Abstract 2255: Patient pharmacodynamic biomarker and pk evaluation results from an ongoing phase I dose-escalation study of q702, an axl, mer and csf1r kinase inhibitor in patients with advanced solid tumors

Background: Axl, Mer and CSF1 receptor tyrosine kinases play vital roles in promoting the immunosuppressive tumor microenvironment (TME) by affecting myeloid functions (e.g., tumor associated macrophage [TAM], myeloid derived suppression cell [MDSC]) and promoting epithelial-to-mesenchymal transition (EMT). Thus, simultaneous inhibition of Axl, Mer and CSF1R may be an effective strategy for TME modification. Q702 is a novel Axl/Mer/CSF1R kinase inhibitor that affects the immune components (modulating TAM and MDSC populations, inducing CD8+ T cell infiltration and increasing IFN-ɣ in CD8+ T cell) as well as changes in malignant cells such as increasing MHC I on the tumor cells of syngeneic mouse models. These nonclinical results suggest that Q702 monotherapy or Q702 combination with conventional therapies may have considerable potential as a novel treatment strategy for patients with advanced solid tumors.

Methods: This is a Phase 1, Multicenter, Open-label, Dose-Escalation, Safety, Pharmacodynamic, Pharmacokinetic Study of Q702 with a Cohort Expansion at the recommended phase 2 dose (RP2D) in Patients with Advanced Solid Tumors (NCT04648254). Q702 was administered orally for seven days every other week. Peripheral blood samples were obtained on days 1,8,15, and 21. Axl, Mer and CSF1R target engagement is assessed by the quantifications of soluble Axl, Mer and M-CSF in plasma by Luminex xMAP® technology or ELISA. The pharmacodynamic biomarker changes are measured by flow cytometry for immune cell population shifts and IFN-ɣ levels in specific immune cells.

Results: PK and PD biomarker samples from 22 patients with various tumor types (e.g. colon, pancreas, esophageal) from the dose escalation phase (4 mg to 240 mg) have been analyzed. Pharmacokinetic studies demonstrated dose proportional increase in Cmax and AUClast of Q702 and its two active metabolites which have activity against Axl and/or CSF1R. Axl and CSF1R target engagement by Q702 treatment is observed in a dose dependent manner. From the 60 mg cohort, target engagement for Axl and CSF1R reached a inhibitory level that was observed in nonclinical models. In the pharmacodynamic biomarker analysis, IFN-ɣ in CD8+ T cells and non-T cell populations is increased. Monocytes and M-MDSC population are decreased in peripheral blood.

Conclusion: Up to 240 mg, Q702 has demonstrated the intended pharmacologic activity with acceptable safety profile. In biomarker analysis, immune modulation activity is exerted by Axl/Mer/CSF1R inhibition. Further assessment of pharmacokinetics, pharmacodynamics, safety and antitumor activity will be performed at the expansion phase at the RP2D in patients with selected advanced tumors.

Citation Format: Bae Jung Choi, Devalingam Devalingam, Angela Alistar, Anthony El-Khoueiry, Alain Mita, Hwankyu Kang, Jinho Choi, Hyunji Ahn, Jeongjun Kim, Seung-Joo Lee, Yeong-In Yang, Jiye Ahn, Borami Jeon, Jaeseung Kim, Kiyean Nam. Patient pharmacodynamic biomarker and pk evaluation results from an ongoing phase I dose-escalation study of q702, an axl, mer and csf1r kinase inhibitor in patients with advanced solid tumors [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 2255.

Phase 1 study to determine the safety and dosing of autologous PBMCs modified to present HPV16 antigens (SQZ-PBMC-HPV) in HLA-A*02+ patients with HPV16+ solid tumors

We conducted a dose escalation Phase 1 study of autologous PBMCs loaded by microfluidic squeezing (Cell Squeeze® technology) with HPV16 E6 and E7 antigens (SQZ-PBMC-HPV), in HLA-A*02+ patients with advanced/metastatic HPV16+ cancers. Preclinical studies in murine models had shown such cells resulted in stimulation and proliferation of antigen specific CD8+ cells, and demonstrated antitumor activity. Administration of SQZ-PBMC-HPV was every 3 weeks. Enrollment followed a modified 3+3 design with primary objectives to define safety, tolerability, and the recommended Phase 2 dose. Secondary and exploratory objectives were antitumor activity, manufacturing feasibility, and pharmacodynamic evaluation of immune responses. Eighteen patients were enrolled at doses ranging from 0.5 × 106 to 5.0 × 106 live cells/kg. Manufacture proved feasible and required < 24 h within the overall vein-to-vein time of 1 - 2 weeks; at the highest dose, a median of 4 doses were administered. No DLTs were observed. Most related TEAEs were Grade 1 - 2, and one Grade 2 cytokine release syndrome SAE was reported. Tumor biopsies in three patients showed 2 to 8-fold increases in CD8+ tissue infiltrating lymphocytes, including a case that exhibited increased MHC-I+ and PD-L1+ cell densities and reduced numbers of HPV+ cells. Clinical benefit was documented for the latter case. SQZ-PBMC-HPV was well tolerated; 5.0 × 106 live cells/kg with double priming was chosen as the recommended Phase 2 dose. Multiple participants exhibited pharmacodynamic changes consistent with immune responses supporting the proposed mechanism of action for SQZ-PBMC-HPV, including patients previously refractory to checkpoint inhibitors.

Case Report of CCDC149-ALK Fusion: A Novel Genetic Alteration and a Clinically Relevant Target in Metastatic Papillary Thyroid Carcinoma

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer, usually with an indolent course. ALK fusions are rare in PTC but may give rise to a more aggressive behavior. We report a novel ALK fusion, CCDC149-ALK, not previously described in PTC, detected by next-generation sequencing in a 30-year-old woman with progressive widely metastatic radioiodine-refractory (RAIR) disease to lung, muscle, and brain. The patient was started on alectinib, a second-generation anaplastic lymphoma kinase (ALK) inhibitor. Within eight weeks, her palpable disease had completely regressed, and the serum thyroglobulin decreased dramatically. Restaging imaging demonstrated an objective partial response. Our case highlights the role of ALK fusions in thyroid cancer and highlights its clinical significance in PTC. We recommend deep mutational sequencing in BRAFV600E-negative RAIR PTC to identify targetable genetic alterations, including gene fusions, that may result in dramatic therapeutic benefits.

Abstract 1975: Potential novel Immuno-oncology mechanism revealed during translational phase I Immuno-blood profiling of experimental ADC medicine OBT076 in a gastric cancer patient

CD205 is a type I transmembrane glycoprotein, with unique characteristics that make it an ideal target for Antibody Drug Conjugate (ADC) therapy. Here we report on a potential novel immuno-oncology mechanism revealed during the Translational Phase I (NCT04064359) immuno-blood profiling of a chemo-refractory patient treated with OBT076, an experimental CD205-directed ADC.

A chemo-refractory advanced gastric cancer patient with 60% CD205 expression in the primary tumor via IHC and having previously undergone 2 lines of chemotherapy treatment (Docetaxel/cisplatin/5FU and Ramucirumab/Paclitaxel), received five 21-day cycles of OBT076 (one at 2.5mg/kg and four cycles at 2.0 mg/kg) followed by 1 cycle of Pembrolizumab (PZ; 200mg) ~4 weeks later. Clinical response was evaluated and immunological markers (CD45, CD205, CD4, CD8, and PD1) in peripheral blood cells were quantified using flow cytometry.

After 2 OBT076 cycles at 2.0 mg/kg, there was an ~40% shrinkage in the primary gastric tumor size and resolution of ascites and lymph node metastases were observed. Following 2 further cycles and PZ, complete response was achieved for the primary tumor. Flow cytometry showed (1) an initial decrease in the absolute numbers of dendritic cells by day 8, followed by a 2-fold increase in numbers by day 21 after treatment; (2) a near total decrease in the population of CD8+ CD205+ cells by day 8, no recovery in levels were observed; (3) a 3-fold increase in CD4+ and CD8+ T-cell numbers between days 8 and 21 and (4) an initial decrease in CD4+ PD1+ and CD8+ PD1+ T-cell numbers followed by an ~4-fold increase between days 8 and 21.

In summary our results show that increases in PD1+ T-cells, T-cell induction, and decreases in immuno-suppressive CD4+ CD205+ and CD8+ CD205+ cells occur simultaneously; coinciding with rapid resolution of the primary tumor, lymph node metastases and ascites. These findings suggest that OBT076 activates the patient’s immune response against the tumor through a potentially novel mechanism: drug-induced depletion of CD8+ CD205+ immuno-suppressive cells and subsequent T-cell activation. Additionally, our data support the use of immune checkpoint inhibitors in conjunction with OBT076 to achieve favorable clinical outcomes.

Citation Format: Christian Rohlff, Solmaz Sahebjam, Alain Mita, Rosen Lee, Chander Sekhar Peddaboina, Arnima Bisht, Lindsey Hudson, Wolf Fridman, Abderrahim Fandi, Olivier Rixe. Potential novel Immuno-oncology mechanism revealed during translational phase I Immuno-blood profiling of experimental ADC medicine OBT076 in a gastric cancer patient [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 1975.

525 Preliminary safety, PK/PD and efficacy results from a first-in-human phase I/IIa clinical trial of BNT411, a systemic Toll-like receptor 7 agonist in patients with solid tumors

Background

The intravenously administered small-molecule Toll-like receptor 7 (TLR7) agonist BNT411 was developed to systemically activate plasmacytoid dendritic cells, characterized by a Type 1 interferon-dominated release of cytokines. The activation of cytotoxic CD8+ T cells and broad modulation of the innate immune system is intended to enhance pre-existing anti-tumor responses and induce de novo responses, especially in combination with cytotoxic therapies and immune checkpoint inhibitors.

Methods

This first-in-human, open label, multi-center trial (BNT411-01) involves dose titration in patients (ECOG 0 or 1) with solid tumors with BNT411 administered weekly (q1w) for a month, then q3w thereafter until disease progression, unacceptable toxicity, or death. Part 1A is a single-agent dose escalation (accelerated titration) of BNT411 in patients with metastatic or unresectable solid tumors that have exhausted available treatment options, with bifurcation to Part 1B, a dose escalation of BNT411 in combination with atezolizumab, carboplatin and etoposide in patients with chemotherapy-naïve extensive-stage small cell lung cancer (ES-SCLC), followed by expansion cohorts (Part 2). Endpoints of Part 1A and 1B are safety, determination of maximum-tolerated dose (MTD)/recommended phase 2 dose (RP2D), pharmacokinetics, pharmacodynamic (PD) profiling of immune activation, and preliminary efficacy of BNT411 (RECIST 1.1).

Results

As of 1st July 2021, 11 patients have received BNT411 in Part 1A and 5 of 8 dose levels have been cleared. Patients (median age 62 years) had previously received a median of 3 (range 2–5) prior systemic cancer therapies. The only drug-related adverse events (AEs) reported in two or more patients were pyrexia (n=2 patients [18.2%], Grades 1 and 3 [non-serious]) and anaemia (n=2 patients, [18.2%], Grades 1 and 2). There were no dose limiting toxicities, grade 4–5 AEs, or related SAEs reported. Plasma cytokine levels showed the strongest response at BNT411 Dose Level (DL) 5 (2.4 µg/kg), with an increase (2.7–9.2 fold) of interferon-γ induced protein IP10 in 3/4 patients. The best response seen was 5 months of stable disease in one patient with squamous cell carcinoma of the lung at DL4 after 13 doses. Three dose levels remain to be tested in Part 1A (up to 16 µg/kg), with recruitment to Part 1B initiated.

Conclusions

BNT411 has an acceptable safety profile at all doses tested as monotherapy, with encouraging PD signals that warrants study continuation. Updated data will be presented, including combination treatment in the first-line setting of ES-SCLC.

Acknowledgements

BNT411-01 is funded by BioNTech SE. The authors would like to acknowledge Andrew Finlayson (BioNTech SE) for medical writing support.

Trial Registration

Clinicaltrials.

gov: NCT04101357

Ethics Approval

Ethics & Institutional Review Board approvals were obtained from the respective participating countries prior to initiation of the trial.

469 A phase 1 first in human study of HMBD-002, an IgG4 monoclonal antibody targeting VISTA, as a monotherapy and combined with pembrolizumab in patients with advanced solid malignancies

Background

V-domain Ig suppressor of T cell Activation (VISTA), an immune checkpoint regulator predominantly expressed on myeloid cells, represents a promising therapeutic target due to its role in suppressing pro-inflammatory, anti-tumor responses within the tumor microenvironment (TME). Based on VISTA’s broad expression across immune cell subtypes, HMBD-002 has been designed as a non-depleting, IgG4 monoclonal antibody with high affinity and specificity to VISTA across species (human, cynomolgus monkey, and rodent) that has the ability to block a predicted counter-structure binding site. In preclinical studies, HMBD-002 significantly inhibited tumor growth, both as a monotherapy and in combination with pembrolizumab, while decreasing infiltration of suppressive myeloid cells within the TME and increasing T cell activity. While rapid serum clearance and immune toxicities (e.g. cytokine release syndrome) have been reported for IgG1 antibodies, these were not observed preclinically with HMBD-002. In addition to VISTA expression on pro-inflammatory immune cells, examination of VISTA expression across cancer types has revealed that several malignancies, particularly human samples of triple negative breast cancer (TNBC) and non-small cell lung cancer (NSCLC), express high levels of VISTA, thereby providing a rationale for exploring these indications in clinical studies.

Methods

This Phase 1, first in human study is being conducted in two parts and will evaluate multiple doses and schedules of intravenously (IV) administered HMBD-002, with or without pembrolizumab, in patients with advanced solid tumors. Part 1 (dose escalation) seeks to identify the maximum tolerated dose (MTD), or the maximum tested dose, of HMBD-002 as a monotherapy, and separately, in combination with pembrolizumab to define the recommend doses for subsequent disease directed studies (i.e., recommended phase 2 dose [RP2D]). Part 2 (dose expansion) will assess the anti-cancer activity of HMBD-002 as a monotherapy at the RP2D in previously treated patients with TNBC, and NSCLC, and in combination with pembrolizumab in patients with TNBC, NSCLC, and other VISTA-expressing malignancies. The size of the disease-directed cohorts will be determined based on an interim futility analysis conducted upon enrollment of 15 patients. Safety, efficacy, pharmacokinetic, and pharmacodynamic endpoints will be monitored and reported. Correlative studies will assess pre- and post-treatment markers of immune activity in the periphery and the tumor microenvironment.

Acknowledgements

This work was funded in part by the Cancer Prevention and Research Institute of Texas (CPRIT).

Ethics Approval

The study was approved by each participating Institution’s Institutional Review Board.

523 Preliminary clinical experience with XmAb20717, a PD-1 x CTLA-4 bispecific antibody, in patients with advanced solid tumors

Background

XmAb20717 is a humanized bispecific monoclonal antibody that simultaneously targets PD-1 and CTLA-4. We report updated data on patients treated at the recommended expansion dose from an ongoing, multicenter, Phase 1, dose-escalation and -expansion study of intravenous XmAb20717 in patients with selected advanced solid tumors that progressed after treatment with all standard therapies or with no standard therapeutic options.

Methods

A maximum tolerated dose was not reached in dose escalation. XmAb20717 10 mg/kg every 2 weeks (Q2W) was selected as the expansion dose, based on consistent T-cell proliferation in peripheral blood indicative of dual PD-1/CTLA-4 checkpoint blockade, and response to treatment (RECIST[1.1]).1 Parallel expansion cohorts included ~20 patients each with melanoma, renal cell carcinoma (RCC), non-small cell lung cancer (NSCLC), castration-resistant prostate cancer (CRPC), and a basket of tumor types without an FDA-approved checkpoint inhibitor (CI). Patients treated with 10 mg/kg in dose escalation were pooled with expansion cohorts for analysis of clinical activity and safety.

Results

As of 9 June 2021, 110 patients, ranging in age from 39 to 89 years and 66.4% male, were treated, and 5 were continuing treatment. Patients had received a median of 4 prior systemic treatment regimens, including CI therapy for 64.5%. The objective response rate was 13.0% (10/77 patients evaluable for efficacy), including 1 complete response (melanoma [confirmed]) and 9 partial responses (confirmed: 1 melanoma, 2 RCC, 2 CRPC, 1 ovarian cancer; unconfirmed: 1 melanoma, 2 NSCLC). The CRPC responders (2/7 with RECIST-measurable disease) had confirmed PSA decreases ≥ 50% from baseline (to 0.02 and 0.3 ng/mL); neither had progression on bone scans. All responders had prior CI exposure, except those with CRPC. Robust CD4 and CD8 T-cell activation was seen. Low baseline tumoral expression of myeloid recruitment genes, including IL-8, was associated with clinical benefit. Grade ≥ 3 immunotherapy-related adverse events in ≥ 3 patients included rash (16.4%), transaminase elevations (9.1%), hyperglycemia (4.5%), acute kidney injury (3.6%), amylase and lipase increased (2.7%), and lipase increased (2.7%).

Conclusions

Preliminary data indicate 10 mg/kg XmAb20717 Q2W was associated with complete and partial responses in multiple tumor types and was generally well-tolerated in these heavily pretreated patients with advanced cancer. Changes in T-cell populations in the periphery and tumor are consistent with robust dual checkpoint blockade. These findings support further development of XmAb20717 in advanced solid tumors, including metastatic prostate cancer.

Trial Registration

NCT03517488

References

Shum E, Daud A, Reilley M, et al. Preliminary safety, pharmacokinetics/pharmacodynamics, and antitumor activity of XmAb20717, a PD-1 x CTLA-4 bispecific antibody, in patients with advanced solid tumors. JITC 2020;8(3):A247-8.

Ethics Approval

The study was approved by each institution’s IRB.

Avelumab for platinum-ineligible/refractory recurrent and/or metastatic squamous cell carcinoma of the head and neck: phase Ib results from the JAVELIN Solid Tumor trial

Background

Recurrent and/or metastatic (R/M) disease develops in approximately 65% of patients with squamous cell carcinoma of the head and neck (SCCHN) and is associated with a poor prognosis. Immune checkpoint inhibitors have proven effective in multiple tumor types, including R/M SCCHN. We report the efficacy and safety of avelumab (antiprogrammed death ligand 1 antibody) in an expansion cohort of patients with platinum-refractory/ineligible R/M SCCHN enrolled in the phase I JAVELIN Solid Tumor trial (NCT01772004).

Methods

Eligible patients with R/M SCCHN were aged ≥18 years and had received ≥1 line of platinum-based chemotherapy with disease progression or recurrence within 6 months of the last dose or were ineligible for platinum-based chemotherapy. All patients received avelumab 10 mg/kg every 2 weeks. Tumor assessments were carried out by a blinded independent review committee (IRC) and investigators according to Response Evaluation Criteria in Solid Tumors V.1.1 (RECIST 1.1). Key endpoints included best overall response, duration of response (DOR) and progression-free survival (PFS) assessed by IRC and investigator per RECIST 1.1, overall survival (OS), and safety.

Results

Between April 24, 2015, and November 13, 2015, 153 patients were enrolled. Patients had a median of two prior lines of therapy for metastatic or locally advanced disease (range 0–6); 12 patients (7.8%) were not eligible for platinum-based chemotherapy. At data cut-off (December 31, 2017), the confirmed objective response rate was 9.2% (95% CI 5.1% to 14.9%) assessed by IRC and 13.1% (95% CI 8.2% to 19.5%) assessed by investigator. Median DOR was not reached (95% CI 4.2 to not estimable) based on IRC assessment. Median PFS was 1.4 months (95% CI 1.4 to 2.6) assessed by IRC and 1.8 months (95% CI 1.4 to 2.7) assessed by investigator; median OS was 8.0 months (95% CI 6.5 to 10.2). Any-grade treatment-related adverse events (TRAEs) occurred in 83 patients (54.2%) and were grade ≥3 in 10 patients (6.5%). The most common TRAEs were fatigue (n=19, 12.4%), fever (n=14, 9.2%), pruritus (n=12, 7.8%), and chills (n=11, 7.2%), and there were no treatment-related deaths.

Conclusion

Avelumab showed clinical activity and was associated with a low rate of grade ≥3 TRAEs in heavily pretreated patients with platinum-refractory/ineligible R/M SCCHN.

Abstract CT108: A first-in-human, Phase 1 study of ASTX029, a dual-mechanism inhibitor of ERK1/2, in relapsed/refractory solid tumors

Background: The RAS-RAF-MEK-ERK pathway is commonly upregulated in human cancers. This is an open-label Phase 1 study of ASTX029, a dual-mechanism extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor, in subjects with relapsed/refractory solid tumors (NCT03520075). Methods: The primary objectives are to identify a maximum tolerated dose and/or recommended Phase 2 dose. ASTX029 was administered orally daily of 21-day cycles as powder-in-bottle (PiB, Cohort 1/10mg) and tablet formulation (beginning with Cohort 6/80 mg) under fed conditions, and as tablet formulation under fasting conditions (beginning with Cohort 8/40 mg). Dose escalation occurred according to a “3+3 design” based on dose-limiting toxicity (DLT) events. Disease response was evaluated according to RECIST v1.1 and exploratory indicators, including tumor variant allele frequency changes detected by cell-free DNA (cfDNA) quantitation. Results: 56 subjects were treated with at least one dose of ASTX029 in Phase 1A (dose escalation). Of 46 subjects with data, 35 (76%) had any RAS mutations and 4 (9%) had BRAF mutations; 1 subject had both. At the 200 mg dose level (Cohort 5, PiB/fed), one of six evaluable subjects developed a DLT (grade 3 maculopapular rash). At the 280 mg dose level (Cohort 12, tablet/fasting), two subjects experienced grade 2 central serous retinopathy adverse events (CSR AEs) within a few days of dosing. These were the only CSR AEs noted and one event was declared a DLT. Both subjects recovered to baseline within days of dose interruption. One cohort level below this dose was expanded (Cohort 11/200 mg, tablet/fasting); this dose level was deemed safe (without a DLT or grade ≥2 visual AE in 7 subjects) and was selected for Phase 1B dose expansion. Mean pharmacokinetic (PK) exposure was 151% of target exposure, which is defined as the level expected to have biological activity based on animal studies. The most frequent grade ≥2 AEs assessed as drug-related included nausea (4 subjects, grade 2) and transaminitis (4 subjects: 3 grade 2, 1 grade 3). The grade 3 transaminitis occurred in a subject with metastatic sarcoma involving the liver. There was one serious AE of malaise considered related to study drug. Two subjects, one with KRAS-G12A and BRAF-D549N non-small cell lung cancer (120 mg) and one with KRAS-G12D metastatic pancreatic cancer (200 mg), achieved partial responses (cycle 15/ongoing and cycle 3/ongoing, respectively). In 2 subjects with stable disease as the best response, longitudinal cfDNA sequencing showed a decrease of tumor variant allele frequencies after 2 cycles of ASTX029, followed by a return to baseline levels before disease progression. The most common reason for ASTX029 discontinuation was disease progression. Conclusions: This Phase 1A study of the ERK1/2 inhibitor ASTX029 has identified a dose level of 200 mg daily of a 21-day cycle for investigation in the Phase 1B portion of the study. Pharmacokinetic and pharmacodynamic data suggest target exposures are achieved with preliminary clinical activity.

Citation Format: Patricia LoRusso, Drew Rasco, Geoffrey Shapiro, Filip Janku, Alain Mita, Nilofer Azad, Marcia Toguchi, Chris Hindley, Shannon Bradley, Danna Chan, Harold Keer, Kim-Hien Dao, Ryan J. Sullivan, Alexander Spira. A first-in-human, Phase 1 study of ASTX029, a dual-mechanism inhibitor of ERK1/2, in relapsed/refractory solid tumors [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 CT108.

407 Preliminary safety, pharmacokinetics/pharmacodynamics, and antitumor activity of XmAb20717, a PD-1 x CTLA-4 bispecific antibody, in patients with advanced solid tumors

Background

XmAb20717 is a humanized bispecific monoclonal antibody that simultaneously targets PD-1 and CTLA-4. We report preliminary data from an ongoing, multicenter, Phase 1 study investigating the safety/tolerability, pharmacokinetics/pharmacodynamics, and clinical activity (RECIST 1.1) of XmAb20717 in patients with selected advanced solid tumors.

Methods

A 3+3 dose-escalation design was used to establish a maximum tolerated (MTD)/recommended dose for evaluation in parallel expansion cohorts, including melanoma, renal cell carcinoma, non-small cell lung cancer (NSCLC), prostate cancer, and a basket of tumor types without an FDA-approved checkpoint inhibitor (CI; n≤20 each). XmAb20717 was administered as an infusion on Days 1 and 15 of each 28-day cycle.

Results

As of 08Jul2020, 109 patients had been treated (table 1), and 30 were continuing treatment. In escalation, 6 dose levels (0.15–10.0 mg/kg) were evaluated (n=34); an MTD was not established. Expansion cohorts were initiated at 10 mg/kg (n=72), and a 15 mg/kg escalation cohort was added (n=3). T-cell proliferation was noted in peripheral blood at doses as low as 3 mg/kg and was highest at 10 mg/kg. At this dose, consistent proliferation of CD8+ and CD4+ T cells was observed, indicative of dual PD-1 and CTLA-4 checkpoint blockade (figure 1). Paired pre- and post-dosing biopsies showed increased intratumoral T-cell infiltration and IFN-response signatures following treatment. Grade 3/4 treatment-related adverse events (TRAEs) reported for ≥3 patients included rash (13%), transaminase elevations (7%), lipase increased (4% [2% with amylase increased]), and acute kidney injury (3%), all considered immune-related. There were 2 Grade 5 TRAEs: immune-mediated pancreatitis (in the presence of pancreatic metastases) and immune-mediated myocarditis (Grade 4) that contributed to respiratory failure. A complete response was reported as the best overall response for 1 patient (melanoma); partial responses were reported for 5 patients (2 melanoma, 2 NSCLC, 1 ovarian). The objective response rate was 13% overall and 21% at 10 mg/kg (6/46 and 6/29 evaluable patients, respectively). All responders had prior CI exposure. Responses were observed only at 10 mg/kg and, within the 10 mg/kg group, appeared to correlate with higher peak serum concentration and area under the curve.

Abstract 407 Table 1

Demographics and baseline characteristics

Abstract 407 Figure 1

Mean change from baseline in percentage of Ki67+ T–cell expression in peripheral blood during first two cycles of XmAb20717

Conclusions

XmAb20717 induced T-cell proliferation in peripheral blood consistent with dual-checkpoint blockade. Preliminary data indicate XmAb20717 was generally well-tolerated and associated with evidence of antitumor activity in CI-pretreated patients with various types of advanced solid tumors.

Trial Registration

NCT03517488

Ethics Approval

The study was approved by each institution’s IRB.

Phase Ib clinical trial of the anti-frizzled antibody vantictumab (OMP-18R5) plus paclitaxel in patients with locally advanced or metastatic HER2-negative breast cancer

PURPOSE

Vantictumab is a monoclonal antibody that binds to frizzled (FZD) receptors and inhibits canonical WNT signaling. This phase Ib dose escalation study enrolled patients with locally recurrent or metastatic HER2-negative breast cancer who were treated with weekly paclitaxel in combination with escalating doses of vantictumab.

METHODS

Patients were enrolled in dose escalation cohorts treated with weekly paclitaxel 90 mg/m² on days 1, 8 and 15 in combination with vantictumab 3.5-14 mg/kg days 1 and 15 or 3-8 mg/kg day 1 of every 28-day cycle. Primary endpoints were safety, dose-limiting toxicities (DLTs). Secondary endpoints included pharmacokinetics, efficacy and an exploratory biomarker analysis.

RESULTS

Forty-eight female patients with a mean age of 54 were enrolled. The majority (66.6%) received prior chemotherapy for recurrent or metastatic disease; 45.8% were hormone receptor (HR)-positive, HER2-negative and 54.2% triple-negative. The most frequent adverse events related to any study treatment were nausea (54.2%), alopecia (52.1%), fatigue (47.9%), and peripheral neuropathy (43.8%). No DLTs occurred; however, 6 patients experienced fractures outside of the DLT window. The overall response rate was 31.3% and the clinical benefit rate was 68.8%. A 6-gene WNT pathway signature showed significant association with progression-free survival (PFS) and overall survival (OS) for the biomarker high versus biomarker low groups (PFS: p = 0.029 and OS: p = 0.00045, respectively).

CONCLUSIONS

The combination of vantictumab and weekly paclitaxel was generally well tolerated with promising efficacy; however, the incidence of fractures limits future clinical development of this particular WNT inhibitor in metastatic breast cancer.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov registration: NCT01973309.

Quantitative lymph node burden as a 'very-high-risk' factor identifying head and neck cancer patients benefiting from postoperative chemoradiation

Background

Adjuvant chemoradiation (CRT) is standard for head and neck squamous cell carcinoma (HNSCC) patients with positive margins or extranodal extension (ENE) following surgery. However, emerging evidence suggests the number of positive lymph nodes (LNs) is the dominant determinant of survival in non-oropharyngeal HNSCC and thus may better identify those benefiting from treatment intensification.

Patients and methods

Patients from the National Cancer Database diagnosed with non-oropharyngeal HNSCC (oral cavity, larynx, hypopharynx) between 2004 and 2014 and undergoing surgical resection, neck dissection, and postoperative radiotherapy (RT) were included. Multivariable regression with first-order interaction terms was used to model the interaction between postoperative CRT and continuous number of positive LNs with respect to overall survival.

Results

In total, 7144 patients met inclusion criteria. In multivariable analysis, increasing number of positive LNs was associated with both increasing mortality (P < 0.001) and increasing benefit from postoperative CRT versus RT alone (interaction P < 0.001). While there was no benefit from postoperative CRT in patients with 0-2 LN+ [hazard ratio (HR) 0.96, 95% confidence interval (CI) 0.86-1.07, P = 0.47], increased benefit was seen in those with 3-5 LN+ (HR 0.84, 95% CI 0.70-1.00, P = 0.05) and those with ≥6 LN+ (HR 0.65, 95% CI 0.51-0.82, P < 0.001) in multivariable models. By contrast, margin status and ENE did not reliably identify patients benefitting from postoperative CRT based on statistical tests of interaction. Even in patients with ENE, positive margins, or both, only those with ≥6 LN+ had improved survival with postoperative CRT.

Conclusion

Increasing metastatic nodal burden was associated with increased benefit from CRT compared with RT alone, surpassing conventional high-risk factors in identifying patients benefiting from CRT. Stratification by metastatic LN number may characterize a very-high-risk patient cohort best suited for treatment intensification.

Survival outcomes with concomitant chemoradiotherapy in older adults with oropharyngeal carcinoma in an era of increasing human papillomavirus (HPV) prevalence

BACKGROUND

Human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC) has dramatically increased in incidence and prevalence among patients aged 70 and older. There are virtually no data regarding outcomes in this population, and thus optimal therapy, including the role of chemotherapy for those undergoing radiotherapy (RT), remains unclear.

METHODS

The National Cancer Database was queried for older adults (defined as age 70 years and older) with locally advanced OPSCC (cT1-2N1-3, cT3-4N0-3) diagnosed from 2010 to 2014 with known HPV-status undergoing definitive RT alone or chemoradiation (CRT).

RESULTS

Overall, 1,965 older adults with locally advanced OPSCC met inclusion criteria, including 1,141 HPV-positive (58%) and 824 HPV-negative (42%) patients. 1,211 patients (62%) received CRT. In multivariable analysis, CRT was associated with improved survival in older patients when compared to RT alone (hazard ratio [HR] = 0.74, 95% confidence interval [CI] 0.64-0.86, P < 0.001). CRT was associated with improved survival in both HPV-positive (HR = 0.80, 95% CI: 0.64-1.00, P = 0.05) and HPV-negative (HR = 0.69, 95% CI: 0.56-0.85, P < 0.001) subgroups. There was no significant interaction between HPV status and the impact of CRT on survival (P interaction = 0.57).

CONCLUSIONS

Despite the radiosensitivity of HPV-positive OPSCC and the challenges in delivering CRT to older adults, CRT was associated with improved survival in older patients with HPV-positive OPSCC, similar in magnitude to the benefit in HPV-negative patients. As the incidence of HPV-positive OPSCC in older patients continues to increase, further studies are needed to investigate optimal therapeutic strategies in this population.

Association of Quantitative Metastatic Lymph Node Burden With Survival in Hypopharyngeal and Laryngeal Cancer

Importance

Nodal staging for laryngohypopharyngeal cancers is based primarily on size and laterality, with less value placed on absolute number of metastatic lymph nodes (LNs). We are aware of no studies to date that have specifically addressed the prognostic effect of quantitative nodal burden in larynx or hypopharynx malignancies.

Objective

To assess the independent impact of quantitative metastatic LN burden on mortality risk.

Design, Setting, and Participants

Univariate and multivariable models were constructed to evaluate the association between patients' number of metastatic LNs and their survival, adjusting for factors such as nodal size, laterality, extranodal extension, margin status, and adjuvant treatment. Participants were patients with squamous cell carcinoma of the larynx or hypopharynx undergoing upfront surgical resection for curative intent at a US hospital between 2004 and 2013, as identified in the National Cancer Database. A neck dissection of a minimum of 10 LNs was required.

Main Outcomes and Measures

Overall survival.

Results

Overall, 8351 cases were included (mean [SD] age, 61 [10.1] years; 6499 men [77.8%]; 4710 patients with metastatic LNs and 3641 with no metastatic LNs). Mortality risk escalated continuously without plateau as number of metastatic nodes increased, with the hazard per node (hazard ratio [HR], 1.19; 95% CI, 1.16-1.23; P < .001) most pronounced up to 5 positive LNs. Extranodal extension was also associated with increased mortality (HR, 1.34; 95% CI, 1.13-1.59; P < .001). Increasing number of nodes examined was associated with improved survival, albeit to a lesser degree (per 10 LNs: HR, 0.97; 95% CI, 0.96-0.98; P < .001) and without a detectable change point. Other nodal factors, including nodal size, contralateral LN involvement (TNM stage N2c), and lower LN involvement (levels 4-5), were not associated with mortality in multivariable models when accounting for number of positive LNs. A novel, parsimonious nodal staging system derived by recursive partitioning analysis exhibited greater concordance with survival than the TNM staging system outlined in the American Joint Committee on Cancer's AJCC Staging Manual, 8th edition.

Conclusions and Relevance

The number of metastatic nodes is a predominant independent factor associated with mortality in hypopharyngeal and laryngeal cancers. Moreover, standard nodal staging factors like LN size and contralaterality have no independent prognostic value when accounting for positive LN number. Deeper integration of quantitative metastatic nodal disease may simplify staging and better triage the need for adjuvant therapy.

A phase 2 study of an oral mTORC1/mTORC2 kinase inhibitor (CC-223) for non-pancreatic neuroendocrine tumors with or without carcinoid symptoms

Second-generation mammalian target of rapamycin (mTOR) inhibitors such as CC-223 may have theoretical advantages over first-generation drugs by inhibiting TOR kinase in mTOR complex 1 (mTORC1) and 2 (mTORC2), potentially improving clinical efficacy for well-differentiated neuroendocrine tumors (NET).Enrolled patients had metastatic, well-differentiated NET of non-pancreatic gastrointestinal or unknown origin, with/without carcinoid symptoms, had failed ≥1 systemic chemotherapy, and were taking a somatostatin analog (SSA). Oral once-daily CC-223 was administered in 28-day cycles starting at 45 mg (n = 24), with a subsequent cohort starting at 30 mg (n = 23). Objectives were to evaluate tolerability, preliminary efficacy, and pharmacokinetic and biomarker profiles of CC-223. Forty-seven patients completed the study, with mean treatment duration of 378 days and mean dose of 26 mg; 26% of patients remained on the starting dose. Most frequent grade ≥3 toxicities were diarrhea (38%), fatigue (21%), and stomatitis (11%). By investigator, 3 of 41 evaluable patients (7%) showed partial response (PR) and 34 (83%) had stable disease (SD) for a disease control rate (DCR) of 90% (95% confidence interval [CI] 76.9–97.3%). Duration of PR was 125–401 days; median SD duration was 297 days (min–max, 50–1519 days). Median progression-free survival was 19.5 months (95% CI 10.4–28.5 months). Carcinoid symptoms of flushing, diarrhea, or both improved in 50%, 41%, and 39% of affected patients, respectively. For the first time, this study describes that a second-generation mTOR pathway inhibitor can result in highly durable tumor regression and control of NET carcinoid symptoms. The manageable safety profile, high DCR, and durable response, coupled with reduction in carcinoid symptoms refractory to SSA, make CC-223 a promising agent for further development.

Abstract CT023: Dose escalation of tinostamustine in patients with advanced solid tumors

Despite advances in the treatment of solid tumors in recent years, unmet medical needs remain for patients with advanced disease. The alkylating deacetylase inhibiting molecule tinostamustine (EDO-S101) is a novel multi-action drug that has been shown in preclinical studies to improve drug access to the DNA strands within cancer cells, break them and counteract damage repair. Here we report findings from the dose escalation phase of an open-label Phase I/II study to investigate the safety, pharmacokinetics and efficacy of tinostamustine in patients with advanced solid tumors (NCT03345485).

In the Phase I part of the study, patients were recruited using a standard 3+3 design, with the first cohort receiving 60mg/m2 tinostamustine administered IV over 30 minutes, with six ascending cohorts to a maximum dose of 100mg/m2 administered over 30 or 60 minutes.

A total of 26 patients were screened and 22 patients enrolled into the study as the safety population. Patients had a mean ± SD age of 59.7 ± 11.1 years, 59.1% were female, 77.3% Caucasian and 22.7% Asian; all patients had received prior systemic therapy with or without radiotherapy. The (mean ± SD) tinostamustine dose was 407.3 ± 218.44 mg/m2, and the mean ± SD time on therapy was 10.4 ± 8.6 weeks. All patients experienced ≥1 treatment-emergent adverse events (TEAE), of which 22.7% were serious; 3 patients withdrew from the study due to TEAEs (CTCAE Grade 4 thrombocytopenia). The most common TEAEs related to study treatment were mild or moderate in intensity and included nausea (81.8% of patients), QTc prolongation (59.1%), thrombocytopenia (54.5%), anemia (45.5%), lymphopenia (40.9%), fatigue (36.4%), vomiting (31.8%) and leukopenia (31.8%). Importantly, despite a high percentage of patients experiencing some degree of QTc prolongation, external review determined that the majority of abnormalities were not clinically significant. Only one of the 22 patients enrolled (4.5%) experienced a QTc prolongation event that was considered to be clinically significant, this was a dose-limiting toxicity of Grade 3 QTc-prolongation in a patient receiving 100mg/m2 tinostamustine over 60 minutes. Nausea and vomiting were well managed using antiemetics. At 16 weeks’ follow-up, 4.5% of patients had a tumour response of partial response and 36.4% stable disease. Pharmacokinetic (PK) studies showed that peak serum concentrations (Cmax) of tinostamustine reached therapeutic levels. A more detailed analysis of PK data will be presented at the conference.

In patients with advanced solid tumors and limited treatment options, tinostamustine was generally well tolerated with preliminary signs of efficacy observed in this Phase I study across diverse tumor types. The Phase II portion of this study will enable a more comprehensive assessment of the efficacy of tinostamustine in larger patient cohorts within five specific tumor types.

Funding: Mundipharma-EDO GmbH.

Citation Format: Alain Mita, Markus Loeffler, Nam Bui, Thomas Mehrling, Bobbie J. Rimmel, Ronald B. Natale, Shivaani Kummar. Dose escalation of tinostamustine in patients with advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT023.

Abstract CT012: Open-label, multicenter, Phase Ib study to assess safety, tolerability and efficacy of adavosertib monotherapy in patients with advanced solid tumors: Expansion cohorts

Background

Adavosertib (AZD1775) is a first-in-class, selective, small-molecule inhibitor of Wee1. Previously we reported safety and efficacy of adavosertib monotherapy in patients (pts) with advanced solid tumors (NCT02482311; Bauer et al Cancer Res 2016;76[14 Suppl]); here we report safety and efficacy data from expansion cohorts based on tumor type.

Methods

A total of 80 pts grouped into 6 biomarker-matched cohorts (Table) received adavosertib (175 mg PO bid; days 1–3 and 8–10 per 21-day cycle). Eligible pts had: confirmed diagnosis of ovarian cancer (OC), small-cell lung cancer (SCLC) or triple-negative breast cancer (TNBC); prior treatment (Tx) for metastatic/recurrent disease (≥3 prior Tx for pts with BRCAwt OC; progression following PARPi Tx for BRCA1/2m OC pts; ≤1 chemotherapy-based Tx for SCLC and ≥1 chemotherapy-based Tx for TNBC); measurable disease. Primary objective assessments: ORR; DCR; PFS (RECIST v1.1); safety. Tumor assessments were performed every 6 weeks in year 1 and every 12 weeks thereafter until disease progression or intolerable toxicity. Blood and tumor samples were collected for correlative biomarker and pharmacokinetic (PK) analyses.

Results

Median total Tx duration was 2.4 months. Most frequently reported adverse events (AEs) were diarrhea (61%), nausea (50%) and fatigue (43%). Most commonly reported grade ≥3 AEs were diarrhea (7.5%), nausea, fatigue and small intestine obstruction (6%). AEs leading to dose interruptions (22.5%), reductions (11.3%) or discontinuations (16.3%) were reported. The study showed preliminary antitumor activity, particularly in BRCAwt as well as PARPi-failure BRCAm OC pts (Table). PK and biomarker analyses will be presented.

Conclusions

Adavosertib was generally well tolerated and showed preliminary antitumor activity. DCR was modest across all patient cohorts.

Patient cohortParameterOC, BRCAwtOC, BRCAm, PARPi failureTNBC, CCNE1/MYC/MYCL1/ MYCN non-amplifiedTNBC, CCNE1/MYC/MYCL1/ MYCN amplifiedSCLC, CCNE1/MYC/MYCL1/ MYCN non-amplifiedSCLC, CCNE1/MYC/MYCL1/MYCN amplifiedTotalPatients who received treatment, n163013612380Median age, years (range)62.5 (47–83)59.5 (44–73)58.0 (35–81)54.0 (43–78)64.5 (54–74)63.0 (56–69)60.0(35–83)Prior regimens, n (%) 1 2 3 4 5 6 &gt;6 Median0 0 1 (6) 3 (19) 2 (13) 1 (6) 9 (56) 70 0 2 (7) 3 (10) 7 (23) 8 (27) 10 (33) 60 3 (23) 2 (15) 1 (8) 2 (15) 3 (23) 2 (15) 50 0 1 (17) 2 (33) 2 (33) 1 (17) 0 4.53 (25) 5 (42) 3 (25) 0 1 (8) 0 0 20 1 (33) 2 (67) 0 0 0 0 33 (4) 9 (11) 11 (14) 9 (11) 14 (18) 13 (16) 21 (26) 5ECOG PS, n (%) 0 18 (50) 8 (50)10 (33) 20 (67)4 (31) 9 (69)1 (17) 5 (83)2 (17) 10 (83)1 (33) 2 (67)26 (33)54 (68)ORR, n (%) CR* PR* SD ≥5 weeks PD NE1 (6) 0 1 (6) 10 (63) 4 (25) 1 (6)1 (3) 0 1 (3) 22 (73) 5 (17) 2 (7)0 0 0 9 (69) 3 (23) 1 (8)0 0 0 3 (50) 3 (50) 01 (8) 0 1 (8) 3 (25) 7 (58) 1 (8)0 0 0 1 (33) 2 (67) 03 (4) 0 3 (4) 48 (60) 24 (30) 5 (6)DCR, n (%)†11 (69)23 (77)9 (69)3 (50)4 (33)1 (33)51 (64)Median PFS, months4.53.93.12.01.31.23.0*Confirmed CR/PR; †DCR determined by CR + PR + SD. BRCA1/2m, BRCA1 or BRCA2 mutated; BRCAwt, BRCA1 and BRCA2 wild type; CR, complete response; DCR, disease control rate; ECOG PS, Eastern Cooperative Oncology Group performance status; NE, not evaluable; ORR, objective response rate; PARPi, PARP inhibitor; PD, progressive disease; PFS, progression-free survival; PR, partial response; SD, stable disease

Citation Format: Todd M. Bauer, Kathleen Moore, Janet S. Rader, Fiona Simpkins, Alain Mita, J Thaddeus Beck, Lowell Hart, Quincy Chu, Amit Oza, Anna V. Tinker, Karen So, Esteban Rodrigo Imedio, Sanjeev Kumar, Ganesh M. Mugundu, Suzanne Jenkins, Juliann Chmielecki, Suzanne Jones, David R. Spigel, Siqing Fu. Open-label, multicenter, Phase Ib study to assess safety, tolerability and efficacy of adavosertib monotherapy in patients with advanced solid tumors: Expansion cohorts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT012.

A Phase 1b/2 Study of the Bruton Tyrosine Kinase Inhibitor Ibrutinib and the PD-L1 Inhibitor Durvalumab in Patients with Pretreated Solid Tumors

BACKGROUND

Ibrutinib, a first-in-class, once-daily inhibitor of Bruton's tyrosine kinase, is approved in the United States for the treatment of various B-cell malignancies. Preclinical data suggest synergistic antitumor activity of ibrutinib with programmed death-ligand 1 (PD-L1) inhibitors in solid tumors. This study evaluated ibrutinib plus durvalumab, a PD-L1-targeting antibody, in patients with relapsed/refractory solid tumors.

METHODS

This open-label, multicenter, phase 1b/2 study enrolled previously treated patients with stage III/IV pancreatic adenocarcinoma, breast cancer, or non-small cell lung cancer (NSCLC). Phase 1b determined the recommended phase 2 dose (RP2D). In phase 2, patients were treated at the RP2D to evaluate the safety and antitumor activity of ibrutinib plus durvalumab.

RESULTS

The RP2D was identified as ibrutinib 560 mg p.o. daily and durvalumab 10 mg/kg i.v. every 2 weeks, with 122 patients treated at the RP2D. Median age was 61 years, and the majority of patients (94%) had stage IV disease. Overall response rates (complete or partial responses) were 2% for pancreatic cancer, 3% for breast cancer, and 0% for NSCLC. Median progression-free survival was 1.7, 1.7, and 2.0 months in the pancreatic cancer, breast cancer, and NSCLC cohorts, respectively. Median overall survival was 4.2, 4.2, and 7.9 months in the pancreatic cancer, breast cancer, and NSCLC cohorts, respectively. The safety profiles observed across tumor types were consistent with the known safety profiles for ibrutinib and durvalumab. Grade ≥3 adverse events in ≥5% of all patients were hyponatremia (10%), dyspnea (7%), maculopapular rash (7%), pneumonia (7%), anemia (6%), and diarrhea (6%).

CONCLUSIONS

The combination of ibrutinib 560 mg daily and durvalumab 10 mg/kg every 2 weeks had an acceptable safety profile. The antitumor activity of the ibrutinib-durvalumab combination was limited in our study population.

Multicenter Phase I Study of Erdafitinib (JNJ-42756493), Oral Pan-Fibroblast Growth Factor Receptor Inhibitor, in Patients with Advanced or Refractory Solid Tumors

PURPOSE

Here, we report results of the first phase I study of erdafitinib, a potent, oral pan-FGFR inhibitor.

PATIENTS AND METHODS

Patients age ≥18 years with advanced solid tumors for which standard antineoplastic therapy was no longer effective were enrolled (NCT01703481). Parts 2 to 4 employed molecular screening for activating FGFR genomic alterations. In patients with such alterations, two selected doses/schedules identified during part 1 dose-escalation [9 mg once daily and 10 mg intermittently (7 days on/7 days off), as previously published (Tabernero JCO 2015;33:3401-8)] were tested.

RESULTS

The study included 187 patients. The most common treatment-related adverse events were hyperphosphatemia (64%), dry mouth (42%), and asthenia (28%), generally grade 1/2 severity. All cases of hyperphosphatemia were grade 1/2 except for 1 grade 3 event. Skin, nail, and eye changes were observed in 43%, 33%, and 28% of patients, respectively (mostly grade 1/2 and reversible after temporary dosing interruption). Urothelial carcinoma and cholangiocarcinoma were most responsive to erdafitinib, with objective response rates (ORR) of 46.2% (12/26) and 27.3% (3/11), respectively, in response-evaluable patients with FGFR mutations or fusions. All patients with urothelial carcinoma and cholangiocarcinoma who responded to erdafitinib carried FGFR mutations or fusions. Median response duration was 5.6 months for urothelial carcinoma and 11.4 months for cholangiocarcinoma. ORRs in other tumor types were <10%.

CONCLUSIONS

Erdafitinib shows tolerability and preliminary clinical activity in advanced solid tumors with genomic changes in the FGFR pathway, at two different dosing schedules and with particularly encouraging responses in urothelial carcinoma and cholangiocarcinoma.

Avelumab (anti-PD-L1) as first-line switch-maintenance or second-line therapy in patients with advanced gastric or gastroesophageal junction cancer: phase 1b results from the JAVELIN Solid Tumor trial

Background

We evaluated the antitumor activity and safety of avelumab, a human anti–PD-L1 IgG1 antibody, as first-line switch-maintenance (1 L-mn) or second-line (2 L) treatment in patients with advanced gastric/gastroesophageal cancer (GC/GEJC) previously treated with chemotherapy.

Methods

In a phase 1b expansion cohort, patients without (1 L-mn) or with (2 L) disease progression following first-line chemotherapy for advanced GC/GEJC received avelumab 10 mg/kg intravenously every 2 weeks. Endpoints included best overall response, progression-free survival (PFS), overall survival (OS), and safety.

Results

Overall, 150 patients were enrolled (1 L-mn, n = 90; 2 L, n = 60) and median follow-up in the 1 L-mn and 2 L subgroups was 36.0 and 33.7 months, respectively. The confirmed objective response rate was 6.7% in both subgroups (95% CI, 2.5–13.9% and 1.8–16.2%, respectively), including complete responses in 2.2% of the 1 L-mn subgroup (n = 2). In the 1 L-mn and 2 L subgroups, median duration of response was 21.4 months (95% CI, 4.0–not estimable) and 3.5 months (95% CI, 2.8–8.3) and disease control rates were 56.7 and 28.3%, respectively. Median PFS in the 1 L-mn and 2 L subgroups was 2.8 months (95% CI, 2.3–4.1) and 1.4 months (95% CI, 1.3–1.5), with 6-month PFS rates of 23.0% (95% CI, 14.7–32.4%) and 7.9% (95% CI, 2.6–17.2%), and median OS was 11.1 months (95% CI, 8.9–13.7) and 6.6 months (95% CI, 5.4–9.4), respectively. In the 1 L-mn subgroup, median OS measured from start of 1 L chemotherapy was 18.7 months (95% CI, 15.4–20.6). Across both subgroups, 20.7% had an infusion-related reaction of any grade. Other common treatment-related adverse events (TRAEs) of any grade included fatigue (10.0%) and nausea (6.7%). Treatment-related serious adverse events occurred in 4.0% of patients. Overall, 8.7% had a grade ≥3 TRAE, including 1 treatment-related death.

Conclusion

Avelumab showed clinical activity and an acceptable safety profile in patients with GC/GEJC.

Trial registration

ClinicalTrials.govNCT01772004; registered 21 January 2013.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0508-1) contains supplementary material, which is available to authorized users.

Physiologically-based pharmacokinetic modelling to predict oprozomib CYP3A drug-drug interaction potential in patients with advanced malignancies

AIMS

Oprozomib is an oral, second-generation, irreversible proteasome inhibitor currently in clinical development for haematologic malignancies, including multiple myeloma and other malignancies. Oprozomib is a rare example of a small molecule drug that demonstrates cytochrome P450 (CYP) mRNA suppression. This unusual property elicits uncertainty regarding the optimal approach for predicting its drug-drug interaction (DDI) risk. The current study aims to understand DDI potential during early clinical development of oprozomib.

METHODS

To support early development of oprozomib (e.g. inclusion/exclusion criteria, combination study design), we used human hepatocyte data and physiologically-based pharmacokinetic (PBPK) modelling to predict its CYP3A4-mediated DDI potential. Subsequently, a clinical DDI study using midazolam as the substrate was conducted in patients with advanced malignancies.

RESULTS

The clinical DDI study enrolled a total of 21 patients, 18 with advanced solid tumours. No patient discontinued oprozomib due to a treatment-related adverse event. The PBPK model prospectively predicted oprozomib 300 mg would not cause a clinically relevant change in exposure to CYP3A4 substrates (≤30%), which was confirmed by the results of this clinical DDI study.

CONCLUSIONS

These results indicate oprozomib has a low potential to inhibit the metabolism of CYP3A4 substrates in humans. The study shows that cultured human hepatocytes are a more reliable system for DDI prediction than human liver microsomes for studying this class of compounds. Developing a PBPK model prior to a clinical DDI study has been valuable in supporting clinical development of oprozomib.

Quantitative survival impact of composite treatment delays in head and neck cancer

BACKGROUND

Multidisciplinary management of head and neck cancer (HNC) must reconcile increasingly sophisticated subspecialty care with timeliness of care. Prior studies examined the individual effects of delays in diagnosis-to-treatment interval, postoperative interval, and radiation interval but did not consider them collectively. The objective of the current study was to investigate the combined impact of these interwoven intervals on patients with HNC.

METHODS

Patients with HNC who underwent curative-intent surgery with radiation were identified in the National Cancer Database between 2004 and 2013. Multivariable models were constructed using restricted cubic splines to determine nonlinear relations with overall survival.

RESULTS

Overall, 15,064 patients were evaluated. After adjustment for covariates, only prolonged postoperative interval (P < .001) and radiation interval (P < .001) independently predicted for worse outcomes, whereas the association of diagnosis-to-treatment interval with survival disappeared. By using multivariable restricted cubic spline functions, increasing postoperative interval did not affect mortality until 40 days after surgery, and each day of delay beyond this increased the risk of mortality until 70 days after surgery (hazard ratio, 1.14; 95% confidence interval, 1.01-1.28; P = .029). For radiation interval, mortality escalated continuously with each additional day of delay, plateauing at 55 days (hazard ratio, 1.25; 95% confidence interval, 1.11-1.41; P < .001). Delays beyond these change points were not associated with further survival decrements.

CONCLUSIONS

Increasing delays in postoperative and radiation intervals are associated independently with an escalating risk of mortality that plateaus beyond certain thresholds. Delays in initiating therapy, conversely, are eclipsed in importance when appraised in conjunction with the entire treatment course. Such findings may redirect focus to streamlining those intervals that are most sensitive to delays when considering survival burden. Cancer 2018. © 2018 American Cancer Society.

Abstract P5-21-32: AZD5363 in combination with fulvestrant in AKT1-mutant ER-positive metastatic breast cancer

Background: E17K is the most common activating AKT1 mutation and was shown to be a therapeutic target in this multipart Phase 1 study of AZD5363 (NCT01226316), an oral and selective pan-AKT kinase inhibitor, in patients (pts) with AKT1-mutant (AKT1m) advanced solid tumors. In heavily pretreated AKT1m (E17K) ER+ metastatic breast cancer (MBC) pts, monotherapy achieved an objective response rate (ORR) of 20% and a median progression-free survival of 5.5 months (95% CI, 2.9−6.9). Suppression of PI3K-AKT signaling results in induction of ER-dependent transcription, potentially limiting the response to single-agent PI3K/AKT inhibitors. We explored the hypothesis that simultaneous inhibition of AKT and ER signaling would enhance antitumor efficacy in AKT1m ER+ MBC.

Methods: In an expansion of this study, we administered oral AZD5363 400 mg twice daily, 4 days on 3 days off, and fulvestrant 500 mg, to AKT1m (detected in tumor tissue by local screening and/or plasma BEAMing) ER+ HER2– MBC pts, enrolled into a fulvestrant-naïve (FN) or fulvestrant-resistant (FR) cohort (max 24 pts/cohort). Key objectives included safety and efficacy by RECIST v1.1. We report results of a planned interim analysis conducted when 12 pts/cohort reached maturity for assessment of 24-week clinical benefit rate (CBR), defined as the percentage of responders plus those with stable disease (SD) ≥24 weeks.Data cut-off occurred in June 2017.

Results: At the time of analysis, 24 AKT1m pts (23 E17K, 1 E40K) had received treatment. FN had more visceral disease (83.3% vs 66.7%) and ER+/PR– status (25% vs 8.3%) than FR. Median number of prior anticancer regimens was 4.5 (range 1–9) and 6 (2–11) in FN and FR, respectively, with more chemotherapy (CT) and less hormone therapy (HT) exposure in FN vs FR [3 (0–5) vs 2 (0–6) and 2 (0–4) vs 4 (2–6) prior CT and HT, respectively]. Prior palbociclib was received by 1 (8.3%) and 4 (33.3%) pts in FN and FR, respectively. Clinical efficacy is detailed below; CBR was 33% and 42% in FN and FR, respectively (Table 1). There was 1 unconfirmed partial response in patients treated with prior palbociclib and 3 SD. At data cut-off, 18 pts had discontinued treatment: progressive disease, n=12; adverse events (AEs), n=2; other reasons, n=4. AEs were observed in all 24 pts, most commonly diarrhea (71%), nausea (63%), vomiting and decreased appetite (29%). Grade ≥3 AEs occurred in 13 (54%) pts, most frequently maculopapular rash (n=3), nausea, hyperglycemia and back pain (all n=2). Dose reduction due to AEs occurred in 3 pts.

Table 1. Clinical efficacy FNFREligible for interim data cut-off, n1212ORR, n (%)2 (17)4 (33)CBR, n (%)4 (33)5 (42)Confirmed response (complete/partial response), n (%)2 (17)4 (33)SD ≥24 weeks, n (%)2 (17)1 (8)

Conclusions: AZD5363 plus fulvestrant is clinically active in AKT1m ER+ MBC pts, including in pts with demonstrated prior resistance to fulvestrant. Comparatively lower efficacy was observed in the FN cohort; factors that may have potentially contributed (eg disease characteristics) will be explored. cfDNA and genomic data will also be presented.

Citation Format: Smyth LM, Oliveira M, Ciruelos E, Tamura K, El-Khoueiry A, Mita A, You B, Renouf DJ, Sablin M-P, Lluch A, Mayer IA, Bando H, Yamashita H, Ambrose H, de Bruin E, Carr TH, Corcoran C, Foxley A, Lindemann JPO, Maudsley R, Pass M, Rutkowski A, Schiavon G, Banerji U, Scaltriti M, Taylor BS, Chandarlapaty S, Baselga J, Hyman DM. AZD5363 in combination with fulvestrant in AKT1-mutant ER-positive metastatic breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-21-32.

Abstract P5-21-05: Withdrawn

This abstract was withdrawn by the authors.

Postoperative chemoradiotherapy in patients with head and neck cancer aged 70 or older with positive margins or extranodal extension and the influence of nodal classification

BACKGROUND

Postoperative concomitant chemoradiotherapy (CRT) improves outcomes for younger adults with head and neck squamous cell carcinoma (HNSCC) and positive margins or extranodal extension (ENE), but its benefit for older adults is not well established.

METHODS

Patients from the National Cancer Data Base (NCDB) with HNSCC undergoing curative-intent resection, neck dissection, and postoperative radiation with positive margins or ENE were identified.

RESULTS

This analysis included 1199 patients aged ≥ 70 years with median follow-up of 42.6 months. Postoperative concurrent CRT was associated with improved overall survival (OS; hazard ratio [HR] 0.752; 95% confidence interval [CI] 0.638-0.886) compared to radiation alone in multivariable analysis. Three-year OS was 52.4% with CRT versus 43.4% with radiation (P = .012) in propensity-score matched cohorts. The survival impact of CRT varied by N classification (P = .002 for interaction), with benefit seen only in those with N2 to N3 disease.

CONCLUSION

Postoperative concurrent CRT may benefit older patients with HNSCC with positive margins or ENE, particularly those with higher nodal burden.

LXR/ApoE Activation Restricts Innate Immune Suppression in Cancer

Therapeutic harnessing of adaptive immunity via checkpoint inhibition has transformed the treatment of many cancers. Despite unprecedented long-term responses, most patients do not respond to these therapies. Immunotherapy non-responders often harbor high levels of circulating myeloid-derived suppressor cells (MDSCs)-an immunosuppressive innate cell population. Through genetic and pharmacological approaches, we uncovered a pathway governing MDSC abundance in multiple cancer types. Therapeutic liver-X nuclear receptor (LXR) agonism reduced MDSC abundance in murine models and in patients treated in a first-in-human dose escalation phase 1 trial. MDSC depletion was associated with activation of cytotoxic T lymphocyte (CTL) responses in mice and patients. The LXR transcriptional target ApoE mediated these effects in mice, where LXR/ApoE activation therapy elicited robust anti-tumor responses and also enhanced T cell activation during various immune-based therapies. We implicate the LXR/ApoE axis in the regulation of innate immune suppression and as a target for enhancing the efficacy of cancer immunotherapy in patients.

Abstract A091: Phase 1 study of IAP inhibitor ASTX660 in adults with advanced cancers and lymphomas

Background: We report dose escalation results from a phase 1/2 trial of ASTX660 (NCT02503423). This non-peptidomimetic, dual XIAP and cIAP antagonist inhibits tumor cell lines at nanomolar concentrations and is active against xenografts. Methods: Study ASTX660-01, an open-label, multi-center, dose-escalation study in subjects with advanced cancers and lymphomas, used a 3+3 dose escalation design. Study drug was administered orally once daily in 28 day cycles of alternating 7 days on, then 7 days off therapy. Dose escalation was planned from a starting fixed 15 mg dose until the maximum tolerated dose (MTD) was reached. Endpoints included safety, MTD, recommended phase 2 dose (RP2D), pharmacokinetics, pharmacodynamics, and antitumor effects. Results: Forty-five subjects received at least 1 dose of ASTX660 (range 15 mg - 270 mg). Mean age was 62 years (range 36-77); 60% of subjects were female. Median duration of study therapy was 2 cycles (range 1-8). Four dose-limiting toxicities (DLTs) were observed: 3 at 270 mg QD (grade 3/4 lipase increased), and 1 at 210 mg QD (grade 3 lipase increased). These lipasemia DLTs were all asymptomatic. Most declined after dose interruption and did not recur after dose reduction. The MTD was 210 mg QD, and the RP2D was 180 mg QD. Common adverse events (AEs) included fatigue, lipasemia, and vomiting (29%); nausea and lymphopenia (27%); anemia (24%); rash and edema (20%); ALT increase and pruritus (18%); AST increase (16%); appetite decrease and diarrhea (13%); and amylasemia and hyponatremia (11%). Lipasemia and amylasemia appeared to be dose-related. Most AEs were CTCAE grades 1-2 and manageable with supportive treatment. Median time to peak plasma concentration (tmax) was 1 hour. ASTX660 t ½ was 15.3 hours at the RP2D. Day 1 and 7 AUC0-24h plasma exposures after 180 mg ASTX660 were 1450 (67%) and 2080 (62%) ng*hr/mL (geometric mean [CV]), respectively. Modest accumulation (1.4 fold) at Day 7 vs Day 1 was observed for ASTX660 AUC0-24h exposures but not for Cmax. Human RP2D exposure levels reached the biologically active exposure range seen in preclinical models. ASTX660 at all dose levels suppressed cIAP1 in peripheral blood mononuclear cells (PBMCs). At 180 mg cIAP1 suppression was sustained beyond the off-therapy week. A clinical response in cutaneous T cell lymphoma was observed at the 180-mg dose level. Conclusions: In phase 1, ASTX660 caused manageable toxicities, achieved target study drug exposures, and demonstrated both biologic and clinical activity at the RP2D. Enrollment to phase 2 expansion cohorts in lymphoma and other selected cancers is ongoing.

Citation Format: Monica Mita, Patricia LoRusso, Michael S. Gordon, Aram Oganesian, Xiaoping Zhang, Roberta Ferraldeschi, Simone Jueliger, Harold N. Keer, Purvee Kumar, Chihche Lin, Edwin P. Rock, Alain Mita, Anthony W. Tolcher. Phase 1 study of IAP inhibitor ASTX660 in adults with advanced cancers and lymphomas [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A091.

Perspectives in Head and Neck Medical Oncology

The modern treatment of locoregionally advanced disease often requires a multimodality combination approach. A number of chemotherapeutic agents can be combined with radiation, but the platinum agent cisplatin, a potent radiation sensitizer, is best studied in head and neck cancer. Newer agents such as cetuximab can be used in combination with radiation therapy for those patients who cannot tolerate cisplatin. For chemotherapy-naïve patients with metastatic head and neck cancer who demonstrate a good performance status, platinum doublet regimens are commonly used. Doublet regimens generally improve response rates compared to single-agent chemotherapies, although they have not demonstrated a survival benefit over single agents and they have added toxicity. Immunotherapies, alternative cytotoxic chemotherapies, and targeted therapies are second-line options for patients with disease that has progressed on platinum-based therapy. Immunotherapy, in particular, has gained focus by enhancing the ability of the immune system to recognize and destroy malignant cells. When multimodal approaches are used, as in combined chemotherapy and radiation therapy, toxicities are increased. It is imperative that patients are followed closely in order to maximize treatment benefit while minimizing complications.

Metastatic Lymph Node Burden and Survival in Oral Cavity Cancer

Purpose Current staging systems for oral cavity cancers incorporate lymph node (LN) size and laterality, but place less weight on the total number of positive metastatic nodes. We investigated the independent impact of numerical metastatic LN burden on survival. Methods Adult patients with oral cavity squamous cell carcinoma undergoing upfront surgical resection for curative intent were identified in the National Cancer Data Base between 2004 and 2013. A neck dissection of a minimum of 10 LNs was required. Multivariable models were constructed to assess the association between the number of metastatic LNs and survival, adjusting for factors such as nodal size, laterality, extranodal extension, margin status, and adjuvant treatment. Results Overall, 14,554 patients met inclusion criteria (7,906 N0 patients; 6,648 node-positive patients). Mortality risk escalated continuously with increasing number of metastatic nodes without plateau, with the effect most pronounced with up to four LNs (HR, 1.34; 95% CI, 1.29 to 1.39; P < .001). Extranodal extension (HR, 1.41; 95% CI, 1.20 to 1.65; P < .001) and lower neck involvement (HR, 1.16; 95% CI, 1.06 to 1.27; P < .001) also predicted increased mortality. Increasing number of nodes examined was associated with improved survival, plateauing at 35 LNs (HR, 0.98; 95% CI, 0.98 to 0.99; P < .001). In multivariable models accounting for the number of metastatic nodes, contralateral LN involvement (N2c status) and LN size were not associated with mortality. A novel nodal staging system derived by recursive partitioning analysis exhibited greater concordance than the American Joint Committee on Cancer (8th edition) system. Conclusion The number of metastatic nodes is a critical predictor of oral cavity cancer mortality, eclipsing other features such as LN size and contralaterality in prognostic value. More robust incorporation of numerical metastatic LN burden may augment staging and better inform adjuvant treatment decisions.

AKT Inhibition in Solid Tumors With AKT1 Mutations

Purpose AKT1 E17K mutations are oncogenic and occur in many cancers at a low prevalence. We performed a multihistology basket study of AZD5363, an ATP-competitive pan-AKT kinase inhibitor, to determine the preliminary activity of AKT inhibition in AKT-mutant cancers. Patients and Methods Fifty-eight patients with advanced solid tumors were treated. The primary end point was safety; secondary end points were progression-free survival (PFS) and response according to Response Evaluation Criteria in Solid Tumors (RECIST). Tumor biopsies and plasma cell-free DNA (cfDNA) were collected in the majority of patients to identify predictive biomarkers of response. Results In patients with AKT1 E17K-mutant tumors (n = 52) and a median of five lines of prior therapy, the median PFS was 5.5 months (95% CI, 2.9 to 6.9 months), 6.6 months (95% CI, 1.5 to 8.3 months), and 4.2 months (95% CI, 2.1 to 12.8 months) in patients with estrogen receptor-positive breast, gynecologic, and other solid tumors, respectively. In an exploratory biomarker analysis, imbalance of the AKT1 E17K-mutant allele, most frequently caused by copy-neutral loss-of-heterozygosity targeting the wild-type allele, was associated with longer PFS (hazard ratio [HR], 0.41; P = .04), as was the presence of coincident PI3K pathway hotspot mutations (HR, 0.21; P = .045). Persistent declines in AKT1 E17K in cfDNA were associated with improved PFS (HR, 0.18; P = .004) and response ( P = .025). Responses were not restricted to patients with detectable AKT1 E17K in pretreatment cfDNA. The most common grade ≥ 3 adverse events were hyperglycemia (24%), diarrhea (17%), and rash (15.5%). Conclusion This study provides the first clinical data that AKT1 E17K is a therapeutic target in human cancer. The genomic context of the AKT1 E17K mutation further conditioned response to AZD5363.

Phase Ib dose-finding study of abiraterone acetate plus buparlisib (BKM120) or dactolisib (BEZ235) in patients with castration-resistant prostate cancer

BACKGROUND

The phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) signalling axis and androgen receptor (AR) pathways exhibit reciprocal feedback regulation in phosphatase and tensin homologue (PTEN)-deficient metastatic castration-resistant prostate cancer (CRPC) in preclinical models. This phase Ib study evaluated the pan-PI3K inhibitor buparlisib (BKM120) and the dual pan-PI3K/ mammalian target of rapamycin (mTOR) inhibitor dactolisib (BEZ235) in combination with abiraterone acetate (AA) in patients with CRPC.

MATERIALS AND METHODS

Patients with CRPC who had progressed on AA therapy received escalating doses of either buparlisib or dactolisib, along with fixed doses of AA (1000 mg once daily (qd)) and prednisone (5 mg twice daily (bid)). The primary objective was to define the maximum tolerated dose (MTD) and/or the recommended dose for expansion (RDE) of either buparlisib or dactolisib in combination with AA. Secondary objectives included safety, antitumour activity (Prostate Cancer Working Group 2 (PCWG2) criteria; 30% of prostate-specific antigen (PSA) decline at ≥week 12) and pharmacokinetic (PK) profile.

RESULTS

In buparlisib + AA arm, 25 patients received buparlisib + AA (median age, 67 years; Eastern Cooperative Oncology Group performance status (ECOG PS) of 0/1/2 for 7/17/1 patients, respectively). At 100 mg qd; two patients experienced dose-limiting toxicities (DLTs) (grade 3 hyperglycaemia; grade 2 asthenia), and this was the maximum buparlisib dose explored. Buparlisib + AA showed a 26% lower median area under the curve from time zero to 24°h (AUC_0-24) and 48% lower median maximum serum concentration (Cmax) versus the single-agent buparlisib assessed in first-in-human study. No objective response and few PSA decreases were reported. In dactolisib + AA arm, 18 patients (median age, 71 years; ECOG PS of 0/1 for 6/12 patients, respectively) received dactolisib + AA at the first dose level (200 mg bid). Five patients had 9 DLTs (grades 2&3 stomatitis; grade 3 hyperglycaemia; grades 2& 3 diarrhoea; grades 1& 2 pyrexia, grade 2 vomiting, and grade 2 chills).

CONCLUSIONS

Based on the assessment of available pharmacokinetics, safety, and efficacy data, no further study is planned for either buparlisib or dactolisib in combination with AA in CRPC.

Phase I trial of MEK 1/2 inhibitor pimasertib combined with mTOR inhibitor temsirolimus in patients with advanced solid tumors

Background Dual inhibition of activated MAPK and mTOR signaling pathways may enhance the antitumor efficacy of the MEK 1/2 inhibitor pimasertib and the mTOR inhibitor temsirolimus given in combination. Methods In this phase I study, patients with refractory advanced solid tumors (NCT01378377) received once-weekly temsirolimus plus once-daily oral pimasertib in 21-day cycles in a modified 3 + 3 dose-escalation design. The maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of pimasertib in combination with temsirolimus, safety and pharmacokinetics (PK) were investigated. Results Of 33 patients evaluated, all experienced ≥1 treatment-emergent adverse event (TEAE) and 31 had treatment-related TEAEs, most frequently stomatitis and thrombocytopenia. TEAEs were reversible. No deaths were attributed to treatment. Nine patients had dose-limiting toxicities (stomatitis, thrombocytopenia, serum creatinine phosphokinase increase, visual impairment) and the MTD was determined as 45 mg/day pimasertib plus 25 mg/week temsirolimus. However, due to overlapping toxicities no further investigations were performed and the RP2D was not defined. PK profiles of both agents were not adversely affected. Seventeen patients (17/26 patients) had a best response of stable disease; five had stable disease lasting >12 weeks. Conclusions The RP2D was not defined and the pimasertib plus temsirolimus combination investigated did not warrant further study.