FDA Approves Oncomine Dx Target Test Companion Diagnostic for Pralsetinib in RET+ NSCLC


The FDA has approved the Oncomine Dx Target Test as a companion diagnostic to identify patients with RET fusion–positive non¬–small lung cancer who are candidates to receive the recently approved targeted therapy pralsetinib.

The FDA has approved the Oncomine Dx Target Test as a companion diagnostic to identify patients with RET fusion–positive non­–small lung cancer who are candidates to receive the recently approved targeted therapy pralsetinib (Gavreto), according to Thermo Fisher Scientific, the developer of the test.1

The test previously received regulatory approval in 2017 for biomarkers linked with 3 FDA-approved therapies in NSCLC; it was the first targeted next-generation sequencing (NGS)­–based companion diagnostic to be approved for this indication. Now, the diagnostic is the first to obtain FDA approval for a therapy targeting RET fusion–positive NSCLC, according to a press release.

“It is our goal to provide [patients with] cancer globally greater access to highly actionable, NGS-based multi-biomarker testing in important indications like NSCLC as recommended by multiple guidelines. [The] approval underscores this endeavor,” Garret Hampton, president of Clinical Next-Generation Sequencing and Oncology at Thermo Fisher Scientific, stated in a press release. “Our tests are designed to require the least amount of sample of any NGS IVD test on the market, leading to more patients benefiting from the test and put on the right therapy up front.”

The Oncomine Dx Target Test is a qualitative in vitro diagnostic assay that utilizes targeted high-throughput, parallel-sequencing technology to identify sequence variations in 23 genes within DNA and RNA extracted from FFPE tissue samples collected from patients with NSCLC using the Ion PGM Dx System.2

The test features integrated bioinformatic that allows for the production of a results report after the test is performed. Because it is based on AmpliSeq technology, it requires 10 ng per pool, 20 ng total, of nucleic acid. Additionally, the assay is provided as part of a complete kit for workflow.

On September 4, 2020, The FDA approved pralsetinib for the treatment of adult patients with metastatic RET fusion­–positive NSCLC based on data from the phase 1/2 ARROW trial (NCT03037385), which showed that the agent led to durable clinical responses in those with this disease who had or had not received prior treatment, irrespective of RET fusion partner or central nervous system involvement.3

Specifically, pralsetinib elicited an overall response rate (ORR) of 57% (95% CI, 46%-68%) and a complete response (CR) rate of 5.7% in 87 participants with NSCLC who had previously received platinum-based chemotherapy. Additionally, the median duration of response (DOR) had not yet been reached with the agent (95% CI, 15.2­­–not reached). Of 27 treatment-naïve patients, the ORR experienced with pralsetinib was even higher, at 70% (95% CI, 50%-86%) with a CR rate of 11%.

Regarding safety, the adverse effects most commonly experienced by patients who received the treatment included fatigue, constipation, musculoskeletal pain, and increased blood pressure.

In the open-label, first-in-human trial, investigators set out to examine the safety, tolerability, and efficacy of oral pralsetinib in patients with RET fusion–positive NSCLC, RET-mutant medullary thyroid cancer, RET fusion–positive thyroid cancer, and other RET-altered solid tumors.

The trial was comprised of 2 parts: a dose-escalation phase, which has been completed, and an expansion phase in which a total of 400 patients have received the agent at a once-daily dose of 400 mg. The primary end points of the phase 2 portion of the trial include centrally reviewed ORR per RECIST v1.1 criteria and safety.

Results from a basket-study population of all-comers with RET alterations were presented during the 2020 ASCO Virtual Scientific Program.4 This subgroup was comprised of 27 patients; 13 participants had thyroid cancer and 14 had other solid tumors.

In 11 evaluable patients with RET fusion–positive thyroid cancer, the ORR reported with pralsetinib was 91% (95% CI, 59%-100%); this was comprised entirely of partial responses (PRs). One patient had stable disease (SD), translating to a disease control rate was 100% (95% CI, 72%-100%). The ORR was 50% in 12 patients with RET fusion–positive solid tumors (95% CI, 21%-79%); these were all PRs, as well. SD was also achieved by 5 participants, translating to a DCR of 92% (95% CI, 62%-100%). Notably, all responses were observed regardless of fusion partner in heavily pretreated patients.

On the same day that the agent was approved for patients with RET fusion–positive NSCLC, the FDA granted pralsetinib a priority review for the treatment of patients with advanced or metastatic RET fusion–positive thyroid cancer.

The Oncomine Dx Target Test was also approved by Japan’s Ministry of Health, Labour and Welfare (MHLW) as a companion diagnostic for EGFR, ALK, ROS1, and BRAF biomarkers linked with 12 targeted therapies for patients with NSCLC.

Following a CDx agreement that Thermo Fisher signed earlier this year with Chugai Pharmaceutical Co, Ltd, a member of the Roche Group, the MHLW also approved the assay to evaluate patients who could be candidates for treatment with entrectinib (Rozlytrek). The test is approved and reimbursed by government and commercial insurers in the United States, Europe, Japan, South Korea, and Israel.

“As part of our commitment, we remain focused on developing our next-generation companion diagnostic by taking Oncomine Precision Assay and Genexus System through the FDA’s approval process,” Hampton added.


  1. FDA approves first NGS-based companion diagnostic forRET fusion-positive non-small cell lung cancer. News release. ThermoFisher Scientific. September 8, 2020. Accessed September 11, 2020. https://bit.ly/3imXmkY.
  2. Oncomine Dx Target Test. ThermoFisher Scientific. Accessed September 11, 2020. https://bit.ly/32kjNS2.
  3. Genentech announces FDA approval of Gavreto (pralsetinib) for the treatment of adults with metastatic RET fusion-positive non-small cell lung cancer. News release. Genentech. September 11, 2020. Accessed September 4, 2020. https://bwnews.pr/2QWJ4LM.
  4. Subbiah V, Hu MI, Gainor JF, et al. Clinical activity of the RET inhibitor pralsetinib (BLU-667) in patients with RET fusion+ solid tumors. J Clin Oncol. 2020;38(suppl):109. doi:10.1200/JCO.2020.38.15_suppl.109
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