Phase Ib Study Research Articles

Abstract CT107: Phase Ib Study of Pembrolizumab in Combination with Intratumoral Injection of Clostridium novyi-NT in Patients with Advanced Solid Tumors

Abstract BACKGROUND: Intra-tumoral Clostridium novyi-NT (non-toxic) is an attenuated strain of C. novyi lacking alpha toxin replication within hypoxic tumor regions, causing tumor cell lysis and inflammation. Immunotherapy (IO) augments anticancer activity with intratumoral agents in prior preclinical and clinical studies. This phase 1b dose escalation study assessed safety and potential synergistic effects of pembrolizumab and C. novyi-NT in advanced solid tumors. METHODS: We enrolled patients with percutaneous injectable, solid tumors to receive single intratumoral injection of C. novyi-NT administered on Day 8 across 4 dose cohorts (3 × 10^4 to 100 × 10^4 spores, 3+3 design) with pembrolizumab 200mg IV Q3weekly starting on Day 0 up to 24 months. Primary objectives: Safety, tolerability and maximum tolerated dose (MTD) of combination. Secondary objectives: anti-tumor activity of combination in the injected tumor lesion and overall response by iRECIST 1.1. RESULTS: At data cutoff on October 24, 2022, 16 patients were enrolled and evaluable for toxicity and efficacy. It was well tolerated across all cohorts without dose limiting toxicities with median number of 5 cycles administered (1-34). 10 patients (63%) experienced progression; 1 withdrew consent; 1 completed therapy; 1 came off trial due to toxicity (immune related dermatitis) and 3 patients remain on trial. Median age was 62.5 years (40-71) while all patients (100%) had performance status of 1. 8 (50%) received prior IO and 7 (44%) had > 4 lines of prior therapies. Confirmed overall objective response rate (ORR) was 25% in 4 patients [non-keratinizing undifferentiated nasopharyngeal squamous carcinoma (NPC), human papilloma virus positive squamous cell carcinoma of base of tongue, vulvar melanoma and chordoma] with 3 partial responses (PR) and 1 complete response (CR). Among responders, median duration of response was 8.18 months and 1/4 (25%) had prior IO. NPC patient completed 24 months on trial to completion with best response at PR (-87%) while vulvar melanoma patient remains on trial with best response at CR (-100%). Median injected tumor size was 2.65cm (1-11) with confirmed ORR in injected lesions at 19% with 2 PRs and 1 CR. Most prevalent grade 1 and 2 adverse events were injection site reaction (25%), pyrexia (19%), pruritus (13%), leukopenia (13%) and anemia (13%). No grade 3 or 4 treatment related adverse events noted. Signs and symptoms of C. novyi-NT germination (infection) including fever, injection site pain, erythema, swelling, tenderness, and in some cases, ulceration, spontaneous drainage, tissue sloughing, bleeding, and malodor were observed in 5 patients. CONCLUSIONS: Intratumoral C. novyi-NT with pembrolizumab demonstrates clinical activity with favorable tolerability in patients regardless of tumor histology. This study is ongoing to define the recommended phase 2 dose (NCT03435952). Citation Format: Blessie Elizabeth Nelson, Filip Janku, Siqing Fu, Ecaterina I. Dumbrava, David S. Hong, Daniel Karp, Aung Naing, Jordi Rodon, Apostolia Tsimberidou, Rodabe N. Amaria, Anthony Conley, Senthil Damodaran, Kanwal P. Raghav, Brent L. Kreider, David Tung, Mary Varterasian, Khashayarsha Khazaie, Sarina Piha-Paul. Phase Ib Study of Pembrolizumab in Combination with Intratumoral Injection of Clostridium novyi-NT in Patients with Advanced Solid Tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT107.

Abstract CT263: A phase Ib dose-expansion study of porustobart, an anti-CTLA-4 heavy chain only monoclonal antibody, in combination with toripalimab in patients with advanced high-grade neuroendocrine neoplasms (NENs)

Abstract Background: Porustobart (HBM4003) is a fully human heavy chain only monoclonal antibody targeting CTLA-4. In addition to blocking the CTLA-4 pathway, porustobart was engineered to deplete Treg cells by enhanced antibody-dependent cellular cytotoxicity (ADCC) that was clinically validated. The prognosis of advanced high-grade NENs is poor without standard second line treatments. 4003.6, a multi-center phase Ib study is evaluating porustobart plus toripalimab (an anti-PD-1 antibody) in advanced high-grade NENs (NCT05167071). Methods: Patients (pts) with pretreated advanced high-grade NENs received porustobart at one of the two dose levels (0.3 mg/kg and 0.45 mg/kg) plus toripalimab 240 mg every three weeks (Q3W). The primary endpoint is objective response rate (ORR) per RECIST 1.1 by investigator. Results: As of 31 Aug 2022, 21 pts had been dosed, including 15 pts with neuroendocrine carcinoma (NEC), 3 pts with grade 3 neuroendocrine tumor (G3-NET) and 3 pts with mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN). 66.7% (14/21) pts received at least 2 prior lines of chemotherapy. Nine tested pts were all microsatellite stable (MSS). Median follow up time was 163 days for 0.3mg/kg dose group and 56 days for 0.45mg/kg dose group.Sixteen pts had post-baseline tumor assessments. The ORR and DCR were 37.5% and 62.5%, respectively. Median duration of response was not reached. For the 11 evaluable pts with NEC, the ORR and DCR were 36.4% and 72.7%, respectively. No significant difference in efficacy was observed between the two dose groups. Treatment-related adverse events (TRAEs) were reported in 100.0% (21/21) pts, and ≥Grade 3 TRAEs were reported in 33.3% (7/21) pts. In 0.3mg/kg dose group, 75% (6/8) pts received 5-16 cycles of study treatment, and 50% (4/8) pts experienced ≥Grade 3 TRAEs. In 0.45mg/kg dose group, 92.3% (12/13) pts received ≤4 cycles, and 23.1% (3/13) pts experienced ≥Grade 3 TRAEs. Most common (≥20%) TRAEs by pooled term were hepatic function abnormal, hyperthyroidism, rash, leukopenia, anaemia, pyrexia, hypothyroidism, neutrophil count decreased and thrombocytopenia. PK data indicated no potential interaction between porustobart and toripalimab. Increase of T cell proliferation were observed in the peripheral blood of all pts. Conclusions: Porustobart 0.3 mg/kg or 0.45 mg/kg plus toripalimab 240mg Q3W showed promising anti-tumor activity and an acceptable safety profile in pts with advanced high-grade NENs. Citation Format: Ming Lu, Panpan Zhang, Lin Shen, Kai Chen, Jianwei Yang, Lijie Song, Humphrey Gardner, Kedan Lin, Luyin Ding, Shuai Zhao, Yuan Geng, Jie Ding, Zailian Lu, Yedong Wang. A phase Ib dose-expansion study of porustobart, an anti-CTLA-4 heavy chain only monoclonal antibody, in combination with toripalimab in patients with advanced high-grade neuroendocrine neoplasms (NENs) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT263.

Abstract CT029: Phase Ib study of GDC-6036 in combination with cetuximab in patients with colorectal cancer (CRC) with KRAS G12C mutation

Abstract Background: GDC-6036 is an oral, highly potent and selective KRAS G12C inhibitor that demonstrated anti-tumor activity in patients with KRAS G12C-positive advanced solid tumors, including CRC. In a previously reported single-agent cohort, GDC-6036 achieved a best response of partial response or complete response in 35% (19/55) of patients, with a confirmed overall response rate (ORR) of 24% (13/55 patients) in KRAS G12C-positive CRC patients (Desai et. al., ESMO 2022). EGFR blockade may sensitize tumors to KRAS G12C inhibition and the combination of an anti-EGFR antibody (cetuximab) with a KRAS G12C inhibitor showed greater anti-tumor activity than single-agent KRAS G12C inhibition in preclinical models (Amodio et. al., 2020). Methods: In an ongoing Phase I study (NCT04449874), patients with advanced or metastatic KRAS G12C-positive CRC were administered GDC-6036 (200-400 mg orally once a day) with cetuximab (400 mg/m2 intravenously initially, then 250 mg/m2 weekly) until intolerable toxicity or disease progression. Endpoints included safety (NCI-CTCAE v5), pharmacokinetics (PK), and preliminary anti-tumor activity (RECIST v1.1). Results: As of the clinical data cut-off date of 21 Nov 2022, 29 patients (enrolled by 07 Oct 2022) had received GDC-6036 and cetuximab. The median lines of prior metastatic therapy was 2 (range 1-8) and the median time on study treatment was 5.2 (range 1.4-11.2) months. All patients experienced at least one treatment-related adverse event (TRAE); the most common TRAEs (≥15%) were rash (grouped terms), diarrhea, nausea, vomiting, dry skin, and paronychia. Grade 3-4 TRAEs occurred in 11 patients (38%). Five patients (17%) experienced at least one serious AE, none of which were treatment-related (including 2 patients who died of CRC progression during the safety follow-up). AEs led to GDC-6036 modifications (interruptions and/or reductions) in 13 (45%) patients, dose reduction in 3 (10%) patients, and no patients discontinued due to AEs. Eleven patients discontinued from study treatment (10 due to disease progression and 1 due to physician’s discretion). The PK profile of GDC-6036 (400 mg once a day) was similar in combination with cetuximab when compared with single-agent. A partial response was achieved in 66% (19/29) of patients, with a confirmed ORR of 62% (18/29 patients). Conclusions: GDC-6036 in combination with cetuximab demonstrated a manageable safety profile and promising clinical activity. These data support that the addition of anti-EGFR therapy to GDC-6036 may lead to robust clinical benefit in patients with KRAS G12C-positive CRC. Citation Format: Jayesh Desai, Sae-Won Han, Jong-Seok Lee, Einat Shacham-Shmueli, Erminia Massarelli, Andrés Cervantes, Elena Garralda, Alejandro Falcon, Wilson H. Miller, Eelke Gort, Thomas Karasic, Salvatore Siena, Rafal Stec, Laura Medina, Luis Paz-Arez, Angelo Delmonte, Adrian Sacher, Hans Prenen, Martin Forster, Tae Won Kim, Matthew G. Krebs, Rasha Cosman, Yoonha Choi, Sandhya Mandlekar, Mark T. Lin, Kenneth K. Yau, Julie Chang, Stephanie Royer-Joo, Neekesh V. Dharia, Jennifer L. Schutzman, Manish Patel. Phase Ib study of GDC-6036 in combination with cetuximab in patients with colorectal cancer (CRC) with KRAS G12C mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT029.

Safety, efficacy and pharmacokinetics of BPI-9016M in c-MET overexpression or MET exon 14 skipping mutation patients with locally advanced or metastatic non-small-cell lung cancer: a phase Ib study

BackgroundAs a potential target receptor tyrosine kinase, mesenchymal-epithelial transition factor (MET) exhibits high aberrant expression across various tumors. This study aimed to evaluated the safety, tolerability, efficacy and pharmacokinetics (PK) of BPI-9016M, a novel tyrosine kinase inhibitor (TKI) targeting c-MET, in c-MET overexpression or MET exon 14 skipping mutation patients with locally advanced or metastatic non-small-cell lung cancer (NSCLC).Methods/designIn this two-part multicenter phase Ib study, eligible patients with locally advanced or metastatic NSCLC harboring c-MET overexpression or MET exon 14 skipping mutation were enrolled into Part A (tested positive for c-MET overexpression [immunohistochemical staining score ≥ 2+]; 300 mg quaque die [QD], 450 mg QD and 600 mg QD cohorts) or Part B (tested positive for MET exon 14 skipping mutation; 400 mg bis in die [BID] cohort), respectively. The primary endpoints were safety, objective response rate (ORR) and disease control rate (DCR), the second endpoints were PK parameters, progression-free survival (PFS) and overall survival (OS).ResultsBetween March 15, 2017 and September 18, 2021, 38 patients were enrolled (Part A, n = 34; Part B, n = 4). Of 38 patients, 32 (84.2%) patients completed the treatment protocol. As of the data cut-off date on January 27, 2022, all patients reported at least one treatment-emergent adverse event (TEAE). Ninety-two point one percent (35/38) of patients experienced treatment-related adverse events (TRAEs), and grade ≥ 3 TRAEs were observed in 11 (28.9%) patients. The most common TRAEs were elevated alanine aminotransferase (ALT, 14/38, 36.8%) and elevated aspartate aminotransferase (AST, 11/38, 28.9%). Only one (2.6%) patient had treatment-related serious adverse event (SAE) in 600 mg QD cohort due to thrombocytopenia. PK analysis showed BPI-9016M and its main metabolites (M1 and M2-2) reached steady state after seven days of continuous administration. At the dose of 300 mg QD and 450 mg QD, the exposure of BPI-9016M increased with increasing dose. Exposure of BPI-9016M was similar at 450 mg QD and 600 mg QD, which may exhibit a saturation trend. In all patients, ORR and DCR were 2.6% (1/38, 95% confidence interval [CI] 0.1–13.8%) and 42.1% (16/38, 95% CI 26.3–59.2%), respectively. Only one partial response (PR) patient was observed at a dose of 600 mg QD in Part A. In Part B, DCR was 75.0% (3/4, 95% CI 19.4–99.4%). The median PFS and OS in all 38 patients were 1.9 months (95% CI 1.9–3.7) and 10.3 months (95% CI 7.3–not evaluable [NE]), respectively.ConclusionBPI-9016M showed manageable safety profile in c-MET overexpression or MET exon 14 skipping mutation patients with locally advanced or metastatic NSCLC, but showed limited efficacy.Trial registrationClinicaltrials.gov NCT02929290 (11/10/2016).

Abstract 3923: Identification of membrane-expressed CAPRIN-1 as a novel and universal cancer target and generation of a therapeutic anti-CAPRIN-1 antibody TRK-950

Abstract Specific targets for cancer treatment are highly desirable, but still remain to be discovered. While previous reports suggested that CAPRIN-1 localizes in the cytoplasm, here we now show that part of this molecule is strongly expressed on the cell membrane surface in most solid cancers, but not normal tissues. Notably, the membrane expression of CAPRIN-1 extended to the subset of highly tumorigenic cancer stem cells and EMT induced metastatic cancer cells. In addition, we revealed that cancer cells with particularly high CAPRIN-1 surface expression exhibited enhanced tumorigenicity. We generated a therapeutic humanized anti-CAPRIN-1 antibody (TRK-950), which strongly and specifically binds to various cancer cells and shows anti-tumor effects via engagement of immune cells. TRK-950 was further developed as a new cancer drug and a series of pre-clinical studies demonstrates its therapeutic potency in a tumor bearing mouse model and safety in a relevant cynomolgus monkey model. Together our data demonstrate that CAPRIN-1 is a novel and universal target for cancer therapies. A phase I clinical study of TRK-950 (NCT02990481) has been completed and a phase Ib study (combination with approved drugs) is currently underway (NCT03872947). Citation Format: Fumiyoshi Okano, Takanori Saito, Yoshitaka Minamida, Shinichi Kobayashi, Takayoshi Ido, Yasushi Miyauchi, Ukei Wasai, Jiang Ke, Alexandra Aicher, Christopher Heeschen, Tetsu Yonehara. Identification of membrane-expressed CAPRIN-1 as a novel and universal cancer target and generation of a therapeutic anti-CAPRIN-1 antibody TRK-950. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3923.

132TiP Boosting immune response with copanlisib in locally advanced unresectable non-small cell lung cancer starting durvalumab consolidation: A phase Ib study

132TiP Boosting immune response with copanlisib in locally advanced unresectable non-small cell lung cancer starting durvalumab consolidation: A phase Ib study

Results of a phase Ib study of SB-121, an investigational probiotic formulation, a randomized controlled trial in participants with autism spectrum disorder

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by core impairments in social communication as well as restricted, repetitive patterns of behavior and/or interests. Individuals with ASD, which includes about 2% of the US population, have challenges with activities of daily living and suffer from comorbid medical and mental health concerns. There are no drugs indicated for the core impairments of ASD. As such, there is a significant need for the development of new medication strategies for individuals with ASD. This first-in-human placebo-controlled, double-blind, crossover study investigated the safety (primary objective) and efficacy of oral SB-121, a combination of L. reuteri, Sephadex® (dextran microparticles), and maltose administered once daily for 28 days in 15 autistic participants. SB-121 was safe and well tolerated. SB-121-associated directional improvements in adaptive behavior measured by Vineland-3 and social preference as measured with eye tracking were noted. These results provide support for further clinical evaluation of SB-121 as a treatment in autistic patients. To evaluate the safety and tolerability of multiple doses of SB-121 in subjects with autism spectrum disorder. Single-center, randomized, placebo-controlled, double-blind, crossover trial. 15 patients with autism spectrum disorder were randomized and analyzed. Daily dosing of SB-121 or placebo for 28 days, followed by approximately a 14 day washout, then 28 days of dosing with other treatment. Incidence and severity of adverse events, presence of Limosilactobacillus reuteri and Sephadex® in stool, and incidence of bacteremia with positive L. reuteri identification. Additional outcomes include changes from baseline on cognitive and behavior tests as well as biomarker levels. Adverse event rates were similar between SB-121 and placebo, with most reported as mild. There were no severe or serious adverse events. No participants had features of suspected bacteremia or notable changes in vital signs, safety laboratory, or ECG parameters from baseline. There was a statistically significant increase from baseline in the Vineland-3 Adaptive Behavior Composite score (p = 0.03) during SB-121 treatment. There was a trend for increased social/geometric viewing ratio following SB-121 treatment compared to placebo. SB-121 was safe and well tolerated. SB-121-associated directional improvements in adaptive behavior measured by Vineland-3 and social preference as measured with eye tracking were noted.Trial registration: clinicaltrials.gov Identifier: NCT04944901.

Predicted Bezlotoxumab Exposure in Patients Who Have Received a Hematopoietic Stem Cell Transplant

Bezlotoxumab is approved for prevention of recurrent Clostridioides (Clostridium) difficile infection (CDI) in adults receiving antibacterial treatment for CDI who are at high risk for recurrent CDI. Previous studies have shown that although serum albumin levels are an important predictor for bezlotoxumab exposure, this has no clinically meaningful impact on efficacy. This pharmacokinetic modeling study assessed whether hematopoietic stem cell transplant (HSCT) recipients, at increased risk of CDI and exhibiting decreased albumin levels within the first month posttransplant, are at risk of clinically relevant reductions in bezlotoxumab exposure. Observed bezlotoxumab concentration-time data pooled from participants in Phase III trials MODIFY I and II (ClinicalTrials.gov identifiers NCT01241552/NCT01513239) and three Phase I studies (PN004, PN005, and PN006) were used to predict bezlotoxumab exposures in two adult post-HSCT populations: A Phase Ib study of posaconazole including allogeneic HSCT recipients (ClinicalTrials.gov identifier NCT01777763; posaconazole-HSCT population); and a Phase III study of fidaxomicin for CDI prophylaxis (ClinicalTrials.gov identifier NCT01691248; fidaxomicin-HSCT population). The bezlotoxumab PK model used the minimum albumin level for each individual in post-HSCT populations to mimic a "worst-case scenario." Predicted worst-case bezlotoxumab exposures for the posaconazole-HSCT population (N=87) were decreased by 10.8% versus bezlotoxumab exposures observed in the pooled Phase III/Phase I data set (N=1587). No further decrease was predicted for the fidaxomicin-HSCT population (N=350). Based on published population pharmacokinetic data, the predicted decrease in bezlotoxumab exposure in the post-HSCT populations is not expected to have a clinically meaningful effect on bezlotoxumab efficacy at the recommended 10 mg/kg dose. Dose modification is therefore not required in the hypoalbuminemia setting expected post-HSCT.

Abstract PD13-05: PD13-05 Updated results of a Phase 1b study of gedatolisib plus palbociclib and endocrine therapy in women with hormone receptor positive advanced breast cancer: Subgroup analysis by PIK3CA mutation status

Abstract Background: Addition of PI3K/mTOR inhibitor after progression on CDK4/6 inhibitor (CDK4/6i) and endocrine therapy (ET) can potentially restore sensitivity to CDK4/6i and prevent adaptive activation of the PI3K/mTOR pathway. To evaluate this hypothesis, we conducted a Phase Ib study of gedatolisib (G), a dual inhibitor of PI3K/mTOR, palbociclib (P) a CDK4/6i, and ET (with letrozole [LET] or fulvestrant [FUL]) in women with hormone receptor positive (HR+)/HER2- advanced breast cancer (ABC). Manageable toxicity and preliminary antitumor activity were observed in 35 patients(pts) enrolled in the dose escalation portion of the study (Forero-Torres, ASCO 2018) and 103 pts enrolled in the expansion portion of the study (Layman, SABCS 2021). Here, we report updated efficacy and safety data and sub-group analysis by PIK3CA mutation status in the four expansion study arms with a March 3, 2022, data cut-off. Methods: Pts with HR+/HER2- ABC were treated in four expansion arms: A) G+P+LET as first-line treatment, B) G+P+FUL as 2nd line treatment in pts without prior CDK4/6i; C & D) G+P+FUL as 2nd or 3rd line therapy in pts with prior CDK4/6i. P, LET, and FUL were administered at standard doses. G 180 mg was intravenously administered weekly in Arms A, B, and C and three weeks on/one week off in Arm D. The primary endpoint was investigator assessed objective response rate (ORR). Secondary endpoints included safety, duration of response and progression free survival (PFS). Results: Of the 103 pts treated with G+P+ ET in the expansion arms (A-D), 100% had measurable disease at baseline, 71% (73/103) lacked PIK3CA mutations (wild type; WT), 27% (28/103) had PIK3CA-mutations (MT), 70% (72/103) had evidence of bone metastases, and 59% (61/103) had liver metastases. The most frequent grade 3 and 4 treatment related AEs (TRAE) with G+P+ET included neutropenia (63%), stomatitis (27%), rash (20%), fatigue (11%) and hyperglycemia (7%). Treatment discontinuation due to TRAEs was 6.5% in Arm A, 15.4% in Arm B, 9.4% in Arm C and 3.7% in Arm D. Efficacy data for each arm is presented in Table 1. Promising ORR and PFS were seen in all arms regardless of PIK3CA mutation status. In Arm D, ORR was 63% overall, 73% in PIK3CA-MT pts, and 60% in PIK3CA-WT pts. Median PFS in Arm D was 12.9 months with a median follow up of 29 months. 60% and 48% of pts in the PIK3CA-MT and PIK3CA-WT Arm D sub-groups, respectively, were progression free at 12 months. Conclusions: These preliminary data demonstrate promising activity of G+P+ET combination in pts who were CDK4/6i-naïve and in those whose disease progressed on or after CDK4/6i therapy regardless of PIK3CA mutation status. Encouraging results in CDK4/6i treatment naïve patients warrant further evaluation of gedatolisib in combination with CDK4/6i treatment in the front-line setting. Arm D results provide a strong basis for the initiated Phase 3 study (VIKTORIA-1) in pts whose disease progressed on or after CDK4/6i therapy. Table 1. Efficacy Data by Expansion Arms Citation Format: Robert Wesolowski, Hope Rugo, Erica Stringer-Reasor, Hyo S. Han, Jennifer M. Specht, E. Claire Dees, Peter Kabos, Ulka Vaishampayan, Seth A. Wander, Janice Lu, Keerthi Gogineni, Alexander I. Spira, Anne F. Schott, Maysa Abu-Khalaf, Pratima Nayak, Brian F. Sullivan, Igor Gorbatchevsky, AND Rachel M. Layman. PD13-05 Updated results of a Phase 1b study of gedatolisib plus palbociclib and endocrine therapy in women with hormone receptor positive advanced breast cancer: Subgroup analysis by PIK3CA mutation status [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD13-05.

Phase Ib study of talimogene laherparepvec in combination with atezolizumab in patients with triple negative breast cancer and colorectal cancer with liver metastases

Talimogene laherparepvec (T-VEC), a first-in-class oncolytic viral immunotherapy, enhances tumor-specific immune activation. T-VEC combined with atezolizumab, which blocks inhibitor T-cell checkpoints, could provide greater benefit than either agent alone. Safety/efficacy of the combination was explored in patients with triple negative breast cancer (TNBC) or colorectal cancer (CRC) with liver metastases. In this phase Ib, multicenter, open-label, parallel cohort study of adults with TNBC or CRC with liver metastases, T-VEC (106 then 108 PFU/ml; ≤4 ml) was administered into hepatic lesions via image-guided injection every 21 (±3) days. Atezolizumab 1200 mg was given on day 1 and every 21 (±3) days thereafter. Treatment continued until patients experienced dose-limiting toxicity (DLT), had complete response, progressive disease, needed alternative anticancer treatment, or withdrew due to an adverse event (AE). The primary endpoint was DLT incidence, and secondary endpoints included efficacy and AEs. Between 19 March 2018 and 6 November 2020, 11 patients with TNBC were enrolled (safety analysis set:n= 10); between 19 March 2018 and 16 October 2019, 25 patients with CRC were enrolled (safety analysis set: n= 24). For the 5 patients in the TNBC DLT analysis set, no patient had DLT; for the 18 patients in the CRC DLT analysis set, 3 (17%) had DLT, all serious AEs. AEs were reported by 9 (90%) TNBC and 23 (96%) CRC patients, the majority with grade ≥3 [TNBC, 7 (70%); CRC, 13 (54%)], and 1 was fatal [CRC, 1 (4%)]. Evidence of efficacy was limited. Overall response rate was 10% (95% confidence interval 0.3-44.5) for TNBC; one (10%) patient had a partial response. For CRC, no patients had a response; 14 (58%) were unassessable. The safety profile reflected known risks with T-VEC including risks of intrahepatic injection; no unexpected safety findings from addition of atezolizumab to T-VEC were observed. Limited evidence of antitumor activity was observed.

A phase Ib study of interleukin-2 plus pembrolizumab for patients with advanced melanoma.

High-dose interleukin-2 (HD IL-2) and pembrolizumab are each approved as single agents by the U.S. F.D.A. for the treatment of metastatic melanoma. There is limited data using the agents concurrently. The objectives of this study were to characterize the safety profile of IL-2 in combination with pembrolizumab in patients with unresectable or metastatic melanoma. In this Phase Ib study, patients received pembrolizumab (200 mg IV every 3 weeks) and escalating doses of IL-2 (6,000 or 60,000 or 600,000 IU/kg IV bolus every 8 hours up to 14 doses per cycle) in cohorts of 3 patients. Prior treatment with a PD-1 blocking antibody was allowed. The primary endpoint was the maximum tolerated dose (MTD) of IL-2 when co-administered with pembrolizumab. Ten participants were enrolled, and 9 participants were evaluable for safety and efficacy. The majority of the evaluable participants (8/9) had been treated with PD-1 blocking antibody prior to enrollment. Patients received a median of 42, 22, and 9 doses of IL-2 in the low, intermediate, and high dose cohorts, respectively. Adverse events were more frequent with increasing doses of IL-2. No dose limiting toxicities were observed. The MTD of IL-2 was not reached. One partial response occurred in 9 patients (11%). The responding patient, who had received treatment with an anti-PD-1 prior to study entry, was treated in the HD IL-2 cohort. Although the sample size was small, HD IL-2 therapy in combination with pembrolizumab appears feasible and tolerable. ClinicalTrials.gov, identifier NCT02748564.

Phase Ib open-label study to evaluate safety, tolerability, immunogenicity, and efficacy of multiple subcutaneous injections of PolyPEPI1018 vaccine as an add-on immunotherapy to TAS-102 in participants with late-stage microsatellite-stable metastatic colorectal cancer (MSS mCRC; OBERTO-201).

147 Background: PolyPEPI1018 is an off-the-shelf, multi-peptide vaccine containing 12 immunogenic epitopes derived from 7 cancer testis antigens (CTAs) frequently expressed in patients with colorectal cancer (CRC). PolyPEPI1018 successfully induced anticancer immunity and triggered recruitment and infiltration of cytotoxic T cells into the tumor of MSS mCRC subjects demonstrating also early evidence of clinical activity, in first-line mCRC. Here we report the initial results of the phase Ib study of PolyPEPI1018 vaccine plus trifluridine/tipiracil (TAS-102) in late-stage mCRC patients. Methods: Patients with MSS mCRC who have progressed on ≤2 lines of prior chemotherapy regimen for mCRC received PolyPEPI1018 subcutaneously on days 1 and 15 and TAS-102 orally twice daily on days 1-5 and 8-12 of a 28-day cycle. Treatment continued for up to 7 cycles until disease progression or unacceptable toxicity. Immunomonitoring was performed at both blood and tumor levels prior to- and on study treatment. The primary endpoint of the study was safety and tolerability. Data on objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and correlation studies will be also presented. Results: 15 patients (67% male) started treatment. At baseline, median age was 55 years (range 31–71), 73% had liver metastases and the primary tumor site was colon-sigmoid in 40% and rectum in 33%. The combination was well-tolerated; most common side effect related to PolyPEPI1018 was Grade (Gr) 1-2 local skin reactions in 93% of patients. Gr 3 events. There were no Gr 4 or 5 events. The ORR was 0% and the DCR was 50%. The mPFS was 2.5 months (95%CI 2.1-NR). At the data cut-off (September 7, 2022), the mOS has not been reached; median follow-up was 4.0 months (95% CI 2.2-4.4). Post-treatment, vaccine-specific T cell responses were detected ex vivo in the PBMC of 4/5 subjects tested. In addition, one subject who had no detectable T cell response at peripheral level, responded at the tumor level with more than 300% increase of both CD3+ and CD8+ tumor-infiltrating lymphocytes compared to baseline. Patients with increased PFS (≥ 16 weeks) had robust vaccine-specific T cell responses. Conclusions: To our knowledge, this is the first phase Ib study investigating combination of a cancer vaccine with TAS-102 chemotherapy in advanced MSS mCRC. Our results show that PolyPEPI1018 plus TAS-102 was well-tolerated with few grade 3 AEs beyond what is expected with TAS-102 monotherapy. PolyPEPI1018 induced immunological responses at both peripheral and tumor level, albeit no objective tumor responses could be detected. The study is on-going for the collection of overall survival data. Clinical trial information: NCT05130060 .

Phase Ib study testing neoadjuvant transforming growth factor (TGF)-β antibody, NIS793, plus 5-fluorouracil, irinotecan, and oxaliplatin chemotherapy (FOLFIRINOX) in patients (pts) with borderline resectable (BR)/locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC).

TPS762 Background: Overcoming resistance to chemotherapy and immune checkpoint inhibitors remains an unmet need for PDAC. In this context, TGF-β plays a key role in PDAC by promoting the activation of fibroblasts and extracellular matrix deposition, facilitating epithelial-to-mesenchymal transition, immune evasion, and resistance to chemotherapy. Combination of FOLFIRINOX with losartan, an indirect TGF-β inhibitor with antifibrotic properties, has shown an increased R0 resection rate in pts with BR/LA PDAC, providing the rationale to explore the combination of other TGF-β targeting agents with FOLFIRINOX in the neoadjuvant setting (PMID: 34884782; PMID: 31145418). NIS793 is a first-in-class monoclonal antibody that directly binds TGF-β and reduces intratumoral fibrosis in preclinical models (PMID: 33298926). NIS793 also has an acceptable safety profile and preliminary clinical activity. This study investigates whether NIS793 modulation of the tumor fibrotic network improves clinical outcomes of FOLFIRINOX neoadjuvant therapy in BR/LA PDAC. Our aim is to demonstrate how TGF-β inhibition and stroma remodeling contribute to clinical outcomes. Methods: This is a single institution, open label, 2-part, 2-arm, non-comparator, Phase Ib study (NCT05417386) of FOLFIRINOX + NIS793 as neoadjuvant therapy for pts with untreated BR/LA PDAC. Eligible pts are adults with measurable disease, adequate organ and bone marrow function, and ECOG PS ≤1. In Part 1 (safety run-in), 6-18 pts with histologically confirmed untreated metastatic PDAC receive FOLFIRINOX + NIS793 at different dose levels. Dose escalation is primarily guided by the number of dose-limiting toxicities. Primary objectives are assessing safety, defining the recommended Phase II dose (RP2D), and providing initial evidence of clinical benefit of the combination. In Part 2, pts with untreated BR/LA PDAC are randomized 4:1 and stratified by BR vs LA. Pts in Arm 1 (n=5) receive 8 cycles of FOLFIRINOX followed by chemoradiation therapy (CRT) and surgery. Pts in Arm 2 (n=23) receive 8 cycles of FOLFIRINOX + NIS793 at RP2D followed by CRT + NIS793, surgery, and 12 cycles of adjuvant NIS793. The primary endpoint is R0 resection rate. Secondary endpoints are disease-free survival, progression-free survival, overall survival, and pathologic complete response. The effect of neoadjuvant therapy will be assessed by ferumoxytol-MRI, circulating cell-free DNA dynamics analysis, single-cell RNA sequencing, immunohistochemistry, and digital spatial analysis. Together, these correlative analyses may enable development of a mechanistic model for TGF-β inhibition in PDAC. This study is ongoing. The first pt was treated on Aug 2, 2022. Clinical trial information: NCT05417386 .

Phase Ib study of dabrafenib, trametinib, irinotecan and cetuximab in BRAF V600E-mutated metastatic colorectal cancer.

156 Background: The low efficacy of single-agent BRAF inhibitor in metastatic colorectal cancer (mCRC) is usually due to EGFR feedback upregulation caused by BRAF blockade. Therefore, multi-drug combination therapy with BRAF inhibitor has been tried. Here, we reported the preliminary results of quadruple therapy with dabrafenib, a selective BRAF inhibitor, trametinib, a selective MEK inhibitor, irinotecan and cetuximab in patients with BRAF V600E-mutated mCRC. Methods: This was an ongoing phase Ib study, patients with mCRC who relapse or refractory to standard treatments were enrolled. Patients were treated with dabrafenib (150mg/150mg doses orally twice daily), trametinib (2mg orally once daily), irinotecan (80mg/m2 weekly) and cetuximab (400mg/m2 in first dose and 250mg/m2 weekly). Treatment was continued until disease progression, development of unacceptable toxicity, or drawal of consent. The primary end-point was disease control rate (DCR), and the secondary end-points included progression-free survival (PFS) and duration of disease remission (DOR). This trial is registered with Chinese ClinicalTrials.gov, number ChiCTR2200063316. Results: From July 2018 to January 2021, 10 patients were enrolled. The median age was 53.5 (age 25-65), nine with colon cancer and one with rectal cancer. The most common adverse events (AEs) (50% or more) were fatigue, fever, rash, vomit, leukopenia, anemia, ALT elevation, and AST elevation. Four patients suffered rash which was the most common severe AE (SAE). Two patients presented with grade 3/4 anemia. Only one patient suffered grade 3/4 AEs with nausea and vomit. The DCR was 90% (9/10). After a median follow-up of 19.7 months, the median PFS was 7.5 months (range 1.8-32.4 months). The median DOR was 5.2 months (range 0-27.7 months). Conclusions: Dabrafenib, trametinib, irinotecan and cetuximab has tolerable toxicity and promising antitumor activity in BRAF V600E-mutated mCRC. This regimen warrants a further phase II clinical trial. Clinical trial information: ChiCTR2200063316 . [Table: see text]

Phase Ib of pembrolizumab (pem) in combination with stereotactic body radiotherapy (SBRT) for resectable liver oligometastatic MMR-proficient (pMMR) colorectal cancer (CRC): Final results.

161 Background: SBRT is a standard treatment option for oligometastatic CRC and is associated with an increase in immunogenic antigen release and influx of immune cells. We hypothesized that radiation would enhance the immunogenicity of pMMR CRC and potentiate the effectiveness of PD-1 blockade. This phase Ib study examined the safety and efficacy of the sequential combination of SBRT and Pem in patients (pts) undergoing resection of their disease. Additionally, the accumulation and proteolysis of versican (VCAN), an immunoregulatory tumor matrix proteoglycan was examined as a novel immunotherapy biomarker. Proteolysis of VCAN results in the release of an immunostimulatory fragment, versikine. Cancers with low VCAN and high versikine (VCAN proteolysis predominant (VPP)) are hypothesized to respond better to immunotherapies. Methods: Eligibility criteria included resectable liver-confined metastatic pMMR CRC. Prior surgery and systemic chemotherapy were allowed. Subjects received sequential SBRT and cycle 1 of Pem prior to operative management and adjuvant Pem. The primary objectives were to determine the safety/tolerability of this regimen and the recurrence free survival (RFS) at 1 year following operative management. Correlative studies examined tumor infiltrating CD8+ T lymphocytes (TILs), VCAN, and versikine using immunohistochemistry. Results: 15 pts (median age 61.5 [range 39-69], 26% female) were enrolled. All pts had prior FOLFOX. The number of liver lesions ranged from 1-6. SBRT median dose was 50 Gy (40-60 Gy) to 1-2 liver lesions. Grade 3/4 AEs included one case of biliary tract injury and biloma, and one case of G3 hypophosphatemia. No grade 3/4 immune-related AEs occurred. All pts completed a minimum follow-up of 1 year post resection (median follow-up 41 months [range 15-64]). In the intention to treat analysis, the 1 year RFS was 67% (historic control 50%), 40% of patients remained cancer free, and 67% of pts are still alive. 2 of 3 pts with BRAF V600E mutations have had early recurrences. 2 pts had VCAN high tumors and both recurred prior to 1 year. 6 pts had VPP cancers and 83% were recurrence free at 1 year and 66% are currently without evidence of cancer. Conclusions: The combination of SBRT with Pem was well tolerated with no signal of increased immunotherapy-related toxicity. This study met its primary endpoint and this regimen deserves further investigation in confirmatory studies. Additionally, VCAN accumulation and proteolysis are promising biomarkers in this setting. Clinical trial information: NCT02837263 .

A Proactive Approach to Prevent Hematopoietic Exhaustion During Cancer Chemotherapy in Older Patients: Temporary Cell-Cycle Arrest.

Age is associated with the decline of multiple organ systems. In older patients, hematological toxicities associated with chemotherapy are often dose limiting, impairing dose intensity and treatment efficacy. Contrary to the classical path using growth factors to activate tissue regeneration, a novel strategy is emerging to prevent chemotherapy toxicity that involves temporary cell-cycle arrest of normal cells, such as hematopoietic or epithelial precursors. This proactive approach may allow the sparing of the stem cell reserve of these tissues. Two molecules are included in this new category, trilaciclib and ALRN-6924, which induce cell-cycle arrest by two different pathways. Previous approaches, such as the use of myelopoietic growth factors, were reactive and they might even have accelerated the depletion of stem cells by enhancing the commitment of these elements. Trilaciclib causes cell-cycle arrest by CDK 4/6 inhibition and ALRN-6924 by p53 activation. In a pooled analysis of three randomized phase II studies of patients with small cell lung cancer, trilaciclib prevented neutropenia, thrombocytopenia, and anemia. Similar chemoprotective results were observed with ALRN-6924 in an open-label phase Ib study of patients with p53-mutated small cell lung cancer. Trilaciclib is now approved as a myelopreservation agent in patients with extensive-stage small cell lung cancer. ALRN-6924 is currently in phase Ib clinical development in patients with p53-mutated cancer. In addition to preserving the normal hemopoietic pool, these drugs promise to preserve the stem cell reserve of other normal tissues with high turnover, preventing potentially other dose-limiting toxicities, such as mucositis and diarrhea. An "ex vivo" study provided early evidence that ALRN-6924 may prevent chemotherapy-induced alopecia. By affording protection from multiple toxicities with a single drug, trilaciclib and ALRN-6924 have the potential to transform the current standards of supportive care for oncology patients and may prevent the depletion of tissue stem cells already compromised with age.

Nab-PIPAC: a phase IB study protocol of intraperitoneal cisplatin and nab-paclitaxel administered by pressurised intraperitoneal aerosol chemotherapy (PIPAC) in the treatment of advanced malignancies confined to the peritoneal cavity

IntroductionIntraperitoneal dissemination is a major problem resulting in very poor prognosis and a rapid marked deterioration in the quality of life of patients. Pressurised intraperitoneal aerosol chemotherapy (PIPAC) is an...

Phase Ib study of HSP90 inhibitor, onalespib (AT13387), in combination with paclitaxel in patients with advanced triple-negative breast cancer.

Heat shock protein 90 (HSP90) is a molecular chaperone required for stabilization of client proteins over-activated in triple-negative breast cancer (TNBC). Over-expression of HSP90 client proteins has been implicated in paclitaxel resistance. Onalespib (AT13387) is a potent inhibitor of HSP90 that could improve paclitaxel efficacy when administered in combination. This phase Ib trial administered onalespib with paclitaxel in patients with advanced TNBC to assess safety and establish a recommended phase II dose (RP2D). The primary objectives were determining the dose-limiting toxicities and maximum tolerated dose of combination therapy. Secondary objectives included pharmacokinetic (PK) analysis and determination of overall response rate (ORR), duration of response (DOR), and progression-free survival (PFS). Patients with advanced TNBC were treated with standard dose intravenous paclitaxel in combination with intravenous onalespib at doses ranging from 120 to 260 mg/m2 administered on days 1, 8, and 15 of a 28-day cycle using a standard 3 + 3 design. A total of 15 patients were enrolled to dose expansion cohort at RP2D to confirm safety profile. Thirty-one patients were enrolled in the study, of which over 90% had received prior taxane therapy. Paclitaxel was given for metastatic disease in 23% of patients. Adverse events (AEs) included anemia (grade 3: 20%), lymphopenia (grade 3: 17%), and neutropenia (grade 3: 33%, grade 4: 4%). The most frequent grade ⩾3 non-hematologic AE was diarrhea (7%). The established RP2D was 260 mg/m2 onalespib when given with paclitaxel at 80 mg/m2. PK analysis revealed a modest drug interaction profile for onalespib in the combination regimen. ORR was 20%. Three patients achieved complete responses, all of whom had received prior taxane therapy. Median DOR was 5.6 months; median PFS was 2.9 months. Combination treatment with onalespib and paclitaxel had an acceptable toxicity profile and RP2D was determined to be 260 mg/m2 of onalespib. Combination therapy showed antitumor activity in patients with advanced TNBC. Onalespib and paclitaxel in treating patients with advanced TNBC https://clinicaltrials.gov/ct2/show/NCT02474173.

A pilot phase Ib study to evaluate tadalafil to overcome immunosuppression during chemoradiotherapy for IDH-wild-type glioblastoma.

Myeloid-derived suppressor cells (MDSCs) are critical regulators of immunosuppression and radioresistance in glioblastoma (GBM). The primary objective of this pilot phase Ib study was to validate the on-target effect of tadalafil on inhibiting MDSCs in peripheral blood and its safety when combined with chemoradiotherapy in GBM patients. Patients with newly diagnosed IDH-wild-type GBM received radiation therapy (RT) and temozolomide (TMZ) combined with oral tadalafil for 2 months. A historical cohort of 12 GBM patients treated with RT and TMZ was used as the comparison group. The ratio of MDSCs, T cells, and cytokines at week 6 of RT compared to baseline were analyzed using flow cytometry. Progression-free survival (PFS) and overall survival (OS) were estimated by the Kaplan-Meier method. Tadalafil was well tolerated with no dose-limiting toxicity among 16 evaluable patients. The tadalafil cohort had a significantly lower ratio of circulating MDSCs than the control: granulocytic-MDSCs (mean 0.78 versus 3.21, respectively, P = 0.01) and monocytic-MDSCs (1.02 versus 1.96, respectively, P = 0.006). Tadalafil increased the CD8 ratio compared to the control (1.99 versus 0.70, respectively, P < 0.001), especially the PD-1-CD8 T cells expressing Ki-67, CD38, HLA-DR, CD28, and granzyme B. Proinflammatory cytokine IL-1β was also significantly increased after tadalafil compared to the control. The tadalafil cohort did not have significantly different PFS and OS than the historical control. Concurrent tadalafil is well tolerated during chemoradiotherapy for GBM. Tadalafil is associated with a reduction of peripheral MDSCs after chemoradiotherapy and increased CD8 T-cell proliferation and activation.

Niclosamide in prostate cancer: An inhibitor of AR-V7, a mitochondrial uncoupler, or more?

A recent phase Ib study investigating the use of reformulated niclosamide in combination with abiraterone and prednisone in patients with castration-resistant prostate cancer (CRPC) demonstrated encouraging preliminary efficacy with low toxicity. Preclinical studies have reported that niclosamide at clinically relevant concentrations inhibits androgen receptor splice variant 7 (AR-V7), a known tumor driver in CRPC. However, the magnitude of anti-tumor effects of niclosamide either used alone or in combination with abiraterone in these experimental models, far exceeded what could have been explained as a simple AR-V7 inhibition. Niclosamide at clinically relevant concentrations also acts as an oxidative phosphorylation (OxPhos) uncoupler in mitochondria. This raises the question whether the observed effects of niclosamide were partly mediated by OxPhos inhibition. Most OxPhos inhibitors did not demonstrate selectivity towards cancer cells and failed to enter clinical practice due to unacceptable toxicity. However, some mitochondrial uncouplers have greater cytotoxicity against cancerous cells compared to non-cancerous. Hyperpolarization of cancer cell mitochondria, or the more alkaline mitochondrial matrix of cancer cells could be potential reasons for this. Niclosamide can also alter Wnt/β-catenin, mTOR, Notch, NF-kB and STAT3 signaling pathways. Hence, the mechanism of action of reformulated niclosamide in CRPC patients requires further investigation. This will potentially lead to new opportunities to develop and investigate even more selective and effective treatments against prostate cancer.