MRI of a patient with a glioblastoma tumor. Photo: BSIP/UIG via Getty Images

An international team of scientists say they've developed a molecule that can target the two most common brain cancers, successfully slowing down tumor growth in a pre-clinical study on animals published in Nature Wednesday.

Why it matters: The targeted brain cancers — adults' glioblastoma and children's medulloblastoma — are aggressive cancers often fatal within 2 years (as seen when glioblastoma claimed the life of Sen. John McCain). This team hopes this new method, which successfully breaches the blood-brain barrier, may be an important step forward in finding an effective treatment.

Background: Glioblastoma and medulloblastoma tumors are often deep in the brain where it's difficult to surgically remove them. Immunotherapies are thought by many to offer great promise in treating the tumors, but they face many challenges, including safely breaching the blood-brain barrier.

The barrier offers important protection for the brain, but can keep out drugs that doctors want to send to the brain to trigger the body's own immune system to fight the cancer.

What they did: The team first determined the best way to breach the brain barrier by studying the mechanism used by another disease, multiple sclerosis, to get around the barrier.

  • Then, "using lessons learned from MS," they developed a molecule that can get around the barrier by attaching to certain cells of the barrier (known as ALCAM), study co-author Nabil Ahmed tells Axios.
  • The T-cells are engineered to bind to an antigen produced by the cancer (called HER2), allowing it to locate and attack the tumors.

What they found: In testing in mice, the molecule, known as HS-CD6, "robustly infiltrated brain cancers after intravenous injection and exhibited potent antitumor activity," the study states.

  • The therapy did not appear to be toxic, which is a common failing of immunotherapies, as the mice lived longer. In addition, the therapy appeared to only attack the tumor sites, the authors said.
"The HS molecule that can overcome this [blood-brain] obstacle is a first-in-class; no similar molecules have been previously described. ... I am quite excited about the possible advantage of this to patients with incurable brain cancers that could hopefully benefit from using this in the clinic."
— Nabil Ahmed, Baylor College of Medicine

Outside comment: Two experts not involved with the study say these results show promise, but are a first step towards a bigger goal.

"This study represents a major leap forward in our understanding of [trafficking T cells] to brain tumors... Engineering T cells to overcome mechanistic barriers to tumor infiltration, the authors demonstrate a marked increase in tumor-infiltrating lymphocytes and increased efficacy of a [CAR-T] cell therapy. This is an elegant study with exciting implications for therapy of these lethal cancers." 
— Michelle Monje-Deisseroth, associate professor of neurology, Stanford University
"This study lays out a viable strategy for immunotherapy in glioblastoma. But key challenges must be overcome before we can translate the discovery from mice to patients. For instance, ALCAM is expressed by a variety of cell types, including bone-marrow cells. More studies will be required."
— Michael Platten, of Heidelberg University, in a News and Views piece in Nature

What's next: Ahmed tells Axios they are currently working on securing approvals from regulatory bodies to test this on humans with hard-to-treat or incurable brain cancers.

Go deeper: Read the National Cancer Institute's in-depth look at challenges facing glioblastoma and immunotherapy.

Go deeper

Updated 2 hours ago - Politics & Policy

Coronavirus dashboard

Illustration: Eniola Odetunde/Axios

  1. Global: Total confirmed cases as of 6:30 a.m. ET: 30,199,007 — Total deaths: 946,490— Total recoveries: 20,544, 967Map
  2. U.S.: Total confirmed cases as of 6:30 a.m. ET: 6,675,593 — Total deaths: 197,644 — Total recoveries: 2,540,334 — Total tests: 90,710,730Map
  3. Politics: Former Pence aide says she plans to vote for Joe Biden, accusing Trump of costing lives in his coronavirus response.
  4. Health: Pew: 49% of Americans wouldn't get COVID-19 vaccine if available today Pandemic may cause cancer uptick The risks of moving too fast on a vaccine — COVID-19 racial disparities extend to health coverage losses.
  5. Business: Retail sales return to pre-coronavirus trend.
Mike Allen, author of AM
2 hours ago - Politics & Policy

Scoop: Mike Bloomberg's anti-chaos theory

CNN's Anderson Cooper questions Joe Biden last night at a drive-in town hall in Moosic, Pa., outside Scranton. Photo: CNN

Mike Bloomberg's $100 million Florida blitz begins today and will continue "wall to wall" in all 10 TV markets through Election Day, advisers tell me.

Why it matters: Bloomberg thinks that Joe Biden putting away Florida is the most feasible way to head off the national chaos we could have if the outcome of Trump v. Biden remained uncertain long after Election Day.

Biden's hardline Russia reset

Photo Illustration: Eniola Odetunde/Axios. Getty Images photos: Mark Reinstein

When he talks about Russia, Joe Biden has sounded like Ronald Reagan all summer, setting up a potential Day 1 confrontation with Russian President Vladimir Putin if Biden were to win.

Why it matters: Biden has promised a forceful response against Russia for both election interference and alleged bounty payments to target American troops in Afghanistan. But being tougher than President Trump could be the easy part. The risk is overdoing it and making diplomacy impossible.