EXTH-93. THE IRAK-4 INHIBITOR EMAVUSERTIB (CA-4948) FOR THE TREATMENT OF PRIMARY CNS LYMPHOMA

BACKGROUND

PCNSL is an aggressive brain tumor accounting for 3% of all CNS malignancies and is associated with poor prognosis. Standard of care treatment includes induction with high-dose methotrexate based chemoimmunotherapy followed by consolidation with autologous stem cell transplant or whole brain radiation. However, more than half of PCNSL patients cannot tolerate this intensive therapeutic intervention. Novel treatments are urgently needed. Toll-like receptor signaling pathway via MyD88/IRAK-4 signalosome is constitutively active in PCNSL secondary to MYD88 L265P mutation and represents an excellent therapeutic target. Emavusertib (CA-4948) is an oral first-in-class small molecule inhibitor of IRAK-4 that demonstrates clinical activity in patients with systemic Non-Hodgkin’s Lymphoma, however it has not been evaluated in the CNS space. HYPOTHESIS: Emavusertib has anti-tumor activity against preclinical PCNSL.

METHODS

Using multiparameter immunohistochemistry (IHC) and proteomics analysis, IRAK-1, IRAK-4, and NF-κB pathway activation were examined in patient PCNSL tissues as compared to normal controls. Plasma, cerebrospinal fluid, and brain tissue were assessed via UPLC-MS/MS for emavusertib drug concentration following single oral high dose in a murine model. Survival responses in preclinical PCNSL models were measured in response emavusertib treatment, along with in vivo tumor proliferation and downstream biomarker expression by multi-parameter IHC.

RESULTS

Our data confirm elevated IRAK-1, IRAK-4, and NF-κB signaling in patient PCNSL. We show that emavusertib can achieve therapeutically relevant concentrations in the brain and CSF. Emavusertib impairs tumor cell proliferation in vitro and in vivo, and shows dose-dependent single-agent activity in preclinical PCNSL models. We confirm decreased ERK1/2, MAPK and NF-κB activation, indicative of downstream IRAK-4 inhibition.

CONCLUSIONS

Our data supports that emavusertib demonstrates anti-tumor activity in the CNS space, warranting further preclinical and clinical evaluation of this agent for the treatment of PCNSL.

CTIM-34. PRELIMINARY SAFETY AND EFFICACY DATA ON TWO PATIENTS WITH RELAPSED/REFRACTORY CNS LYMPHOMA TREATED WITH EMAVUSERTIB (CA-4948) AND IBRUTINIB COMBINATION: A SUBSET ANALYSIS OF TAKEAIM LYMPHOMA TRIAL

BACKGROUND

Emavusertib, an oral interleukin-1 receptor-associated kinase 4 (IRAK4) inhibitor, targets toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling pathway in B-cell proliferation. IRAK4 forms a Myddosome complex with MYD88 adaptor protein and drives overactivation of NF-κB, causing inflammation and tumor growth. Emavusertib has been reported to be well tolerated and active as monotherapy in heavily pretreated relapsed/refractory (R/R) non-Hodgkin lymphoma (NHL). In a murine PDX model of primary CNS lymphoma (PCNSL), emavusertib crossed the blood-brain barrier, resulting in tumor response and prolonged survival. In combination with Bruton tyrosine kinase (BTK) inhibitors, emavusertib showed in vivo anti-cancer synergy in B-cell NHL.

METHODS

This is an ongoing open-label trial (NCT03328078) in patients with R/R NHL. Currently, we are in the dose escalation portion of combination therapy to evaluate safety and efficacy following treatment of emavusertib at dose levels of 200 or 300mg BID with ibrutinib at full prescribed dose. As of May 6th, 2022, 13 patients have been treated with emavusertib+ibrutinib combination therapy.

RESULTS

Among the 13 patients, two were diagnosed with R/R PCNSL and had several prior lines of anti-cancer therapy. Emavusertib in combination with ibrutinib (560 mg daily) appeared to be well tolerated in these two subjects. One patient experienced Gr3 treatment-related adverse events (thrombocytopenia, muscle weakness, pain). The preliminary efficacy data demonstrated one CR and one SD. The patient who achieved CR after the combination therapy was originally intolerant to high-dose methotrexate based chemoimmunotherapy and did not achieve complete remission after switching to ibrutinib, providing early clinical evidence of CNS penetration and anti-tumor activity of emavusertib.

CONCLUSION

In R/R PCNSL, these preliminary data suggest that combination therapy has a tolerable safety profile with promising anti-cancer activity and may overcome ibrutinib resistance.

Phase I trial of CA-4948, an IRAK4 inhibitor, in combination with FOLFOX/PD-1 inhibitor +/- trastuzumab for untreated unresectable gastric and esophageal cancer

TPS4168

Background: Activated NFκB has been linked to aggressive phenotype, poor survival outcomes and resistance to chemotherapy in multiple gastrointestinal cancers including gastroesophageal cancer (GEC). Preclinical studies established that: 1) Genotoxic stress incurred by chemotherapy induces TLR9, which signals through IRAK4 to drive pro-survival NFκB signaling; 2) The survival mechanism through IRAK4 is independent of cancer types and mutational profiles based on colorectal and pancreatic cancer models; and 3) IRAK4 inhibition reduces tumor desmoplasia and revitalizes intratumoral T cells, setting the stage for successful combination with immune checkpoint inhibitors in a highly aggressive autochthonous pancreatic cancer mouse model. These data combined provide a strong rationale to add CA-4948 to systemic therapy for multiple advanced gastrointestinal malignancies, where resistance to chemotherapy is inevitable and benefit of PD-1 inhibitors is limited to small population. CA-4948 is a novel, first-in-class reversible inhibitor of IRAK4. In a phase I trial, patients with relapsed/refractory hematologic malignancies tolerated CA-4948 monotherapy well with mild fatigue, neutropenia, and nausea as most common adverse events. Recommended phase 2 dose (RP2D) was determined as 300 mg orally twice daily. CA-4948 has not been tested in combination with cytotoxic chemotherapy or immune checkpoint inhibitors for solid tumors in clinic. We hypothesize that inhibition of IRAK4 with CA-4948 will potentiate the effect of immune checkpoint inhibitor while deepening the efficacy of cytotoxic chemotherapy in GEC. Methods: This is a phase I trial of CA-4948 in combination with FOLFOX/PD-1 inhibitor with or without trastuzumab for unresectable GEC. During Dose Escalation, we will investigate CA-4948 in combination with FOLFOX/nivolumab by BOIN algorithm evaluating 4 different dose levels. Starting dose of CA-4948 for Part A will be 200 mg twice daily. Once RP2D is determined, the study will proceed to Dose Expansion, including Cohorts A and B. Cohort A will enroll up to 12 patients with HER2 negative disease at the RP2D of CA-4948 determined at the Dose Escalation phase. Cohort B will investigate CA-4948 in combination with FOLFOX/pembrolizumab and trastuzumab. The initial 6 patients in Cohort B will be considered safety lead-in to confirm the safety and tolerability at the RP2D, followed by additional patients, up to 12 patients treated at the RP2D. The primary objective is to determine the safety and RP2D of CA-4948 in combination with FOLFOX/PD-1 inhibitor with or without trastuzumab. Secondary objectives are to determine the preliminary efficacy of the combination. Correlative studies to evaluate pharmacodynamic effects and to identify biomarkers associated with disease response are planned. Clinical trial information: NCT05187182.

Abstract P243: The IRAK4 inhibitor CA-4948 demonstrates antitumor activity in a preclinical model of CNS lymphoma

Background: Central nervous system (CNS) lymphoma, both primary and secondary disease, carries the worst prognosis of all Non-Hodgkin’s lymphoma with a 5 year survival of less than 30% with current therapeutic options. Recent studies have shown constitutive activation of both NF-κB and MAPK signaling pathways in the maintenance and progression of CNS lymphoma. This often coincides with mutations in MYD88. IRAK4 is a serine/threonine kinase that mediates interleukin 1 receptor (IL-1R) and Toll-like receptor (TLR) signaling downstream of MYD88, and is a novel therapeutic target for this disease. CA-4948 is an oral first-in-class small molecule inhibitor of IRAK4 that has demonstrated clinical activity in patients with systemic Non-Hodgkin’s Lymphoma. Our study goal was to evaluate CA-4948 efficacy in a syngeneic preclinical model of primary CNS B cell lymphoma (A20), supporting future clinical investigation of this agent in this difficult to treat disease. Materials and Methods: Plasma, cerebrospinal fluid (CSF), and brain tissue (both naïve and tumor bearing) were assessed for CA-4948 drug concentration following single high-dose oral administration using UPLC-MS/MS. Biomarker expression, including NF-κB and MAPK, was measured in control and CA-4948 treated brain tissue resected from tumor-bearing animals using multi-parameter immunohistochemistry and 3D modeling of cleared tissue. Dose-dependent survival responses were also measured using the A20 preclinical model of primary CNS lymphoma. Results: While brain concentrations of CA-4948 remained low with respect to plasma (~4-5%), therapeutic dose levels were attained in both CSF and brain tissue (>502 nM). No significant difference between naïve and A20 tumor bearing brain tissue was observed, indicating the blood brain barrier remained intact in this model. Biomarker analyses revealed significant downregulation of both MAPK and NF-κB signaling pathways in response to CA-4948, as evidenced by reduced protein levels of phospho-p38Thr180/Tyr182, phospho-ERK1/2Thr202/Tyr204, and phospho-p65Ser536 in both the tumor cells and the tumor microenvironment. Finally, CA-4948 treatment produced a dose-dependent survival response in syngeneic animals harboring CNS A20 tumors. Conclusions: CA-4948 is able to reach therapeutic dose levels in the CNS in a preclinical murine model of CNS lymphoma, producing significant and dose-dependent anti-tumor activity and survival advantage. These data support further evaluation of CA-4948 in clinical investigation and treatment of patients with CNS lymphoma.

Citation Format: Christina A. von Roemeling, Bently P. Doonan, Lan Hoang-Minh, Han W. Tun, Elizabeth Martinez, Raul Soikes, Reinhard von Roemeling, Duane A. Mitchell. The IRAK4 inhibitor CA-4948 demonstrates antitumor activity in a preclinical model of CNS lymphoma [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P243.

Abstract P073: Pharmacological inhibition of IRAK4 with CA-4948 is beneficial in marginal zone lymphoma models with secondary resistance to PI3K and BTK inhibitors

Background. Marginal zone lymphoma (MZL) is a heterogeneous B-cell malignancy for which no standard treatment exists. B-cell receptor (BCR) signaling dysregulation is a hallmark of MZL and can mimic antigen dependent BCR activation. However, single treatment with BCR signaling inhibitors shows limited complete response rate and relapsing patients. IRAK4 is a protein kinase downstream the Toll-like receptor signaling. CA-4948 is the first-in-class inhibitor of IRAK4 and it is in phase 1/2 studies for patients with relapsed/refractory clinical studies with favorable activity in lymphomas and myeloid neoplasms. Here, we assessed IRAK4 inhibition with CA-4948 against a panel of MZL cell lines in which we have developed secondary resistance to inhibitors of PI3K (idelalisib, copanlisib) or BTK (ibrutinib). Methods. Models with secondary resistance were developed by continuous exposing cell lines derived from splenic MZL (Karpas 1718 and VL51) to high doses of drugs for long period of times. Resistant and parental lines were exposed to increasing doses of CA-4948, alone or in combination with compounds they are resistant to. Cell viability was tested by MTT assay (72h treatment). Synergy of combinations was evaluated according to the Chou-Talalay combination index (CI), as well as potency and efficacy, estimated according to the MuSyC algorithm. Results. The parental Karpas1718, bearing a MYD88 L265P mutation, had an IC50 of 3.29 µM for CA-4948 as single agent, while the parental VL51 and all resistant models presented IC50 values in the range of 19-35 µM. IRAK4 inhibition with CA-4948 had strong benefit when combined to downstream BCR inhibitors. In resistant cells, CA-4948 was strongly synergistic with idelalisib, ibrutinib and, at lesser extent, with copanlisib. CA-4948 in combination with ibrutinib was strongly synergistic especially in the VL51 ibrutinib resistant model compared to the parental one. CA-4948 (from 1 to 5 µM) recovered sensitivity to ibrutinib at IC50 values close to the parental condition. Similarly, CA-4948 in combination with idelalisib was also synergistic and increased sensitivity to idelalisib in idelalisib resistant VL51. Less benefit was seen adding CA-4948 to copanlisib: the combination was synergistic in VL51 parental cell, but with only weak efficacy. In the Karpas1718, CA-4948 was synergistic either in idelalisib resistant or in parental, with improved benefit in the latter, in which synergistic effect was observed when combined with both idelalisib and ibrutinib. The synergistic activity of CA-4948 was mainly due to improved efficacy rather than potency of the combinatorial partners. Conclusions. Our results in MZL cell lines show that the IRAK4 inhibitor CA-4948 is synergistic with small molecules targeting BCR signaling, especially with idelalisib and ibrutinib. Data also suggest that concentrations of CA-4948 comparable to those achieved in patients might overcome or reduce secondary resistance to the tested tyrosine kinase inhibitors.

Citation Format: Francesca Guidetti, Alberto J. Arribas, Filippo Spriano, Laura Barnabei, Reinhard von Roemeling, Elizabeth Martinez, Emanuele Zucca, Francesco Bertoni. Pharmacological inhibition of IRAK4 with CA-4948 is beneficial in marginal zone lymphoma models with secondary resistance to PI3K and BTK inhibitors [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P073.

324 Preclinical evaluation of anti-VISTA antibody CI-8993 in a syngeneic huVISTA-KI model

Background

VISTA (V-domain Ig suppressor of T-cell activation) inhibits anti-tumour immune responses. The Investigational product CI-8993 is a fully human IgG1k monoclonal antibody that binds specifically to this immune checkpoint molecule. Phase I safety has been established in prior trials in patients with advanced cancer (NCT02671955). To assist determining the pharmacokinetics and biodistribution of CI-8993 in patients we aimed to develop a Zirconium-89 (89Zr)-labelled CI-8993 for PET imaging and quantitation, and validate in preclinical models prior to a planned human trial.

Methods

Conjugation conditions of CI-8993 to the metal ion chelator desferrioxamine B (Df-) were established by optimisation of Df:mAb ratio, reaction temperature, time and purification method. Conjugates were assessed by SE-HPLC, SDS-PAGE, and ELISA. Radiolabelling was performed with 89Zr and the radioconjugate was tested for specific activity, radiochemical purity and binding affinity for huVISTA. The in-vivo biodistribution and properties of 89Zr-Df-CI-8993 and IgG1 isotype control radioconjugates were assessed in huVISTA knock-in female (C57BL/6N-Vsir< sup >tm1.1(VSIR)Geno</sup >) or control C57BL/6 mice bearing syngeneic MB49 bladder cancer tumours. Whole body animal PET/CT imaging was performed on day of radioconjugate synthesis and injection and day 1 and day 3 p.i. Biodistribution was assessed by image analyses, and tissue counting, with IHC analyses performed to verify VISTA antigen expression.

Results

Conjugation of Df- to CI-8993 for 60 minutes at room temperature followed by purification via gel filtration resulted in stable constructs with an average chelator-to-antibody ratio of 1.81. SDS-PAGE showed integrity of CI-8993 was maintained after conjugation, and ELISA indicated no impact of conjugation on binding to human VISTA. Radiochemical purity (iTLC) and protein integrity (SE-HPLC) at EOS were > 99% and 93%. PET imaging and biodistribution in MB49 tumour-bearing huVISTA knock-in female mice showed specific localisation of 89Zr-Df-CI-8993 to VISTA expressing organs (liver: 14.98 ± 0.50 %ID/g; spleen: 292.00 ± 14.51 %ID/g; n = 3) compared to 89Zr-Df-IgG1 control (liver: 4.615 ± 0.15 %ID/g; spleen: 6.37 ± 0.22 %ID/g; n = 4) or in the presence of competing unlabelled CI-8993 (liver: 8.14 ± 0.50 %ID/g; spleen: 41.14 ± 3.00 %ID/g; n = 5). Tumour-to-blood ratios indicated specific tumour targeting of 89Zr-Df-CI-8993 in the presence of unlabelled CI-8993 (20.47 ± 3.09) compared to trace dose 89Zr-Df-CI-8993 (0.97 ± 0.12; P = 0.0001) or 89Zr-Df-IgG1 control (1.75 ± 0.11; P < 0.0001).

Conclusions

We have validated 89Zr-Df-CI-8993 for specific binding to huVISTA in-vivo. A clinical trial of 89Zr-Df-CI-8993 is planned in solid tumour patients.

Ethics Approval

All animal studies were approved by the Austin Health Animal Ethics Committee and were conducted in compliance with the Australian Code for the care anduse of animals for scientific purposes.

Fimepinostat (CUDC-907) in patients with relapsed/refractory diffuse large B cell and high-grade B-cell lymphoma: report of a phase 2 trial and exploratory biomarker analyses

Fimepinostat (CUDC-907), a first-in-class oral small-molecule inhibitor of histone deacetylase and phosphatidylinositol 3-kinase, demonstrated efficacy in a phase 1 study of patients with relapsed/refractory (R/R) diffuse large and high-grade B-cell lymphomas (DLBCL/HGBL), particularly those with increased MYC protein expression and/or MYC gene rearrangement/copy number gain (MYC-altered disease). Therefore, a phase 2 study of fimepinostat was conducted in this patient population with 66 eligible patients treated. The primary end-point of overall response (OR) rate for patients with MYC-IHC ≥40% (n = 46) was 15%. Subsequently, exploratory pooled analyses were performed including patients treated on both the phase 1 and 2 studies based upon the presence of MYC-altered disease as well as a biomarker identified by Virtual Inference of Protein activity by Enriched Regulon analysis (VIPER). For these patients with MYC-altered disease (n = 63), the overall response (OR) rate was 22% with seven responding patients remaining on treatment for approximately two years or longer, and VIPER yielded a three-protein biomarker classification with positive and negative predictive values of ≥85%. Prolonged durations of response were achieved by patients with MYC-altered R/R DLBCL/HGBL treated with single-agent fimepinostat. Combination therapies and/or biomarker-based patient selection strategies may lead to higher response rates in future clinical trials.

Abstract 385: Identification of NF-kappaB phospho-p50 as a predictive biomarker for IRAK4 inhibitor CA-4948 in patients with non-Hodgkin's lymphoma

Background: IRAK4, a serine/threonine kinase, was identified as a therapeutic target in hematological malignancies. IRAK4-mediated activation of NF-kappaB could play an important role in NF-kappaB-regulated survival and chemoresistance of cancer cells. CA-4948, a first-in-class small molecule inhibitor of IRAK4, has been tested in Phase 1 clinical trial with evidence of clinical activity in Non-Hodgkin's Lymphoma (NHL) patients. To support the development of companion diagnostic for CA-4948, we developed an immunohistochemical (IHC) assay and explored expression of potential biomarkers of response to CA-4948 in tumor biopsy samples obtained from NHL patients.

Materials and Methods: IHC assay was developed and used for analysis of NF-kappaB p-p50 and p-IRAK1 expression in tumor biopsy samples obtained from 14 patients with NHL. Patients were defined according to their clinical response to CA-4948 treatment: stable disease (SD), 6 cases and progressive disease (PD), 8 cases.

Results: We found nuclear and/or cytoplasmic expression of NF-kappaB p-p50 in all 6 SD cases treated with 50 mg QD (2 cases, tumor regression), 50 mg BID (1 case), 200 mg BID (1 case, tumor regression) and 400 mg BID (2 cases). Expression of NF-kappaB p-p50 was not detected in 7 of 8 cases with PD including patients treated with 50 mg QD (1 case), 100 mg QD (1 case), 100 mg BID (3 cases), 200 mg BID (1 case) and 400 mg BID (1 case). We found statistically significant correlation between expression of NF-kappaB p-p50 in tumor biopsy and SD in NHL patients treated with CA-4948 (p&lt;0.05). Analysis of NF-kappaB p-p50 expression in paired tumor biopsy samples (3 cases) collected before and after the treatment with CA-4948 revealed a significant downregulation of NF-kappaB p-p50 expression in tumors obtained from CA-4948-treated NHL patients. In support of our in vivo findings, our in vitro experiments demonstrated that expression of NF-kappaB p-p50 was depleted in 3D lymphoma organoids treated with a clinically relevant concentration of CA-4948. Our results support further development of NF-kappaB p-p50 as a potential predictive and pharmacodynamic biomarker of IRAK4 inhibitor CA-4948. We found that expression of p-IRAK1 in tumor biopsies was not correlated with clinical response.

Conclusions: Although the cohort size is small, our findings suggest that expression of NF-kappaB p-p50 can serve as biomarker to predict SD in response to the treatment with IRAK4 inhibitor CA-4948 in NHL patients. NF-kappaB p-p50 selection strategy might be used in future clinical trials to identify NHL patients which are most likely to respond to CA-4948 in combination with chemotherapy or targeted therapeutics.

Citation Format: Andrey Ugolkov, Maria Samson, Rosanna Hok, Reinhard von Roemeling, Robert Martell. Identification of NF-kappaB phospho-p50 as a predictive biomarker for IRAK4 inhibitor CA-4948 in patients with non-Hodgkin's lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 385.

A randomized, placebo-controlled, phase 1/2 study of tivantinib (ARQ 197) in combination with irinotecan and cetuximab in patients with metastatic colorectal cancer with wild-type KRAS who have received first-line systemic therapy

Cetuximab in combination with an irinotecan-containing regimen is a standard treatment in patients with KRAS wild-type (KRAS WT), metastatic colorectal cancer (mCRC). We investigated the addition of the oral MET inhibitor tivantinib to cetuximab + irinotecan (CETIRI) based on preclinical evidence that activation of the MET pathway may confer resistance to anti-EGFR therapy. Previously treated patients with KRAS WT advanced or mCRC were enrolled. The phase 1, open-label 3 + 3, dose-escalation study evaluated the safety and maximally tolerated dose of tivantinib plus CETIRI. The phase 2, randomized, double-blinded, placebo-controlled study of biweekly CETIRI plus tivantinib or placebo was restricted to patients who had received only one prior line of chemotherapy. The phase 2 primary endpoint was progression-free survival (PFS). The recommended phase 2 dose was tivantinib (360 mg/m(2) twice daily) with biweekly cetuximab (500 mg/m(2)) and irinotecan (180 mg/m(2)). Among 117 patients evaluable for phase 2 analysis, no statistically significant PFS difference was observed: 8.3 months on tivantinib vs. 7.3 months on placebo (HR, 0.85; 95% confidence interval, 0.55-1.33; P = 0.38). Subgroup analyses trended in favor of tivantinib in patients with MET-High tumors by immunohistochemistry, PTEN-Low tumors, or those pretreated with oxaliplatin, but subgroups were too small to draw conclusions. Neutropenia, diarrhea, nausea and rash were the most frequent severe adverse events in tivantinib-treated patients. The combination of tivantinib and CETIRI was well tolerated but did not significantly improve PFS in previously treated KRAS WT mCRC. Tivantinib may be more active in specific subgroups.

Abstract B194: Tivantinib in combination with erlotinib vs erlotinib alone for EGFR mutant NSCLC: Subgroup results from the phase 3 MARQUEE study

This abstract has been withheld from publication due to its inclusion in the AACR-NCI-EORTC Molecular Targets Conference 2015 Official Press Program. It will be posted online at the time of its presentation in a press conference or in a session: 10:00 AM ET Saturday, November 7.

Citation Format: Giorgio V. Scagliotti, Sergey Orlov, Joachim von Pawel, Frances A. Shepherd, Wallace Akerley, Jeffrey S. Ross, Dale Shuster, Qiang Wang, Brian Schwartz, Reinhard von Roemeling. Tivantinib in combination with erlotinib vs erlotinib alone for EGFR mutant NSCLC: Subgroup results from the phase 3 MARQUEE study. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B194.

Phase III Multinational, Randomized, Double-Blind, Placebo-Controlled Study of Tivantinib (ARQ 197) Plus Erlotinib Versus Erlotinib Alone in Previously Treated Patients With Locally Advanced or Metastatic Nonsquamous Non-Small-Cell Lung Cancer

PURPOSE

Tivantinib, a MET receptor tyrosine kinase inhibitor, demonstrated increased anticancer activity in preclinical and early clinical studies when combined with erlotinib. Our study aimed to confirm efficacy and safety of the combination in previously treated patients with non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Patients with advanced nonsquamous NSCLC previously treated with one to two systemic regimens, including a platinum doublet, were randomly assigned at a 1:1 ratio to receive erlotinib 150 mg daily plus oral tivantinib 360 mg twice daily (E + T) or erlotinib plus placebo (E + P) until disease progression. Tumor specimens were evaluated for EGFR and KRAS mutations, MET expression, and MET gene amplification. The primary end point was overall survival (OS). Secondary and exploratory objectives included progression-free survival (PFS), OS in molecular subgroups, and safety.

RESULTS

The study enrolled 1,048 patients and was discontinued for futility at the interim analysis. OS did not improve with E + T versus E + P (median OS, 8.5 v 7.8 months, respectively; hazard ratio [HR], 0.98; 95% CI, 0.84 to 1.15; P = .81), even though PFS increased (median PFS, 3.6 v 1.9 months; HR, 0.74; 95% CI, 0.62 to 0.89; P < .001). Exploratory subgroup analyses suggested OS improvement in patients with high MET expression (HR, 0.70; 95% CI, 0.49 to 1.01). Most common adverse events occurring with E + T versus E + P were rash (33.1% v 37.3%, respectively), diarrhea (34.6% v 41.0%), asthenia or fatigue (43.5% v 38.1%), and neutropenia (grade 3 to 4; 8.5% v 0.8%).

CONCLUSION

E + T was well tolerated and increased PFS but did not improve OS in the overall nonsquamous NSCLC population.

Phase 2, multicenter, open-label study of tigatuzumab (CS-1008), a humanized monoclonal antibody targeting death receptor 5, in combination with gemcitabine in chemotherapy-naive patients with unresectable or metastatic pancreatic cancer

Tigatuzumab is the humanized version of the agonistic murine monoclonal antibody TRA-8 that binds to the death receptor 5 and induces apoptosis of human cancer cell lines via the caspase cascade. The combination of tigatuzumab and gemcitabine inhibits tumor growth in murine pancreatic xenografts. This phase 2 trial evaluated the efficacy of tigatuzumab combined with gemcitabine in 62 chemotherapy-naive patients with histologically or cytologically confirmed unresectable or metastatic pancreatic cancer. Patients received intravenous tigatuzumab (8 mg/kg loading dose followed by 3 mg/kg weekly) and gemcitabine (1000 mg/m² once weekly for 3 weeks followed by 1 week of rest) until progressive disease (PD) or unacceptable toxicity occurred. The primary end point was progression-free survival (PFS) at 16 weeks. Secondary end points included objective response rate (ORR) (complete responses plus partial responses), duration of response, and overall survival (OS). Safety of the combination was also evaluated. Mean duration of treatment was 18.48 weeks for tigatuzumab and 17.73 weeks for gemcitabine. The PFS rate at 16 weeks was 52.5% (95% confidence interval [CI], 39.3–64.1%). The ORR was 13.1%; 28 (45.9%) patients had stable disease and 14 (23%) patients had PD. Median PFS was 3.9 months (95% CI, 2.2–5.4 months). Median OS was 8.2 months (95% CI, 5.1–9.6 months). The most common adverse events related to tigatuzumab were nausea (35.5%), fatigue (32.3%), and peripheral edema (19.4%). Tigatuzumab combined with gemcitabine was well tolerated and may be clinically active for the treatment of chemotherapy-naive patients with unresectable or metastatic pancreatic cancer.

Abstract 4606: Randomized phase 2 study of efatutazone in combination with carboplatin and paclitaxel as first-line therapy for metastatic non-small cell lung cancer (NSCLC)

Background: Efatutazone, a highly-selective peroxisome proliferator-activated receptor gamma (PPARδ) agonist, has demonstrated antitumor activity in multiple preclinical cancer models, including NSCLC, and has shown anticancer effects and a favorable toxicity profile in Phase 1 trials. The current study evaluated the safety and efficacy of efatutazone in combination with carboplatin and paclitaxel as first-line therapy for NSCLC. Methods: Patients with histologically/cytologically confirmed, untreated metastatic NSCLC, with no significant pleural effusion or pleural involvement from the tumor and an ECOG score of 0-1 participated in this 2-part, multinational study. Part 1 comprised a single-arm portion evaluating safety; Part 2, a double-blind, placebo-controlled, randomized Phase 2 portion evaluating safety and efficacy. Efatutazone (0.5 mg) or placebo was administered orally BID, continuously. Carboplatin was administered at a projected AUC of 6 mg/ml*min and paclitaxel at 200 mg/m2. In Part 1, patients were evaluated for treatment-related dose-limiting toxicities (DLTs). In Part 2, the primary endpoint was the progression-free survival (PFS) rate at Week 18, assessed by the investigators using RECIST. Results: 3 patients enrolled in Part 1; no DLTs were observed. 108 patients were randomized into Part 2. Demographic characteristics were generally similar between treatment arms with fewer patients in the efatutazone arm aged &gt; 65 years (11% vs 28%), female (24% vs 32%), ECOG = 0 (30% vs 35%), and with squamous histology (26% vs 37%). Efatutazone was associated with a lower PFS rate at Week 18 vs placebo (41.1% [95% CI: 26.3, 55.3%] vs 64.9% [95% CI: 50.1, 76.3%]; P &lt; 0.001) and a shorter PFS (102 vs 142 days; HR = 1.62, P = 0.04). There was no difference in overall survival (HR = 1.11, P = 0.71) at a median duration of follow-up of 6.7 months. Most adverse events more frequent with efatutazone were consistent with fluid retention, a known side effect of PPARδ agonists, and included edema, weight gain, pleural effusion, dyspnea, and anemia. In addition, a higher incidence of febrile neutropenia, nausea, and pain in extremity occurred in the efatutazone arm. Exploratory analyses are ongoing to try to understand the reason for the unexpected negative effect on PFS. The higher incidence of pleural effusion with efatutazone, which might be related to a treatment side effect rather than tumor progression, may provide some explanation: in some cases, pleural effusion was judged as progressive disease, whereas other target lesions were stable; no cytology was obtained in these cases. Interpretation: The efatutazone safety profile in this trial was largely consistent with prior studies and known effects of PPARδ agonists. Efatutazone does not improve the efficacy of carboplatin/paclitaxel as first-line therapy of unselected patients with NSCLC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4606. doi:1538-7445.AM2012-4606

Abstract 1278: Phase 1 study of CS-7017, an oral PPAR-γ agonist, in combination with paclitaxel in advanced anaplastic thyroid cancer

Background: Stage IVC (metastatic) anaplastic thyroid cancer (ATC) has a median overall survival (OS) of only 1.9 months. Single agent paclitaxel has modest activity in ATC. In pre-clinical studies, CS-7017 inhibited ATC proliferation through a novel mechanism–activation of PPAR-γ, followed by sequential upregulation of RhoB, then p21. Moreover, CS-7017 augmented the proapoptotic effects of paclitaxel. Based on these results, a multicenter study was conducted to determine if CS-7017+paclitaxel might prove safe and effective in advanced ATC.

Design: A Phase 1 study was conducted to determine the Phase 2 dose. In Phase 1, patients received CS-7017 orally BID for one week (run-in phase), followed by a 3 h iv infusion of paclitaxel (175 mg/m2) every 3 weeks in combination with BID CS-7017. CS-7017 doses were escalated (0.15, 0.3, or 0.5 mg). Tissue biopsies were obtained at baseline and at one and three weeks for immunohistochemistry of PPAR-γ responsive proteins; serum CS-7017 PK studies were also performed.

Results: Nineteen patients were enrolled, but 4 were not dosed (3 due to progression, 1 ineligible). Seven participated in CS-7017 dose levels 1a/1b (0.15 mg BID), six in dose level 2 (0.3 mg BID), and two in dose level 3 (run-in phase only–0.5 mg BID).

Demographics: Of the 15 treated patients, 10 (67%) were women. Median age was 59 years (range: 43-82)

Efficacy: Of 15 patients receiving drug, one had a confirmed partial response (PR) lasting from Day 69 to Day 175, and eight had stable disease (SD) as their best response. Median Time to Progression in 7 patients at Dose Level 1 was 49 days, but 70 days in Dose Level 2 (43% prolongation); corresponding median survival was 99 (0.15 mg BID) vs. 140 days (0.3 mg BID, 42% increase). Median peak CS-7017 blood level was 8.6 ng/mL (range: 5.1 to 13.7) for Level 1 and 22.0 ng/mL (17.0 to 31.5) for Dose Level 2.

Adverse Events: Ten patients had AEs ≥ Grade 3, with two (anemia and localized edema) related to CS-7017. Thirteen events of fluid retention/edema were reported in 8 patients, with only 2 events of CTCAE grade ≥ 3. Eight patients had ≥ one SAE, with one (anemia) due to CS-7017. One SAE (anaphylactic reaction) was related to paclitaxel. No dose limiting toxicity was observed.

Immunohistochemistry: Biopsies were available on 7 patients. PPAR-γ, RXR-α, RhoB were present in all; Angiopoietin-like 4 was induced by CS-7017.

Conclusions: Combination therapy with CS-7017 and paclitaxel was tolerated and has biologic activity in patients with metastatic anaplastic thyroid carcinoma, with initial exploratory data suggesting a dose-dependent improvement in time to progression and survival in response to escalating CS-7017 dosage.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1278. doi:10.1158/1538-7445.AM2011-1278

Muscle cramping in phase I clinical trials of tirapazamine (SR 4233) with and without radiation

PURPOSE

Tirapazamine (SR 4233) is a benzotriazine di-N-oxide which acts as a hypoxic cytotoxic agent and as a radiation enhancer when given shortly before or after radiation. Three Phase I clinical trials were designed to determine the maximum tolerated dose, toxicities, pharmacokinetics, and effects on irradiated tumors and normal tissues.

METHODS AND MATERIALS

Tirapazamine 9 mg/m2 to 21 mg/m2 was given i.v. 1/2 to 1 h prior to irradiation on a multiple dose schedule of 10 consecutive doses. This was later revised to a three times-per-week schedule for 12 doses. In a second clinical trial, tirapazamine was given in a single dose of 18 mg/m2 to 293 mg/m2 i.v. after irradiation. In a third trial, tirapazamine was administered without irradiation in single doses of 36 mg/m2 to 250 mg/m2, with an option for retreatment.

RESULTS

Subjects reported muscle cramping of varying degrees of severity on all three dose schedules. One patient experienced Grade 3 cramping and treatment was discontinued. The most frequent site of cramping were the lower extremities. Creatine phosphokinase (CPK) values were elevated in three patients with associated muscle soreness in one patient. MB (cardiac) isoenzymes were elevated in one patient with no evidence of cardiac muscle damage, and returned to baseline at drug completion. No consistent abnormalities in clinical laboratory values were found. Stretching of the muscle was most effective in relieving the cramping.

CONCLUSION

Muscle cramping has been the most frequently reported toxicity in Phase I studies of tirapazamine, though it does not appear to be dose limiting. Dose escalation on the three clinical trials continues. In vitro studies to investigate the cramping are ongoing.

Dihydropyrimidine dehydrogenase activity in human blood mononuclear cells

Dihydropyrimidine dehydrogenase (DPD; EC 1.3.1.2) catalyzes the rate-limiting reaction in the catabolism of endogenous uracil and thymine and exogenous fluoropyrimidines. DPD activity was studied in human blood mononuclear cell supernatants utilizing a new and sensitive radiochromatographic assay. Total DPD activity showed a linear correlation with supernatant protein concentration. The affinity constants (Km) for NADPH and thymine were approximately 10 and 1 mumol/l, respectively. Maximal activity (Vmax) was observed at 0.25 mmol/l NADPH and 10 mumol/l thymine, respectively. DPD activity in normal individuals was 8.0 +/- (SD) 2.2 nmol/mg protein/h, and ranged from 4.4 to 12.3 nmol/mg/h (n = 25). This activity range was quite similar to values obtained in patients with metastatic solid tumors treated with fluorodeoxyuridine (FUdR; n = 33, p = 0.57). No correlation was found to exist between mononuclear leucocyte DPD activity and the observed toxicity of FUdR in the tested patients. A bimodal distribution of DPD activity was observed in the patients and in normal individuals. The entire study population tested could be divided into two groups with respect to DPD activity; one group with high (greater than 8 nmol/mg/h) activity and another with low (less than 8 nmol/mg/h) activity. The possibility that sex differences may have been responsible for this distribution of DPD activity could not be excluded. The findings of this study are relevant to the pharmacogenetics of fluoropyrimidines in humans.

High-dose intensity, circadian-timed doxorubicin and cisplatin adjuvant chemotherapy for bladder cancer

Thirteen patients with transitional cell carcinoma of the bladder received monthly circadian-timed doxorubicin and cisplatin chemotherapy immediately after radical cystectomy. In five patients cancer had spread through the serosa of the bladder wall and/or into the perivesical fat (stage C). In eight patients cancer had spread to other pelvic tissues and pelvic lymph nodes (stage D1). Ten of these 13 patients showed no recurrence of disease after a median follow-up period of 3.5 years (range, 1 to greater than 5.5); these patients received no chemotherapy for a median duration of 3 years (range, 2-5). Two of the three patients who ultimately failed had local tumor recurrence which occurred much later than is the usual case (40 and 52 months). This circadian-timed two-drug regimen, given in full doses for nine courses as adjuvant treatment, delays and may prevent local and distant recurrence of stage C and D1 bladder cancer.

High-dose intensity systemic therapy of metastatic bladder cancer

Forty-three consecutively diagnosed patients with widely metastatic transitional cell carcinoma of the bladder (TCCB) were treated with a high-dose intensity, chronobiologically timed combination of doxorubicin and cisplatin, followed by Cytoxan (Mead Johnson Pharmaceuticals, Evansville, IN), 5-fluorouracil (5-FU), and cisplatin maintenance for up to 2 years. Fifty-seven percent of the 35 evaluable patients with widespread metastatic cancer responded objectively. Twenty-three percent had complete disappearance of all cancer. Median survival from first treatment for complete responders (CRs) was more than 2 years, and 1 year for partial responders (PRs). Three of the CRs were alive without evidence of cancer more than 2 years after stopping all therapy. High-dose intensity combination chemotherapy can induce durable CRs of widespread bladder cancer.

Cisplatin chronotherapy and disulfiram rescue reduce toxicity without interfering with anticancer activity: animal findings and preliminary clinical experiences

Cisplatin-induced mortality and nephrotoxicity are each predictably worse when the drug is given at certain points within the circadian schedule. Oral disulfiram protects rats from toxic effects at some circadian stages but not others. This manuever does not diminish the anticancer activity of cisplatin in these rats. Human beings given 2 g of oral disulfiram and high doses of cisplatin at the circadian stage associated with least cisplatin nephrotoxicity (prospectively determined potassium excretion acrophase) suffer little or no kidney damage. Disulfiram administration apparently does not interfere with the antineoplastic activity of cisplatin in humans. This is the first demonstration of the feasibility of assignment of treatment time according to a measure of the patient's 'internal clock' as assessed by pretreatment marker rhythmometry. It also establishes the feasibility of giving disulfiram to human beings.

Advanced transitional cell bladder cancer: a treatable disease

Although metastatic bladder cancer is difficult to treat effectively, chemotherapy combinations and schedules have emerged recently that can result in long-lasting complete responses in some patients. Response rates, response durations, and survival patterns of the entire patient population are, however, unsatisfactory. Whereas survival times of these patients following therapy with cisplatin alone or in combination with other drugs are not significantly different, complete response rates are higher and disease-free survival is longer when combinations are used. Higher dosages are associated with better response rates but also with substantial toxicity. Extensive local pretreatment or prior systemic chemotherapy reduces the likelihood of clinically meaningful disease response. Several adjuvant studies have demonstrated an advantage in length of disease-free survival for chemotherapy-treated patients when compared to those who are observed following operation. Metastatic transitional cell bladder cancer is a chemotherapeutically treatable malignancy. Locally advanced disease may be most effectively treated by aggressive surgery followed by cisplatin-based combination chemotherapy. The highest response rates and longest disease-free survivals are uniformly associated with aggressive and prolonged multidrug therapy.

Lack of antiemetic effect of high-dose metoclopramide

Sixteen of 26 patients given 51 courses of treatment of the doxorubicin and cisplatin combination with no antiemetic therapy suffered the same number of vomiting episodes and had the same duration of vomiting as did the remaining ten patients given 20 cycles of this chemotherapy plus the standard high-dose metoclopramide regimen. This antiemetic regimen caused significant side effects in one fifth of the patients receiving it.