The FDA has approved Myriad Genetics’ myChoice CDx as a companion diagnostic for Zejula (niraparib) to identify women with advanced ovarian cancer in the late-line treatment setting—an indication added by the agency to its approved uses for the poly ADP-ribose polymerase (PARP) inhibitor marketed by GlaxoSmithKline (GSK).
The FDA’s approval for myChoice CDx was concurrent with the agency authorizing Zejula as a treatment for advanced ovarian, fallopian tube, or primary peritoneal cancer patients, who have been treated with three or more prior chemotherapy regimens and whose cancer is associated with homologous recombination deficiency (HRD) positive status.
That status is based on defined by either a deleterious or suspected deleterious BRCA mutation; or genomic instability and who have progressed more than six months after response to the last platinum-based chemotherapy.
Despite high response rates to platinum-based chemotherapy in the frontline, Myriad noted, approximately 85% of patients will experience disease recurrence. Once the disease recurs, it is considered incurable with time to each future recurrence getting shorter. The proportion of patients achieving an overall response is typically less than 10% when treated with chemotherapy.
According to Myriad, myChoice CDx is the first and only tumor test designed to determine homologous recombination deficiency status by detecting BRCA1 and BRCA2 (sequencing and large rearrangement) variants with comprehensive assessment of genomic instability using three biomarkers: loss of heterozygosity, telomeric allelic imbalance and large-scale state transitions.
“Today’s approval marks a historic milestone for the myChoice CDx test after more than 10 years of development and demonstrates Myriad’s commitment to pioneering science and collaboration with pharmaceutical partners in order to accelerate precision therapies for people with cancer,” Myriad CSO Jerry Lanchbury, Ph.D., said in a statement.
The FDA’s latest approval for Zejula marks the first time that a PARP inhibitor has been approved for use in patients beyond those with a BRCA-positive (BRCA+) mutation as monotherapy in the late-line treatment setting.
“Women with advanced ovarian cancer who have had multiple rounds of chemotherapy have limited treatment options and today’s approval offers new hope,” added Nicole Lambert, president of Myriad Oncology. “We look forward to working with the medical community to make the myChoice CDx test widely accessible and in helping clinicians determine whether their patients are eligible for treatment with Zejula.”
GSK won approval for Zejula’s new indication based on the Phase II QUADRA trial (NCT02354586), the largest clinical trial of a PARP inhibitor in women who received three or more treatments for advanced ovarian cancer. The trial enrolled a broad patient population including women with BRCA+ platinum-sensitive, resistant and refractory disease as well as women with HRD+ platinum-sensitive disease.
Clinically meaningful and durable benefit was demonstrated in the FDA-indicated patient population with an objective response rate (ORR) of 24%. A median duration of response of 8.3 months was observed.