eprenetapopt (APR-246)

DN TP53 mutations correlated with worse prognosis in prostate cancer patients and higher metastatic potential, which could be counteracted by APR-246 treatment suggesting a potential future therapeutic avenue.

The molecular target agents eprenetapopt, tazemetostat, and vorinostat efficiently induced apoptosis in ENKL-J1 cells in vitro. Furthermore, GD2-directed chimeric antigen receptor T cells showed cytotoxicity against ENKL-J1 cells in vivo. These findings not only contribute to understanding the molecular and genomic characteristics of ENKL; they also suggest new treatment options for patients with advanced or relapsed ENKL.

The progress of developing a cancer treatment that may successfully and efficiently target mutant p53 is on the verge of development. Mutant p53 proteins not only initiate oncogenesis but also cause resistance in cancer cells to certain chemo or radiotherapies, further endorse cancer cell survival and promote migration as well as metastasis of cancerous cells. With this regard, many mutant p53 inhibitors have been developed, some of which are currently being evaluated at the pre-clinical level and have been identified and discussed. To date, APR-246 is the most prominent one that has progressed to the Phase III clinical trial.

In primary CLL samples, AS-1763, pirtobrutinib or ibrutinib induced a modest apoptosis...Evaluation of drug interaction models utilizing Compusyn and Synergy Finder applications predominantly indicated additive effects between AS-1763 with BCL-2 inhibitor, venetoclax as well as p53 activator APR-246... AS-1763 is a selective ncBTKi that inhibits both wild-type and mutant BTKs listed in Table 1. In CLL cells, AS-1763 was effective in inhibiting BCR pathway signaling and sensitized cells to other agents such as venetoclax. Based on these encouraging data we have initiated a clinical trial to test AS-1763 in patients with CLL and other B cell malignancies who have failed or are intolerant to at least two prior lines of systemic therapy, including cBTKi (NCT05602363 Clinical Trials.gov).

We propose that the immunogenic effect of MQ can be linked to its thiol-reactive alkylating ability as we observed similar immunogenic effects with the broad-spectrum cysteine-reactive compound, iodoacetamide. Our results thus indicate that combination of APR-246 with immunomodulatory agents may elicit effective antitumor immune response irrespective of the tumor's p53 mutation status.

Promisingly, in vitro MDM2 inhibition with Idasnutlin and TP53 reactivation via Eprenetapopt was able to renew TNFRSF10B protein expression. Additionally, applying the BRD4-degrading PROTAC ARV-825 and the CDK4/6 inhibitor Abemaciclib as single-agents and in synergistic combination significantly reduced TP53-altered DLBCL cell line viability. Our analysis presents key associations within a genomic network of actionable targets capable of providing clarity within the evolving precision CAR-T treatment landscape.

DN TP53 mutations were associated with poorer survival outcomes for mCSPC patients. DN TP53 mutations also promoted prostate cancer pro-metastatic behaviors in vitro, which was effectively counteracted by APR-246, making it a promising treatment option that should be explored further in early-phase clinical studies.

The triple combination of azacitidine and venetoclax with either magrolimab or eprenetapopt have demonstrated safety in early trials, with phase III trials currently underway, and promising interim clinical results. This review compiles background on TP53 biology, available and emerging therapies along with their mechanisms of action for the TP53m disease entity, current treatment challenges, and recently published data and status of ongoing clinical trials for TP53m AML/MDS.

The synergism of the combination was associated with significant apoptosis induction through p53-dependent and p53-independent pathways. Preclinical confirmation of these data in in vivo models is highly recommended.

DN TP53 mutations were associated with poorer survival outcomes for mCSPC patients. DN TP53 mutations also promoted prostate cancer pro-metastatic behaviors in vitro , which was effectively counteracted by APR-246, making it a promising treatment option that should be explored further in early-phase clinical studies.

P1/2, N=1, Terminated, Aprea Therapeutics | N=100 --> 1 | Suspended --> Terminated; Sponsor decision

APR-246 mediated radio-sensitization effects through p53-dependent and -independent ways. The results may provide evidence for a clinical trial of the combination in rectal cancer patients.

Frontline acute myeloid leukemia (AML) treatment is determined by a combination of patient and genetic factors. These combinations include isocitrate dehydrogenase-1/2 (IDH1/2) inhibitors (i.e., ivosidenib and enasidenib), fms-like tyrosine kinase 3 (FLT3) inhibitors (i.e., gilteritinib), anti-CD47 antibodies (i.e., magrolimab), mouse double minute-2 (MDM2) inhibitors, and p53 reactivators (i.e., eprenetapopt). This review summarizes ongoing trials aimed at overcoming known VEN resistance mechanisms and improving outcomes beyond that observed with HMA + VEN combinations in the treatment of AML.

Drugs that target the p53 pathway (mutant p53 re-activator PRIMA-1MET, dual MDM2/MDMX inhibitor RO-5963, and LEM3, a new molecule targeting interactions of MDM2/p53 family proteins) markedly inhibited viability of tumorigenic Ewing's sarcoma cells, demonstrating their increased vulnerability to restoring the p53 activity compared with nontumorigenic cells. Treatment with RO-5963 and LEM3 in tumorigenic cells stabilized p53 and induced apoptosis in a dose-dependent manner.ConclusionSOX2 expression and the p53 pathway deregulation are associated with sarcoma stemness. Our results indicate that enhanced p53 activity might effectively target aggressive stem-like childhood sarcomas, therefore showing promising clinical potential for p53 pathway re-activation in sarcoma therapy.

A significant decrease in intracellular ROS was observed and resulted in disruption of mitochondrial transmembrane potential. This study uncovers the underlying mechanism of Prima-1 and could be helpful to design further leads against lung cancers.Communicated by Ramaswamy H. Sarma.

Pevonedistat (NEDD-8 inhibitor) and APR-246 (TP53 reactivator) both did not meet trial endpoints. Due to intolerance, primary, and secondary resistance to HMA, there is a large unmet need to develop new safe and effective therapies for patients with MDS. In this review, we focus on the current management strategies and novel therapies in development for treatment of high-risk MDS.

DN TP53 mutations were associated with poorer survival outcomes for mCSPC patients. DN TP53 mutations also promoted prostate cancer pro-metastatic behaviors in vitro, which was effectively counteracted by APR-246, making it a promising treatment option that should be explored further in early-phase clinical studies.

These data supported the phase 3 study of APR-246 in combination with azacitidine versus azacitidine alone (NCT03745716)...We have reported the phase Ib study combining magrolimab with azacitidine in treatment-naïve higher risk MDS patients (26% with TP53 mutations) with the most recent data update at EHA 2022 11...Sabatolimab is a novel immuno-myeloid therapy targeting TIM-3, an immune regulator expressed on immune cells and myeloid leukemic progenitors 13...Lastly, venetoclax is an oral BCL-2 inhibitor with promising synergy with azacitidine and is a standard of care for elderly AML patients 15...TP53 mutant MDS/AML patients represent a molecular cohort with very poor outcomes and lack of disease modifying therapy. Ideally, future translational data will further elucidate the underpinnings driving the poor outcomes for this molecular subgroup to lead to additional novel therapeutic strategies.

The sensitivity of non-transformed cells to APR-246 also depended on the cell type. These findings reveal that the clinical testing of APR-246 should not be limited to cancers expressing mutant TP53 but expanded to cancers that express wt TP53 or are TP53-deficient.

Eprenetapopt and venetoclax with azacitidine had an acceptable safety profile and encouraging activity, supporting further frontline evaluation of this combination in the treatment of TP53-mutated acute myeloid leukaemia.

COTI-2 activity correlated with nitrogen mustard, cisplatin and gemcitabine, doxorubicin and selumetinib, with a trend for APR-246 with doxorubicin. Cisplatin synergy is consistent with P53's role in DNA damage. Different mechanisms of action may underlie disease specificity and offer better disease targeting.

To further evaluate for a time-dependent effect, 2 representative variants (R248Q and R273C) after 6 and 24 hours of incubation with 50μM APR-246 and 10μM of Nutlin-3. APR-246 demonstrated a negative, dose-dependent effect on cell viability in all EC cell lines. Our results demonstrate that APR-246's cytotoxic effects in EC seem to be p53-independent. Potential mechanisms for the anti-neoplastic effects of APR-246 include activity targeting antioxidant pathways demonstrated in other solid tumors and provides an area for further investigation in TP53mut EC.

Recent data indicate that the TP53 allelic state, co-occurring somatic mutations, and the position of the TP53 mutation within the clonal hierarchy define genetic heterogeneity among TP53-mutated MDS and acute myeloid leukemia that may influence clinical outcomes, thereby informing the selection of patients most suitable for transplantation. Further, novel therapeutic methods such as antibody-based agents (monoclonals or dual-affinity retargeting antibodies), cellular therapies (natural killer cells, chimeric antigen receptor T cells), or targeted agents (eprenetapopt) may offer opportunities to modify the approach to pretransplant conditioning or posttransplant maintenance and improve clinical outcomes.

We screened 2300 articles and included articles citing novel therapies such as "Venetoclax" (VEN), "Hypomethylating agents (HMA), 5-azacytidine (5-AZA), "checkpoint inhibitors, and "MDM2 inhibitors"...VEN with low-dose cytarabine (LDAC) had 27% CR, whereas LDAC alone had 7%.Checkpoint inhibitors such as nivolumab showed favorable responses, as in the phase II study of nivolumab in combination with azacitidine in relapsed/refractory (R/R) AML; it demonstrated acceptable toxicity and an overall response rate (ORR) of 33%. However, increased response rates were seen in HMA-naïve patients.HDAC inhibitors : In two phase II trials incorporating AZA vs AZA + entinostat, the CR was 46% vs 44%..., the combination therapy of Decitabine and valproic acid showed CR of 34% and mOS of 11.9 months...described a remission of 82% with a median OS of 14.7 months in Eprenetapopt + 5-AZA. The most common grade ≥ 3 hematological adverse events were anemia, neutropenia, thrombocytopenia, and leukopenia.MDM2 Inhibitors : In the MIRROS trial, a phase III trial incorporating idasanutlin + cytarabine + placebo + cytarabine in R/R AML; 436 patients were enrolled...Still a daunting challenge, a combination of these therapies may ultimately be necessary to obtain adequate and sustained responses. Participation in clinical trials for all newly diagnosed AML patients should be encouraged to promote the development of innovative therapeutics.

Overall, we demonstrate that DNA vaccination against xCT can synergize with APR-246 treatment and enhance its therapeutic effect. Thus, APR-246 treatment in combination with xCT immunetargeting may open new perspectives in the management of breast cancer.

Our results suggest the presence of an interconnected genomic DLBCL phenotype characterized by TP53 loss, reduced TNFRSF10B expression, and a debilitated immune presence, collectively predictive of an inferior CD19 CAR-T response. We applied the targeted therapies Eprenetapopt and Idasnutlin vs. cell line models, with both displaying anti-tumor activity as single agents.

We incubated peripheral blood mononuclear cells for three days with cBTKi – ibrutinib; glutathione inhibitor (also known as mtTP53 modulator) - APR-246; Bcl-2 antagonist - venetoclax; and Mcl-1 antagonist - AZD5991; as single agent and in double or triple combinations and apoptosis was assessed by flow cytometry. Patients were re-sensitized to ibrutinib after loss of C481S clone. Genomic and genetic profile along with pharmacological landscape provide precision medicine for these heavily pretreated patients whose disease is resistant to BTK inhibitors.

To determine whether XPO1 can be therapeutically exploited in TP53-MNs, we performed in vitro viability assays with increasing doses of eprenetapopt and the XPO1 inhibitor selinexor and the second generation eltanexor. Our data collectively suggest that XPO1 is overexpressed after eprenetapopt and 5-azacitidine treatment resulting in re-folded TP53 being shuttled to the cytoplasm leading to therapeutic resistance. Patient derived xenograft assays testing this novel combination therapy in vivo with TP53-MN primary samples are underway and will be presented during the ASH meeting.

This study demonstrated that the combination of p53 protein agonist and lorlatinib may provide a new therapeutic strategy for NSCLC patients with lorlatinib resistance and TP53 mutation. Furthermore, the results also provide guidance for selecting optimal chemo-regimens for NSCLC patients after ALK-TKIs failure.

Breast carcinomas with mtp53 displayed enhanced inflammation. APR-246 boosted the interferon response or represses immune checkpoints in p53 mutant tumour cells, and restores cancer immune surveillance in vivo.

Several such reactivating drugs are currently undergoing evaluation in clinical trials, including eprenetapopt (APR-246), COTI-2, arsenic trioxide and PC14586. With all of these ongoing trials, we should soon know if targeting mutant p53 can be used for cancer treatment. If any of these trials show clinical efficacy, it may be a transformative development for the treatment of patients with cancer since mutant p53 is so prevalent in this disease.

We discuss the possible/potential improvement in outcome based on recent results obtained with new drugs (especially eprenetapopt and magrolimab). We also focus on the impact of allogeneic hematopoietic stem cell transplantation (aHSCT) including post aHSCT treatment.

Our preclinical data led to the development of a clinical trial in patients with solid tumors combining APR-246 with pembrolizumab. Biospecimens from select patients participating in this ongoing trial showed that there was a suppression of M2-polarized myeloid cells and increase in T cell proliferation with therapy in those who responded to the therapy. Our findings, based on both genetic and a small molecule-based pharmacological approach, suggest that increasing p53 expression in tumor-associated macrophages reprograms the tumor microenvironment to augment the response to immune checkpoint blockade.

We uncovered that sustained depletion of MDM4 is growth inhibitory in prostate cancer cells, involving either apoptosis or senescence, depending on the cell and genetic context. We identified that the potency of MDM4 targeting could be potentiated in prostate cancers with mutant p53 through the addition of a first-in-class small molecule drug that was selected as a p53 reactivator and has the capacity to elevate oxidative stress in cancer cells to drive their death.

In patients with mTP53 AML and MDS, post-HCT maintenance therapy with eprenetapopt combined with azacitidine was well tolerated. RFS and OS outcomes were encouraging in this high-risk population.

P3, N=154, Completed, Aprea Therapeutics | Active, not recruiting --> Completed

Scavenging ROS with N-acetylcysteine (NAC) disrupts the inhibitory effect of APR-246 on cisplatin-resistant cells. Mechanistically, NRF2 is specifically degraded by the proteasome following its own ubiquitylation in APR-246-treated cisplatin-resistant cells, which in turn decreases NRF2/SLC7A11/GSH axis activity. Our study provides new insights into the biology driving cisplatin resistance of lung cancer and highlights APR-246 as a potential therapeutic reagent for overcoming cisplatin resistance.

P1/2, N=100, Suspended, Aprea Therapeutics | Active, not recruiting --> Suspended

P1/2, N=37, Completed, Aprea Therapeutics | Active, not recruiting --> Completed