Response to COVID-19 Vaccines in Patients Receiving Intensified Post-ASCT Therapy with Daratumumab, Lenalidomide, Bortezomib (Dara-VR) Due to Ultra-High Risk (UHiR) Newly Diagnosed Myeloma (NDMM) or Primary Plasma Cell Leukemia (pPCL): Exploratory Analysis of the UK Optimum/Muknine Trial

Background: Successful vaccination against SARS-CoV2 is highly effective in preventing serious COVID-19 illness and is particularly recommended for at risk populations including patients with multiple myeloma (MM). However, there is uncertainty to which extent modern intensified therapies targeting plasma cell features might attenuate vaccination responses; some early vaccination recommendations for MM have proposed extended treatment breaks of several weeks to maximise vaccination success. Such an approach can be challenging in UHiR MM and pPCL, where maintaining treatment intensity is hallmark for preventing rapid relapse of the aggressive tumor. To address this uncertainty, we measured post-vaccination serological responses in patients treated uniformly with intensified Dara-VR consolidation and Dara-R maintenance post-ASCT for UHiR NDMM or pPCL in the UK OPTIMUM/MUKnine trial (NCT03188172).