Trial Finds Genetic Clue to Which Children May Benefit From a Targeted Cancer Therapy

New biomarker emerges from pediatric solid tumor trial

Researchers at the University of Birmingham have identified a biomarker that may help show which children are more likely to respond to a specific cancer therapy. The finding comes from a Phase I/II treatment arm within the eSMART trial, which examined a combination of low-dose irinotecan and a PARP inhibitor in children and adolescents with relapsed solid tumors.

The work focused on some of the most difficult pediatric cancers to treat after relapse, including Ewing sarcoma, osteosarcoma, neuroblastoma, rhabdomyosarcoma, nephroblastoma, medulloblastoma and choroid plexus carcinoma. According to the supplied source text, patients enrolled in the trial had already relapsed several times, and a cure was not expected.

How the study was structured

The trial recruited 70 patients, with 66 treated across four countries: the United Kingdom, France, the Netherlands and Spain. Of those patients, 36 had Ewing sarcoma and 34 had other tumor types, mainly sarcomas and central nervous system tumors.

Researchers wanted to answer two related questions. First, could the irinotecan and PARP inhibitor combination be tolerated and show activity in pediatric cancers? Second, were tumors with gene alterations linked to faulty DNA repair especially sensitive to the treatment?

What the researchers found

The study, published in Clinical Cancer Research, found that 12 patients benefited from the therapy. That benefit included either partial or complete tumor shrinkage or stable disease lasting more than six months. In a population of heavily pretreated patients, even that degree of disease control is notable.

The more important long-term result may be the biomarker signal. The source text reports that gene alterations were associated with response, giving researchers a potential indicator for selecting patients more precisely in future studies. That matters because PARP inhibitors are intended to exploit weaknesses in DNA repair, and the trial was designed in part to test whether that logic seen in laboratory work could translate into clinical benefit for children with Ewing sarcoma and related cancers.

Why the result matters

Relapsed pediatric solid tumors often leave families and clinicians with limited treatment options. The source text notes that cure rates can fall below 30% when these cancers spread or recur. That makes better patient selection especially valuable. A therapy that works only in a subset of patients can still be important if doctors can identify that subset early.

The trial also shows the value of combining early-stage treatment testing with biomarker discovery. Rather than asking only whether a regimen works in the broadest sense, the study also asked why some tumors respond while others do not. That approach can shape later-phase trials and reduce the guesswork around which patients should receive targeted combinations.

What comes next

The source material does not provide the full biomarker description in the visible text, but it does make clear that researchers uncovered a genomic indicator tied to response. That gives future pediatric oncology studies a more focused starting point. If the signal holds up in further research, it could help move treatment decisions away from trial-and-error and toward a more tailored model for children with relapsed solid tumors.

• The eSMART trial tested low-dose irinotecan plus a PARP inhibitor in relapsed pediatric solid tumors.
• Sixty-six patients were treated across four European countries.
• Twelve patients showed tumor shrinkage or stable disease lasting more than six months.
• Researchers identified a biomarker linked to response.

This article is based on reporting by Medical Xpress. Read the original article.