Results from a phase I expansion cohort of the first-in-class oral HIF-2α inhibitor PT2385 in combination with nivolumab in patients with previously treated advanced RCC.

2019 ◽  
Vol 37 (7_suppl) ◽  
pp. 558-558 ◽  
Author(s):  
Brian I. Rini ◽  
Leonard Joseph Appleman ◽  
Robert A. Figlin ◽  
Elizabeth R. Plimack ◽  
Jaime R. Merchan ◽  
...  

558 Background: The transcription factor hypoxia-inducible factor (HIF)-2α has been established as an oncogenic driver in clear cell renal cell carcinoma (ccRCC) due to underlying VHL deficiency. Activation of HIF-2α can also promote immunosuppression. In preclinical models, HIF-2α inhibition demonstrated increased efficacy in combination with checkpoint inhibitors (Han et al. AACR 2016). In a Phase 1 dose escalation/expansion trial in heavily pre-treated advanced ccRCC patients, PT2385 monotherapy was associated with variability in drug exposure with higher therapeutic exposure associated with improved anti-tumor activity (Courtney et al. JCO 2018). Methods: In the current Phase 1 expansion cohort, patients with advanced ccRCC who had received 1-3 prior therapies (including at least one VEGF(R)-targeting agent) were treated with PT2385 (800 mg PO BID) in combination with nivolumab (3 mg/kg IV Q2Weeks) to evaluate safety, efficacy, and pharmacokinetics. Results: 50 patients were enrolled. Median age was 62 with 58% ECOG 1 and 42% ECOG 2. Median number of prior therapies was 1; 42% of patients received ≥2 prior lines of therapy. The most common all-grade AEs were anemia (46%), fatigue (46%), nausea (36%), and arthralgia (30%). The most common Grade 3 AE’s were anemia (4%), fatigue (4%), and hypoxia (4%). Two Grade 4 events of elevated ALT and increased lipase/amylase were observed. As of August 31, 2018, ORR = 22% (1 CR, 10 PR). At a median follow up of 12.4 months (m), median PFS was 7.3 m for all patients. Patients who had sub-therapeutic exposures ( < 300 ng/ml) of PT2385 (n = 17) had a median PFS of 4.7 m compared to patients with therapeutic exposures of PT2385 (n = 33), who had a median PFS of 10.0 m. Conclusions: The combination of PT2385 + nivolumab was well tolerated and demonstrated promising anti-tumor activity in advanced ccRCC patients, most notably in patients who achieved therapeutic exposure of PT2385. Single agent and combination studies with PT2977, a second-generation HIF-2α inhibitor with an improved PK profile, are ongoing. Clinical trial information: NCT02293980.

2020 ◽  
Vol 38 (6_suppl) ◽  
pp. 611-611 ◽  
Author(s):  
Toni K. Choueiri ◽  
Elizabeth R. Plimack ◽  
Todd Michael Bauer ◽  
Jaime R. Merchan ◽  
Kyriakos P. Papadopoulos ◽  
...  

611 Background: Hypoxia-inducible factor (HIF)-2α is a transcription factor that is a key oncogenic driver in RCC. MK-6482 is a first-in-class small molecule HIF-2α inhibitor that blocks the heterodimerization of HIF-2α with HIF-1β and induces regression in mouse xenograft RCC models. Methods: Pts with advanced ccRCC who had received at least 1 prior therapy were enrolled in an expansion cohort from the first-in-human phase 1/2 study of MK-6482 in advanced solid tumors (NCT02974738). Pts were administered 120 mg of MK-6482 orally once daily. Primary end point: safety. Key secondary end points: ORR, duration of response (DOR), and PFS. Results: Fifty-five pts were enrolled in the dose expansion cohort. Median (range) number of prior therapies was 3 (1-9); 67% received anti–PD-1 and anti-VEGF agents. Five pts (9%) were favorable risk, 40 (73%) were intermediate risk, and 10 (18%) were poor risk by IMDC criteria. With a median follow-up of 13 mo the most common all-grade, all-cause AEs > 30% were anemia (75%), fatigue (67%), dyspnea (47%), nausea (33%), and cough (31%). Anemia (26%) and hypoxia (15%) were the most common grade 3 AEs. No grade 4/5 drug-related AEs were observed. ORR was 24% with 13 confirmed PRs. Thirty-one pts (56%) had SD, with a disease control rate (CR+PR+SD) of 80%. Thirty-five of 52 (67%) pts with baseline and postbaseline assessments had tumor shrinkage. Median DOR was not reached; 81% of pts had response ≥6 mo per Kaplan-Meier estimate. Sixteen pts (29%) continued treatment beyond 12 mo. By IMDC risk, 2/5 pts with favorable risk had PR (ORR = 40%), 10/40 with intermediate risk had PR (ORR = 25%), and 1/10 with poor risk had PR (ORR = 10%); disease control rate was 100%, 80%, and 70%, respectively. Median PFS for the total population was 11.0 mo; the 12 mo PFS rate was 49%. Median PFS for favorable, intermediate, and poor IMDC risk was 16.5, 11.0, and 6.9 mo, respectively. As of May 15, 2019, 30 pts (55%) discontinued due to PD, 2 (4%) due to AEs. Sixteen pts (29%) had treatment ongoing. Conclusions: MK-6482 is well tolerated with a favorable safety profile and demonstrated promising single-agent activity in heavily pretreated pts with ccRCC across IMDC risk groups. A phase 3 trial in a similar population is planned. Clinical trial information: NCT02974738.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1987-1987 ◽  
Author(s):  
Daniel A. Pollyea ◽  
Steven Coutre ◽  
Lia Gore ◽  
Nichole Adler ◽  
Pamela Harris ◽  
...  

Abstract Introduction: Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is dependent upon dysregulated signaling through the B-cell receptor (BCR) pathway. Bruton’s tyrosine kinase (BTK) mediates BCR signaling, and inhibition of BTK with ibrutinib, a selective, irreversible BTK inhibitor, is effective and well tolerated for patients (pts) with relapsed/refractory CLL/SLL. However, complete remissions (CRs) are infrequent, mechanisms of resistance to single-agent ibrutinib have been identified, and the duration of response beyond 3 years is unknown. Lenalidomide, a multi-functional immunomodulatory agent, is active in CLL/SLL, but limited by tumor flare reactions, which occur secondary to B-cell activation. Ibrutinib and lenalidomide modulate several key overlapping factors involving the CLL tumor microenvironment, and therefore a phase 1 combination study with lenalidomide dose escalation was undertaken. Methods: The primary objective was to determine the maximum tolerated dose (MTD) of lenalidomide in combination with ibrutinib. Secondary objectives included assessments of efficacy, PK/PD, and other mechanistic correlative studies. A 1-month (cycle 0) period of 420 mg of daily oral ibrutinib was administered as a single agent to decrease BCR signaling and mitigate lenalidomide-associated tumor flare. Beginning with the second month (cycle 1), ibrutinib was given concomitantly with lenalidomide. Four dose escalation cohorts of lenalidomide were planned using a 3+3 design; 2.5, 5, 7.5 and 10 mg. After the 2.5 mg cohort, intra-patient dose escalation was employed: in cohort 2, pts received 2.5 mg in week 1 followed by 5 mg subsequently; pts in cohort 3 received 2.5 mg in week 1, 5 mg in week 2 and 7.5 mg subsequently; pts in cohort 4 will receive 2.5 mg in week 1, 5 mg in week 2, 7.5 mg in week 3 and 10 mg subsequently. Ibrutinib was not dose escalated (420 mg). Pts receive 12 cycles of the combination, after which lenalidomide is discontinued and ibrutinib continues until unacceptable toxicity or disease progression. Eligible pts had relapsed/refractory CLL/SLL with adequate organ and bone marrow function. Pts who relapsed after stem cell transplantation were excluded. Results: To date, 11 pts were enrolled; 9 are evaluable (1 voluntarily withdrew consent prior to completing 3 cycles, the protocol-defined minimum to be evaluable, and 1 was a screen fail). The median age was 65 (49-81). Eight were male and 8 had CLL. Median Rai stage was 1 (1-4). The median number of prior therapies was 2 (range 1-8); 3 were purine analog resistant. Six had bulky (>5 cm) disease. Two had del(17p13.1) and 4 had del(11q22.3). The median number of cycles completed was 8 (range 1-13). Adverse events (AEs) were reported according to the NCI CTCAE v4.0. Possibly related grade 1/2 AEs that occurred in >1 patient included: rash (n=4), muscle cramps (n=3) and abdominal discomfort (n=2). Possibly related grade 3 AEs included neutropenia (n=4), lymphocytosis (n=2), neutropenic fever (n=1), anemia (n=1) and thrombocytopenia (n=1). There was 1 possibly related grade 4 AE, neutropenia, which was pre-defined as DLT, in the 7.5 mg lenalidomide cohort. One patient experienced grade 2 tumor pain, thought to be due to a lenalidomide-associated tumor flare reaction. Four pts required a lenalidomide dose reduction, for neutropenia (n=2) and fatigue (n=2). Six required a treatment hold, of either lenalidomide or both agents, for a median 7 days (2-28), for neutropenia (n=2), anemia (n=1), fatigue/diarrhea (n=1), atrial fibrillation (n=1) and to obtain a lymph node biopsy (n=1). Lymphocytosis was noted in 5 pts, peaking at a median of 22.5 days. The ORR is 100% (9/9), with all responders experiencing PRs. One progressed with Richter’s transformation during cycle 7, 4 months after achieving a PR. All 9 remain alive with a median follow up of 263 days (range 97-391). The 7.5 mg dose cohort is currently being expanded to 6 pts; after the MTD is determined, a 10 patient dose expansion cohort will commence. Conclusions: Ibrutinib with lenalidomide appears to be well tolerated, although lenalidomide dose reductions were common. Tumor flare reactions were rare. Response assessments at higher dose cohorts of lenalidomide are ongoing. Completed phase 1 data, preliminary data from the expansion cohort and correlative findings will be presented. Disclosures Pollyea: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Off Label Use: Lenalidomide for CLL/SLL. Byrd:Genentech: Research Funding; Pharmacyclics: Research Funding.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 3004-3004 ◽  
Author(s):  
Lawrence Fong ◽  
Patrick M. Forde ◽  
John D. Powderly ◽  
Jonathan Wade Goldman ◽  
John J. Nemunaitis ◽  
...  

3004 Background: Adenosine production in the tumor leads to immunosuppression through A2aR on infiltrating immune cells. CPI-444 is an oral A2aR antagonist with single agent(SA) anti-tumor activity in pre-clinical models. This phase 1/1b clinical trial uses a 2-step adaptive design to evaluate CPI-444 as a SA and in combination (combo) with the anti-PDL1 antibody, atezolizumab (atezo). We report results of RCC and NSCLC cohorts. Methods: Primary objectives: safety, efficacy and to identify optimal dose/schedule. Step 1 utilized 3 SA and 1 combo cohort to select dose/schedule. Step 2 included disease-specific expansion cohorts including RCC and NSCLC. Eligible pts had selected advanced cancers and failed standard therapies including checkpoint inhibitors. Results: 34 pts have enrolled and 25 pts were evaluable for response (Table 1). Median prior regimens: 3 (range,1-5) and most pts were resistant/refractory to anti PD1/PDL1 therapy (R/R). Most common AEs were Gr 1 nausea (n = 3) and pyrexia (n = 3); Gr 3 tachycardia was the only possibly related SAE. The selected Step 2 doses were CPI-444 100mg BID as a SA and in combo with atezo 840mg IV q2 weeks. The disease control rate (DCR, CR+PR+SD; duration 2 mo to > 8 mo) for pts with RCC and NSCLC cohorts were 86% and 50%, (100% and 43% for R/R pts), respectively. DCRs were similar in the SA and combo cohorts. Of 7 evaluable RCC pts, 1 pt has an ongoing PR (SA cohort, > 4 mo) and 5 have ongoing SD, duration 3 mo to > 8 mo (2 SA, 3 combo). Biopsy of the PR pt showed no detectable tumor and infiltration with CD8+ lymphocytes. In 18 evaluable NSCLC pts, 1 PR (PDL1 negative pt) and 8 SD were seen. PRs and SDs were seen in R/R pts and in PDL1 negative pts in both diseases. Conclusions: CPI-444 is well tolerated and shows anti-tumor activity in RCC and NSCLC pts as a SA and in combo. Pts who are R/R to anti PD1/PDL1 therapy and who are PDL1 negative can also benefit. Clinical trial information: NCT02655822. [Table: see text]


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A436-A436
Author(s):  
Anthony El-Khoueiry ◽  
Jacob Thomas ◽  
Anthony Olszanski ◽  
Nilofer Azad ◽  
Lewis Bender ◽  
...  

BackgroundINT230-6 is a novel formulation of cisplatin and vinblastine with an amphiphilic cell penetration enhancer that has been shown to enhance dispersion of the drug throughout tumors and allow diffusion into cells when given intratumorally. In preclinical models, INT230-6 has resulted in cell death, dendritic cell influx, antigen presentation and T-cell engagement with strong synergy when combined with checkpoint inhibitorsMethodsThis phase 1/2 study evaluated Q2week injections of INT230-6 x 5 dosed by tumor volume alone or with 200 mg pembrolizumab IV Q3 weeks. Eligble patients had any advanced malignancy refractory to standard therapy with an injectable tumor.ResultsSixty subjects (median 3 prior therapies (range 0–10)) were enrolled (53 monotherapy, 7 combo). Median age was 60 (42–85). 19 different cancer types were accrued with breast cancer and sarcoma being the most frequent. Over 200 deep tumor injections were administered at doses of up to 172 ml of INT230-6 (86 mg of CIS, 17 mg of Vin). PK analysis revealed <5% of the drugs were measured in systemic circulation, indicative of minimal systemic exposure. There was no dose limiting toxicity. The most frequent monotherapy drug related AE’s reported were: injection-site pain 58%, nausea 37%, fatigue 33%, and vomiting 27% with only 18% of subjects experiencing a grade 3 AE (no grade 4 or 5). Rates were comparable for the single agent INT230-6 and the combination with pembrolizumab. In the overall monotherapy cohort, patients completing all 5 doses of INT230-6 over 56 days (n=16), the median overall survival has not yet been reached. after a median followup of 408 days. In the 5 evaluable patients who received the pembrolizumab combination, the median TTP has not been reached with a median follow up of 6 mo. Paired biopsies (pre, 1 month) were available in 10 monotherapy patients and revealed a median of 63% reduction in viable cancer cells on H&E (30% had no viable cancer) that was also associated with qualitative decreases in Ki67, increases of CD4 and CD8 T-cells and reduction in FoxP3 Tregs. Despite receiving only 2 month of monotherapy, short half lives of the active agents, and no subsequent therapies, 8 injected tumors continued to regress past 1 year.ConclusionsINT230-6 is well tolerated when administered intratumorally alone or in combination with pembrolizumab. Pharmacodynamic assessments provides proof of concept that this drug can reduce viable cancer cells and increases CD4/CD8 T-cell infiltrates leading to durable clinical benefit off treatment.Trial RegistrationNCT 03058289Ethics ApprovalThe study was approved by USC, Princess Margaret Cancer Center, Fox Chase, UMass, Columbia, and Johns Hopkins Institution’s Ethics BoardConsentWritten informed consent was obtained from the patient for publication of this abstract and any accompanying images. A copy of the written consent is available for review by the Editor of this journal


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 7556-7556
Author(s):  
Hun Ju Lee ◽  
Michael Y. Choi ◽  
Tanya Siddiqi ◽  
Jacqueline Claudia Barrientos ◽  
William G. Wierda ◽  
...  

7556 Background: Cirmtuzumab (Cirm) is a humanized monoclonal antibody that inhibits the tumor promoting activity of ROR1 and had demonstrated additive/synergistic activity with many anti-cancer agents including ibrutinib (Ibr). Methods: Patients (Pts) with relapsed or refractory (RR) MCL or treatment naïve (TN) or RR CLL were enrolled. In Part 1 (Dose Escalation), doses of Cirm IV q2wks x5 then q4wks of 2-16 mg/kg and 300 or 600 mg were examined. Safety of Cirm alone was assessed during the first 28 days, then Ibr was started at approved doses for each indication. Cirm 600 mg IV q2wks x3 then q4wks in combination with Ibr starting day 0 was chosen as the recommended dosing regimen for use in Part 2 (Expansion) and Part 3 (CLL only, Cirm/Ibr vs. Ibr alone). Results: Twelve evaluable MCL pts were enrolled into Part 1, and 5 into Part 2. Median number of prior regimens was 2 (1-5), including pts relapsing after Ibr (4), auto-SCT (3), auto-SCT/ allo-SCT (1), auto-SCT/CAR-T (1). In CLL, 34 evaluable pts (12 TN and 22 RR) enrolled into Part 1 (18) or Part 2 (16). At least 74% of CLL pts in Parts 1 and 2 were high risk as determined by unmutated IGHV, del17p, and/or del11q. In Part 3, 22 evaluable pts received Cirm/Ibr (15) or Ibr (7). As of the 30OCT2020 safety cut-off for MCL and CLL, common TEAEs (all grades) included diarrhea (41%), contusion (39%), fatigue (39%), URI (31%), hypertension (25%) arthralgia (23%). Grade ≥3 neutropenia was 13% and thrombocytopenia 1%. There were no Cirm dose reductions or discontinuations for toxicity. Overall, Cirm did not appear to negatively impact the safety of Ibr. Efficacy (MCL): As of the 02FEB2021 efficacy cutoff, the best response of 17 evaluable pts in Parts 1 and 2 included an objective response rate (ORR) of 82%, 41% CR/CMR, 41% PR, 12% SD, and 6% PD. CR/CMR remain durable from 8-28+ mos. Most responses occurred rapidly after ̃3 mos of Cirm/Ibr. Notably, responses were achieved in all pts who received prior SCT+/- CAR-T (4CR, 1PR) or prior Ibr (2CR, 2PR). At a median follow-up of 14.6 mos, the median PFS (mPFS) had not been reached (NR) (95% CI: 17.5, NA). Efficacy (CLL): The best response of 34 evaluable pts in Parts 1 and 2 included 91% ORR, 3% CR, 88% PR/PR-L, 9% SD, 0% PD. In Part 3, both arms achieved 100% ORR (all PRs). At a median follow-up of 20.2 mos, the mPFS was NR (95% CI: NA, NA), and the PFS estimate at 24 months was 95% for R/R, and 87% for TN, respectively, for evaluable CLL pts receiving Cirm/Ibr. Conclusions: Cirm/Ibr is a well-tolerated, active regimen in both MCL and CLL. For MCL, the mPFS of NR (95% CI: 17.5, NA) and CRR (41%), with all CRs remaining without PD, compare favorably to mPFS of 12.8 mos (95% CI 8.5-16.6) and CRR (20%) reported for single agent Ibr (Rule 2017). For CLL, the high ORR and PFS are encouraging, particularly for RR CLL. The study is ongoing, with MCL enrollment expanded to study Cirm + Ibr in pts who have had a suboptimal response to an Ibr regimen, or who have failed other approved BTKi agents. Clinical trial information: NCT03088878.


Author(s):  
Adam C. Palmer ◽  
Benjamin Izar ◽  
Peter K. Sorger

ABSTRACTHundreds of clinical trials are testing whether combination therapies can increase the anti-tumor activity of Immune Checkpoint Inhibitors (ICIs). We find that the benefits of recently reported and approved combinations involving ICIs are fully accounted for by increasing the chance of a single-agent response (drug independence), with no requirement for additive or synergistic efficacy. Thus, the degree of success of combinations involving ICIs with other therapies is largely predictable.


2019 ◽  
Vol 14 (10) ◽  
pp. S721 ◽  
Author(s):  
P. Barlow ◽  
M. Jameson ◽  
C. Lin ◽  
J. Wu ◽  
A. Pirzkall ◽  
...  

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 1577-1577
Author(s):  
C. A. Conrad ◽  
C. Meyer ◽  
T. Madden ◽  
W. Priebe ◽  
F. F. Lang

1577 Background: Treatment for high-grade gliomas represents an area of significant unmet medical need, largely because few agents cross the blood-brain barrier (BBB). RTA 744744 (WP744, 4’-O-benzyldoxorubicin hydrochloride) is a potent topoisomerase II poison and novel anthracycline screened for its ability to circumvent P-gp and MRP1allowing it to cross the BBB. To assess the drug’s potential in gliomas, RTA 744 was tested alone or in combination with temozolomide in an intracranial xenograft model of glioblastoma multiforme (GBM). It was hypothesized that a DNA repair inhibitor such as RTA 744 would enhance the effects of temozolomide. In vitro cell based assays confirmed this hypothesis and led to in vivo testing of this novel combination. Methods: U87MG cells were implanted into the right basal ganglia of nu/nu mice via an implantable screw system. In all studies, groups of 5 or 6 mice received PBS, temozolomide, RTA 744, or the combination of RTA 744 and temozolomide administered IP. PBS and temozolomide were given on a QDx5 schedule, and several schedules were tested for RTA 744. The primary endpoint in these studies was survival. Results: In the single agent study, by day 33, all 5 of the control animals had died compared with just one of the RTA 744-treated animals. Median survival for control animals was 28 days versus 37 for RTA 744-treated animals (T/C=132%). In the combination study, median survival was 30 days for controls, 40 days for temozolomide alone (T/C=133%), and 48 days for animals receiving the optimal combination of RTA 744 and temozolomide (T/C=160%). One animal in the combination group survived to day 78, whereas no control or Temodar treated animals survived past days 32 and 45, respectively. Conclusions: RTA 744 demonstrated potent single agent activity in a rigorous preclinical model of GBM. The combination of RTA 744 and temozolomide produced survival results significantly better than those from any chemotherapeutics tested in this model. This data supports the current Phase 1 trial of RTA 744 in patients with brain tumors as well as future trials testing the combination of RTA 744 and temozolomide. [Table: see text]


2016 ◽  
Vol 34 (2_suppl) ◽  
pp. 202-202 ◽  
Author(s):  
Mallika Sachdev Dhawan ◽  
Mina Lee ◽  
Alan H. Bryce ◽  
Vivian K. Weinberg ◽  
Charles J. Ryan ◽  
...  

202 Background: Cabazitaxel and prednisone (Cbz/pred) extend survival in mCRPC patients (pts) following docetaxel and first-line studies comparing Cbz to docetaxel are ongoing. Mito/pred also has anti-tumor activity in mCRPC and a non-overlapping mechanism of action and toxicity profile with Cbz. A multicenter phase 1 trial was initiated to establish the maximally tolerated dose (MTD) and recommended phase 2 dose (RP2D) of the combination of Cbz, Mito, and Pred(CAMP). Methods: Chemotherapy (chemo)-naive pts with mCRPC were enrolled in an accelerated titration design. The primary objective was to determine the MTD and RP2D of CAMP; secondary objectives included PSA response rate and duration of response. Cbz 20 and 25 mg/m2 were evaluated in combination with escalating doses of Mito (starting dose 4 mg/m2), both administered on day 1 of a 21-day cycle. Pred 5 mg BID and pegfilgrastim were given with each cycle. Results: 23 pts were enrolled. The median age was 66 (range 51-78) and the median baseline PSA was 62.5 (range 3-791.2). There were 2 DLTs (sepsis and febrile neutropenia) observed at the dose level of Cbz 25 mg/m2 + Mito 10 mg/m2 (n = 4). There was 1 DLT (febrile neutropenia) observed with Cbz 20 mg/m2 (N = 12), establishing Cbz 20 mg/m2 + Mito 12 mg/m2 as the MTD and RP2D. The most common grade ³ 3 related adverse events were hematologic (neutropenia, n = 9; thrombocytopenia, n = 3; febrile neutropenia, n = 3). The median number of treatment cycles was 7.5 (range 2-16), and 2 pts remain on study. Greater than or equal to 50% maximal PSA declines from baseline were observed in 12 of 19 evaluable pts(63%). The median duration of response has not been reached (range 4.9-10.0+ months). Conclusions: The approved single-agent dose of Mito (12 mg/m2) was safely combined with Cbz 20 mg/m2, a dose with demonstrated activity in mCRPC and potentially less hematologic toxicity than 25 mg/m2. Preliminary efficacy data are encouraging with durable control of disease observed in a subset of pts. Further study of the treatment combination is warranted. Clinical trial information: NCT01594918.


2019 ◽  
Vol 37 (8_suppl) ◽  
pp. TPS24-TPS24
Author(s):  
William Ho ◽  
Nicole Nasrah ◽  
Dan Johnson

TPS24 Background: Regulatory T cells (Treg) can dampen anti-tumor immune responses in the tumor microenvironment (TME). The predominant chemokine receptor on human Treg is CCR4, the receptor for the chemokines CCL17 and CCL22, which are produced by tumor cells, tumor-associated macrophages and dendritic cells, as well as by effector T cells (Teff) in the setting of an inflammatory anti-tumor response. Preclinical studies with orally-available CCR4 antagonists have demonstrated potent inhibition of Treg migration into tumors, an increase in the intratumoral Teff/Treg ratio, and anti-tumor efficacy as a single agent and in combination with checkpoint inhibitors. In a first-in-human trial conducted in healthy volunteers, the oral CCR4 antagonist FLX475 was demonstrated to be well tolerated with outstanding PK properties. A robust PD assay measuring receptor occupancy on circulating Treg demonstrated the ability to safely achieve exposure levels predicted to maximally inhibit Treg recruitment into tumors via CCR4 signaling. These human PK, PD, and safety data have enabled a streamlined design of a Phase 1/2 study of FLX475 in cancer patients both as monotherapy and in combination with checkpoint inhibitor. Methods: This clinical trial is a Phase 1/2, open-label, dose-escalation and cohort expansion study to determine the safety and preliminary anti-tumor activity of FLX475 as monotherapy and in combination with pembrolizumab. The study is being conducted in 2 parts, a dose-escalation phase (Part 1) and a cohort expansion phase (Part 2). In Part 1 (Phase 1) of the study, at least 3 to 6 eligible subjects will be enrolled in sequential cohorts treated with successively higher doses of FLX475 as monotherapy or in combination with pembrolizumab (Part 1b). In Part 2 (Phase 2) of the study, expansion cohorts of both checkpoint-naïve and checkpoint-experienced patients with tumor types predicted to be enriched for Treg and/or CCR4 ligand expression (i.e. “charged tumors”) -- including both EBV+ and HPV+ tumors and NSCLC, HNSCC, and TNBC -- will be enrolled using a Simon 2-stage design. As of November 6, 2018, Cohort 1 has been completed without DLT. Clinical trial information: NCT03674567.


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