Study Published in Nature Suggests immunoSEQ™ Assay May Be Used to Predict Response to anti-PD-1 Therapy for Melanoma

immunoSEQ™ Next Generation Sequencing Assay Confirms Presence of Active Immune Response in Responders Prior to Treatment

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Adaptive Biotechnologies Corp.

Nov 26, 2014, 01:10 ET

SEATTLE, Nov. 26, 2014 /PRNewswire/ -- Adaptive Biotechnologies, a pioneer in leveraging Next Generation Sequencing (NGS) to profile T- and B-cell receptors, reported today that the immunoSEQ Assay was able to help identify patients with metastatic melanoma who would be most likely to respond to treatment with pembrolizumab (an anti-PD-1 therapy), according to a study published in this week's issue of Nature.

The multi-parameter two-year study, led by Drs. Paul Tumeh and Antoni Ribas of the UCLA Jonsson Comprehensive Cancer Center, validated the hypothesis that an immune response depicted by a less diverse (more clonal) immune repertoire prior to treatment, does correlate with clinical response (P=0.004) to treatment with pembrolizumab, the first PD1 inhibitor to receive FDA approval earlier in 2014. In addition, more than ten times as many T-cell clones expanded after therapy in the responders than in those who progressed on treatment.

"Patients who respond to anti-PD1 therapy had their immune system ready to attack the cancer, but it was being held back by PD-1," said Ribas. "By releasing this break, the patients' immune system can mount an even stronger attack on the cancer anywhere in the body. The immunoSEQ Assay confirmed both the existing immune system readiness prior to treatment and the quantitative validation of the stronger presence of T-cells post-treatment in the responders."

In the study, Adaptive's immunoSEQ Assay was used to sequence the T cell repertoire within the tumor before treatment to assess characteristics of the adaptive immune response to the tumor that indicate a higher likelihood of response to pembrolizumab, and after treatment to detect differences in the resultant immune repertoire between responders and non-responders. Expression levels of PD-1/PDL-1 and presence of T-cell antigen receptors (TCRs) were hypothesized to differ between responders and non-responders both prior to and after treatment. In samples from 46 patients, using quantitative immunohistochemistry and quantitative multiplex immunofluourescence, the study reports that higher levels of PD-1/PDL-1 are more prevalent in responders, and high-density effector T cells can be found in the tumors in the response group, suggesting a specific immune response to the tumor.

Harlan Robins, founder of Adaptive Biotechnologies and study author, said, "Adaptive is honored to partake in this critical biomarker study with UCLA, and is committed to using our TCR sequencing assay to enhance our ability to predict responders to PD1 inhibitors and other targeted cancer immunotherapies that leverage the body's own ability to fight cancer. It appears to be a consistent finding that having an immune system that is ready to attack is key to response to many immunotherapies."

About Adaptive Biotechnologies
Adaptive Biotechnologies Corporation is a platform-based, diagnostic-driven company that leverages NGS to profile T-Cell and B-Cell Receptors. This breakthrough enables in-depth characterization of the adaptive immune system, which is the primary defense against cancer. By incorporating immunosequencing into clinical care, Adaptive can enhance the diagnosis, prognosis and monitoring of cancer patients.

About immunoSEQ^TMAdaptive helps researchers make discoveries in oncology, autoimmune disorders and infectious diseases by offering fee-for-service access to its proprietary immune profiling sequencing technology under the immunoSEQ^TMbrand name. The immunoSEQ^TM Kit for research use only is now available to facilitate the integration of immunosequencing into research centers. The immunoSEQ Assay is not for use in diagnostic procedures.

About clonoSEQ^TMAdaptive uses its proprietary immunosequencing platform to validate clinical diagnostics in cancer and other immune-mediated diseases. The company's first CLIA certified clinical application, the clonoSEQ^TMAssay, is used to monitor Minimal Residual Disease (MRD) in blood-based cancers. Improving the ability to accurately detect and track residual disease at a molecular level affords clinicians the potential to detect relapse earlier and improve patient care.

The company is currently validating the tilSEQ^TM Assay, a second novel oncology diagnostic to quantify the presence and clonality of Tumor Infiltrating Lymphocytes ("TILs") and to create a reliable measure of "immunocompetency" to predict or monitor response to cancer treatments that directly alter the host immune system.

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