Two new companion CDx approvals
Regulators cleared MI Cancer Seek as a companion diagnostic across tumor types and approved Myriad’s MyChoice CDx as the companion test for Zejula (niraparib) in ovarian cancer—adding to the surge of tumor‑agnostic and therapy‑linked molecular testing. Those approvals mean labs must be ready to support broader panels and specimen types, including cytology or scant samples that feed into precision care pathways. (onclive.com) (globenewswire.com)
MI Cancer Seek is the first FDA‑cleared CDx that runs whole‑exome and whole‑transcriptome sequencing together and reports alterations across 228 genes plus MSI and tumor mutational burden as part of its labeling. (carislifesciences.com) The assay requires total nucleic acid extracted from FFPE tumor tissue, specifies a minimum input of ~50 ng, and calls for ≥20% tumor cellularity and ≥25 mm² tumor area with manual microdissection when needed. (clpmag.com) Caris reports that MI Cancer Seek sequencing runs on qualified NovaSeq instruments and that peer‑reviewed validation showed 97–100% positive/negative percent agreement versus comparator FDA‑approved companion diagnostics across its claims. (oncotarget.com) Myriad announced FDA approval of the MyChoice CDx as the companion diagnostic for Zejula (niraparib) on March 17, 2026, with the regulatory submission supported by final PRIMA trial data used to stratify HRD status. (investor.myriad.com) MyChoice CDx determines HRD by a Genomic Instability Score composed of LOH, TAI and LST, detects BRCA1/2 sequence and large‑rearrangement variants from FFPE tumor DNA, is performed as a single‑site assay at Myriad, and Myriad states the test can identify roughly 34% more HRD patients than %LOH‑only methods. (s3.amazonaws.com) (myriad.com) Both approvals specify FFPE tumor tissue as the validated specimen type—MI via TNA from FFPE slides and MyChoice via FFPE DNA—so cytology workflows that produce paraffinized cell blocks (accepted in genomic profiling guidance) and strict tumor‑content assessment will be needed to meet MI’s 20%/25 mm² thresholds and Myriad’s collection/shipping requirements. (carislifesciences.com) (mdanderson.cloud-cme.com)
