anti-PD1 Monoclonal Antibodies Research Articles

PD1 blockade improves survival during lethal microbial exposure in old mice

Abstract The elderly and those with chronic diseases have a 2 to 10-fold increased risk of hospitalization and mortality following infection as compared with healthy adults. A significant contributor to disease severity is the aging of the immune system, including an expansion of exhausted T cells. These cells simultaneously promote excessive levels of inflammation and display impaired T cell activation and function. How exhausted T cells from aged individuals respond to infection and whether acute restoration of T cell activation further exacerbates the inflammatory environment or generates functional T cells is unclear. Previously, we used a mouse model of normal microbial exposure (NME), where old specific pathogen-free (SPF) mice show 100% mortality following exposure to multiple microbes ordinarily found in pet store mice. In the present study, we show that when exposed to NME, old SPF mice have increased expression of multiple inflammatory pathways and exhibit elevated frequencies of a heterogenous, exhausted CD8 +T cell pool that expresses differing combinations of programmed cell death protein 1 (PD1), TOX, and CXCR5. Pre-treatment or intervention with an anti-PD1 monoclonal blocking antibody during the exposure of old SPF mice to NME significantly improves both antibody production and survival, without altering the acute inflammatory response. Anti-PD1 checkpoint blockade-mediated survival is dependent on CD8 +, but not CD4 +T cells. Correspondingly, CD8 +PD1 +T cells from old mice given anti-PD1 monoclonal antibody have increased granzyme B production. These data reveal a new approach for reducing vulnerability to infections in the elderly by targeting CD8 +T cell exhaustion through PD1 checkpoint blockade immunotherapy. This work was supported by National Institute on Aging grant R00 AG058800 (C.D.C.), R21AG078638, the Fesler-Lampert Chair in Aging Studies, the Glenn Foundation for Medical Research/AFAR Grants for Junior Faculty, Irene Diamond Fund/AFAR Postdoctoral Transition Award (M.J.Y) and the Medical Discovery Team on the Biology of Aging.

Abstract #1401677: Pembrolizumab Induced Autoimmune Diabetes Mellitus

Immune checkpoint inhibitors (ICIs) are integral in the treatment of a myriad of malignancies. While ICIs have significantly improved outcomes and cancer survivorship, they have also been implicated in immune related adverse events (irAEs), particularly autoimmune endocrinopathies. Common ICI associated endocrine disorders include hypothyroidism, hyperthyroidism, and primary adrenal insufficiency but rarely diabetes mellitus (DM). ICI induced DM is defined as severe and persistent insulin deficiency after treatment with an ICI. Here, we present a rare case of pembrolizumab induced DM presenting with hyperglycemic hyperosmolar state (HHS). A 77-year-old male with a past medical history of prediabetes on no medical therapy and melanoma of the right upper extremity was admitted with progressive polydipsia, polyuria and acute encephalopathy. Notably, the patient completed two cycles of pembrolizumab two weeks prior to admission. Initial workup demonstrated a glucose of 837 mg/dL (65-99), anion gap of 10 (3-11), small amounts of serum acetone and beta hydroxybutyrate, and a serum osmolality of 369 mOsm/kg (279-295). Venous blood gas revealed a pH of 7.33 (7.31-7.41), pCO2 45 mmHg (41-51), HCO3 24 mEq/L (23-29). Objective data supported the diagnosis of HHS. Hemoglobin A1c prior to initiation of pembrolizumab was 6.1% (< 5.7%) and on admission was 9.1%. He improved with intravenous insulin and fluids. After transition to basal/bolus insulin the patient’s fasting glucose was 126 mg/dL (65-99) with a c-peptide level of 0.41 ng/mL (0.80-3.85), consistent with insulin insufficiency. Glutamic acid decarboxylase 65 autoantibodies were positive, while islet cell and IA-2 autoantibodies were negative. Pembrolizumab was discontinued after the diagnosis of ICI induced DM was established. Our case highlights the unique course of a patient with prediabetes on pembrolizumab who developed ICI induced DM. Pembrolizumab (anti PD-1 monoclonal antibody) can cause an abnormal cytotoxic T cell (CD8+ T cell) mediated beta cell destruction and development of ICI induced DM. ICI induced DM shares characteristics of Type 1 DM with positive autoantibodies and insulin insufficiency. Insulin deficiency often precipitates diabetic ketoacidosis which was not seen in our patient. Given low but detectable c-peptide levels, our patient was likely insulin insufficient and not yet insulin deficient. This case highlights the importance of closely monitoring patients on ICIs, especially those with a predisposition to DM. In patients receiving immunotherapy, early identification of adverse events and risk stratification is essential in reducing morbidity and providing comprehensive care.

Targeting USP2 regulation of VPRBP-mediated degradation of p53 and PD-L1 for cancer therapy

Since Mdm2 (Mouse double minute 2) inhibitors show serious toxicity in clinic studies, different approaches to achieve therapeutic reactivation of p53-mediated tumor suppression in cancers need to be explored. Here, we identify the USP2 (ubiquitin specific peptidase 2)-VPRBP (viral protein R binding protein) axis as an important pathway for p53 regulation. Like Mdm2, VPRBP is a potent repressor of p53 but VPRBP stability is controlled by USP2. Interestingly, the USP2-VPRBP axis also regulates PD-L1 (programmed death-ligand 1) expression. Strikingly, the combination of a small-molecule USP2 inhibitor and anti-PD1 monoclonal antibody leads to complete regression of the tumors expressing wild-type p53. In contrast to Mdm2, knockout of Usp2 in mice has no obvious effect in normal tissues. Moreover, no obvious toxicity is observed upon the USP2 inhibitor treatment in vivo as Mdm2-mediated regulation of p53 remains intact. Our study reveals a promising strategy for p53-based therapy by circumventing the toxicity issue.

Abstract 3228: Photodynamic priming enhances immunotherapy responses overcoming oncogenic drivers in pancreatic patient derived tumor organoids

Abstract Photodynamic therapy (PDT) is an anti-cancer therapy that utilizes light, a photoresponsive photosensitizer (PS), and oxygen to confer direct cytotoxicity or vascular damage. PDT alters the tumor microenvironment (TME) transiently in a process termed photodynamic priming (PDP), making it more receptive to subsequent therapies. Previous studies reported that PDP exerts immune stimulatory effects via the release of damage associated molecular patterns (DAMPs) as a potent inducer of immunogenic cell death. Pancreatic cancer (PC) is a lethal human malignancy with no curable treatments available thus far. The desmoplastic stroma in PC limits the delivery of therapeutic agents contributing to treatment resistance. More, the stroma promotes an immunosuppressive TME that leads to immune exclusion, which is largely responsible for the immunotherapy failure in PC. Therefore, there is an unmet need to find more effective combination therapies against PC. In this work, we evaluated whether PDP enhances anti-PD1 therapy response by modulating immunogenicity in PC patient-derived organoids (PDOs). Visudyne (PS) and varied light doses of 25-100 J/cm2 were used for PDP treatments. Our data showed light dose dependent cytotoxicity and the expression of DAMPs including HSP60, calreticulin and HMGB1 in PDOs. Gene expression analysis of PDP treated PDOs showed increases in IFNγ, TNFα and CXCL12 while decreases in PDL1, TGFβ1 and FOXP1. Coculture of healthy donor (HD) monocyte-derived dendritic cells (mDCs) for 24 h with PDOs treated with a sublethal dose of PDP (25 J/cm2) showed increased CD40, CD86 and MHC11 activation markers on mDCs. Addition of matched HD naïve T cells 24 h post mDC-PDO coculture led to the excessive activation of CD4+ and CD8+ T cells highlighted by the PD1 expression on T cells from 0 h of initial T cell coculture to 48 h. This led us to treat PDO-mDC-T cell cocultures at 0 h to 48 h of initial T cell coculture with the anti-PD1 monoclonal antibody, Pembrolizumab. The treatment response was measured by live imaging of PDO growth followed by the analysis of changes in PDO diameter/area from day 0 of PDP to day 7 post-PDP. There were significant decreases in PDO growth in cultures treated with PDP followed by Pembrolizumab at different time points compared to untreated PDOs, untreated PDO-mDC-T cell cocultures, PDOs treated with PDP alone, PDO-mDC-T cell cocultures treated with PDP only or PDO-mDC-T cell cocultures treated with anti-PD1 alone. Also, we sorted T cells from the same cocultures at day 7 of PDP for gene expression analysis of T cell activation markers. There was enhanced expression of IFNγ, TNFα, FAS ligand, Granzyme B, IL2 and IL21 in T cells collected from combination therapy treated cocultures compared to others. Lastly, our data show that PDP can enhance anti-PD1 immunotherapy responses providing insights into a combination therapy option to treat PDAC. Citation Format: Pushpamali De Silva, Demi Wekking, Joanna Joeun Choe, Dario Missael Castellanos, Piotr Zelga, Russell Jenkins, Andrew Scott Liss, Tayyaba Hasan. Photodynamic priming enhances immunotherapy responses overcoming oncogenic drivers in pancreatic patient derived tumor organoids [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 3228.

Abstract 6367: BSI-507, a first-in-class bispecific antibody targeting PD1 and PVRIG for cancer immunotherapy

Abstract Introduction: Despite the success of anti-PD1/PDL1 therapies, only a small fraction of patients benefit from these checkpoint inhibitors (CPIs). Novel approaches to improve outcomes for patients who are resistant to current CPIs are needed. PVRIG is expressed on CD4+ and CD8+ T cells, NKT and NK cells. PVRIG binds with high affinity with its ligand PVRL2, which is expressed on tumor cells and some myeloid cells. The PVRIG-PVRL2 axis exerts an inhibitory effect on the cytotoxic activity of lymphocytes. Bispecific antibodies that exhibit dual blockade of PD1 and PVRIG provide a promising strategy to enhance anti-tumor immune response. Methods: An anti-PD1 mAb was identified from PD1 KO mice immunized with PD1-ECD-Fc and screened by our proprietary H3 (High-throughput, High-content and High-efficiency) platform. An anti-PVRIG mAb was identified from rats immunized with recombinant PVRIG-ECD-Fc and screened by the H3 platform. Both anti-PD1 and anti-PVRIG antibodies were humanized, and the anti-PD1 scFv was fused to the N-terminus of the heavy chain of the anti-PD1 antibody via a flexible linker. The binding activities and affinities were evaluated by ELISA, FACS and SPR, and the ligand blocking activities were measured by ELISA and FACS. Cell-based reporter assays were used to evaluate the functions of the anti-PD1 and anti-PVRIG mAbs alone and the bispecific antibody. In addition, the activity of the bispecific antibody to reverse PD1 and PVRIG mediated suppression of CMV pp65495-503 antigen specific CD8+ T-cell cytotoxicity was evaluated. Results: BSI-507, an anti-PD1xanti-PVRIG bispecific antibody demonstrated comparable activity to the parental anti-PD1 antibody regarding PD1 binding and PD1/PDL1 blocking. It also exhibited comparable activity to the parental anti-PVRIG antibody in PVRIG binding and PVRIG/PVRL2 blocking. Based on cell-based reporter assays, BSI-507 was able to reverse either PD1 or PVRIG mediated T-cell suppression and exhibited comparable potency to the parental antibodies. BSI-507 was also able to show enhanced reversal of both PD1 and PVRIG mediated T-cell suppression, much better than anti-PD1 or anti-PVRIG alone. In addition, BSI-507 showed the ability to reverse PD1 and PVRIG mediated suppression of CMV pp65495-503 antigen specific CD8+ T-cell cytotoxicity, stronger than either the anti-PD1 or anti-PVRIG monoclonal antibody. Summary: BSI-507 is a first-in-class anti-PD1xanti-PVRIG bispecific antibody for dual blockade of PD-1 and PVRIG pathways to enhance reversal of T cell inhibition. BSI-507 demonstrates favorable biophysical and functional characteristics, supporting the initiation of development activities including manufacturing and IND-enabling studies. Citation Format: Zeyu Peng, Xiaodong F. Liu, Hongyan Li, Wenwen Dai, Jinyu Liu, Xiaoyao Hao, Shukai Xia, Qun Lv, Hugh M. Davis, Mingjiu Chen, Mark Z. Ma. BSI-507, a first-in-class bispecific antibody targeting PD1 and PVRIG for cancer immunotherapy. [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 6367.

Isolated adrenocorticotropic hormone deficiency and sialadenitis associated with nivolumab: a case report

Immune checkpoint inhibition with anti-PD(L)1 and anti-CTLA4 antibodies has significantly changed cancer treatment during the last 10years. Nevertheless, boosting the immune system with immune checkpoint inhibition can result in immune-related adverse events, affecting different organ systems, among which the endocrine system is the most affected. However, there are few descriptions of the association of immune-related adverse events, and the pathophysiology of some is still lacking. Here, we report a 70-year-old Caucasian patient treated with nivolumab (anti-PD1 monoclonal antibody) after resection of a unique relapse of melanoma in the neck region who presented with sicca syndrome, extreme fatigue, and weight loss 6months after the start of anti-PD1 therapy. Blood tests revealed hypoglycemia and secondary hypocortisolism due to isolated adrenocorticotrophic hormone deficiency. Interestingly, brain methionine positron emission tomography/magnetic resonance revealed physiological metabolism of the pituitary gland, which was not increased in size, and no hypophyseal metastasis was detected. The sicca syndrome investigation revealed the absence of anti-SSA/SSB antibodies, while the labial salivary gland biopsy showed lymphoplasmatocytic infiltrates with a focus score of 1. To provide new insights into the physiopathology of the anti-PD1-related sialadenitis, we investigated the distribution of aquaporins 5 by immunostaining on the labial salivary gland acini, and compared this distribution with the one expressed in the primary Sjögren's syndrome. Contrary to patients with primary Sjögren's syndrome (in whom aquaporins 5 is mainly expressed at the basolateral side), but similar to the patients with no sialadenitis, we observed expression of aquaporins 5 at the apical pole. This new finding deserves to be confirmed in other patients with anti-PD1-related sialadenitis. Owing to these immune-related adverse events, anti-PD1 was stopped; nevertheless, the patient developed a new relapse 1year later (March 2020) in the neck region, which was treated by radiotherapy. Since then, no relapse of melanoma was seen (1.5years after radiotherapy), but the patient still requires hypophyseal replacement therapy. The sialoadenitis resolved partially. We report a combination of sialoadenitis and hypophysitis explaining extreme fatigue in a patient who was treated in the adjuvant setting with anti-PD1 for a melanoma relapse.

Pembrolizumab in combination with gemcitabine for patients with HER2-negative advanced breast cancer: GEICAM/2015–04 (PANGEA-Breast) study

BackgroundWe evaluated a new chemoimmunotherapy combination based on the anti-PD1 monoclonal antibody pembrolizumab and the pyrimidine antimetabolite gemcitabine in HER2- advanced breast cancer (ABC) patients previously treated in the advanced setting, in order to explore a potential synergism that could eventually obtain long term benefit in these patients.MethodsHER2-negative ABC patients received 21-day cycles of pembrolizumab 200 mg (day 1) and gemcitabine (days 1 and 8). A run-in-phase (6 + 6 design) was planned with two dose levels (DL) of gemcitabine (1,250 mg/m2 [DL0]; 1,000 mg/m2 [DL1]) to determine the recommended phase II dose (RP2D). The primary objective was objective response rate (ORR). Tumor infiltrating lymphocytes (TILs) density and PD-L1 expression in tumors and myeloid-derived suppressor cells (MDSCs) levels in peripheral blood were analyzed.ResultsFourteen patients were treated with DL0, resulting in RP2D. Thirty-six patients were evaluated during the first stage of Simon’s design. Recruitment was stopped as statistical assumptions were not met. The median age was 52; 21 (58%) patients had triple-negative disease, 28 (78%) visceral involvement, and 27 (75%) ≥ 2 metastatic locations. Progression disease was observed in 29 patients. ORR was 15% (95% CI, 5–32). Eight patients were treated ≥ 6 months before progression. Fourteen patients reported grade ≥ 3 treatment-related adverse events. Due to the small sample size, we did not find any clear association between immune tumor biomarkers and treatment efficacy that could identify a subgroup with higher probability of response or better survival. However, patients that experienced a clinical benefit showed decreased MDSCs levels in peripheral blood along the treatment.ConclusionPembrolizumab 200 mg and gemcitabine 1,250 mg/m2 were considered as RP2D. The objective of ORR was not met; however, 22% patients were on treatment for ≥ 6 months. ABC patients that could benefit of chemoimmunotherapy strategies must be carefully selected by robust and validated biomarkers. In our heavily pretreated population, TILs, PD-L1 expression and MDSCs levels could not identify a subgroup of patients for whom the combination of gemcitabine and pembrolizumab would induce long term benefit.Trial registrationClinicalTrials.gov and EudraCT (NCT03025880 and 2016–001,779-54, respectively). Registration dates: 20/01/2017 and 18/11/2016, respectively.

CTIM-03. PEMBROLIZUMAB MONOTHERAPY FOR MICROSATELLITE INSTABILITY-HIGH (MSI-H) OR MISMATCH REPAIR DEFICIENT (DMMR) RECURRENT GLIOMAS: RESULTS FROM THE MULTICOHORT PHASE 2 KEYNOTE-158 STUDY

Abstract BACKGROUND Patients with recurrent glioma have limited treatment options. The anti‒ PD-1 monoclonal antibody pembrolizumab demonstrated antitumor activity as monotherapy in a subset of patients with PD-L1–positive recurrent glioblastoma (GBM) in the KEYNOTE-028 study; and durable clinical benefit in patients with previously treated unresectable/metastatic MSI-H/dMMR non-colorectal tumors in the multicohort KEYNOTE-158 (NCT02628067) study. We report outcomes with pembrolizumab in patients with MSI-H/dMMR recurrent glioma enrolled in KEYNOTE-158. METHODS Adults with MSI-H/dMMR recurrent glioma, measurable disease per RECIST v1.1, ECOG PS 0/1, and tumor sample for biomarker analysis were eligible for cohort K (any MSI-H/dMMR advanced solid tumor, except colorectal cancer; local, prospective determination of MSI-H/dMMR status by PCR and/or IHC). Patients received pembrolizumab 200 mg Q3W for up to 35 cycles or until PD/unacceptable AEs (clinically stable patients could continue treatment until PD confirmed after ≥ 4 weeks). Primary endpoint was ORR per RECIST v1.1 by independent central review. RESULTS Among 21 enrolled patients, all received prior temozolomide, 12 (57%) received prior bevacizumab, and 14 (67%) received ≥ 2 prior lines of therapy. 14 (67%) patients had GBM, 4 (19%) had oligodendroglioma/oligoastrocytoma, and 3 (14%) had glioma NOS. Median time from first dose to data cutoff (January 12, 2022): 50.0 months; 19 (90%) patients discontinued treatment. 1 patient with GBM had PR (ORR, 4.8% [95%CI, 0.1%‒23.8%]); duration of response was 18.9 months, PFS 29.2 months, and OS 32.7 months. 3 (14%) patients had SD; PFS was 23.2, 14.5, and 3.3 months; OS was 23.2, 15.1, and 9.1 months. Overall, median PFS and OS (95%CI) were 1.4 (1.0‒2.1) months and 5.6 (2.6‒16.2) months. Treatment-related AEs occurred in 7 (33%) patients (grade 3/4, n = 1; no grade 5) and led to discontinuation in 1 (5%) patient. CONCLUSIONS Pembrolizumab demonstrated antitumor activity with manageable toxicity in a small subset of patients with relapsing/refractory MSI-H/dMMR glioma.

PD-1 receptor blocker

PD-1 or the programmed cell death protein 1 plays a major role in eliciting the immune checkpoint response of T cells. They are the inhibitory receptors induced in activated T cells. The application of these receptors earns a great interest to investigate, in-depth, their mechanism of action and therapeutic success. The US FDA has successfully approved three categories of immune checkpoint inhibitors. These are PD-1 inhibitors (Nivolumab, Pembrolizumab, and Cemiplimab), PDL-1 inhibitors (Atezolimumab, Durvalumab and, Avelumab), and CTLA-4 inhibitor (Ipilimumab). But still there lie several limitations in using this mode of treatment. Unlikely, not all patients respond well to these drugs. Apart from these, anti PD-1 monoclonal antibody showed its miraculous activity in treating cancer. It showed a hundred percent cure in patients with colorectal cancer without any kind of major side effects following the treatment procedure. Anti PD-1 monoclonal antibody (Dostarlimab) has shown promising results in endometrial cancer, ovarian cancer, melanoma, head and neck cancer, and breast cancer therapy. The current review focuses on the literature regarding the mechanism of action of immune checkpoint inhibitors, their role in cancer treatment.

Combining stereotactic body radiotherapy with camrelizumab for unresectable hepatocellular carcinoma: a single-arm trial

PurposeStereotactic body radiotherapy (SBRT) may have significant immunomodulatory effects that enhance tumor response to immune checkpoint inhibitors. This phase 2 clinical trial was conducted to evaluate the safety and efficacy of combining palliative SBRT with camrelizumab (an anti-PD1 monoclonal antibody) in patients with unresectable hepatocellular carcinoma (uHCC).MethodsPatients with uHCC, Child–Pugh A/B liver function, and at least one measurable lesion were enrolled between April 2020 and August 2022. Patients were administered 200 mg camrelizumab intravenously from the first day of palliative SBRT and then every 3 weeks. Palliative SBRT was delivered daily over five fractions per week, with a dose range of 30–50 Gy. The primary endpoints were objective response rate (ORR) and safety. This trial was registered at ClinicalTrials.gov (NCT04193696).ResultsTwenty-one patients were enrolled; the median radiation dose was 40 Gy, and the median number of cycles of camrelizumab was five. The ORR was 52.4%. After a median follow-up of 19.7 months, the median progression-free and overall survival were 5.8 and 14.2 months, respectively. The overall survival probability was 85.7% at 6 months, 76.2% at 9 months, and 59.9% at 12 months. All grade 3 treatment-related adverse events (TRAEs) occurred in five patients (23.8%) and were manageable. No grade 4/5 TRAEs were observed.ConclusionPalliative SBRT plus camrelizumab showed promising antitumor activity against uHCC. Toxicities were manageable with no unexpected safety issues. This study provides evidence of a new therapeutic method for the treatment of uHCC.

Toxicities of Pembrolizumab in Cancer Patients

Pembrolizumab is a humanized anti-PD1 monoclonal antibody that has been approved for immunotherapy of malignant melanoma, classical hodgkin lymphoma, non-small cell lung cancer, etc. However, the toxicity of pembrolizumab has been demonstrated in preclinical and clinical studies. The main side effects of pembrolizumab are related to the activation of various immune cells in the body. The triggered immune system may attack healthy organs, such as the livers, lungs and kidneys. The resulting toxic reactions can cause varying degrees of damage to the patient's body and need to be taken seriously. In response to the toxic side effects of pembrolizumab, discontinuation of the drug is often taken in conjunction with symptomatic treatment, and the herb is a potentially effective drug in many related diseases. In general, the side effects of immune checkpoint inhibitors are relatively minor and serious toxicities are rare, but some of the serious toxicities are fatal. Therefore, early detection and treatment of adverse reactions are of great interest, and mechanisms as well as treatments of toxicity of pembrolizumab requires further studies.

Brain-derived programmed death-ligand 1 mediates immunosuppression post intracerebral hemorrhage

Immunosuppression commonly occurs after a stroke, which is believed to be associated with the increased risk of infectious comorbidities of stroke patients, while the mechanisms underlying post-stroke immunosuppression is yet to be elucidated. In the brains of intracerebral hemorrhage (ICH) patients and murine ICH models, we identified that neuron-derived programmed death-ligand 1 (PD-L1) is reduced in the perihematomal area, associating increased soluble PD-L1 level in the peripheral blood. ICH induced a significant decrease of T and natural killer (NK) cell numbers in the periphery with an upregulation of programed death-1 (PD-1) in these cells. Blocking PD-1 pathway with an anti-PD1 monoclonal antibody prevented the T and NK cell compartment contraction and spleen atrophy post-ICH, with reduced pulmonary bacterial burden and improved neurological outcome. Thus, we here identified that brain-derived PD-L1 as a new mechanism driving post-stroke immunosuppression, and anti-PD1 treatment could be potentially developed to reducing the risk of post-stroke infections.

Abstract 6219: WM-S1, the novel small molecule inhibitor of mutant RTK/receptor tyrosine kinase, for the treatment of cancer

Abstract As the representative targeted anticancer drug for colon cancer patients, cetuximab is the EGFR targeted therapeutic antibody and used for treatment of KRAS wild type cancers. Even some patient with KRAS wt gene did not respond cetuximab. However, there is no treatment available for cetuximab-resistant patient group, which is almost 50% of KRAS WT gene holders. Recently, our team identified cetuximab primary resistant related proteins named as mtRTK (mutant receptor tyrosine kinase) by array analysis based cetuximab responder or non-responder colon cancer patient tissues. We investigated mtRTK’s oncogenic potential as a novel anti-cancer target. A large proportion of colon cancer patients (36.2% Caucasian, 56.9% Korean) expressed the mtRTK was identified, using the sequencing analysis of patient samples. Based on these results, our efforts have led to the discovery of WM-S1, mtRTK inhibitor, which is the first mtRTK inhibitor in clinical development. The potent enzyme inhibitor showed a high anticancer activity confirmed in Patient-Derived Cells (PDC) and Patient-Derived Xenograft (PDX) animal models expressing the mutation. In preclinical studies demonstrate that WM-S1 is well tolerated in rats and dogs. Furthermore, WM-S1 has potent anticancer activities for various solid tumor (NSCLC, cholangiocarcinoma, etc.) including activated mtKRAS colon cancer expressing the mtRTK. Currently we are investigating WM-S1 in a phase 1a trial in AUS, which is the first mtRTK inhibitor in clinical development. Meanwhile, the mtRTK inhibitor WM-S1 drives antitumor immunity (with anti-PD-L1) in NSCLC. Combinational approaches with immunotherapy showed that synergistic effect of WM-S1 and anti-PD1 monoclonal antibody, suppressing tumor growth by 75% in anti-PD1 resistance NSCLC-derived humanized mouse model. A phase 1b trial is expected to develop WM-S1 through not only indication expansion but also combination therapy with immuno-checkpoint inhibitors in the USA, AUS and KOR from Q2 2022. In conclusion, mtRTK is a potential oncogenic driver mutation in various solid tumor. A first-in-class anticancer agent WM-S1 targeting mtRTK can be promising therapeutic agents for cetuximab-resistant colon cancer patients regardless of KRAS mutation status and other cancers. Citation Format: Joseph Kim, Jai-Hee Moon, Kyung-Mi Lee, Hyun Ryu, Eun Hye Park, Sang Hee Kim, Jeong Seok Kim, Young Ok Ko, Yong Seok Kim, Hyo Jin Kim, Tae Young Kim Kim, Moon Seong Yoo, Soll Jin, Seongrak Kim, Yoon Sun Park, Min Ki Lee, Mi So Lee, Ji Hyun Go, Yu Geun Ji, Jun Hyung Lee, Haneul Lee, Min Hwa Kim, Eun Hee Ko, Yeo Jin Lee, Seung-Mi Kim, Joon-yee Jeong, Yeon-seoung Choi, Seung-geon Bae, Jinwoo Lee, Won Jun Lee, Min-Kyeong Kim, Ji min Shin, Dong-in Koh, Sun-Chul Hur, Chun-Ho Park, Hyun Ho Lee, Dong-Hoon Jin. WM-S1, the novel small molecule inhibitor of mutant RTK/receptor tyrosine kinase, for the treatment of cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6219.

Single agent PD-1 blockade as curative-intent treatment in mismatch repair deficient locally advanced rectal cancer.

LBA5 Background: Neoadjuvant chemotherapy and radiation followed by surgical resection of the rectum is a standard treatment for locally advanced rectal cancer. A subset of rectal cancer is mismatch repair deficient. Since mismatch repair deficient colorectal cancer is responsive to PD-1 blockade in the metastatic setting, we hypothesized that locally advanced mismatch repair deficient rectal cancer is sensitive to checkpoint blockade and may alter the requirements for chemoradiotherapy and surgery. Methods: We conducted a prospective phase II study in which single agent dostarlimab, an anti PD-1 monoclonal antibody, was administered every 3 weeks for 6 months in patients with mismatch repair deficient stage II and III rectal adenocarcinoma, to be followed by standard chemoradiation and surgery. Patients who achieved a clinical complete response were eligible for omission of chemoradiation and surgery. Results: Twelve patients initiated treatment and have at least 6 months of follow up. All 12 (100%, 95% CI:74%-100%) achieved a clinical complete response with no evidence of tumor on MRI, FDG-PET, endoscopic visualization, digital rectal exam, or biopsy, which satisfied the study’s co-primary endpoint. To date, no patients have required chemoradiation or surgery, and no cases of progression or recurrence have been noted during follow up (range 6-25 months). No serious adverse events &gt; grade 3 were observed. Conclusions: Mismatch repair deficient locally advanced rectal cancer is exceptionally sensitive to single agent PD-1 blockade. Longer follow up is needed to assess response duration. Clinical trial information: NCT04165772.

Anti PD-1 monoclonal antibody in patients with MSI-high and/or high tumor mutational burden for solid malignancies.

e15539 Background: High microsatellite instability (MSI-H) tumors have been associated with good responses to check-point inhibitors (CPI). With overall response rates (ORR) ranging between 36-46% among colorectal cancer (CRC) and other solid malignancies. Data regarding predictors of response and responses in non-CRC malignancies remains limited. We sought to evaluate the response to PD-1/PDL-1 CPI in patients with MSI-H and/or high TMB solid malignancies. Methods: Retrospective analysis of 16 patients (pts) who received 18 CPI-based therapies between October 2017 and February 2022. MSI-H and TMB status was assessed by CARIS, Guardant360 or INVITAE genetic testing. Primary objective was to determine objective response rate (ORR), defined as complete response (CR) or partial response (PR) by RECIST1.1. Secondary outcomes included progression-free survival(PFS); overall survival (OS), and duration of overall response (DOR). Results: A total of 16 pts were included. The median age of 72 years (range 53-83), 44% were male and 75% Hispanic. 44% of pts had RCR and 50% were previously treated, and 50% were stage IV at diagnosis. The most common mutations were BRCA2 31%, PIK3cA 31%, KRAS 25%, and GNAS 25%. The majority of pts received single-agent CPI therapy (72%). After a median follow-up of 52 months, 11 pts continued to receive therapy, 2 pts completed treatment. 3 pts died from progression of the disease. 1 pts switched from single-agent pembrolizumab to nivolumab-ipilimumab combination followed by nivolumab maintenance due to disease progression. 15 pts were evaluable for response with an ORR of 33%, including 33% among pts with CRC and 27% for non-CRC malignancies. (Table - Response rates) The OS was not reached (NR), with a PFS of 53 months (PFS of 64% at 1 year and 56% at 4 years). The median DOR was not reached (NR). The treatment was well tolerated and pts received a median of cycles was 19 (range 3-51) with no discontinuations due to toxicities. The molecular mutations, clinical characteristics, type of malignancy, MSI-H, or H-TMB status were not significantly associated with response to CPI after logistical regression analysis. Conclusions: CPIs are an effective treatment option for patients with MSI-H and/or High TMB, with an ORR of 33%. However, pts achieved durable responses, with a median DOR not reached. We identify a higher incidence of SD rates among CRC pts (67% vs. 18% non-CRC). We did not identify any predictors associated with response to CPI, likely due to the small number of pts. However, there was a tendency to highest response rates among pts with MSI-H and high TMB.[Table: see text]

GOTIC-018: Phase I, open-label, multicenter study to assess the safety of pre- and co-administration of ONO-4538 (nivolumab) with concurrent chemoradiation (CCRT) in patients (pts) with locally advanced cervical carcinoma (LACvCa).

5529 Background: LACvCa has a poor prognosis. CCRT is the standard treatment for LACvCa, and the 5-year survival rate is estimated at around 60%. Nivolumab (Nivo), an anti-PD1 monoclonal antibody, showed clinical activity in recurrent or persistent CvCa pts. Nivo may enhance antitumor immune responses induced by CCRT. The safety and feasibility of Nivo plus CCRT for LACvCa pts has not yet been reported. We report data from a phase I trial evaluating safety and feasibility of pre- and co-administration of Nivo with CCRT in pts with LACvCa (GOTIC-018; JMA-IIA00425). Methods: The treatment plan in cohort A is co-administration of Nivo (240mg/body once every 2 weeks) with CCRT followed by maintenance therapy with Nivo. The treatment plan in cohort B is pre- (two doses of Nivo before CCRT) and then co-administration of Nivo with CCRT followed by Nivo maintenance. The CCRT regimen includes 4 or more cycles of cisplatin (40 mg/m2 weekly) and external beam radiotherapy (EBRT) followed by brachytherapy. The Nivo maintenance therapy was scheduled for 52 weeks after completion of CCRT. The primary objective is the rate of Grade≧3 adverse events (AEs) during the acute phase, which is defined as 90 days from the start date of EBRT. Secondary objectives include the incidence of dose limiting toxicity (DLT) and progression-free survival. Results: A total of 30 patients, 15 patients in each cohort, was enrolled in this study. This report is a safety evaluation in the acute phase of the study. There were 1 stage IVA, 11 stage IIIB, 16 stage II and 2 stage IB tumors based on FIGO 2009. 28 squamous cell and 2 adeno/adenosquamous carcinomas were included. No DLT was observed in the first 6 DLT-evaluable pts in each cohort. All 30 patients completed planned EBRT and brachytherapy. 2 and 0 patients required a break from EBRT in cohort A and B, respectively. The median cycles of cisplatin administration was 5 and 6 in cohort A and B, respectively. 2 and 0 patient required cisplatin dose reduction in cohort A and B, respectively. 1 patient required cisplatin discontinuation in each cohort. The median cycles of Nivo administration were 6 and 9 in cohort A and B, respectively. 1 patient required Nivo discontinuation due to AEs in each cohort. All patients experienced Grade≧3 AEs. Most common Grade≧3 AEs were neutropenia (60.0 and 26.7% in cohort A and B, respectively), anemia (13.3 and 16.7%) and diarrhea (13.3 and 26.7%). In cohort B, no patients required delay in starting CCRT due to the AEs related to pre-administration of Nivo, and no patients had disease progression before starting CCRT. Conclusions: No DLT was reported during the acute phase in both cohort A and B, and no new safety signals were observed. Addition of pre-and co- administration of Nivo appears safe and feasible in patients with LACvCa treated with CCRT. Clinical trial information: JMA-IIA00425.

Safety and efficacy evaluation of long course neoadjuvant chemoradiotherapy plus tislelizumab followed by total mesorectal excision for locally advanced rectal cancer: Short-term results of a multicenter, phase II study.

e15599 Background: Long course radiotherapy plus neoadjuvant chemotherapy followed by resection (total mesorectal excision, TME) has accepted widespread recognized in the treatment of locally advanced rectal cancer (LARC). Tislelizumab, an anti-PD1 humanized IgG4 monoclonal antibody, has been demonstrated with clinical activity and is approved for treating recurrent/refractory classical Hodgkin lymphoma and locally advanced/metastatic urothelial carcinoma in China. Long course (neoadjuvant chemoradiotherapy, NCRT) plus tislelizumab followed by TME for LARC might bring better downstaging effect and reduce the risk of distant relapse. Methods: This trial was designed to evaluate the safety and efficacy of LARC patients treated with long course NCRT plus tislelizumab followed by TME. Stage II/III LARC patients (cT3N0M0 and cT1-3N1-2M0) with the tumor distal location ≤ 10 cm from anal verge at six centers in China were consecutively enrolled. The enrolled patients received long course radiotherapy (50 Gy/25 f, 2 Gy/f, 5 days/week) and three 21-day cycles capecitabine (1000 mg/m2, bid, po, day1-14) plus three 21-day cycles tislelizumab (200 mg, iv.gtt, day8), followed by TME 6-8 weeks after the end of radiotherapy. Whether and how to use postoperative adjuvant chemotherapy will be determined according to clinical experience. The primary efficacy endpoint will be the pathological complete response (pCR) rate, which is defined as absence of viable tumor cells in primary tumor and lymph nodes. Results: From June 2021 to January 2022, a total number of patients (n = 20) were enrolled. The median age was 63 (from 32 to 76) years while the median tumor distal location was 4.9 (from 1.5 to 9.9) cm. As of Januray 31, 12 patients with non-MSI-H/pMMR LARC had undergone TME surgery, with sphincter saving resection rate and R0 resection rate of 100%. The pCR rate was 58.3 % (7/12) and objective response rate reached 100 % (12/12). Of patients without pCR, 3 (25 %) patients reached tumor regression grade 1, while 2 (16.7 %) patients reached grade 2 according to AJCC standard. The neoadjuvant rectal (NAR) score of all 12 patients was 7.18 ± 11.01 (from 0.00 to 30.07). 2 (16.7 %) immune-related adverse events (irAEs) including 1 patient with diarrhea (grade 3) and 1 with vitiligo (grade 1) were observed. Anastomotic leakage (Clavien-Dindo grade II) occurred in 1 (8.3 %) of 12 patients, while no treatment-related death occurred. Conclusions: Tislelizumab added to long course NCRT followed by TME exhibited favorable pCR rate with manageable toxicities and postoperative complication, including non-MSI-H/pMMR LARC. The preliminary results are promising, which provide a potential strategy for neoadjuvant therapy against LARC. Research Sponsor: BeiGene, Ltd. Clinical trial information: NCT04911517.

Trial in progress: Phase 1b/3 study of bemarituzumab + mFOLFOX6 + nivolumab versus mFOLFOX6 + nivolumab in previously untreated advanced gastric and gastroesophageal junction (GEJ) cancer with FGFR2b overexpression (FORTITUDE-102).

TPS4165 Background: Fibroblast growth factor receptor 2b (FGFR2b) is overexpressed in approximately 30% of non-human epidermal growth factor receptor 2 (non-HER2) positive gastric cancer (Wainberg, 2021). Bemarituzumab is a first-in-class monoclonal antibody that specifically blocks FGFR2b, inhibiting downstream tumor proliferation and enhancing antibody dependent cellular cytotoxicity (Catenacci, 2020; Xiang, 2021). In the phase 2 FIGHT study (Wainberg, 2021; Catenacci, 2021), progression-free survival (PFS) was improved (HR, 0.68; 95% CI, 0.44-1.04; p = 0.07) and a 5.7 month longer median overall survival (OS) was observed (19.2 months vs 13.5 months; HR, 0.60; 95% CI, 0.38-0.94) with bemarituzumab + mFOLFOX6 vs placebo + mFOLFOX6. Preclinical studies indicate that bemarituzumab modulates the tumor microenvironment to sensitize tumors to anti-PD1 monoclonal antibodies (Powers, 2016; Xiang, 2021) providing rationale for combination with nivolumab. Methods: FORTITUDE-102 (NCT05111626) is a phase 1b/3 study in patients (pts) with unresectable locally advanced or metastatic gastric or GEJ adenocarcinoma not amenable to curative therapy. Part 1 is an open-label safety lead-in; Part 2 is a double-blind, placebo-controlled study to evaluate efficacy and safety. Approximately 702 pts ≥18 years will be enrolled (Part 1, ̃20; Part 2, ̃682). Key eligibility criteria include Eastern Cooperative Oncology Group performance status 0-1, evaluable disease per RECIST v1.1, adequate hematologic and organ function, and no contraindication to receive mFOLFOX6 chemotherapy or nivolumab; for part 2, IHC-confirmed FGFR2b overexpression by central testing is required and no prior treatment for metastatic or unresectable disease allowed except 1 dose of mFOLFOX6 ± nivolumab. Key exclusion criteria include positive HER2 status and untreated or symptomatic CNS metastasis and leptomeningeal disease. Pts on bemarituzumab will receive 15 mg/kg every 2 weeks (Q2W) with an additional 7.5 mg/kg dose on cycle 1 day 8. mFOLFOX6 + nivolumab will be at a fixed dose Q2W. The dose-limiting toxicity (DLT) period is 28 days; observed safety data will influence additional enrollment to Part 1, de-escalation of bemarituzumab, or the recommended phase 3 dose (RP3D). For Part 1, primary endpoints are DLTs and adverse events; secondary endpoints include OS, PFS, and objective response (OR). For Part 2, pts will be randomized 1:1 to mFOLFOX6 + nivolumab Q2W plus either bemarituzumab at RP3D or placebo. Primary endpoint for Part 2 is OS; secondary endpoints include PFS, OR, and safety. The concurrent phase 3 FORTITUDE-101 study (NCT05052801) will evaluate bemarituzumab + mFOLFOX6 vs placebo + mFOLFOX6. Clinical trial information: NCT05111626.

Investigating Susceptibility of ꞵ‐catenin‐mutated Hepatocellular Carcinoma to Checkpoint Inhibitors

Hepatocellular Carcinoma (HCC) is the 5th most common cause of cancer‐related death in the United States with an estimated 32,000 annual deaths. The standard of care for HCC as established by the IMBrave150 trial is a combination of the PD‐L1 inhibitor, Atezolizumab, and an antiangiogenic, Bevacizumab. While this combination extends overall survival to 19.2 months in unresectable HCC, only 52% of patients survive to 18 months. Furthermore, objective response rates are around 32% and hence clarifying underlying mechanisms regulating the immune response in HCC oncogenesis might strengthen immunotherapy efficacy. Especially important is to identify response rates of these agents in specific molecular subclasses of HCC may help in better patient selection. The oncogene ꞵ‐catenin is consistently mutated and activated among 30% of HCC patients. The Wnt/ꞵ‐catenin pathway has been approached as a target for precision medicine in HCC. We recently modeled HCCs with ꞵ‐catenin mutations in mice up to 69% genetic similarity. Here, we combine hydrodynamic tail vein injections with the Sleeping Beauty Transposase which is a non‐viral method of expressing genes of interest. Our model co‐expresses an S45Y point mutant of ꞵ‐catenin with the tyrosine kinase receptor MET (B+M). This combination represents ~10% of patient HCCs and provides a clinically relevant tool for the investigation of personalized HCC therapeutics.A recent study demonstrated HCCs driven by a Δ90‐truncation mutant of ꞵ‐catenin in combination with the Myc oncogene are shown to lack sufficient immune cell surveillance. These HCCs have poor cytotoxic T cell and dendritic cell recruitment while responding poorly to checkpoint inhibitors. Since activating point mutations in CTNNB1 gene are common in patient HCCs, we asked whether poor immune surveillance extends to HCC models harboring point mutations. We first checked and found the presence of CD45+, F4/80+, and CD11b+ cells both 2 and 4 weeks after B+M tumor induction. This indicates the presence of both adaptive and innate immune cells in the B+M tumor microenvironment. We next asked whether checkpoint inhibition will effectively reduce tumor burden in the B+M model. Therefore, we treated B+M mice with either IgG or anti‐PD1 monoclonal antibodies 4 weeks after tumor induction. Tissues were harvested 3.5 weeks after treatment. We found a modest 20% reduction in liver weight to body weight ratio, a measure of tumor burden, in B+M mice treated with anti‐PD1 compared to IgG controls. Our results demonstrate that HCCs with missense ꞵ‐catenin mutations do respond albeit marginally to checkpoint inhibitors. In the future, combination of checkpoint inhibitors with other inhibitors will be tested in these models to determine their efficacy in treating ꞵ‐catenin‐mutated HCCs.

Rationale and design of a prospective, multicenter, phase II clinical trial of safety and efficacy evaluation of long course neoadjuvant chemoradiotherapy plus tislelizumab followed by total mesorectal excision for locally advanced rectal cancer (NCRT-PD1-LARC trial)

BackgroundLong course radiotherapy plus neoadjuvant chemotherapy followed by resection (total mesorectal excision, TME) has accepted widespread recognized in the treatment of locally advanced rectal cancer (LARC). Tislelizumab, an anti-PD1 humanized IgG4 monoclonal antibody, has been demonstrated with clinical activity and is approved for treating recurrent/refractory classical Hodgkin lymphoma and locally advanced/metastatic urothelial carcinoma in China. However, the safety and efficacy of long course (neoadjuvant chemoradiotherapy, NCRT) plus tislelizumab followed by TME for LARC is still uncertain.MethodsThis NCRT-PD1-LARC trial will be a prospective, multicenter and phase II clinical trial designed to evaluate the safety and efficacy of LARC patients treated with long course NCRT plus tislelizumab followed by TME. This trial will consecutively enroll 50 stage II/III LARC patients (cT3N0M0 and cT1-3N1-2M0) with the tumor distal location ≤ 7 cm from anal verge at 7 centers in China. The enrolled patients will receive long course radiotherapy (50 Gy/25 f, 2 Gy/f, 5 days/week) and three 21-day cycles capecitabine (1000 mg/m2, bid, po, day1-14) plus three 21-day cycles tislelizumab (200 mg, iv.gtt, day8), followed by TME 6–8 weeks after the end of radiotherapy. The primary efficacy endpoint will be the pathological complete response (pCR) rate, which is defined as absence of viable tumor cells in the primary tumor and lymph nodes.DiscussionTo our knowledge, this trial is the first multicenter clinical trial in China to assess the safety and efficacy of NCRT plus anti-PD1 therapy followed by TME to treat patients with LARC. NCRT followed by TME was recognized as the most recommended treatment against LARC while could not be completely satisfied in clinic. This study expects to provide a solid basis and encouraging outcomes for this promising combination of radiotherapy, chemotherapy and immunotherapy in LARC.Trial registrationName of the registry: ClinicalTrials.gov. Trialregistration number: NCT04911517. Date of registration: 23 May 2021. URL oftrial registry record: https://www.clinicaltrials.gov/ct2/show/NCT04911517?id=BFH-NCRTPD&draw=2&rank=1.