EGFR mutation detection in ctDNA from NSCLC patient plasma: A cross-platform comparison of leading technologies to support the clinical development of AZD9291

OBJECTIVES

To assess the ability of different technology platforms to detect epidermal growth factor receptor (EGFR) mutations, including T790M, from circulating tumor DNA (ctDNA) in advanced non-small cell lung cancer (NSCLC) patients.

MATERIALS AND METHODS

A comparison of multiple platforms for detecting EGFR mutations in plasma ctDNA was undertaken. Plasma samples were collected from patients entering the ongoing AURA trial (NCT01802632), investigating the safety, tolerability, and efficacy of AZD9291 in patients with EGFR-sensitizing mutation-positive NSCLC. Plasma was collected prior to AZD9291 dosing but following clinical progression on a previous EGFR-tyrosine kinase inhibitor (TKI). Extracted ctDNA was analyzed using two non-digital platforms (cobas(®) EGFR Mutation Test and therascreen™ EGFR amplification refractory mutation system assay) and two digital platforms (Droplet Digital™ PCR and BEAMing digital PCR [dPCR]).

RESULTS

Preliminary assessment (38 samples) was conducted using all four platforms. For EGFR-TKI-sensitizing mutations, high sensitivity (78-100%) and specificity (93-100%) were observed using tissue as a non-reference standard. For the T790M mutation, the digital platforms outperformed the non-digital platforms. Subsequent assessment using 72 additional baseline plasma samples was conducted using the cobas(®) EGFR Mutation Test and BEAMing dPCR. The two platforms demonstrated high sensitivity (82-87%) and specificity (97%) for EGFR-sensitizing mutations. For the T790M mutation, the sensitivity and specificity were 73% and 67%, respectively, with the cobas(®) EGFR Mutation Test, and 81% and 58%, respectively, with BEAMing dPCR. Concordance between the platforms was >90%, showing that multiple platforms are capable of sensitive and specific detection of EGFR-TKI-sensitizing mutations from NSCLC patient plasma.

CONCLUSION

The cobas(®) EGFR Mutation Test and BEAMing dPCR demonstrate a high sensitivity for T790M mutation detection. Genomic heterogeneity of T790M-mediated resistance may explain the reduced specificity observed with plasma-based detection of T790M mutations versus tissue. These data support the use of both platforms in the AZD9291 clinical development program.

Clinical relevance of dissolution testing in quality by design

Quality by design (QbD) has recently been introduced in pharmaceutical product development in a regulatory context and the process of implementing such concepts in the drug approval process is presently on-going. This has the potential to allow for a more flexible regulatory approach based on understanding and optimisation of how design of a product and its manufacturing process may affect product quality. Thus, adding restrictions to manufacturing beyond what can be motivated by clinical quality brings no benefits but only additional costs. This leads to a challenge for biopharmaceutical scientists to link clinical product performance to critical manufacturing attributes. In vitro dissolution testing is clearly a key tool for this purpose and the present bioequivalence guidelines and biopharmaceutical classification system (BCS) provides a platform for regulatory applications of in vitro dissolution as a marker for consistency in clinical outcomes. However, the application of these concepts might need to be further developed in the context of QbD to take advantage of the higher level of understanding that is implied and displayed in regulatory documentation utilising QbD concepts. Aspects that should be considered include identification of rate limiting steps in the absorption process that can be linked to pharmacokinetic variables and used for prediction of bioavailability variables, in vivo relevance of in vitro dissolution test conditions and performance/interpretation of specific bioavailability studies on critical formulation/process variables. This article will give some examples and suggestions how clinical relevance of dissolution testing can be achieved in the context of QbD derived from a specific case study for a BCS II compound.

A collaborative effort to enhance HIV/STI screening in five county jails

Funding from the Centers for Disease Control and Prevention and the Health Resources and Services Administration (HRSA) supports collaborations among health departments (CA, FL, GA, IL, MA, NJ, NY), correctional facilities, and community-based organizations to improve services to HIV-infected inmates, particularly as they return to the community. Additionally, HRSA funded the Evaluation and Program Support Center to guide the implementation of a multi-site evaluation of the Corrections Demonstration Project (CDP). The authors present a model approach to the problem of health disparities that involves forging collaborations among federal funders, public health departments, corrections, community-based organizations, and the scientific research community. They show how such collaboration can promote the reduction of racial/ethnic health disparities. The authors examined disease screening activities in five county jails. Screening for HIV and other sexually transmitted infections (STIs) was offered during the medical intake process and during HIV prevention education sessions. One thousand twenty inmates were tested from July 1, 2000, through December 31, 2000, for HIV infection, and 171 (17%) positive cases were identified (largely due to confirmatory testing). Of HIV-positive inmates, 83 (49%) were started on antiretroviral treatment. Additionally, 2,160 were tested for chlamydia, 1,327 for gonorrhea (largely duplicated), and 937 (duplicated) for syphilis. Across all three STIs, 78% of those who tested positive were treated. The remaining 22% either declined treatment, were released prior to notification of results, or were released prior to starting treatment. The CDP offers a model approach for addressing the poor health status of members of racial/ethnic minority groups by developing collaborations between corrections, public health departments, community-based organizations, and academia. An outgrowth of this collaboration is the improved capacity to detect and treat disease, which is a necessary component of a comprehensive HIV risk reduction program.

Surgical correction of scoliosis in Rett syndrome: cord monitoring and complications

AIM

Rett syndrome is a progressive neurodevelopmental disorder that predominantly affects females and is associated with a high incidence of scoliosis and epilepsy. There is scant published work about intraoperative spinal cord monitoring in these patients and little more regarding the rate of perioperative complications. We investigated our institutions' experience with both.

METHODS

We retrospectively reviewed the records of 11 patients with Rett syndrome who underwent surgical correction of scoliosis at our institution between 2004 and 2010.

RESULTS

Eleven patients underwent successful correction of their scoliosis at an average age of 12. Eight of the patients suffered one or more significant complications. The average curve was corrected from 71° to 27°. Successful spinal cord monitoring was achieved in eight of the nine patients where it was attempted. No patient suffered any neurological complications. Average inpatient stay was 18.2 days.

CONCLUSION

Scoliosis surgery in patients with Rett syndrome carries a very high rate of complications and an average hospital stay approaching 3 weeks. Both caregivers and surgeons should be aware of this when planning any intervention. These patients frequently have useful lower limb function and spinal cord monitoring is a valid tool to aid in its preservation. We would suggest aggressive optimisation of these patients prior to surgery, with an emphasis on nutrition.

A collaborative effort to enhance HIV/STI screening in five county jails

Funding from the Centers for Disease Control and Prevention and the Health Resources and Services Administration (HRSA) supports collaborations among health departments (CA, FL, GA, IL, MA, NJ, NY), correctional facilities, and community-based organizations to improve services to HIV-infected inmates, particularly as they return to the community. Additionally, HRSA funded the Evaluation and Program Support Center to guide the implementation of a multi-site evaluation of the Corrections Demonstration Project (CDP). The authors present a model approach to the problem of health disparities that involves forging collaborations among federal funders, public health departments, corrections, community-based organizations, and the scientific research community. They show how such collaboration can promote the reduction of racial/ethnic health disparities. The authors examined disease screening activities in five county jails. Screening for HIV and other sexually transmitted infections (STIs) was offered during the medical intake process and during HIV prevention education sessions. One thousand twenty inmates were tested from July 1, 2000, through December 31, 2000, for HIV infection, and 171 (17%) positive cases were identified (largely due to confirmatory testing). Of HIV-positive inmates, 83 (49%) were started on antiretroviral treatment. Additionally, 2,160 were tested for chlamydia, 1,327 for gonorrhea (largely duplicated), and 937 (duplicated) for syphilis. Across all three STIs, 78% of those who tested positive were treated. The remaining 22% either declined treatment, were released prior to notification of results, or were released prior to starting treatment. The CDP offers a model approach for addressing the poor health status of members of racial/ethnic minority groups by developing collaborations between corrections, public health departments, community-based organizations, and academia. An outgrowth of this collaboration is the improved capacity to detect and treat disease, which is a necessary component of a comprehensive HIV risk reduction program.

Dentists, allied professionals with AIDS

With about a million people in the United States infected with HIV, health care providers increasingly will encounter infected patients. To minimize transmission in the workplace, recommended infection control measures, including universal precautions, should be followed strictly.

DS-7300 (B7-H3 DXd-ADC) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC): A subgroup analysis of a phase 1/2 multicenter study

87

Background: DS-7300 is an antibody drug conjugate with an exatecan derivative payload that targets B7-H3, which is overexpressed in various cancers. Initial findings from an ongoing phase 1/2 dose escalation study for advanced solid tumors, and dose-expansion studies in esophageal squamous cell carcinoma and mCRPC (NCT04145622) showed that DS-7300 was generally well tolerated with early signs of clinical activity (ESMO 2021, abstract 513O). Here, we present preliminary results from the mCRPC pt subset. Methods: This study consisted of 2 parts: dose- escalation (part 1) and expansion (part 2). Part 1 assessed the safety and tolerability of DS-7300 with doses ranging from 0.8 to 16 mg/kg. A dose of 12 mg/kg was selected for part 2. Part 2 assessed safety and prospective efficacy of DS-7300 in the selected tumor types, including mCRPC. DS-7300 was administered intravenously every 3 weeks in parts 1 and 2. Results: At data cutoff (August 8, 2021), 29 pts with mCRPC from the US and Japan were enrolled in parts 1 (n = 24) and 2 (n = 5). Pts enrolled in this study were heavily pretreated, with a median of 6.0 (range, 2-10) and 5.0 (range, 3-10) prior lines of therapy in parts 1 and 2, respectively. Baseline B7-H3 expression was highly prevalent in the study population. Enrolled pts were 44 to 82 years of age (median, 68.0 years) and had an ECOG performance status ≤1. Treatment-emergent adverse events (TEAEs) occurred in 29 pts (100.0%) in parts 1 and 2, with 7 pts (21.4%) with TEAEs leading to dose interruption, 2 pts (6.9%) with TEAEs leading to dose reduction, and no pts with TEAEs associated with drug discontinuation. The most common (≥20%) all-grade (Gr) TEAEs were nausea (65.5%), infusion-related reactions (IRRs; 34.5%), fatigue (34.5%), chills (31.0%), vomiting (31.0%), anemia (27.6%), diarrhea (27.6%), and dehydration (20.7%). Gr ≥3 TEAEs occurred in 10 pts (34.5%); the most common was anemia (17.2%). There were no Gr ≥3 treatment-related serious TEAEs (SAEs) reported. All IRR cases were Gr 1/2 and manageable with supportive care. No ILD/pneumonitis cases were reported. RECIST responses were observed in pts treated with DS-7300 between 6.4- and 16.0-mg/kg doses, including 6 partial responses (4 confirmed) and 15 stable diseases. The median duration of treatment was 13.9 weeks (range, 3-40 weeks) in part 1 and 6.0 weeks (range, 3-9.14 weeks) in part 2. At data cutoff, 8 pts (66.7%) in the 12.0-mg/kg group in part 1 and 4 pts (80.0%) in part 2 were ongoing treatment. Moreover, preliminary data indicate improvements in prostate-specific antigen (PSA) and bone metastases. Conclusions: DS-7300 was well tolerated with an acceptable safety profile in pts with mCRPC. The preliminary safety and efficacy data are encouraging and warrant further investigation. Clinical trial information: NCT04145622.

Targeting T regulatory (Treg) cells in immunotherapy-resistant cancers

Primary or secondary (i.e., acquired) resistance is a common occurrence in cancer patients and is often associated with high numbers of T regulatory (Treg) cells (CD4+CD25+FOXP3+). The approval of ipilimumab and the development of similar pharmacological agents targeting cell surface proteins on Treg cells demonstrates that such intervention may overcome resistance in cancer patients. Hence, the clinical development and subsequent approval of Cytotoxic T Lymphocyte Antigen-4 (CTLA-4) targeting agents can serve as a prototype for similar agents. Such new agents aspire to be highly specific and have a reduced toxicity profile while increasing effector T cell function or effector T/T regulatory (Teff/Treg) ratio. While clinical development with large molecules has shown the greatest advancement, small molecule inhibitors that target immunomodulation are increasingly entering early clinical investigation. These new small molecule inhibitors often target specific intracellular signaling pathways [e.g., phosphoinositide-3-kinase delta (PI3K-δ)] that play an important role in regulating the function of Treg cells. This review will summarize the lessons currently applied to develop novel clinical agents that target Treg cells.