A combination treatment consisting of an experimental cancer drug – ipatasertib – and Roche’s immunotherapy agent Tecentriq (atezolizumab) has demonstrated early promise in an aggressive type of brain cancer.

The Ice-CAP trial is evaluating the combination of Tecentirq with the precision drug ipatasertib, which is designed to block the AKT molecule.

Cancers that lack a functioning PTEN gene use growth signals involving AKT, meaning patients with PTEN defects could benefit the most from the new combination.

In a Phase I trial, two of the first ten patients with the aggressive brain cancer glioblastoma responded to treatment with Tecentriq plus ipatasertib.

In particular, researchers at The Institute for Cancer Research, London (ICR) and The Royal Marsden NHS Foundation Trust noted signs of effectiveness in patients with PTEN defects.

ICR said in a statement that while it is ‘unusual to see such positive clinical responses’ at this clinical trial stage, the results are still early and more research is needed before any conclusions can be drawn.

Of the ten patients recruited into the Ice-CAP trial so far, seven of them have tumours with defects in the PTEN gene and four had complete loss of PTEN expression.

One of the two patients who responded to the combination treatment and who had aggressive brain cancer with faulty PTEN genes responded ‘remarkably’ well to the therapy, with no signs of diseases after 22 months.

“Brain cancer is able to evade the immune system in complex ways and, until now, immunotherapy has not worked. However, by uncloaking the disease using a new drug called ipatasertib, this study suggests that we could make some brain cancers vulnerable to atezolizumab,” said Juanita Lopez, study leader, clinical researcher at ICR and consultant medical oncologist at The Royal Marsden NHS Foundation Trust.

“We believe that our findings open the door to the further development of what could become a game-changing treatment option for some patients with aggressive glioblastoma brain cancer. Patients with glioblastoma have very poor survival rates, and even fewer new treatment options coming through, so any advance in outcomes would be extremely welcome,” she added.