Belgian company Ablynx has reported positive topline results from the Phase III HERCULES trial with caplacizumab to treat acquired thrombotic thrombocytopenic purpura (aTTP).
In addition to standard-of-care, treatment with caplacizumab, an anti-von Willebrand factor (vWF) Nanobody, resulted in a statistically significant reduction in time to platelet count response, which is the primary endpoint of the trial.
It is reported that patients on caplacizumab were 1.5 times more likely to achieve platelet count response at any given time point, compared with those treated with placebo.
The trial also met the first two key secondary endpoints, while caplacizumab treatment resulted in a 74% reduction in the percentage of patients with aTTP-related death, recurrence of aTTP, or at least one major thromboembolic event during study drug treatment.
In addition, the proportion of patients with a recurrence of aTTP in the overall study period was 67% lower in the caplacizumab arm compared with placebo.
Ablynx chief medical officer Dr Robert Zeldin said: "Patients with aTTP are at risk for significant morbidity and early death. We believe these positive Phase III study results confirm the potential for caplacizumab to address the high unmet medical need in the treatment of aTTP and to have a meaningful impact on the lives of affected patients.
"We continue to analyse the data and look forward to sharing the results with regulatory authorities and the scientific community."
According to the analysis of the third key secondary endpoint, no patients treated with caplacizumab were refractory to treatment compared to three patients treated with placebo.
The fourth key secondary endpoint showed a trend to faster normalisation of the organ damage markers in patients treated with caplacizumab.
The trial data will be used to support the registration process for Ablynx's wholly owned caplacizumab in Europe and the US.
Ablynx CEO Dr Edwin Moses said: "I am delighted by this outcome as it reinforces all our beliefs in the potential for caplacizumab to change the lives of patients affected by aTTP. This is a very important milestone for the dompany as it further validates our Nanobody platform and demonstrates our ability to discover and develop medicines that make a real difference for society.
"These results strengthen our resolve to obtain marketing approval as quickly as possible so that caplacizumab rapidly becomes available to patients suffering from this severe disease for which there is currently no approved drug available."