Optimal Biological Dose Research Articles

Statistical operating characteristics of current early phase dose finding designs with toxicity and efficacy in oncology.

Traditional phase I dose finding cancer clinical trial designs aim to determine the maximum tolerated dose (MTD) of the investigational cytotoxic agent based on a single toxicity outcome, assuming a monotone dose-response relationship. However, this assumption might not always hold for newly emerging therapies such as immuno-oncology therapies and molecularly targeted therapies, making conventional dose finding trial designs based on toxicity no longer appropriate. To tackle this issue, numerous early-phase dose finding clinical trial designs have been developed to identify the optimal biological dose (OBD), which takes both toxicity and efficacy outcomes into account. In this article, we review the current model-assisted dose finding designs, BOIN-ET, BOIN12, UBI, TEPI-2, PRINTE, STEIN, and uTPI to identify the OBD and compare their operating characteristics. Extensive simulation studies and a case study using a CAR T-cell therapy phase I trial have been conducted to compare the performance of the aforementioned designs under different possible dose-response relationship scenarios. The simulation results demonstrate that the performance of different designs varies depending on the particular dose-response relationship and the specific metric considered. Based on our simulation results and practical considerations, STEIN, PRINTE, and BOIN12 outperform the other designs from different perspectives.

PKBOIN-12: A Bayesian Optimal Interval Phase I/II Design Incorporating Pharmacokinetics Outcomes to Find the Optimal Biological Dose.

Immunotherapies and targeted therapies have gained popularity due to their promising therapeutic effects across multiple treatment areas. The focus of early phase dose-finding clinical trials has shifted from finding the maximum tolerated dose (MTD) to identifying the optimal biological dose (OBD), which aims to balance the toxicity and efficacy outcomes, thus optimizing the risk-benefit trade-off. These trials often collect multiple pharmacokinetics (PK) outcomes to assess drug exposure, which has shown correlations with toxicity and efficacy outcomes but has not been utilized in the current dose-finding designs for OBD selection. Moreover, PK outcomes are usually available within days after initial treatment, much faster than toxicity and efficacy outcomes. To bridge this gap, we introduce the innovative model-assisted PKBOIN-12 design, which enhances BOIN12 by integrating PK information into both the dose-finding algorithm and the final OBD determination process. We further extend PKBOIN-12 to TITE-PKBOIN-12 to address the challenges of late-onset toxicity and efficacy outcomes. Simulation results demonstrate that PKBOIN-12 more effectively identifies the OBD and allocates a greater number of patients to it than BOIN12. Additionally, PKBOIN-12 decreases the probability of selecting inefficacious doses as the OBD by excluding those with low drug exposure. Comprehensive simulation studies and sensitivity analysis confirm the robustness of both PKBOIN-12 and TITE-PKBOIN-12 in various scenarios.

Phase I/II Design for Selecting Subgroup-Specific Optimal Biological Doses for Prespecified Subgroups.

We propose a phase I/II trial design to support dose-finding when the optimal biological dose (OBD) may differ in two prespecified patient subgroups. The proposed design uses a utility function to quantify efficacy-toxicity trade-offs, and a Bayesian model with spike and slab prior distributions for the subgroup effect on toxicity and efficacy to guide dosing and to facilitate identifying either subgroup-specific OBDs or a common OBD depending on the resulting trial data. In a simulation study, we find the proposed design performs nearly as well as a design that ignores subgroups when the dose-toxicity and dose-efficacy relationships are the same in both subgroups, and nearly as well as a design with independent dose-finding within each subgroup when these relationships differ across subgroups. In other words, the proposed adaptive design performs similarly to the design that would be chosen if investigators possessed foreknowledge about whether the dose-toxicity and/or dose-efficacy relationship differs across two prespecified subgroups. Thus, the proposed design may be effective for OBD selection when uncertainty exists about whether the OBD differs in two prespecified subgroups.

ROMI: a randomized two-stage basket trial design to optimize doses for multiple indications.

Optimizing doses for multiple indications is challenging. The pooled approach of finding a single optimal biological dose (OBD) for all indications ignores that dose-response or dose-toxicity curves may differ between indications, resulting in varying OBDs. Conversely, indication-specific dose optimization often requires a large sample size. To address this challenge, we propose a Randomized two-stage basket trial design that Optimizes doses in Multiple Indications (ROMI). In stage 1, for each indication, response and toxicity are evaluated for a high dose, which may be a previously obtained maximum tolerated dose, with a rule that stops accrual to indications where the high dose is unsafe or ineffective. Indications not terminated proceed to stage 2, where patients are randomized between the high dose and a specified lower dose. A latent-cluster Bayesian hierarchical model is employed to borrow information between indications, while considering the potential heterogeneity of OBD across indications. Indication-specific utilities are used to quantify response-toxicity trade-offs. At the end of stage 2, for each indication with at least one acceptable dose, the dose with highest posterior mean utility is selected as optimal. Two versions of ROMI are presented, one using only stage 2 data for dose optimization and the other optimizing doses using data from both stages. Simulations show that both versions have desirable operating characteristics compared to designs that either ignore indications or optimize dose independently for each indication.

U-MET: Utility-Based Dose Optimization Approach for Multiple-Dose Randomized Trial Designs

The advent of dose optimization has led to a paradigm shift in oncology clinical trials to find the optimal biologic dose (OBD). Phase 1/2 trials with randomized doses can facilitate additional investigation of the identified OBD in a targeted population by incorporating safety and efficacy data. We propose to compare randomized doses by extending the Bayesian optimal interval phase 1/2 (BOIN12) approach, an OBD-finding design in which a utility is used to account for risk-benefit tradeoffs. Specifically, we used the BOIN12 standardized mean utilities in a hypothesis testing framework, in which frequentist and Bayesian inference were evaluated to compare the standardized mean utilities across doses and identify the OBD. We performed simulation studies and a hypothetical oncology study to compare the proposed BOIN12 utility-based extension (U-MET) design with an empirical design. The results demonstrated that the U-MET design has satisfactory operating characteristics for selecting the OBD. We recommend using the U-MET design as the primary dose comparison approach, or alternatively as supportive evidence, for optimal dose selection.

A Bayesian latent-subgroup platform design for dose optimization.

The US Food and Drug Administration launched Project Optimus to reform the dose optimization and dose selection paradigm in oncology drug development, calling for the paradigm shift from finding the maximum tolerated dose to the identification of optimal biological dose (OBD). Motivated by a real-world drug development program, we propose a master-protocol-based platform trial design to simultaneously identify OBDs of a new drug, combined with standards of care or other novel agents, in multiple indications. We propose a Bayesian latent subgroup model to accommodate the treatment heterogeneity across indications, and employ Bayesian hierarchical models to borrow information within subgroups. At each interim analysis, we update the subgroup membership and dose-toxicity and -efficacy estimates, as well as the estimate of the utility for risk-benefit tradeoff, based on the observed data across treatment arms to inform the arm-specific decision of dose escalation and de-escalation and identify the OBD for each arm of a combination partner and an indication. The simulation study shows that the proposed design has desirable operating characteristics, providing a highly flexible and efficient way for dose optimization. The design has great potential to shorten the drug development timeline, save costs by reducing overlapping infrastructure, and speed up regulatory approval.

Pharmacometrics-Enabled DOse OPtimization (PEDOOP) for seamless phase I-II trials in oncology

ABSTRACT We consider a dose-optimization design for a first-in-human oncology trial that aims to identify a suitable dose for late-phase drug development. The proposed approach, called the Pharmacometrics-Enabled DOse OPtimization (PEDOOP) design, incorporates observed patient-level pharmacokinetics (PK) measurements and latent pharmacodynamics (PD) information for trial decision-making and dose optimization. PEDOOP consists of two seamless phases. In phase I, patient-level time-course drug concentrations, derived PD effects, and the toxicity outcomes from patients are integrated into a statistical model to estimate the dose-toxicity response. A simple dose-finding design guides dose escalation in phase I. At the end of the phase I dose finding, a graduation rule is used to assess the safety and efficacy of all the doses and select those with promising efficacy and acceptable safety for a randomized comparison against a control arm in phase II. In phase II, patients are randomized to the selected doses based on a fixed or adaptive randomization ratio. At the end of phase II, an optimal biological dose (OBD) is selected for late-phase development. We conduct simulation studies to assess the PEDOOP design in comparison to an existing seamless design that also combines phases I and II in a single trial.

REDOMA: Bayesian random-effects dose-optimization meta-analysis using spike-and-slab priors.

The rise of cutting-edge precision cancer treatments has led to a growing significance of the optimal biological dose (OBD) in modern oncology trials. These trials now prioritize the consideration of both toxicity and efficacy simultaneously when determining the most desirable dosage for treatment. Traditional approaches in early-phase oncology trials have conventionally relied on the assumption of a monotone relationship between treatment efficacy and dosage. However, this assumption may not hold valid for novel oncology therapies. In reality, the dose-efficacy curve of such treatments may reach a plateau at a specific dose, posing challenges for conventional methods in accurately identifying the OBD. Furthermore, achieving reliable identification of the OBD is typically not possible based on a single small-sample trial. With data from multiple phase I and phase I/II trials, we propose a novel Bayesian random-effects dose-optimization meta-analysis (REDOMA) approach to identify the OBD by synthesizing toxicity and efficacy data from each trial. The REDOMA method can address trials with heterogeneous characteristics. We adopt a curve-free approach based on a Gamma process prior to model the average dose-toxicity relationship. In addition, we utilize a Bayesian model selection framework that uses the spike-and-slab prior as an automatic variable selection technique to eliminate monotonic constraints on the dose-efficacy curve. The good performance of the REDOMA method is confirmed by extensive simulation studies.

AIPAC-003: A randomized, double-blind, placebo-controlled phase 3 trial testing eftilagimod alpha (soluble LAG-3) in patients with HER2-neg/low metastatic breast cancer receiving paclitaxel, following an open-label dose optimization.

TPS1125 Background: Eftilagimod alpha (efti), a soluble LAG-3 protein, acts as an MHC class II agonist that enhances immunity by mediating antigen presenting cell and CD8 T-cell activation. Data from a randomized, phase 2b trial of efti plus paclitaxel compared to placebo plus paclitaxel in patients (pts) with HR+ HER2– metastatic breast cancer (MBC) (AIPAC; NCT02614833) showed sustained pharmacodynamic activity that was linked to improved overall survival (OS) in the efti arm. AIPAC-003 is a randomized, double-blind, placebo-controlled phase 3 trial testing efti plus paclitaxel in HER2-neg/low MBC pts, following an initial open-label dose optimization lead-in (DOL) component to determine the optimal biological dose (OBD) of efti in this combination. Methods: The DOL phase will determine the OBD of efti prior to start of the P3 part of the study. Enrolment for the DOL began in November 2023 with the aim to recruit 66 pts. Primary objectives in the DOL are: safety and tolerability of 90 mg vs 30 mg efti and defining the OBD of efti in combination with weekly paclitaxel. Determination of the OBD will be based on the totality of safety and tolerability data together with overall response rate (ORR) and pharmacodynamic marker (CD8+ T cells, absolute lymphocyte count) data. Secondary objectives in the DOL include efficacy, QoL and PK profile always of 30 mg efti vs. 90 mg on top of weekly paclitaxel. In the Phase 3 component pts will be randomized to receive either paclitaxel + efti or paclitaxel + placebo in a double-blinded fashion. The primary endpoint (EP) for the proposed Phase 3 is OS and the exact patient population will be defined after determination of the OBD. Key secondary EPs include progression free survival and ORR by RECIST 1.1, quality of life and safety. Pts will receive paclitaxel (80 mg/m2 I.V. on D1, 8 and 15 in a 4-week cycle), followed by efti or placebo (DOL: 30 or 90 mg efti; Phase 3: OBD of efti or placebo) S.C. on D1 and 15 in a 4-week cycle for up to 12 months. Imaging is done every 8 weeks and assessed by the investigator. in the DOL blood samples are taken from 0 to 96 hours in cycle 1 and 4 to determine PK / PD profiles. PK / PD parameters are assessed by a central lab. Key inclusion criteria: Pts with either a) HR+ and HER2-neg/low and endocrine therapy-resistant MBC or b) TNBC not eligible for anti-PD-1-based therapy. Pts must have measurable disease, ECOG PS 0-1 and no prior chemotherapy for metastatic disease. Key exclusion criteria: Pts if HR+ who are not considered endocrine resistant and/or have received < 1 line of therapy in the metastatic setting. Pts who are considered TNBC and are eligible for anti-PD-(L)1 containing therapy. Clinical trial information: NCT05747794 .

A first-in-human study of CRISPR/Cas9-engineered tumor infiltrating lymphocytes (TILs) product GT316 as monotherapy in advanced solid tumors.

2549 Background: A next-generation TIL product GT316 was engineered with CRISPR/Cas9 to genetically disrupt two key immunoregulatory targets identified from a genome-wide CRISPR screening platform and demonstrated significantly enhanced anti-tumor efficacy and persistence in pre-clinical animal studies with ameliorated TIL exhaustion profile. A first-in-human trial was initiated to evaluate the preliminary safety and efficacy of GT316 in advanced solid tumors. Methods: The first-in-class study is to enroll patients (pts) with advanced treatment-refractory solid tumors, especially gynecological tumors. Once the optimal biological dose (OBD) is identified, a monotherapy expansion phase will be initiated for pts with various solid tumors. Enrolled pts were preconditioned with a nonmyeloablative (NMA) lymphodepletion regimen and treated by infusion of the GMP-grade G316 product followed by IL-2 administration. Results: As of January 22, 2024, the dose escalation study enrolled 4 pts, all of whom were female with a median age of 58 years with 1 to 9 prior lines of systemic treatment. The median number of infused TIL cells was 1.0E+10. All pts experienced TRAEs with the majority being grade 1 or 2. Grade 3/4 TRAEs included lymphocyte count decreased, white blood cell count decreased, monocyte count decreased and neutrophil count decreased, which were related to the NMA regimen. No dose-limiting toxicities (DLTs) or TIL-related grade≥3 TRAEs were observed. Median time on study was 33.4 wks (8–35 wks). One pt with treatment-refractory cervical cancer experienced a confirmed complete response (CR) after 4 wks and the duration of response is 32 wks by now (RECIST 1.1). One ovarian cancer pt with 9 lines of previous systemic therapies experienced a confirmed partial response (PR) after 4 wks and the duration of response is 22 wks by now (RECIST 1.1). Response data will be continuously collected. The other two ovarian cancer pts experienced stable disease (SD) and progressive disease (PD), respectively. Despite varying doses of TILs (3.2E+09 to 1.90E+10) and IL-2 (up to 3.0E+05 IU/kg), all pts receiving GT316 showed robust TIL expansion post-infusion, which is positively correlated with administrated IL-2 doses. Enhanced IFN-γ secretion could be detected in the serum of the CR and PR pts compared to the SD and PD pts, indicating potential tumor antigen-specific response. Conclusions: The first-in-human study of GT316, a CRISPR/Cas9-dual KO anti-exhaustion TIL product, demonstrates good tolerability with encouraging preliminary anti-tumor efficacy as a monotherapy in pts with advanced solid cancers. The infusion of GT316 was associated with robust TIL expansion and IFN-γ secretion. Updated data with additional follow-up will be continuously collected, and OBD will be determined based on the overall data of safety and preliminary efficiency. Clinical trial information: NCT06145802 .

Covalent-103: A phase 1, open-label, dose-escalation and expansion study of BMF-500, an oral covalent FLT3 inhibitor, in adults with acute leukemia (AL).

TPS6589 Background: FLT3 mutations occur in 25-35% of AML and result from an internal tandem duplication (ITD) of amino acids in the juxtamembrane domain of FLT3 kinase or point mutations in the tyrosine kinase domain (TKD). FLT3-ITD mutations are associated with increased relapse, shorter remission, and decreased disease-free and overall survival. BMF-500 is a novel oral, highly potent and selective covalent inhibitor of FLT3 including wild-type (WT), ITD, TKD, and resistance mutations (e.g., gatekeeper F691). BMF-500 has high affinity for FLT3, lack of cKIT inhibition, and sustained cell-killing despite drug washout (Law et al., ASH 2022 Abst 2756). BMF-500 shows sustained tumor regression and improved survival in subcutaneous and disseminated xenografts of FLT3-m AML. Methods: COVALENT-103 (NCT05918692) is a multicenter, first-in-human study evaluating the safety, tolerability, and antileukemic activity of escalating doses of daily BMF-500 in patients with relapsed or refractory (R/R) AL, including AML, ALL, or MPAL, with or without FLT3-m. The trial has 2 arms that dose escalate in parallel: Arm A (without) and Arm B (with) concomitant use of a CYP3A4 inhibitor. Using an accelerated titration design (ATD), doses of BMF-500 are escalated in single-subject cohorts until one subject experiences ≥Grade 2 related adverse event or dose-limiting toxicity (DLT). At that point, the cohort will switch to a classical “3 +3” design. Patients with WT FLT3 AL may enroll up to 33% per arm. Treatment continues in 28-day cycles until progression or intolerability. Expansion cohorts will enroll additional patients to obtain further safety and efficacy data. Patients must be refractory, relapsed or have progressed on or following discontinuation of the most recent anti-cancer therapy or be ineligible for any approved standard of care, including hematopoietic stem cell transplant (HSCT). FLT3-positive AML patients must have received a FLT3 inhibitor approved for R/R FLT3-m AML. Additional inclusion criteria include ECOG PS ≤2, adequate organ function, and documented FLT3 mutation status. Key exclusion criteria include known CNS disease, clinically significant cardiovascular disease, and WBC >50,000/µL (uncontrollable with cytoreductive therapy). The primary objective is to evaluate safety and tolerability and determine the optimal biological dose (OBD)/ recommended Phase 2 dose (RP2D) of BMF-500 monotherapy based on available pharmacokinetic/pharmacodynamic (PK/PD), safety and efficacy data. Secondary objectives include characterization of the PK/PD of BMF-500, and assessment of its antitumor activity per modified Cheson (2003) criteria or NCCN Clinical Practice Guidelines (ALL Version 1.2022) as determined by the investigator. The study was initiated in July 2023, is currently in dose escalation, and we plan to enroll approximately 110 patients total. Clinical trial information: NCT05918692 .

AFNT-211: A phase 1 study of autologous CD4+ and CD8+ T cells engineered to express a high avidity HLA-A*11:01-restricted, KRAS G12V-specific, transgenic TCR, a CD8α/β coreceptor, and a FAS41BB switch receptor in patients with advanced/metastatic solid tumors.

TPS8650 Background: Activating mutations in KRAS (including KRAS G12V) are well-described oncogenic drivers in solid tumors. Patients with KRAS driver mutations have a poor prognosis, and most KRAS-mutated cancers lack effective therapies. T cell receptor (TCR)-T cell therapies targeting mutant KRAS have demonstrated proof of concept in the clinic, but duration of response remains a challenge. AFNT-211 represents a novel strategy to address the immunosuppressive tumor microenvironment and improve response rate and duration in solid tumors. AFNT-211 autologous CD4+ and CD8+ T cells are engineered to express a high avidity HLA-A*11:01-restricted, KRAS G12V-specific, transgenic TCR; the wildtype CD8α/β coreceptor; and a FAS-41BB switch receptor. The intended mechanism of action is recognition and elimination of KRAS G12V-mutated tumor cells by AFNT-211. AFNT-211 is designed to enhance anti-tumor activity via the following mechanisms of action as shown in preclinical models: (1) the CD8α/β coreceptor enables MHC-I– restricted TCR recognition of the KRAS G12V target by CD4+ T cells; (2) engaging CD4+ helper T cell responses drives enhanced CD8+ T cell cytotoxic activity and prevents T cell exhaustion; (3) the FAS-41BB chimeric switch receptor drives increased T cell activity, circumventing native FAS apoptotic signaling. Methods: This ongoing Phase 1, first-in-human, multicenter, open-label study of AFNT-211 (1) evaluates safety/tolerability, (2) determines the optimal biological dose (OBD) and recommended Phase 2 dose (RP2D), and (3) assesses preliminary antitumor activity. The study consists of 2 parts: dose escalation and dose expansion. Dose escalation is guided by the Bayesian optimal interval Phase 1/2 (BOIN12) design to determine the OBD. The BOIN12 design quantifies the desirability of a dose in terms of toxicity-efficacy tradeoff and adaptively allocates patients to the dose with the highest estimated desirability. The RP2D will be selected based on the BOIN12 design and the totality of benefit/risk assessment. Patients enrolling in dose expansion will be treated at the OBD/RP2D in indication-specific cohorts. This study is conducted in patients aged ≥ 18 years who are HLA-A*11:01-positive with advanced/metastatic solid tumors harboring a KRAS G12V mutation, and intolerance of/progression on at least 1 prior systemic therapy. Patients undergo leukapheresis to collect T cells for the manufacturing of AFNT-211 and receive lymphodepleting chemotherapy prior to AFNT-211 infusion. This is followed by a 28-day dose-limiting toxicity observation period (dose escalation only) and a post-treatment follow-up period for 24 months/ until disease progression. The study is open for recruitment in the United States. Clinical trial information: NCT06105021 .

Comparative review of novel model-assisted designs for phase I/II clinical trials.

In recent years, both model-based and model-assisted designs have emerged to efficiently determine the optimal biological dose (OBD) in phase I/II trials for immunotherapy and targeted cellular agents. Model-based designs necessitate repeated model fitting and computationally intensive posterior sampling for each dose-assignment decision, limiting their practical application in real trials. On the other hand, model-assisted designs employ simple statistical models and facilitate the precalculation of a decision table for use throughout the trial, eliminating the need for repeated model fitting. Due to their simplicity and transparency, model-assisted designs are often preferred in phase I/II trials. In this paper, we systematically evaluate and compare the operating characteristics of several recent model-assisted phase I/II designs, including TEPI, PRINTE, Joint i3+3, BOIN-ET, STEIN, uTPI, and BOIN12, in addition to the well-known model-based EffTox design, using comprehensive numerical simulations. To ensure an unbiased comparison, we generated 10,000 dosing scenarios using a random scenario generation algorithm for each predetermined OBD location. We thoroughly assess various performance metrics, such as the selection percentages, average patient allocation to OBD, and overdose percentages across the eight designs. Based on these assessments, we offer design recommendations tailored to different objectives, sample sizes, and starting doselocations.

Joint TITE-CRM: A Design for Dose Finding Studies for Therapies with Late-Onset Safety and Activity Outcomes

In Phase I/II dose-finding trials, the objective is to find the Optimal Biological Dose (OBD), a dose that is both safe and shows sufficient activity that maximizes some optimality criterion based on safety and activity. In cancer, treatment is typically given over several cycles, complicating the identification of the OBD as both toxicity and activity outcomes may occur at any point throughout the follow up of multiple cycles. In this work we present and assess the Joint TITE-CRM, a model-based design for late onset toxicities and activity based on the well-known TITE-CRM. It is found to be superior to the currently available alternative designs that account for late onset bivariate outcomes, as well as being both intuitive and computationally feasible.

The 3 + 3 design in dose-finding studies with small sample sizes: Pitfalls and possible remedies.

In the last few years, numerous novel designs have been proposed to improve the efficiency and accuracy of phase I trials to identify the maximum-tolerated dose (MTD) or the optimal biological dose (OBD) for noncytotoxic agents. However, the conventional 3+3 approach, known for its and poor performance, continues to be an attractive choice for many trials despite these alternative suggestions. The article seeks to underscore the importance of moving beyond the 3+3 design by highlighting a different key element in trial design: the estimation of sample size and its crucial role in predicting toxicity and determining the MTD. We use simulation studies to compare the performance of the most used phase I approaches: 3+3, Continual Reassessment Method (CRM), Keyboard and Bayesian Optimal Interval (BOIN) designs regarding three key operating characteristics: the percentage of correct selection of the true MTD, the average number of patients allocated per dose level, and the average total sample size. The simulation results consistently show that the 3+3 algorithm underperforms in comparison to model-based and model-assisted designs across all scenarios and metrics. The 3+3 method yields significantly lower (up to three times) probabilities in identifying the correct MTD, often selecting doses one or even two levels below the actual MTD. The 3+3 design allocates significantly fewer patients at the true MTD, assigns higher numbers to lower dose levels, and rarely explores doses above the target dose-limiting toxicity (DLT) rate. The overall performance of the 3+3 method is suboptimal, with a high level of unexplained uncertainty and significant implications for accurately determining the MTD. While the primary focus of the article is to demonstrate the limitations of the 3+3 algorithm, the question remains about the preferred alternative approach. The intention is not to definitively recommend one model-based or model-assisted method over others, as their performance can vary based on parameters and model specifications. However, the presented results indicate that the CRM, Keyboard, and BOIN designs consistently outperform the 3+3 and offer improved efficiency and precision in determining the MTD, which is crucial in early-phase clinical trials.

Abstract CT076: AFNT-211: A phase1 study of autologous CD4+ and CD8+ T cells engineered to express a high avidity HLA-A*11:01-restricted, KRAS G12V-specific, transgenic TCR; CD8α/β coreceptor; and a FAS41BB switch receptor in patients with advanced/metastatic solid tumors

Abstract Background: Activating mutations in KRAS (including KRAS G12V) are well-described oncogenic drivers in solid tumors. Patients with KRAS driver mutations have a poor prognosis, and most KRAS-mutated cancers lack effective therapies. T cell receptor (TCR)-T cell therapies targeting mutant KRAS have demonstrated proof of concept in the clinic, but duration of response remains a challenge. AFNT-211 represents a novel strategy to address the immunosuppressive tumor microenvironment and improve response rate and duration in solid tumors. Rationale: AFNT-211 autologous CD4+ and CD8+ T cells are engineered to express a high avidity HLA-A*11:01restricted, KRAS G12V-specific, transgenic TCR; the wildtype CD8α/β coreceptor; and a FAS-41BB switch receptor. The intended mechanism of action is recognition and elimination of KRAS G12V-mutated tumor cells by AFNT-211. AFNT-211 is designed to enhance anti-tumor activity via the following mechanisms of action as shown in preclinical models: (1) the CD8α/β coreceptor enables MHC-I-‍restricted TCR recognition of the KRAS G12V target by CD4+ T cells; (2) engaging CD4+ helper T cell responses drives enhanced CD8+ T cell cytotoxic activity and prevents T cell exhaustion; (3) the FAS-41BB chimeric switch receptor drives increased T cell activity, circumventing native FAS apoptotic signaling. Methods: This ongoing Phase 1, first-in-human, multicenter, open-label study of AFNT-211 (1) evaluates safety/tolerability, (2) determines the optimal biological dose (OBD) and recommended Phase 2 dose (RP2D), and (3) assesses preliminary antitumor activity. The study consists of 2 parts: dose escalation and dose expansion. Dose escalation is guided by the Bayesian optimal interval Phase 1/2 (BOIN12) design to determine the OBD. The BOIN12 design quantifies the desirability of a dose in terms of toxicity-efficacy tradeoff and adaptively allocates patients to the dose with the highest estimated desirability. The RP2D will be selected based on the BOIN12 design and the totality of benefit/risk assessment. Patients enrolling in dose expansion will be treated at the OBD/RP2D in indication-specific cohorts. This study is conducted in patients aged ≥ 18 years who are HLA-A*11:01-positive with advanced/metastatic solid tumors harboring a KRAS G12V mutation, and intolerance of/progression on at least 1 prior systemic therapy. Patients undergo leukapheresis to collect T cells for the manufacturing of AFNT-211 and receive lymphodepleting chemotherapy prior to AFNT-211 infusion. This is followed by a 28-day dose-limiting toxicity observation period (dose escalation only) and a post-treatment follow-up period for 24 months/until disease progression. The study is open for recruitment in the United States (NCT06105021). Citation Format: Shaunica Mitchell, Binaish Khan, Francis Payumo, E. Gabriela Chiorean, Zhubin Gahvari, J. Randolph Hecht, Michael Hurwitz, Rom Leidner, Heinz-Josef Lenz, Meredith Pelster, Salman Punekar, Adam Schoenfeld, Dan Zhao, Markus Vallaster, Dirk Nagorsen. AFNT-211: A phase1 study of autologous CD4+ and CD8+ T cells engineered to express a high avidity HLA-A*11:01-restricted, KRAS G12V-specific, transgenic TCR; CD8α/β coreceptor; and a FAS41BB switch receptor in patients with advanced/metastatic solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT076.

Abstract 5977: A first-in-human, open-label, multi-center phase 1 study of TST003, a GREM 1 inhibitor, in subjects with locally advanced or metastatic solid tumors

Abstract Background: Gremlin-1 (GREM1), a member of the TGF-β superfamily, plays a key role in EMT, and cancer cell proliferation by binding to BMPs. GREM1 is widely expressed in various human cancers and TME stromal cells. Overexpression of GREM1 is correlated with poor prognosis. TST003 is a novel humanized IgG1 monoclonal antibody targeting GREM1 with high affinity and selectivity, and it blocks GREM1 binding to BMP2/4 resulting in enhanced BMP signaling. This study will investigate TST003’s safety, tolerability, and preliminary anti-tumor activity in patients with advanced solid tumors. Objectives: The primary objectives are to evaluate the safety and tolerability and determine the maximum tolerated dose and/or optimal biologic dose(s) of TST003. Secondary objectives include pharmacokinetic, pharmacodynamic and preliminary anti-tumor activity of TST003. A comprehensive biomarker plan will be implemented to analyze GREM1 expression, BMP signaling pathway, and tumor microenvironment with tumor tissues (including tumor cells, CAFs, Teff, Treg, MDSCs and TAMs), as well as circulating tumor DNA to explore the correlation among drug exposure, pharmacodynamic markers and clinical outcomes. Method: This is a first in human Phase 1 study in locally advanced or metastatic solid tumor subjects having tumor progression during or after prior therapies and have no standard therapy that could confer clinical benefit. It comprises of the Part 1 Dose Escalation and the Part 2 Pharmacodynamic Cohorts. Part 1 will evaluate sequential dose levels of 1, 3, 10, 20 and 30 mg/kg TST003 iv., every three weeks as a single agent. The traditional “3+3” design were used for dose escalation of the first two cohorts (1 and 3 mg/kg), and Bayesian Optimal Interval (BOIN) Design with prespecified cohort size of 3 is used in the following cohorts. Part 2 will include 2 pharmacodynamic cohorts to evaluate the pharmacokinetic (PK) profile, pharmacodynamic (PD) markers, preliminary tumor response, as well as safety of TST003 as monotherapy in locally advanced or metastatic colorectal adenocarcinoma (CRC) subjects. The 2 doses used in the pharmacodynamic cohorts will be chosen from Part 1 and are expected to be within the pharmacologically active range based on nonclinical PK/PD modeling and available clinical PK/PD data from the ongoing study. Baseline GREM1 expression will be analyzed by immunohistochemistry. In each pharmacodynamic cohort, around 13-18 subjects will be enrolled to ensure at least 7 GREM1 positive subjects. Eligible subjects will receive TST003 until unacceptable toxicity or disease progression by RECIST v1.1. The enrollment is ongoing in clinical centers in the US and China. No significant safety signals were reported in the first few patients treated with TST003. Clinical Trial Information: NCT05731271. Study Sponsor: Suzhou Transcenta Therapeutics Co., Ltd. Citation Format: Ismael Rodriguez Rivera, Lin Shen, Shivaani Kummar, Minal Barve, Caroline Germa, Chuan Qi, Lei Chen, Jenny Milata, Jenny Yao, Li Shen, Xuelian Zhu. A first-in-human, open-label, multi-center phase 1 study of TST003, a GREM 1 inhibitor, in subjects with locally advanced or metastatic solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5977.

Abstract 510: Flow cytometry evaluation of cell cycle arrest in A549 human non-small cell lung cancer cells and tumors following treatment with cell cycle inhibitors: A multifaceted approach to targeting cancer

Abstract The contemporary landscape of cancer treatment has witnessed significant progress with FDA-approved targeted drugs. The FDA's Project Optimus has underscored the growing need for innovative pharmacodynamic endpoints to determine the optimal biological dose in clinical development. Flow cytometry, a potent analytical tool in clinical and preclinical labs, now plays a leading role in cancer research, enabling the evaluation of new drug effects on cell cycle regulation and consideration of rational drug combinations with approved drugs. At TD2, we strive to enhance the translatability of in vitro induced cell cycle arrest studies to in vivo biomarker proof of concept and efficacy. We employ a comprehensive approach, utilizing flow cytometry to assess cell cycle dynamics in cultured cells and in vivo tumor models after treatment with approved and novel drugs. This abstract focuses on the translational relevance of combined in vitro and in vivo testing of well-known drugs that disrupt the cell cycle, laying the foundation for optimized treatment strategies and potentially personalized cancer therapies. Human A549 non-small cell lung carcinoma cells were treated with either thymidine (2.0mM) or the microtubule-depolymerizing drug nocodazole (100ng/ml) for 18 hours, then examined by flow cytometry. Thymidine induced a greater than 85% S-phase arrest, while nocodazole induced a greater than 88% G2/M-phase arrest. A549 cells (5 × 106 cells/mouse) were subcutaneously implanted in SCID mice, followed by treatment with an FDA-approved cell cycle inhibitor, Palbociclib, or cisplatin chemotherapy. Palbociclib, a CDK4/6 inhibitor, and low-dose cisplatin treatment resulted in an increased accumulation of cells in the G0/G1 phase, greater than 80% for each. Both treatments exhibited promising anti-cancer activity, with tumor growth inhibition (TGI) of 69% and 87%, respectively. Our findings highlight flow cytometry's multifaceted utility in assessing cell cycle arrest, providing a comprehensive view of agent effects on cancer cells in culture and within the complex in vivo tumor microenvironment. Determining the impact of any new drug on specific cell cycle checkpoints could allow for a more strategic plan for combination therapy. Integrating flow cytometry could enable early biomarker monitoring of tumor cell cycle changes, offering insights into the therapeutic potential of new agents alone or in combination. This multidimensional evaluation contributes to understanding cancer biology and has the potential to guide the development of novel therapeutic strategies, optimize treatment regimens to identify optimal biological doses, and improve patient outcomes in the era of precision medicine. Citation Format: Erin E. Trachet, Emily Cluff, Ana Lemos de Matos, Damaris Diaz, Chelsea Holmquist, Paul Gonzales. Flow cytometry evaluation of cell cycle arrest in A549 human non-small cell lung cancer cells and tumors following treatment with cell cycle inhibitors: A multifaceted approach to targeting cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 510.

Predictive role of homologous recombination deficiency (HRD) for irinotecan in combination with venadaparib, a novel PARP1/2 inhibitor, as third- or fourth-line treatment in patients with advanced gastric cancer.

380 Background: Tumors with homologous recombination deficiency (HRD), including BRCA and ATM mutations, have shown to predict response to poly (adenosine diphosphate [ADP]–ribose) polymerase (PARP) inhibitors. The associations between treatment efficacy of PARP inhibitor-based regimen and mutations in BRCA (BRCAm) or ATM gene (ATMm) are not well known in previously treated advanced gastric cancer (GC). Combining PARP inhibitor and irinotecan is known to synergize cytotoxicity. The aim of this analysis was to evaluate the association of HRD and efficacy of irinotecan and venadaparib combined, in patients with metastatic GC who had failed at least 2 lines of therapy. Methods: MTT assays were performed in vitro to verify and characterize synergism between venadaparib and SN-38. Data were analyzed using the GraphPad Prism (version 9.5.1) and CompuSyn (version 1.0) software. Patients with at least two prior palliative treatments were enrolled in a multi-national phase Ib trial (NCT04725994). Tumor response was evaluated according to RECIST 1.1. Exploratory genomic analysis was included to assess the correlation between efficacy and HRD. Genomic analysis was conducted using ctDNA (GuardantOMNI Gene Panel version 1.0, Redwood City, CA) on Day 1 pre-dose. Results: In MTT assays, the combination of SN-38 and venadaparib exerted synergistic effect with combination indices (CI) ranging from 0.013 to 0.991 in SNU-638 (BRCA2m), SNU-668 (BRCA1m), AGS (low ATM) and SNU-484 (HR proficient) cells. We observe the synergistic effect between SN-38 and venadaparib remained consistent even at low concentrations of venadaparib (SN-38 IC50; without venadaparib → with 10 nM of venadaparib; SNU-638(1.72→0.28), SNU-668(10.7→1.5), AGS (0.62→0.049), SNU-484(2.25->0.38)). In the dose-finding part of the clinical study, 26 patients were enrolled, 13 had received two prior treatments and 13 had received three prior treatments. At data cut-off, median duration of follow-up (range) was 4.4 (1.3 – 23.7) months. Of the 26 patients enrolled, 5 (1 BRCA2m and 4 ATMm) had HRD (19.2%) and were treated with varying doses of irinotecan and venadaparib. In the five patients with HRD, an objective response rate (ORR) was 60% and median progression-free survival (mPFS) (95% CI) was not reached (1.2–21.5). Of the 26 patients enrolled, 11 received varying doses of venadaparib plus 100 mg/m2 of irinotecan, with an ORR of 36.4% and mPFS (95% CI) of 5.6 (3.5–not reached) months. Conclusions: Venadaparib in combination with irinotecan showed synergistic effect in vitro assays and promising clinical efficacy in the systemic treatment of refractory GC, particularly in patients with HRD. The dose expansion phase of the study is ongoing to investigate the optimal biological dose and patient selection strategies, in a randomized design. Clinical trial information: NCT04725994 .

COVALENT-102: A phase 1/1b dose finding study of BMF-219, an oral covalent menin inhibitor, in adults with locally advanced, unresectable, or metastatic non-small cell lung cancer (NSCLC), pancreatic cancer (PDAC) and colorectal cancer (CRC) with activating KRAS mutations.

TPS716 Background: BMF-219 is a selective covalent inhibitor of menin, a transcriptional regulator of oncogenic signaling pathways in multiple cancers, that inhibits the menin/MYC interaction and downregulates the expression of MYC and MYC target genes, including KRAS. In addition, inhibition of the menin complex by BMF-219 alters function of the AP-1 transcription factor, JunD, a crucial factor for KRAS-driven tumorigenesis. Further, inhibition of the menin-MLL complex suppresses expression of Rasgrf1, a guanine nucleotide exchange factor essential for generation of the active RAS-GTP conformation of KRAS, activation of downstream pathways, and tumorigenesis. Preclinically, BMF-219 shows potent abrogation of menin-dependent oncogenic signaling and exerts pan-mutant KRAS anticancer activity independent of the specific KRAS-activating mutation. Methods: COVALENT-102 (NCT05631574) is a prospective, open-label, dose-finding study evaluating the safety, tolerability, and clinical activity of BMF-219 administered daily in adults with unresectable, locally advanced, or metastatic NSCLC (Cohort 1), PDAC (Cohort 2) and CRC (Cohort 3) with activating KRAS mutations who have received standard therapy. All indications as a group follow a 3+3 dose escalation design. BMF-219 is orally administered once or twice daily as continuous therapy in 28-day cycles until progression or intolerability/unacceptable toxicity. Following dose-escalation, each indication will enroll patients in expansion cohorts independently to obtain further safety and efficacy data. Eligible patients include those with any KRAS mutation and (Cohort 1) stage IIIB/IV NSCLC with 2-4 prior lines of therapy including immune checkpoint inhibitors (ICI) &/or platinum-based chemo ± bevacizumab with ECOG 0-2; (Cohort 2) stage III/IV PDAC with ≥ 1 prior line of therapy including either FOLFIRINOX or gemcitabine/nab-paclitaxel, ECOG 0-1; or (Cohort 3) stage III/IV CRC with ≥ 1 prior line of therapy including FOLFOX or FOLFIRI ± bevacizumab (prior ICI if MSI-H/dMMR), ECOG 0-2. Patients must have documented progression and measurable disease as defined by RECIST 1.1. Patients with prior KRAS inhibitor exposure are eligible. Key exclusion criteria include untreated CNS metastasis, prior menin inhibitor therapy, and clinically significant cardiovascular disease. The primary objective is to determine the optimal biological dose/ recommended Phase 2 dose of BMF-219 monotherapy. Secondary objectives include further evaluation of safety and tolerability, characterization of the PK/PD of BMF-219, and efficacy based on duration of response and disease control rate. PFS, OS, and time to response are exploratory endpoints. Accrual began in January 2023 and is ongoing. Clinical trial information: NCT05631574 .