. In October 2020, the FDA issued a Refuse to File letter to the company .
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FDA scientists question evidence of efficacy for Y-mAbs' neuroblastoma therapy omburtamab