Targeted therapy stalls or shrinks tumors in some medulloblastoma patients

A new era of personalized therapy has begun for some patients with the brain tumor medulloblastoma.

In clinical trials led by St. Jude for the Pediatric Brain Tumor Consortium, tumors stopped growing, got smaller or disappeared for a time in some patients treated with the drug vismodegib. The patients all had a subtype of medulloblastoma called sonic hedgehog, which accounts for about 30% of all medulloblastoma cases.

Vismodegib shuts down the sonic hedgehog signaling pathway, which is mistakenly switched on in this subtype.

In the trials that included children and adults, 13 of 32 patients with the sonic hedgehog subtype had their tumors stop growing for as long as 17 months. In four patients the tumors shrank or even disappeared for at least two months.

Researchers are working on how best to include the drug in treatments for new patients with this subtype. The drug is already approved for use against basal cell skin cancer. Two key questions are how to identify patients who are most likely to respond to vismodegib and how to prevent tumors from becoming drug resistant.

“The great hope is that targeted therapies like vismodegib will help more patients survive their disease with fewer long-term side effects,” said Giles Robinson, MD, of St. Jude Oncology.

The study appears in the Journal of Clinical Oncology.

July 29, 2015

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Full citation:
Robinson GW, Orr BA, Wu G, Gururangan S, Lin T, Qaddoumi I, Packer RJ, Goldman S, Prados MD, Desjardins A, Chintagumpala M, Takebe N, Kaste SC, Rusch M, Allen SJ, Onar-Thomas A, Stewart CF, Fouladi M, Boyett JM, Gilbertson RJ, Curran T, Ellison DW, Gajjar A. Vismodegib Exerts Targeted Efficacy Against Recurrent Sonic Hedgehog-Subgroup Medulloblastoma: Results From Phase II Pediatric Brain Tumor Consortium Studies PBTC-025B and PBTC-032. J Clin Oncology July 13, 2015. Epub ahead of print. doi: 10.1200/JCO.2014.60.1591.