FDA Grants Fast Track Designation to Silmitasertib for Recurrent Sonic Hedgehog-Driven Medulloblastoma

Silmitasertib (Senhwa Biosciences Inc) has received FDA Fast Track designation for the treatment of patients with recurrent sonic hedgehog (SHH)-driven medulloblastoma, according to a press release.¹

Silmitasertib is a highly selective casein kinase 2 (CK2) inhibitor that is safe, well-tolerated, and easily administered with an oral formulation, according to the manufacturer.¹ CK2 play an important role in repairing DNA damage and has increased activity in several cancers. Because of its activity in DNA repair, inhibition of the pathway has been shown to boost the efficacy of DNA-damaging chemotherapeutics when used in combination regimens.²

In clinical trials of these regimens, silmitasertib has produced clinical benefit as a monotherapy and in combination with drugs such as gemcitabine and cisplatin. Earlier trials have found that it has a favorable safety profile as well as pharmacokinetic characteristics and pharmacodynamic responses.²

“We are delighted to receive Fast Track Designation and look forward to working closely with the FDA to accelerate the development of silmitasertib, aiming to promptly bring a meaningful treatment to patients with recurrent SHH-driven medulloblastoma,” said Tai-Sen Soong, chief executive officer of Senhwa Biosciences, in the press release.¹

Silmitasertib is under investigation for children and adults with recurrent medulloblastoma who may or may not undergo surgery in a multicenter phase 1/2 trial sponsored by the Pediatric Brain Tumor Consortium. Patients eligible for inclusion must be skeletally immature at the time of enrollment and between 3 and 18 years of age. Investigators are hoping to enroll between 6 and 10 skeletally immature patients each year.²

The researchers’ goal is to estimate the maximum-tolerated dose and/or the recommended phase 2 dose, to establish the safety profile and define dose-limiting toxicities, and to identify the pharmacokinetic profile. Documenting preliminary antitumor activity will be a key secondary endpoint.²

In the surgical cohort of the trial, researchers expect to enroll 2 to 3 patients annually who are clinically indicated for surgical resection, are at least 3 years of age, and are able to receive silmitasertib for 5 to 7 days before the procedure. The primary endpoint of this portion of the trial is to characterize the concentrations of the drug in the tumor following administration and surgical resection. A secondary focus is to evaluate the ability of the drug at the maximum-tolerated dose and/or recommended phase 2 dose to inhibit CK2-mediated signaling in the tumor.²

A phase 2 investigator-initiated trial investigating its use in patients with moderate COVID-19 recently completed enrollment and another phase 2 trial for severe COVID-19 is enrolling patients in the United States.¹

REFERENCE

1. Senhwa’s Silmitasertib Receives US FDA Fast Track Designation for the Treatment of Recurrent Sonic Hedgehog Driven Medulloblastoma. News release. August 18, 2021. Accessed August 26, 2021. https://www.prnewswire.com/news-releases/senhwas-silmitasertib-receives-us-fda-fast-track-designation-for-the-treatment-of-recurrent-sonic-hedgehog-driven-medulloblastoma-301358557.html

2. Testing the safety and tolerability of CX-4945 in patients with recurrent medulloblastoma who may or may not have surgery. ClinicalTrials.gov. Updated June 22, 2020. Accessed August 25, 2021. https://clinicaltrials.gov/ct2/show/NCT03904862