The present invention relates to methods and kits for detecting in a sample the presence of a virus particle or a virus-like particle that has reverse transcriptase activity and methods for preparing a retroviral contaminant-free substance. An aspect of the present invention is a method for detecting the presence of a virus particle in a sample of a Virus-like Particle (VLP) drug substance comprising a step of performing PCR-based reverse transcriptase (PBRT) on a sample of the VLP drug substance that has been treated with a protease.

The invention relates to the use of a reverse-transcriptase inhibitor in the prevention or treatment of a degenerative disease.

The present invention relates to methods and kits for detecting in a sample the presence of a virus particle or a virus-like particle that has reverse transcriptase activity and methods for preparing a retroviral contaminant-free substance. An aspect of the present invention is a method for detecting the presence of a virus particle in a sample of a Virus-like Particle (VLP) drug substance comprising a step of performing PCR-based reverse transcriptase (PBRT) on a sample of the VLP drug substance that has been treated with a protease.

The invention relates to the use of a reverse-transcriptase inhibitor in the prevention or treatment of a degenerative disease.