Achilles Therapeutics Presents Encouraging Phase I/IIa Update on Clonal Neoantigen Reactive T Cells in Advanced NSCLC and Melanoma at ESMO IO Congress 2022

On December 6, 2022 Achilles Therapeutics plc (NASDAQ: ACHL), a clinical-stage biopharmaceutical company developing AI-powered precision T cell therapies to treat solid tumors, reported an encouraging interim Phase I/IIa update on the use of clonal neoantigen reactive T cells (cNeT) from the CHIRON study in advanced unresectable or metastatic non-small cell lung cancer (NSCLC) and the THETIS study in recurrent or metastatic malignant melanoma at the ESMO (Free ESMO Whitepaper) Immuno-Oncology Congress 2022 (ESMO IO) (Press release, Achilles Therapeutics, DEC 6, 2022, View Source [SID1234625326]).

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"The early safety, tolerability, and durable clinical benefit in heavily pre-treated patients presented today are encouraging and illustrate the promising therapeutic potential of cNeT monotherapy. Further, the strength of our translational science platform was shown by our ability to track key elements of activity that correlated to cNeT presence," said Dr Iraj Ali, CEO of Achilles Therapeutics. "We look forward to providing further updates in 2023, including additional monotherapy data from CHIRON and THETIS, and initial THETIS combination data evaluating cNeT with a PD-1 checkpoint inhibitor."

"The partial response and stable disease observed with low doses of cNeT in this difficult to treat patient population are encouraging, and coupled with the well-tolerated safety profile, highlight a favorable therapeutic window to further dose escalate and help drive deeper, more durable responses," added Dr. Karl Peggs, Chief Medical Officer of Achilles Therapeutics. "We believe this is the first time a response in lung cancer has been demonstrated using a cell therapy with a low dose conditioning and IL-2 regimen, which importantly, could expand eligibility of this therapy to include patients with comorbidities or reduced fitness that may not be candidates for traditional TIL therapy."

Dr. Sergio Quezada, Chief Scientific Officer of Achilles Therapeutics added, "In addition to the durable clinical benefit, our translational science platform begins to deliver key mechanistic insights for our cNeT therapy that are not possible with a standard TIL product, including assessment of phenotypic markers as well as proliferative and cytolytic capacity of the tumor reactive cNeT component. By virtue of knowing the cNeT targets and being able to characterize and track specific cNeT in the product and in the blood of patients, we can monitor cNeT dose, markers of function and exhaustion, engraftment, activation, and other features related to the patient, product, and performance in vivo."

Early, encouraging proof-of-concept data support the potential of cNeT monotherapy to deliver durable clinical benefit
14 patients treated (8 NSCLC in CHIRON, 6 melanoma in THETIS) with median of two prior lines of therapy
Two additional patients dosed since ESMO (Free ESMO Whitepaper) IO cut-off: one in CHIRON and one in THETIS Cohort B (checkpoint combination)
Confirmed partial response and stable disease achieved with low doses of cNeT and reduced dose lymphodepletion and IL-2 in NSCLC
1 partial response (PR, 56% tumor reduction maintained at week 36) and 6 patients with stable disease (SD) with overall durable clinical benefit at 12 weeks in 71% of evaluable patients (5/7) with advanced NSCLC
cNeT driven anti-tumor activity in the partial responder is supported by T cell engraftment and cytokine profiles
Stable disease in 50% of evaluable patients (3/6) with melanoma
cNeT product characterization supports a polyfunctional active component
Encouraging early safety and tolerability profile for cNeT
Safety and tolerability observations of cNeT compare favorably to standard tumor infiltrating lymphocytes (TIL) due to less IL-2 related toxicity
Lymphopenia and neutropenia were the most common adverse events, which are principally associated with the conditioning regimen, and no dose limiting high-grade toxicities associated with IL-2 were reported
Reduced dose lymphodepletion and IL-2 may expand patient eligibility criteria to include those with greater co-morbidities
Robust translational science platform correlates cNeT to activity
cNeT display an activated and functional phenotype including markers associated with tissue migration and a transcriptional profile supporting proliferation and cytotoxic function
Effective lymphodepletion and subsequent immune reconstitution were observed in all patients despite lower doses of lymphodepleting agents
Functional activity of cNeT supported by the observation of peak expansion of cytokine-secreting cNeT 21 days post infusion, coinciding with a peak in IL-6, with detection of cNeT beyond 12 weeks by TCR analysis
Manufacturing process evolution continues to increase cNeT doses
78 million median cNeT dose of first Process 2 products (n=3, CHIRON), with median 17% reactivity
47 million median cNeT dose across patient products since last update vs. 14 million in the first eight patients reported at SITC (Free SITC Whitepaper) 2021

Webcast and Conference Call Details

The company will host a live webcast and conference call today, Tuesday, December 6, 2022 at 8:00am ET / 1:00pm UK to review the interim update presented at ESMO (Free ESMO Whitepaper) IO. The live conference call will be webcast in listen-only mode and a slide presentation will be made available in the Events & Presentations section of the Company website at View Source For listeners who wish to participate in the question-and-answer session via telephone, please pre-register here.