Co-amplification of MET and PIK3CA in NSCLC and data on a PDX mouse model.

11591 Background: Amplification of the mesenchymal-epithelial transition ( MET) proto-oncogene or phosphatidylinositol3-kinase ( PI3K) is common in non-small-cell lung cancer (NSCLC) and represents a potential therapeutic target. NSCLC with coexisting driver mutations or amplifications is a cause of great concern. Methods: From 2013 until now, fluorescence in situ hybridization was used to screen for MET amplified NSCLC patients.The amplification of the MET was defined as centromere 7 ratio ≥ 2.0 and the criterion of Cappuzzi. The amplification of the PIK3CA was copy numbers ≥ 4.0. We established the patient-derived exnograft (PDX) mouse model from a dual MET/PIK3CA-amplified patient. Preclinical efficacy of single versus dual inhibition was evaluated in vivo. Six groups were allocated to receive the treatment of vehicle control, bozitinib,crizotinib, taselisib (PI3K inhibitor), bozitinib+taselisib, or crizotinib+taselisib, respectively. Results: Totally, 568 (568/2321, 24.47%) patients harbored positive MET amplification and 6 (6/568,1%) were comfirmed with dual MET/PI3K amplification. The two stageⅣ patients received MET inhibitor treatment.One trial (NCT02896231) patient was treated with bozitinib and achieved confirmed PR, but with 3 months PFS and 5 months OS. The best response was PR and PFS was 5.6 months for the other one receiving the study drug capmatinib (NCT02276027). In the PDX mouse model experiment, we found three single-anget inhibitors monotherapy to be active but only transiently effective in controlling the growth of PDX. The PDX models showed more sensitivity to taselisib among the three single-anget groups. In contrast, the combination of the two inhibitors caused a stronger and long-lasting growth inhibition in PDX models. The addition of taselisib to bozitinib or crizotinib monotherapy provided obvious enhanced activity. Regretfully, two mice died because of the toxicities in the crizotinib+taselisib group. Conclusions: Patients with dual MET/PIK3CA amplification represent a rare molecular subtype of NSCLC and have a relatively short duration of response to MET inhibitors.The combination of MET/PI3K inhibitors is synergistic preclinically.

Download Full-text

Patient-derived xenograft models capture genomic heterogeneity in endometrial cancer

Genome Medicine ◽

10.1186/s13073-021-00990-z ◽

2022 ◽

Vol 14 (1) ◽

Author(s):

Vanessa F. Bonazzi ◽

Olga Kondrashova ◽

Deborah Smith ◽

Katia Nones ◽

Asmerom T. Sengal ◽

...

Keyword(s):

Endometrial Cancer ◽

Mismatch Repair ◽

Primary Tumor ◽

Copy Number ◽

Tumor Heterogeneity ◽

Molecular Subtypes ◽

Molecular Subtype ◽

Patient Derived Xenograft ◽

Pdx Models

Abstract Background Endometrial cancer (EC) is a major gynecological cancer with increasing incidence. It comprises four molecular subtypes with differing etiology, prognoses, and responses to chemotherapy. In the future, clinical trials testing new single agents or combination therapies will be targeted to the molecular subtype most likely to respond. As pre-clinical models that faithfully represent the molecular subtypes of EC are urgently needed, we sought to develop and characterize a panel of novel EC patient-derived xenograft (PDX) models. Methods Here, we report whole exome or whole genome sequencing of 11 PDX models and their matched primary tumor. Analysis of multiple PDX lineages and passages was performed to study tumor heterogeneity across lineages and/or passages. Based on recent reports of frequent defects in the homologous recombination (HR) pathway in EC, we assessed mutational signatures and HR deficiency scores and correlated these with in vivo responses to the PARP inhibitor (PARPi) talazoparib in six PDXs representing the copy number high/p53-mutant and mismatch-repair deficient molecular subtypes of EC. Results PDX models were successfully generated from grade 2/3 tumors, including three uterine carcinosarcomas. The models showed similar histomorphology to the primary tumors and represented all four molecular subtypes of EC, including five mismatch-repair deficient models. The different PDX lineages showed a wide range of inter-tumor and intra-tumor heterogeneity. However, for most PDX models, one arm recapitulated the molecular landscape of the primary tumor without major genomic drift. An in vivo response to talazoparib was detected in four copy number high models. Two models (carcinosarcomas) showed a response consistent with stable disease and two models (one copy number high serous EC and another carcinosarcoma) showed significant tumor growth inhibition, albeit one consistent with progressive disease; however, all lacked the HR deficiency genomic signature. Conclusions EC PDX models represent the four molecular subtypes of disease and can capture intra-tumor heterogeneity of the original primary tumor. PDXs of the copy number high molecular subtype showed sensitivity to PARPi; however, deeper and more durable responses will likely require combination of PARPi with other agents.

Download Full-text

Safety and efficacy of single-agent rovalpituzumab tesirine (SC16LD6.5), a delta-like protein 3 (DLL3)-targeted antibody-drug conjugate (ADC) in recurrent or refractory small cell lung cancer (SCLC).

Journal of Clinical Oncology ◽

10.1200/jco.2016.34.18_suppl.lba8505 ◽

2016 ◽

Vol 34 (18_suppl) ◽

pp. LBA8505-LBA8505 ◽

Cited By ~ 8

Author(s):

Charles M. Rudin ◽

Maria Catherine Pietanza ◽

Todd Michael Bauer ◽

David R. Spigel ◽

Neal Ready ◽

...

Keyword(s):

Clinical Benefit ◽

Single Agent ◽

Human Study ◽

Study Drug ◽

Antibody Drug Conjugate ◽

Skin Reactions ◽

Best Response ◽

Duration Of Response ◽

Grade 3 ◽

Tissue Specimens

LBA8505 Background: SCLC remains among the most deadly of malignancies. Rovalpituzumab tesirine is a first-in-class ADC comprised of a humanized monoclonal antibody against DLL3, a dipeptide linker, and a pyrrolobenzodiazepine (PBD) dimer toxin. DLL3 is highly expressed in neuroendocrine tumors, including approximately 80% of SCLC. The emerging results of the SCLC patients (pts) in a first-in-human study (NCT01901653) are reported here. Methods: Pts with progressive SCLC after at least 1 previous systemic therapy were eligible. Efficacy was assessed by the investigator via RECIST v1.1, and toxicity graded per CTCAE v4.03. When available, archived tumor tissue was assessed retrospectively for DLL3 expression by immunohistochemistry. Results: Seventy-four (74) pts were enrolled at dose levels ranging from 0.05 to 0.8 mg/kg at either q3w or q6w. Among evaluable pts treated at doses of 0.2-0.4 mg/kg, 15/61 (25%; 95% CI 15-37%) achieved a best response of PR or CR, and 44/61 (72%; 95% CI 59-83%) achieved clinical benefit (best response of at least SD). Among pts with available archive tissue specimens and ≥ 50% of cells expressing DLL3 (DLL3hi, an intended companion diagnostic cutoff), 12/22 (55%; 95% CI 32-76%) achieved a best response of PR or CR, and 20/22 (91%; 95% CI 71-99%) achieved clinical benefit, with a median overall survival of 8 (range 1-18+) months. In 3rd line DLL3hi pts (n = 10), where no approved therapy currently exists, the ORR and CBR were 70% and 90%, respectively, with at least 4 evaluable pts achieving OS of > 6 (8, 15, 18 and 18) months. Among responders treated at the phase 2 dose of 0.3 mg/kg, the median duration of response was 6 (range 1-8+) months. Among all SCLC pts, the most common grade 3+ toxicities considered study drug-related have included serosal effusions (14%), thrombocytopenia (12%) and skin reactions (8%). Conclusions: With manageable toxicity, rovalpituzumab tesirine demonstrates encouraging single-agent anti-tumor activity and durability in recurrent or refractory SCLC. A single-arm pivotal study in 3rd line DLL3-expressing SCLC has been initiated. Clinical trial information: NCT01901653.

Download Full-text

Humanized Anti-PR1/HLA-A2 T Cell Receptor-like Monoclonal Antibody, h8F4, Has Multiple Effector Mechanisms

Blood ◽

10.1182/blood.v128.22.4061.4061 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4061-4061

Author(s):

Anna Sergeeva ◽

Hong He ◽

Kathryn Cox ◽

Lisa St John ◽

Mei Sang ◽

...

Keyword(s):

Monoclonal Antibody ◽

T Cell ◽

Mouse Model ◽

T Cell Receptor ◽

Cell Receptor ◽

Target Cells ◽

Nsg Mouse ◽

Pdx Models

Abstract Previously we developed a T cell receptor (TCR) -like murine IgG2a monoclonal antibody, m8F4, which binds to the PR1 peptide/HLA-A2 complex, and targets both HLA-A2+ leukemia cell lines and primary HLA-A2+ patient blasts of various AML subtypes. We reported that m8F4 mediated complement dependent cytotoxicity (CDC) of AML in vitro and actively depleted AML in vivoin AML patient-derived xenograft (PDX) models. Due to the therapeutic potential of 8F4, we humanized 8F4 for clinical development. Here we report the specificity of this humanized IgG1κ 8F4 (h8F4) to PR1/HLA-A2 and document the activity of h8F4 against AML. Both ELISA and surface plasmon resonance (SPR) were used to study h8F4 specificity to recombinant monomer, consisting of PR1 peptide, HLA-A2 and β2 microglobulin. Like mouse 8F4, human 8F4 bound PR1/HLA-A2 monomer with high affinity (KD= 6.5 nM), while no binding was detected to control monomers pp65/HLA-A2 and WT1/HLA-A2. Moreover, FACS of peptide-pulsed T2 cells showed that h8F4 bound PR1- pulsed T2, but did not bind T2 cells loaded with other HLA-A2-restricted peptides, including MART1, pp65, WT1 and gp100, thus confirming h8F4 specificity to PR1/HLA-A2. To test whether h8F4 retains the in vivoanti-leukemia activity seen with m8F4, we used an NSG mouse model. Similar to m8F4, h8F4 treatment reduced leukemia growth in NSG mice with established disease in 3 out of 4 AML PDX models tested. To determine the mechanism of action (MOA) of humanized 8F4, we first tested h8F4 activity in the presence of complement because we had previously demonstrated the primary MOA of m8F4 to be CDC. However, unlike m8F4, even when tested at high concentrations up to 20 µg/ml, h8F4 did not mediate CDC of HLA-A2 transduced U937, HL60, or PR1-loaded T2 cells. To further examine h8F4 MOA, we tested antibody dependent cellular cytotoxicity (ADCC) of h8F4 using an lactase dehydrogenase (LDH) assay with pooled human PBMC as effectors. H8F4 induced ADCC of U937-A2 at E:T ratio 50 (EC50=0.95 µg/ml), thus indicating improved ADCC anti-AML activity of h8F4. Introduction of alanine substitutions in positions 234-235 (AAh8F4), which disrupted the binding of h8F4 to Fc receptor (FcR), abolished ADCC activity against U937-A2 in vitro. In contrast, AA8F4 still retained partial in vivo activity against the same target cells in the NSG mouse model, suggesting that ADCC is important, but not the exclusive mechanism of h8F4 in vivo. To investigate whether h8F4 had direct activity against AML, as possible alternative MOA, we measured apoptosis of target cells by h8F4 with and without crosslinking anti-Fc antibody fragments (CLA). Indeed, we found, by using annexin V and propidium iodide staining, that a 24 hours incubation with h8F4 (1µg/ml) in the presence of CLA induced apoptosis of 55.5 ± 3.5% of U937-A2 cells, as compared to 23.5 ± 2.1% in CLA-only control (p < 0.05). Moreover, caspase 3 activation was observed as early as 10 minutes after adding h8F4+CLA, and was time- and h8F4 concentration- dependent. Our data demonstrate that specificity of humanized anti-PR1/HLA-A2 TCR-like antibody, h8F4, is preserved and that h8F4 has a similar affinity compared with m8F4. In addition to inducing apoptosis, h8F4 mediates greater ADCC compared with m8F4, but lacks CDC activity in vitro. Together, our data is consistent with multiple mechanisms of action in vivo, including ADCC. Our results support further testing of h8F4 for patients with AML. Disclosures Sergeeva: Astellas Pharma: Patents & Royalties. Molldrem:Astellas Pharma: Patents & Royalties.

Download Full-text

PDCT-12. CLINICAL EFFICACY OF ONC201 IN THALAMIC H3 K27M-MUTANT GLIOMA

Neuro-Oncology ◽

10.1093/neuonc/noz175.773 ◽

2019 ◽

Vol 21 (Supplement_6) ◽

pp. vi186-vi186

Author(s):

Abed Rahman Kawakibi ◽

Sharon Gardner ◽

Andrew Chi ◽

Sylvia Kurz ◽

Patrick Wen ◽

...

Keyword(s):

Clinical Efficacy ◽

Clinical Analysis ◽

Best Response ◽

Duration Of Response ◽

Post Radiation ◽

Cutoff Date ◽

Tumor Dna

Abstract ONC201, the first bitopic DRD2 antagonist for clinical oncology, has shown efficacy in H3 K27M-mutant glioma. We performed an integrated preclinical and clinical analysis of ONC201 in thalamic H3 K27M-mutant glioma. ONC201 was effective in mouse intra-uterine electroporation (IUE)-generated H3 K27M-mutant gliomas, with an in vitro IC50 of 500 nM and 50% prolongation of median survival in vivo (p=0.02, n=14). Elevated DRD2 expression was found in the thalamus of non-malignant brain tissue, leading to the hypothesis that thalamic tumors may be a particularly ONC201-sensitive sub-group. We analyzed thalamic H3 K27M-mutant glioma patients treated with ONC201 as of the 05/22/2019 cutoff date, which included patients who had recurrent disease prior to initiating ONC201 (n=20; 15–73 years old) and post-radiation non-recurrent patients (n=11; 5–19 years old). As of 5/22/2019, 10 of 20 recurrent patients and 9 of 11 non-recurrent patients remain on-treatment. Median PFS has not been reached for either cohort: median follow-up of 2.2 months (range: 0.6–37.9) for recurrent patients and 10.6 months (range: 4.3–20.5) from diagnosis for non-recurrent patients. Best response so far by RANO includes 1 CR, 2 PR, 7 SD, 9 PD, 1 NE for recurrent patients and 1 PR, 7 SD, 3 PD for non-recurrent patients. Additionally, 3 recurrent (-66%, -47%, -34%) and 2 non-recurrent (-40%, -10%) patients experienced regressions but are not yet confirmed PRs. For recurrent patients, median onset of response is 3.5 months (range: 2.2–3.8) and median duration of response has not been reached with a median follow-up of 12.5 months (range: 8.1–32.8). Preliminary analyses demonstrated a strong correlation of cell-free tumor DNA in plasma and CSF with MRI response. In summary, ONC201 demonstrates promising clinical efficacy in thalamic H3 K27M-mutant glioma patients, regardless of age. Micro-environmental DRD2 expression may enhance the overall ONC201 response and extend its therapeutic utility beyond H3 K27M-mutant glioma.

Download Full-text

Genomic analysis of patient-derived xenograft models reveals intra-tumor heterogeneity in endometrial cancer and can predict tumor growth inhibition with talazoparib

10.1101/2021.03.30.436914 ◽

2021 ◽

Author(s):

Vanessa F. Bonazzi ◽

Olga Kondrashova ◽

Deborah Smith ◽

Katia Nones ◽

Asmerom T. Sengal ◽

...

Keyword(s):

Endometrial Cancer ◽

Primary Tumor ◽

Tumor Heterogeneity ◽

Molecular Subtypes ◽

Molecular Subtype ◽

Primary Tumors ◽

Patient Derived Xenograft ◽

Wide Range ◽

Pdx Models

Background: Endometrial cancer (EC) is a major gynecological cancer with increasing incidence. It comprised of four molecular subtypes with differing etiology, prognoses, and response to chemotherapy. In the future, clinical trials testing new single agents or combination therapies will be targeted to the molecular subtype most likely to respond. Pre-clinical models that faithfully represent the molecular subtypes of EC are urgently needed, we sought to develop and characterize a panel of novel EC patient-derived xenograft (PDX) models. Methods: Here, we report whole exome or whole genome sequencing of 11 PDX models and the matched primary tumor. Analysis of multiple PDX lineages and passages was performed to study tumor heterogeneity across lineages and/or passages. Based on recent reports of frequent defects in the homologous recombination (HR) pathway in EC, we assessed mutational signatures and HR deficiency scores and correlated these with in vivo responses to the PARP inhibitor (PARPi) talazoparib in six PDXs representing the different molecular subtypes of EC. Results: PDX models were successfully generated from all four molecular subtypes of EC and uterine carcinosarcomas, and they recapitulated morphology and the molecular landscape of primary tumors without major genomic drift. We also observed a wide range of inter-tumor and intra-tumor heterogeneity, well captured by different PDX lineages, which could lead to different treatment responses. An in vivo response to talazoparib was detected in two p53mut models consistent with stable disease, however both lacked the HR deficiency genomic signature. Conclusions: EC PDX models represent the four molecular subtypes of disease and can capture intra-tumoral heterogeneity of the original primary tumor. PDXs of the p53mut molecular subtype showed sensitivity to PARPi, however, deeper and more durable responses will likely require combination of PARPi with other agents.

Download Full-text

HGG-18. CLINICAL EFFICACY OF ONC201 IN THALAMIC H3 K27M-MUTANT GLIOMA

Neuro-Oncology ◽

10.1093/neuonc/noaa222.305 ◽

2020 ◽

Vol 22 (Supplement_3) ◽

pp. iii347-iii347

Author(s):

Abed Rahman Kawakibi ◽

Rohinton S Tarapore ◽

Sharon Gardner ◽

Andrew Chi ◽

Sylvia Kurz ◽

...

Keyword(s):

Clinical Efficacy ◽

Single Agent ◽

Clinical Analysis ◽

Best Response ◽

Duration Of Response ◽

Post Radiation ◽

Tumor Dna

Abstract ONC201, a bitopic DRD2 antagonist and allosteric ClpP agonist, has shown encouraging efficacy in H3 K27M-mutant glioma. Given that the thalamus has the highest extra-striatal expression of DRD2, we performed an integrated preclinical and clinical analysis of ONC201 in thalamic H3 K27M-mutant glioma. ONC201 was effective in mouse intra-uterine electroporation (IUE)-generated H3 K27M-mutant gliomas, with an in vitro IC50 of 500 nM and 50% prolongation of median survival in vivo (p=0.02, n=14). We analyzed thalamic H3 K27M-mutant glioma patients treated with ONC201 on active clinical trials as of 5/22/19 enrollment (n=19 recurrent and 10 post-radiation, non-recurrent; 5–70 years old). As of 12/18/2019, PFS6 and OS12 are 26.3% and 36.8%, respectively, in the recurrent group. For non-recurrent patients, with median follow up of 21.9 months (8.6–26.6) from diagnosis, median PFS or OS have not been reached. This surpasses historical OS of 13.5 months. Best response by RANO includes 1 CR, 3 PR, 4 SD, 8 PD for recurrent patients and 2 PR, 4 SD, 1 PD for non-recurrent patients (4 on-trial patients experienced regressions that are yet unconfirmed responses). Median duration of response for recurrent patients is 14.0 months (2.0–33.1). Furthermore, H3 K27M cell-free tumor DNA in plasma and CSF correlated with MRI response. In summary, single agent ONC201 administered at recurrence, or adjuvantly following radiation, demonstrates promising clinical efficacy in thalamic H3 K27M-mutant glioma patients who currently have no effective treatments following radiation. Investigations are ongoing to assess whether micro-environmental DRD2 expression explains the early exceptional responses in thalamic H3 K27M-mutant glioma.

Download Full-text