QD Dosing Research Articles

An oral androgen receptor PROTAC degrader for prostate cancer.

381 Background: The Androgen Receptor (AR) remains the principal driver of castration-resistant prostate cancer during the transition from a localized to metastatic disease. Most patients initially respond to inhibitors of the AR pathway, but the response is often short-lived. The majority of patients progressing on enzalutamide or abiraterone exhibit genetic alterations in the AR locus, either in the form of amplifications or point mutations in the AR gene. Given these mechanisms of resistance, our goal is to eliminate the AR protein using the PROteolysis TArgeting Chimera (PROTAC) technology. Methods: Here we report an orally bioavailable small molecule AR PROTAC that leads to ubiquitination and degradation of AR. This molecule has been characterized in in vitro degradation and functional assays, DMPK, toxicology and preclinical efficacy studies. Results: This AR PROTAC completely degrades AR in all cell lines tested, with an observed 50% degradation concentration (DC50) < 1 nM. PROTAC-mediated AR degradation suppresses the expression of the AR-target gene PSA, inhibits AR-dependent cell proliferation, and induces potent apoptosis in VCaP cells. The AR PROTAC degrades all clinically relevant mutant AR proteins and retains activity in a high androgen environment. In mouse xenograft studies, greater than 90% AR degradation is observed at a 1 mg/kg PO QD dose. Significant inhibition of tumor growth and AR signaling can be achieved in both an intact and castrate setting. Further, the AR PROTAC demonstrates in vivo efficacy and reduction of oncogenic Erg protein in a long term, castrate, enzalutamide-resistant VCaP tumor model. DMPK and exploratory toxicology studies show robust oral, dose proportional drug exposure in rodent and non-rodent species. Conclusions: In summary, we report preclinical data on an orally bioavailable AR PROTAC degrader that demonstrates efficacy in enzalutamide-resistant prostate cancer.

Abstract PD5-10: A first-in-human phase I study to evaluate the oral selective estrogen receptor degrader (SERD), GDC-0927, in postmenopausal women with estrogen receptor positive (ER+) HER2-negative metastatic breast cancer (BC)

Abstract Background: Modulation of estrogen activity and/or synthesis is the mainstay therapeutic strategy in the treatment of ER+ BC. However, despite the effectiveness of available endocrine therapies, many patients ultimately relapse or develop resistance to these agents via estrogen-dependent and estrogen-independent mechanisms, including mutations in ESR1 affecting the ER ligand binding domain that drive ER-dependent transcription and proliferation in the absence of estrogen. ER antagonists that are efficacious against ligand-dependent and ligand-independent, constitutively active ESR1 mutant tumors may be of substantial therapeutic benefit. GDC-0927 (formerly known as SRN-927) is a novel, potent, non-steroidal, orally bioavailable, selective ER antagonist/ER degrader (SERD) that induces tumor regression in ER+ BC patient-derived xenograft models. Methods: A phase I dose escalation study with 3+3 design was conductedin postmenopausal women with ER+ (HER2-) metastatic BC (progressing ≥ 6 months on endocrine therapy and with ≤ 2 prior chemotherapies in the advanced or metastatic setting) to determine the safety, pharmacokinetics (PK) and the recommended Phase 2 dose (RP2D) of GDC-0927. Pharmacodynamic (PD) activity was assessed with [18F]-fluoroestradiol (FES)-PET scans. Plasma PK samples (after single dose and at steady state), CT scans, and when feasible, pre and on-study tumor biopsies were obtained Results: From March 16, 2015 to March 17, 2017 patients (pts) with a median age of 53 years (range 44-69) and a median number of prior therapies for MBC 4 (range 1-7) were enrolled at 3 total daily dose levels (600, 1000, 1400 mg) once daily (QD) given orally with fasting (n = 12). Increases in GDC-0927 exposure were approximately dose proportional. Treatment related adverse events (AEs) were all grade 1 or 2. The most common treatment-related AEs were nausea (54%, n = 7), diarrhea (46%, n = 6), elevated aspartate aminotransferase (39%, n = 5) and anemia, constipation, (each 31%, n = 4). Treatment interruption was required for 2 pts due to nausea and vomiting. Of those pts with FES-PET avid disease at baseline (9 of 12), all post-therapy scans showed complete or near complete (> 90%) suppression of FES uptake to background levels, including pts with ESR1 mutations. Evidence of reduced ER levels and Ki67 staining was observed in on-treatment biopsies. Five of 12 pts (1 at 600 mg and 4 at 1400 mg) were on study ≥ 24 weeks (CBR = 41.6 %) with the best overall response of stable disease with 1 patient (ESR1 mt+ D538G) on study for over 490 days. There were no dose limiting toxicities and no SAEs related to study drug. R2PD was 1400 mg and was selected for single arm dose-expansion which is now complete with last patient enrolled on March 17, 2017. Updated results from dose-escalation and dose-expansion will be presented at the meeting (N = 43). Conclusions: GDC-0927 appears well-tolerated to date with PK exposure supporting QD dosing, evidence of robust PD target engagement, and encouraging anti-tumor activity in heavily pretreated pts with advanced or metastatic ER+ BC, including pts with ESR1 mutations. Citation Format: Dickler MN, Villanueva R, Perez Fidalgo JA, Mayer IA, Boni V, Winer EP, Hamilton EP, Bellet M, Urruticoechea A, Gonzalez-Martin A, Cortes J, Martin M, Giltnane J, Gates M, Cheeti S, Fredrickson J, Wang X, Friedman LS, Spoerke JM, Metcalfe C, Liu L, Li R, Morley R, McCurry U, Chan IT, Mueller L, Milan S, Lauchle J, Humke EW, Bardia A. A first-in-human phase I study to evaluate the oral selective estrogen receptor degrader (SERD), GDC-0927, in postmenopausal women with estrogen receptor positive (ER+) HER2-negative metastatic breast cancer (BC) [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 PD5-10.

Abstract B201: A phase 1 dose-finding study of X4P-001 (an oral CXCR4 inhibitor) and axitinib in patients with advanced renal cell carcinoma (RCC)

Abstract Background: X4P-001 is an orally bioavailable, selective, allosteric inhibitor of the chemokine receptor CXCR4, and has been shown to downregulate hypoxia inducible factor-2α (HIF-2α) and myeloid-derived suppressor cell (MDSC) trafficking in the tumor microenvironment. In multiple RCC xenograft models, the addition of X4P-001 to tyrosine kinase inhibitors (TKIs), including axitinib, has demonstrated increased efficacy and delayed onset of TKI resistance. Methods: This is an ongoing phase 1/2 open-label study of X4P-001 in combination with axitinib in patients (pts) with histologically confirmed clear cell RCC (ccRCC) who have received ≥1 prior systemic therapy. The Ph1 portion of the study evaluates safety, tolerability, PK, PD, and antitumor activity of the combination using a 3+3 dose escalation schema (escalating doses of X4P-001+ axitinib at 5 mg BID). The Ph2 portion is a single-arm expansion cohort evaluating this combination treatment in ~ 45 ccRCC pts. The radiologic assessment is performed every 8 weeks with central review. Results: As of 30 June, 2017, enrollment for the Ph1 portion of the study has been completed. Sixteen (16) pts were enrolled and the median age was 64 years (range 50-76). Pts had received a median of 2 prior lines of therapy (range 1-5). The doses tested were 200 mg BID, 400 and 600 mg QD of X4P-001 + axitinib. There were two dose-limiting toxicities (DLTs) observed at the X4P-001 600 mg QD dose level: one pt had multiple grade (G) 2 adverse events (AEs), including anorexia, cognitive disturbance, fatigue, nausea, vomiting, and somnolence; another pt had G3 dyspnea and fatigue. The MTD/RP2D was determined to be 400 mg QD of X4P-001 + axitinib. Treatment-related AEs (≥ 10%) of any grade were diarrhea, fatigue, hypertension, nausea, headache, anorexia, vomiting, dry eye, dysphonia, abnormal loss of weight, increased lipase, proteinuria, dry mouth, stomatitis, cognitive disorder, dysgeusia, and palmar-plantar erythrodysaesthesia syndrome. Treatment-related G3/4 AEs (≥ 10%) were hypertension. In addition, one pt had SAE due to G2 diarrhea and G2 creatinine elevation. Drug exposures (AUC0-24hr) at steady state (SS) are similar for 200 mg BID and 400 mg QD dose. Mean Cmax and AUC0-24hr at SS increased approximately 1.6- and 1.9-fold, respectively, from 400 mg to 600 mg QD dose. Leukocyte mobilization is a well-established surrogate marker for CXCR4 inhibition. At both 400 mg and 600 mg daily dose levels, X4P-001 demonstrated approximately 2 to 2.5-fold increase of WBC (range: 1.4-4.7 fold) and nearly 4-fold increase of CD34+ progenitor cells (range: 1.8-6.4 fold). The peak elevation of both markers occurred around 2 to 4 hours following dosing. Of the 12 clinically evaluable pts, 3 had confirmed partial response, 8 had stable disease, and 1 had progressive disease. As of 30 June 2017, 9 pts remain on study and median duration on treatment was 27 weeks (range 7.4-60). Conclusions: The combination treatment is well tolerated at a dose of 400 mg QD of X4P-001 + axitinib with preliminary evidence of clinical activity. The doses used in this phase I study were biologically active in inhibiting CXCR4 in peripheral blood as demonstrated by elevating WBC and CD34+ cell counts. The Ph2 portion of the study is ongoing. Citation Format: Michael Atkins, Richard Joseph, Thai Ho, Ulka Vaishampayan, Sarah Ali, Marc Matrana, Robert Alter, Jeff Edenfield, Yan Wang, Sarah Blanchette, Lu Gan, David McDermott. A phase 1 dose-finding study of X4P-001 (an oral CXCR4 inhibitor) and axitinib in patients with advanced renal cell carcinoma (RCC) [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 B201.

PF-114 Mesylate, a Novel Third Generation ATP-Competitive BCR-ABL Tyrosine Kinase Inhibitor: First Safety and Efficacy Data from a Phase I Study in Patients with CML with Failure of Prior TKI Therapy

Background: PF-114 mesylate is a novel third generation oral tyrosine kinase inhibitor (TKI) that blocks native and mutated Bcr-Abl isoforms, including the gatekeeper mutant T315I, which is uniformly resistant to all approved first- and second generation TKIs. At the present time extensive pre-clinical studies of PF-114, including mechanism of action, kinase profiling, in vitro and in vivo efficacy, safety pharmacology, ADME, and toxicology studies in mice, rats and dogs have been completed and supported initiation of phase I clinical trial of PF-114 mesylate in patients with chronic or accelerated phase Ph+ CML who are resistant to at least one of the second generation TKIs or intolerant to previous treatment with TKIs or who have T315I mutation in the BCR-ABL gene (NCT02885766).Methods: The trial represents a classical 3+3 design of dose escalation till the maximum tolerated dose (MTD) followed by the expanded cohorts planned for dose(s) below the MTD. The total expected enrollment is 44 patients. Escalating doses of single-agent PF-114 mesylate were administered orally on a continuous once daily (QD) dosing schedule. Treatment continued until disease progression, unacceptable toxicity, consent withdrawal, or death. The primary objective was to study the dose-limiting toxicities (DLTs) occurring in cycle 1 of treatment and determine the MTD. Secondary objectives included safety, anti-CML activity (based on hematologic, cytogenetic, and molecular assessments), pharmacodynamic and pharmacogenetic properties. Adverse events (AEs) were assessed and graded according to NCI-CTCAE v4.03.Results: At data cutoff, 4-dose cohorts - 50 mg, 100 mg, 200 mg and 400 mg have completed cycle 1 and 500 mg cohort has started cycle 1 of treatment. Overall 18 patients (8 males) had been treated at the following QD doses: 50 mg (n = 1), 200 mg (n = 5), 400 mg (n = 11), 500 mg (n = 1), and the MTD has not yet been reached. A total of 7 patients with T315I mutation were included into the trial thus far. Median age was 50.5 years (range, 32-66 years). Median time from diagnostics to treatment was 11.5 years (range, 16-1 years) All patients had baseline Eastern Cooperative Oncology Group performance status 0-1. Patients were heavily pretreated; 9 (50%) had received ≥ 3 prior TKIs, 6 (33%) had received 2 prior TKIs and 3 (17%) patients with T315I had received 1 prior TKI. In 11 patients, treatment is ongoing at doses 200-500 mg QD, with median duration of exposure of 8 months (range, 2-12 months), and 7 patients discontinued (disease progression [n = 5], AEs [n = 2]). Preliminary data suggest PF-114 pharmacokinetics is dose-proportional. At the end of cycle 1 of study therapy, no drug-related adverse events greater than grade 1 in severity were observed in patients treated at the 50 mg, 100 mg and 200 mg dose levels. At the dose of 400 mg QD, a single DLT case of grade 3 erythematous rash was observed. Most common grade 2/3 AEs on 400 mg QD were dermatologic toxicity (4/11), neutropenia (1/11). No deterioration of the ankle-brachial index (ABI), which is being prospectively measured, or vascular occlusive events were observed so far. The patient with recurrent pleural effusions on previous treatment with dasatinib did not reveal effusions after 11 cycle of therapy; the patient with ischemic stroke on previous treatment with nilotinib did not reveal cardio-vascular events after 9 cycles. To date, no SAEs have been reported. Overall, during the period of 3 cycles, major cytogenetic response (CyR) have been obtained in 4 of 11 patients who completed 3 cycles (2 cases of complete CyR in and 2 cases of partial CyR). Of those patients who revealed cytogenetic response two patients have T315I mutation. Pharmacodynamic and pharmacogenetic assessments are underway.Conclusion: PF-114 mesylate exhibits antitumor activity in a heavily pretreated subgroup of patients with resistant forms of CML including cases with T315I mutation. The evaluation of the safety profile continues. The dose escalation stage of the current phase 1 study continues, while the including of patients into the expanded cohorts with doses below the MTD has already started. DisclosuresChelysheva:Fusion Pharma LLC: Consultancy. Nemchenko:Fusion Pharma LLC: Consultancy. Zaritskey:Janssen: Consultancy; Novartis: Consultancy, Speakers Bureau. Shuvaev:Fusion Pharma LLC: Consultancy. Novikov:Fusion Pharma LLC: Employment. Shulgina:Fusion Pharma LLC: Employment. Chilov:Fusion Pharma LLC: Employment, Patents & Royalties.

Abstract P493: Multiple-ascending-dose Study of IW-1973, a Soluble Guanylate Cyclase Stimulator

Background: Soluble guanylate cyclase (sGC), an enzyme that catalyzes the formation of cyclic guanosine monophosphate (cGMP) in response to nitric oxide (NO) binding, is a key mediator of local blood flow, inflammation, and fibrosis. IW-1973 is an orally available sGC stimulator that enhances NOsGC-cGMP signaling and reduces blood pressure (BP) in animal models of hypertension, both alone and in combination with other antihypertensive agents. Methods: A Phase 1b placebo-controlled, randomized, multiple-ascending-dose study was conducted to assess safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (BP, heart rate, platelet function, and plasma biomarkers) of IW-1973 in healthy subjects. Four successive cohorts of 11 subjects each (8 active and 3 placebo) were enrolled. Subjects received a starting dose once daily (QD) for 14 days followed by an up-titrated QD dose for 7 days. Results: IW-1973 doses ranging from 15 to 40 mg were tolerated. There were no serious adverse events (AEs), severe AEs, or discontinuations due to AEs. Among the 32 subjects who received IW-1973, the most common AEs (which occurred mainly at doses ≥30 mg) were headache (15 subjects), dizziness/postural dizziness (6) and orthostatic hypotension/BP decreased (4). AEs tended to resolve with continued dosing. The AE profile of higher doses was not clearly improved by up-titration from a lower starting dose. PK was dose proportional, both for C max and AUC, with a T max of 2-4 hours and an effective half-life of 24-37 hours. After 14 days of treatment, least squares mean change from baseline in 24-h ambulatory systolic BP (±SE) was -0.85±1.32 (placebo), -7.29±1.62 (15 mg), -3.27±1.61 (20 mg), -6.75±1.62 (30 mg), and -5.23±1.61 mmHg (≤40 mg, ≤0.5 mg/kg). After 21 days, the change from baseline was -4.81±1.19 (placebo), -8.21±1.46 (15 to 30 mg), -6.29±1.45 (20 to 40 mg), -9.05±1.56 (30 to 40 mg), and -6.58±1.45 mmHg (≤40 to ≥40 mg). IW-1973 produced a dose-related increase in plasma cGMP indicating target engagement. There was no clear effect of IW-1973 administration on platelet function as assessed by the PFA-100 ® system. Conclusion: Further clinical investigation of IW-1973 is ongoing or planned in multiple indications, including resistant hypertension.

Twice-Daily vs. Once-Daily Dosing with 0.075% Bromfenac in DuraSite: Outcomes from a 14-Day Phase 2 Study.

IntroductionBromfenac is a well-known topical ophthalmic nonsteroidal anti-inflammatory drug (NSAID) that is commercialized in the USA and other regions of the world. A new formulation, 0.075% bromfenac in DuraSite®, was developed to treat postoperative inflammation and reduce pain in patients who have undergone cataract surgery. We hypothesized that efficacy and safety would be enhanced with twice-daily (BID) dosing compared to once-daily (QD) dosing.MethodsThis was a multicenter, double-masked, comparative study in which 40 and 45 subjects were randomized to groups receiving BID dosing and QD dosing, respectively. Subjects self-instilled the study drug for 14 days postoperative and were followed for an additional 2-week evaluation phase. The primary efficacy endpoint was the proportion of subjects with an anterior chamber cell (ACC) grade of 0 at day 15.ResultsA total of 45 subjects had cleared ACC (grade “0”) at day 15, of whom 21 were in the BID group (52.5%) and 24 were in the QD group (53.5%). A secondary analysis found 7/40 (17.5%) subjects in the BID group and 10/45 (22.2%) subjects in the QD group achieved an ACC grade of 0 at day 8. There were more adverse events in the QD group (n = 16) than in the BID group (n = 12).ConclusionSimilar outcomes were observed for subjects using Bromfenac 0.075% in DuraSite® in the BID and QD dosing regimens for the treatment of post-cataract surgery inflammation.Trial registrationClinicalTrials.gov identifier, NCT01190878.FundingInSite Vision (now a division of Sun Pharma).

Abstract CT116: BMS-986205, an optimized indoleamine 2,3-dioxygenase 1 (IDO1) inhibitor, is well tolerated with potent pharmacodynamic (PD) activity, alone and in combination with nivolumab (nivo) in advanced cancers in a phase 1/2a trial

Abstract Background: IDO1 is highly expressed in multiple cancers and may be an immunosuppressive mechanism for tumor escape via its production of metabolites that inhibit T-cell function. Nivo, a mAb that targets PD-1, causes IDO1 upregulation, supporting a rationale for combining it with an IDO1 inhibitor. Our preclinical program aimed to identify a best in class IDO1 inhibitor with favorable pharmacokinetic (PK) characteristics (Hunt J, et al. AACR 2017 [abst 6774]). Here we present BMS-986205, a selective IDO1 inhibitor validated in a novel phase 1/2a trial alone and in combination with nivo. Methods: During dose escalation, patients (pts) with advanced cancers were treated in escalating cohorts with BMS-986205 (25-200 mg as of Jan 5, 2017) orally once daily (QD) for 2 wk, followed by BMS-986205 + nivo 240 mg IV every 2 wk. Objectives included safety (primary), PK, and PD. Preclinical analyses included measurement of enzyme inhibition in HEK293 cells overexpressing human IDO1 or tryptophan 2,3-dioxygenase (TDO) and IFNγ-stimulated HeLa cells. Results: In support of clinical testing, BMS-986205 was evaluated preclinically. In vitro characteristics included potent inhibition of kynurenine (kyn) production in IDO1-HEK293 cells (IC50 = 1.1 nM) but not in TDO-HEK293 cells, sustained inhibition in IDO1 cell-based assays after washout, and single-digit nM potency in human tolerogenic MLR assays. Based on preclinical data, a 150 mg QD human dose was projected to maximally inhibit IDO1. In the ongoing clinical study, 42 pts have been treated. All treatment-related adverse events were grade 1/2 except three grade 3 toxicities (autoimmune hepatitis [dose limiting; BMS-986205 100 mg/nivo 240 mg], rash, and asymptomatic hypophosphatemia). Day 14 individual trough concentrations began exceeding the human whole blood IC50 starting with 25 mg QD, and the IC90 starting with 50 mg QD; all pts treated at 200 mg QD exceeded the IC90. Serum kyn was substantially reduced at all doses (> 45% mean reduction at each dose), with > 60% mean reduction at the 100 and 200 mg QD doses. Importantly, intratumoral kyn was reduced up to 90% in evaluable paired pre- and on-treatment samples. Conclusions: BMS-986205 is an optimized, once-daily, selective and potent oral IDO1 inhibitor at clinically relevant concentrations. It is well tolerated up to at least 200 mg in combination with nivo in this novel trial. Evidence of substantial serum kyn reduction was observed at doses as low as 25 mg QD; inhibition at 100 and 200 mg QD appears greater than that reported for other in-class compounds. In addition, we have presented the first evidence of intratumoral kyn reduction by an IDO1 inhibitor. These data suggest the potential of BMS-986205 as an IDO1 inhibitor with superior PD properties and support further evaluation in combination with nivo. Citation Format: Lillian L. Siu, Karen Gelmon, Quincy Chu, Russell Pachynski, Olatunji Alese, Paul Basciano, Justine Walker, Priyam Mitra, Li Zhu, Penny Phillips, John Hunt, Jayesh Desai. BMS-986205, an optimized indoleamine 2,3-dioxygenase 1 (IDO1) inhibitor, is well tolerated with potent pharmacodynamic (PD) activity, alone and in combination with nivolumab (nivo) in advanced cancers in a phase 1/2a trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT116. doi:10.1158/1538-7445.AM2017-CT116

Pharmacokinetic-driven phase I study of DCC-2618 a pan-KIT and PDGFR inhibitor in patients (pts) with gastrointestinal stromal tumor (GIST) and other solid tumors.

2515 Background: DCC-2618 is a potent switch control inhibitor of KIT and PDGFR kinases active in a broad range of mutations. GIST is an important disease to achieve a proof-of-concept due to the heterogeneity of KIT resistance mutations, which emerge on treatment with approved KIT inhibitors. Methods: This was a PK-guided dose escalation study of oral DCC-2618 (QD or BID q28 days) in advanced solid tumors. FDG-PET scans were used to assess changes in FDG uptake in GIST pts after 3 wks of therapy. Next generation sequencing (NGS) of plasma cell-free (cf) DNA was performed throughout the study to assess and quantify KIT and other molecular alterations in drug targets and potential mechanisms of resistance. Results: 38 pts were enrolled (30 GIST; 4 glioma; 1 mastocytosis, 3 other carcinoma) to 8 dose levels: BID doses: 20 (4 pts), 30 (4), 50 (5), 100 (6), 150 (6) and 200 mg (3); QD doses: 100 (5) and 150 mg (4). Safety of evaluable pts is as follows: G3 or G4 adverse effects (regardless of attribution and occurring in > 1 pt) included anemia (5), lipase increase (4), hypertension (2). Two of the G3/4 lipase increase at 100 mg BID and 200 mg BID were DLTs. All G3/4 lipase increase were asymptomatic. G1/2 AEs (considered at least possibly related to DCC-2618) and occurring in ≥15% (n > 5) of pts include fatigue (12), alopecia & lipase increase (7), weight decrease (6). Starting with 50 mg BID dose level, trough concentrations of total drug exceeded the IC90 of the least sentivitive KIT mutations. Plasma concentrations > 5μM were achieved starting at 100 mg BID and the selection of the expansion phase dose is being finalized. Of 18 pts with KIT mutant GIST assessed by FDG PET, 14 (78%) had partial metabolic response per EORTC criteria. RANO/RECIST partial responses (PRs) were reported in 3 patients (1 GBM with PDGFRA/KIT amplifications and 2 GIST with Ex 11 & 17 / Ex 11 & 18 mutations, respectively). NGS of plasma cfDNA revealed 44 KIT mutations in baseline samples from 19 of 21 pts with GIST. Conclusions: DCC-2618 is well tolerated with encouraging preliminary activity in GIST pts with a broad spectrum of mutations and prior therapies. PR was also seen in a pt with GBM with PDGFRA/KIT amplifications. Clinical trial information: NCT02571036.

Phase I study of AG-120, an IDH1 mutant enzyme inhibitor: Results from the cholangiocarcinoma dose escalation and expansion cohorts.

4015 Background: Mutations in the metabolic enzyme isocitrate dehydrogenase 1 (mIDH1) occur in patients (pts) with cholangiocarcinoma (CC) and are detected in up to 25% of intrahepatic CC. mIDH1 produce the oncometabolite, D-2-hydroxyglutarate (2-HG), resulting in epigenetic and genetic dysregulation and oncogenesis. AG-120 is a first-in-class, potent, oral inhibitor of mIDH1 tested in this phase I study in mIDH1 solid tumors, including CC. Methods: AG-120 was escalated in a 3+3 design from 100 mg twice daily to 1200 mg once daily (QD) in 28-day cycles (N = 60, mIDH1 advanced solid tumors). Key eligibility for CC: recurrence of progressive mIDH1 CC following standard therapy (dose escalation) or at least a prior gemcitabine-based regimen (expansion cohort). Response (RECIST 1.1) was assessed every 8 weeks. Plasma and tumor tissue were collected for exploratory analyses. Results: Based on the safety, pharmacokinetic, and pharmacodynamic data from dose escalation, the 500 mg QD dose was selected for expansion in mIDH1 CC and other mIDH1 solid tumors. As of Dec 16, 2016, 73 pts with mIDH1 CC had been dosed in the dose escalation (n = 24) and expansion (n = 49) cohorts. Demographics: M/F = 24/49, median number of prior therapies = 2 (range 1–5), ECOG 0–1 = 26/47. There were no dose-limiting toxicities. Treatment-related adverse events (AEs) in ≥5% pts: fatigue (21%), nausea (18%), vomiting (12%), diarrhea (10%), decreased appetite (8%), dysgeusia (5%), QT prolongation (5%). Two (3%) pts experienced related grade 3 AEs: fatigue and low phosphorus. There were no AG-120-related AEs leading to discontinuation. Among the 72 efficacy evaluable (≥1 post baseline response assessment or discontinued prematurely) mIDH1 CC pts (24 in escalation and 48 in expansion cohort), 6% (n = 4) had a confirmed partial response and 56% (n = 40) experienced stable disease. The progression-free survival rate at 6 months was 40%, and 8 pts have been treated with AG-120 for ≥1 year. Conclusions: In this pretreated mIDH1 CC population, AG-120 was associated with a favorable safety profile and prolonged stable disease. A global, phase III, randomized, placebo-controlled study of AG-120 in mIDH1 CC has been initiated (ClarIDHy). Clinical trial information: NCT02073994.

Pharmacokinetic/pharmacodynamic (PK/PD) profile of AG-120 in patients with IDH1-mutant cholangiocarcinoma from a phase 1 study of advanced solid tumors.

4082 Background: Somatic mutations in isocitrate dehydrogenase 1 (IDH1) produce the oncometabolite D-2-hydroxyglutarate (2-HG). AG-120 is a first-in-class selective inhibitor of mutant IDH1 (mIDH1) under evaluation in an ongoing phase 1 study in patients with mIDH1 advanced solid tumors, including cholangiocarcinoma (CC) (NCT02073994). Objectives for this abstract were to 1) characterize the PK profile of AG-120 and the relationship between AG-120 exposure and 2-HG suppression, and 2) evaluate the influence of intrinsic patient factors on AG-120 clearance, in patients with mIDH1 CC. Methods: AG-120 was administered orally once daily (QD) or twice daily (BID) in continuous 28-day cycles. As of Dec 5, 2016, 60 of 73 patients enrolled with mIDH1 CC had PK/PD samples available for analysis at 100 mg BID, 300 mg QD, 400 mg QD, 500 mg QD, 800 mg QD, and 1200 mg QD in dose escalation (n = 24) and 500 mg QD (n = 36) in dose expansion. Blood (n = 60) and fresh tumor biopsy samples (n = 14) were collected to assess AG-120 and 2-HG using qualified liquid chromatography-tandem mass spectrometry methods. Results: Following both single and multiple doses, AG-120 plasma exposure increased less than dose proportionally from 100 to 1200 mg. Mean terminal half-life was 38.4–85.8 h, supporting a QD dosing regimen. Following multiple doses, steady state was reached within 15 days, with approximately 2-fold accumulation in plasma AG-120 exposure. No patient-specific factors were identified as clinically significant covariates affecting AG-120 plasma clearance. After multiple doses, plasma 2-HG levels were reduced (up to 98.4% inhibition, achieving levels similar to those in healthy volunteers) and tumor biopsy 2-HG levels were also substantially reduced (by up to 99.9%) at all dose levels tested. The 500 mg QD dose resulted in the largest magnitude of 2-HG inhibition vs. other dose levels. Conclusions: AG-120 demonstrated a long half-life in patients with mIDH1 CC and robustly inhibited 2-HG in plasma and tumor samples. These PK/PD data, along with emerging safety and clinical activity data, support the selection of 500 mg QD for future clinical investigation. Clinical trial information: NCT02073994.

Evaluation of RAD1901, a novel investigational, selective estrogen receptor degrader (SERD), for the treatment of ER-positive (ER+) advanced breast cancer.

1014 Background: The treatment of advanced ER+ breast cancer remains a clinical challenge with the majority of patients eventually progressing due to resistance to endocrine therapy. RAD1901 is a novel, nonsteroidal, oral SERD that has demonstrated dose dependent degradation of ER, and ER regulated genes in preclinical studies. In multiple in vivo patient derived xenograft models of breast cancer, including those harboring ESR1 mutations, RAD1901 demonstrated significant antitumor activity. Methods: In a phase-1 Study RAD1901-005 (ClinicalTrials.gov ID: NCT02338349), patients with advanced ER+ breast cancer were enrolled in dose escalation cohorts, followed by a safety expansion cohort. Key inclusion criteria include postmenopausal women aged 18 years or older, with advanced ER+, HER2- breast cancer, who have received ≤ 2 prior chemotherapy regimens in the metastatic setting and > 6 months of prior endocrine therapy. ESR1 mutation status was determined from circulating tumor DNA (ctDNA) samples. Clinical outcomes were evaluated based on RECIST v1.1 criteria. Results: As of January 25, 2017, total of 39 patients were enrolled at the 400 mg qd dose. Patients were heavily pre-treated (median lines of prior therapy = 3), with 38% and 41% having previously received fulvestrant and palbociclib/CDK4/6 inhibitor, respectively. RAD1901 was generally well-tolerated, with the most common adverse events being low grade nausea (Grade 3/4 = 0%) and dyspepsia (Grade 3/4 = 0%). ESR1 mutations, including D538G, Y537S/N/C, L536H/P/R, S436P and E380Q, were detected at baseline in 44% of patients and dynamic changes in the allele frequency of ESR1 mutations were observed in response to treatment. Confirmed partial responses were observed in patients with ESR1 mutations, and those who had previously received fulvestrant and palbociclib. Conclusions: RAD1901 has demonstrated evidence of single agent activity, with confirmed partial responses in heavily pre-treated patients with advanced ER+ breast cancer, including those with ESR1 mutations, warranting additional clinical development. Clinical trial information: NCT02338349.

BBI608-503-103HCC: A phase Ib/II clinical study of napabucasin (BBI608) in combination with sorafenib or amcasertib (BBI503) in combination with sorafenib (Sor) in adult patients with hepatocellular carcinoma (HCC).

4077 Background: Napabucasin, a first-in-class cancer stemness inhibitor in clinical development, suppresses cancer stemness by targeting STAT3-driven gene transcription. Amcasertib targets multiple serine threonine stemness kinases and inhibits Nanog and other cancer stemness pathways. Preclinically, potent and broad-spectrum anti-cancer activity was observed in vitro and in vivo, alone and in combination with sorafenib. Methods: A phase Ib/II open-label, multi-center study in adult patients with advanced HCC who have not received prior systemic chemotherapy was performed to determine the safety, tolerability, and recommended Phase II dose (RP2D) ,according to the criteria for DLT and for dose-escalation of Napabucasin (Arm 1), administered at 160 mg BID (dose level I) and at 240 mg BID (dose level II) in combination with sorafenib and of Amcasertib (Arm 2), administered at 100 mg QD (dose level I) and at 200 mg QD (dose level II) in combination with sorafenib. Results: 20 pts were enrolled, 10 in Arm 1 and 10 in Arm 2. 12 patients were evaluable for DLT determination; 2 pts d/c prior to starting protocol treatment; 11 pts received evaluation by RECIST, 6 pts in Arm 1 and 5 pts in Arm 2. The safety profile was consistent with that of each agent as monotherapy and most common AEs were attributed to (Sor) and included rash, PPE, grade 1/2 diarrhea, nausea, abdominal cramps, and vomiting. No signs of drug-drug interactions were observed in pharmacokinetics. Among all patients who received RECIST evaluation, Disease Control Rate (DCR=CR+PR+SD) for Arm 1 was 100% (6/6pts) and 100% (5/5pts) for Arm 2. DCR in ITT Arm 1 population was 67% and 50% in Arm 2. Median OS is not yet reached. Conclusions: In this phase Ib study, RP2D were determined for napabucasin and amcasertib to be safely combined with sorafenib at full dose, showing encouraging anti-tumor activity in patients with HCC who have not received prior systemic chemotherapy. A randomized phase II is schedule to start. Clinical trial information: NCD02279719. [Table: see text]

First-in-human phase I study of an oral HSP90 inhibitor, TAS-116, in advanced solid tumors.

2546 Background: TAS-116 is an oral non-ansamycin, non-purine, and non-resorcinol highly selective inhibitor of HSP90α/β. The objective of this FIH study was to determine the MTD and investigate the safety, tolerability, PK, PD (HSP70 protein levels in PBMCs), and antitumor activity of TAS-116. Methods: The study is being conducted in Japan and the UK. Patients with advanced solid tumors received escalating doses of TAS-116 once daily (QD) with an accelerated titration design. After the MTD was determined, safety and tolerability of 5 days on / 2 days off per week administration (QDx5) at the MTD in QD was explored. In parallel, the MTD with every other day administration (QOD) was evaluated by using a 3 + 3 design. Results: As of 20 September 2016, 52 patients were enrolled. TAS-116 was evaluated at doses of 4.8 to 150.5 mg/m2/day in the QD schedule and doses of 107.5 to 295.0 mg/m2/day in the QOD schedule. The MTD was 107.5 mg/m2/day with QD and 210.7 mg/m2/day with QOD. QDx5 at the MTD in QD using a flat dose of 160 mg was evaluated. The most common adverse events in all regimens were gastrointestinal disorders and increased creatinine. DLTs were observed in 4 patients in QD (night blindness, visual disorder, AST/ ALT/gamma-GTP elevations, and anorexia) and in 2 patients in QOD (platelet count decreased, febrile neutropenia, pneumonia, respiratory failure, and septic shock). Reversible eye disorders were observed in all schedules, but those observed in QDx5 were limited to grade 1. The PK level demonstrated dose proportionality without unexpected accumulation under repeated administration. Dose-related HSP70 induction of PBMCs was observed. As of 20 September 2016, three confirmed durable PRs by RECIST were observed (239 days in GIST and 173 days in NSCLC with QD; 293 + days in NSCLC with QOD). PR and SD ≥ 12 weeks were observed in 15 out of 47 patients. Conclusions: TAS-116 had an acceptable safety profile under all schedules, especially QDx5. Preliminary antitumor activity was demonstrated with evidence of target engagement. Dose expansion at the MTD in this phase 1 study and the phase 2 study in patients with GIST are ongoing. Parts of this study will be expanded to the US with an amended study protocol. Clinical trial information: NCT02965885.

Characterisation of CCS1477: A novel small molecule inhibitor of p300/CBP for the treatment of castration resistant prostate cancer.

11590 Background: Targeted degradation of androgen receptor (AR) and AR variants (ARV) remains an attractive therapeutic opportunity for patients with castrate resistant prostate cancer (CRPC). E1A binding protein (p300) and CREB binding protein (CBP) are two closely related transcriptional activators of AR. We have developed CCS1477 which is a potent, selective and orally active small molecule inhibitor of the bromodomain of p300/CBP and investigated its role in regulating androgen receptor expression and function. Methods: Binding of CCS1477 to p300, CBP and BRD4, was measured in a surface plasmon resonance (SPR) assay. Potency and functional activity (proliferation and biomarker knockdown) was demonstrated in prostate cell lines in vitro (22Rv1, VCaP). Cross species in vivo pharmacokinetic (PK) properties were assessed, and in vivo efficacy, linked to inhibition of biomarkers, was determined in 22Rv1 and LNCaP xenograft models. Results: CCS1477 binds to p300 and CBP with high affinity (Kd = 1.3/1.7nM) and selectivity (Kd = 222nM; BRD4). It is a potent inhibitor of cell proliferation in prostate cell lines (IC50 = 96nM,22Rv1; 49nM,VCaP) with minimal effect in AR-ve lines. In 22Rv1 cells, p300/CBP inhibition down-regulates AR-FL, AR-V7 and c-Myc protein by Western, an effect not seen with the BET inhibitor, JQ1 at equivalent proliferation IC50s. Inhibition of p300/CBP also reduces c-Myc, KLK3 and TMPRSS2 gene expression (qPCR) in 22Rv1 cells in vitro. The in vivo PK properties of CCS1477 are consistent with qd or qod oral dosing in mouse. CCS1477 dosed at 10mg, 20mg/kg qd or 30mg/kg qod, caused complete tumour growth inhibition over 28 days in a 22RV1 xenograft model, including extended duration in the absence of the drug for a further 24 days. This was accompanied by complete inhibition of plasma PSA and significant knockdown of tumour AR-FL, AR-V7, and C-Myc protein as well as C-Myc and TMPRSS2 mRNA expression. Conclusions: Taken together these data support the clinical testing of CCS1477 in castrate resistant prostate cancer by down-regulation of AR, AR-SV and c-MYC expression and function.

Clinical activity of BLU-285 in advanced gastrointestinal stromal tumor (GIST).

11011 Background: Oncogenic mutations in KIT or PDGFRα drive > 85% of GIST. However, primary and acquired mutations in the activation loop of PDGFRα and KIT are not effectively treated by approved therapies. A phase 1 study (NCT02508532) was initiated in advanced GIST to assess the safety, PK and clinical activity of BLU-285, a potent, highly-selective oral inhibitor that targets KIT Exon 17 and PDGFRα D842 activation loop mutants. Methods: Adult patients (pts) with unresectable GIST, who had received ≥2 kinase inhibitors including imatinib or who had a primary PDGFRα D842 mutation regardless of prior therapy, were given BLU-285 once daily on a 4-week cycle following a 3+3 escalation design, which allowed additional accrual to dose levels demonstrated to be safe. Adverse events (AEs) per CTCAE v4.03, PK and plasma/tumor mutant DNA levels were assessed. Response was determined by RECIST 1.1 every 8 weeks. Results: At a 01JAN17 cutoff, 40 pts (21 PDGFRa/19 KIT) have been treated with BLU-285 at doses of 30-600 mg. Median number of prior kinase inhibitor regimens was 4.5 (2-12) KIT/2.5 (0-4) PDGFRα. RECIST 1.1 responses were seen across all dose levels for PDGFRα GIST and at higher dose levels for KIT GIST. Of 17 PDGFRα D842V pts with ≥1 radiographic assessment, 7 had confirmed PR (ORR 41%) and 10 had SD. Of 11 evaluable KIT pts treated at doses ≥ 135 mg, 2 had PR (1 confirmed; ORR 18%) and 5 SD. BLU-285 is rapidly absorbed (Tmax 2-8 h), exposure increases linearly with dose, and half-life is > 24 h supporting QD dosing. Most AEs were grade 1 or 2, most commonly nausea (48%), fatigue (45%), peripheral edema, periorbital edema, vomiting (30% each), diarrhea (25%), anemia, dizziness, and lacrimation (23% each). There were no grade 4 or 5 BLU-285-related AEs, dose limiting toxicities, or discontinuations. 29 pts (all 21 PDGFRα pts) remain on treatment (duration 1-14 mo). Updated results including MTD, ct-DNA and central radiographic assessments will be presented. Conclusions: Precision targeted therapy with BLU-285 demonstrates important clinical activity in pts with both PDGFRα- and KIT-mutant GIST that is resistant to available therapies. Clinical trial information: NCT02508532.

A phase I study of the tolerability, safety, pharmacokinetics and preliminary antitumor effects of KBP-5209, a novel pan-HER inhibitor, in patients with advanced solid tumors.

2565 Background: KBP-5209 is a novel potent and irreversible inhibitor of tyrosine kinases of the human epidermal growth factor receptor (EGFR) family that preclinically has demonstrated potent antitumor activities in esophageal and gastric cancers and NSCLC. Methods: This first-in-human study (NCT02442414) was conducted to determine tolerability, safety, pharmacokinetics and antitumor activity of KBP-5209 administered QD or BID in patients (pts) with advanced solid tumors. Dose escalation (DE) initially was based on a modified accelerated titration plan and then shifted to a standard 3+3 design. The starting dose was 20 mg QD. Eligible patients were adults with advanced, refractory solid tumors with ECOG PS < 1. A cycle was 28 days. DLTs were evaluated for during the first cycle. DE enriched for patients with tumors having molecular alterations in EGFR or HER2/3. Dose escalation continues so dose expansion has not initiated. Results: As of 26 Nov, 2016, 23 pts (15 females, 8 males) are a part of the evaluable population with a median age 57 (37-79) treated at doses of 20mg (1), 40mg (3), 60mg (7), 70mg (4), 80mg (6) QD and 20mg BID (2).Tumor types included breast (6), CRC (4), ovarian (3), H&N (2), sarcoma (2), and NSCLC, sinus, gastric, gallbladder, pancreas, CUP tumor (1 each). Tumor genetic profiles were available for 20 pts. DLTs were G3 diarrhea, nausea, and vomiting, which occurred in 1 pt at 80mg QD and G3 Diarrhea, occurring in 1pt at 80mg QD. The most common adverse events related to study drug were diarrhea (60.9%), nausea (47.8%), vomiting (43.5%), fatigue (21.7%), decreased appetite (17.4%) and lipase increased (17.4%). Serious adverse events (SAEs) related to study drug were reported in 4pts: diarrhea (1 pt, 70mg QD; 1pt, 80mg QD), nausea and vomiting (1pt, 70mg QD), and diarrhea, nausea and vomiting (1 pt, 80mg QD). Stable disease has been observed in 7pts up to 24 weeks, in which 2/28 pts (7%) achieved tumor shrinkage. Conclusions: Based on the present data, KBP-5209 has been well tolerated with a safety profile similar to other pan-HER inhibitors. For QD dosing, maximum tolerated dose has been identified as 70mg QD. The BID dose escalation continues. Clinical trial information: NCT02442414.

Phase 1/2a trial of daily oral BAL101553, a novel tumor checkpoint controller (TCC), in advanced solid tumors.

2532 Background: BAL101553 (prodrug of BAL27862) is a small molecule TCC that binds microtubules and promotes tumor cell death by activation of the spindle assembly checkpoint. In a previous study (NCT01397929, Lopez et al. JCO 34, 2016; abstr 2525), 2-h IV infusion on Days 1, 8, 15 (q28d) of BAL101553 up to 80 mg/m2 (maximum administered dose, MAD) showed vascular toxicities, including transient hypertension, which appeared to be Cmax related. The recommended Phase 2 dose (RP2D) was 30 mg/m2 weekly IV. Based on nonclinical models, antiproliferative effects of BAL27862 are driven by AUC. This trial explores whether once daily oral administration of BAL101553 reduces Cmax-related toxicity and improves the therapeutic window (NCT02490800). Methods: Patients (pts) with advanced solid tumors who failed standard therapy, received QD oral BAL101553 (28-d cycles) in a 3+3 dose-escalation design to determine the MTD. Adverse events were assessed by CTCAEv4 grade (G); tumor response by RECIST 1.1; serial PK on Day 1 of Cycles 1 and 2. Results: In the ongoing study, 19 pts (9M/10F; median age 67 y) received doses of 2, 4, 8, 16 or 30 mg oral BAL101553 QD. The MAD was 30 mg with DLTs of reversible G2 hallucination and asymptomatic, reversible G3 electrolyte imbalances. No DLTs were observed at ≤ 16 mg. Dosing is ongoing between 16 and 30 mg QD to determine the MTD. BAL27862 exposures after oral QD dosing of BAL101553 compared to weekly 2-h infusions suggested high relative oral bioavailability. The BAL27862 weekly AUC at the oral MAD (30 mg QD) compared to the RP2D of 30 mg/m2 for 2-h IV was more than 5-fold higher (19,656 vs 3,584 ng*h/mL) and Cmax was 1.5-fold lower (171 vs 266 ng/mL). Both Cmaxand AUC were dose-proportional, with low/moderate variability. Oral BAL101553 had no effects on blood pressure and showed no vascular toxicity. 5 pts had stable disease (2 pts [cholangiocarcinoma, neuroendocrine pancreatic cancer] > 4 cycles). Conclusions: Daily oral BAL101553 enables higher weekly exposures of BAL27862 with lower Cmax levels compared with a 2-h weekly infusion, due to the absence of Cmax related vascular toxicity. Doses up to 16 mg QD are well tolerated. The MAD has been identified as 30 mg QD; definition of the MTD is ongoing. Clinical trial information: NCT02490800.

Abstract 223: Impact of Differences in Once- vs Twice-Daily Medications Adherence on the Risk of Bleed and Stroke in Non-Valvular Atrial Fibrillation: Analysis of Randomized Trials and Claims Data Sources

Background: In non-valvular atrial fibrillation (NVAF) patients, those receiving once-daily (QD) versus twice-daily (BID) non vitamin-K antagonist oral anticoagulants (NOACs) may have better medication adherence. The impact on stroke and bleed risk is not known. Objective: To estimate the impact of adherence differences between QD vs BID therapies on bleed and stroke risks in NVAF patients. Methods: The relation between adherence (proportion of days covered [PDC]) for QD vs BID NOACs and one year bleed risk was modeled using claims data from Truven Health Analytics MarketScan databases (7/2012-10/2015). Next, the relation between adherence and bleeding was calibrated to match that seen in the placebo and NOAC arms of previous randomized controlled trials (RCTs). Finally, we used adherence rates for QD (PDC=0.849) and BID (PDC=0.738) cardiovascular medications from a meta-analysis (Coleman et al.). These rates were used in the calibrated model to estimate bleeds. An analogous method was applied to evaluate the impact of QD vs BID adherence on stroke risk. Results: The relation between PDC and risks of bleed and stroke was modeled using claims data (N=65,022) and calibrated using RCTs. In the calibrated model, compared with BID dosing, QD dosing was associated with 81 fewer strokes (34% reduction) and 14 more bleeds (6% more) per 10,000 patients/year (Figure). Conclusion: Among NVAF patients, better adherence to QD dosing was associated with a significantly lower stroke risk of QD but similar risk of bleed.

How recent findings on the pharmacokinetics and pharmacodynamics of integrase inhibitors can inform clinical use.

This review of recent published literature and data presented at scientific meetings on integrase stand transfer inhibitors (InSTIs) examines how these findings may impact on their future clinical use. Elvitegravir (EVG), raltegravir (RAL) and dolutegravir (DTG) are InSTIs recommended as first-line options for treatment naive patients by the European AIDS Clinical Society, British HIV Association, International AIDS Society-USA and DHHS. InSTIs have gained a leading role in the management of HIV-1 because of increased viral suppression and maintaining undetectability with fewer side-effects.RAL 1200 mg once-daily (QD) has been shown to be noninferior to 400 mg BD, and the European Medicines Agency has approved QD RAL for review. RAL and DTG are not metabolized via cytochrome P450 (CYP) resulting in fewer drug interactions and less toxicity risk in patients receiving direct-acting antivirals and other coadministered medications.EVG is currently available as a single tablet regimen and requires cobisistat, a pharmacokinetic booster and CYP3A inhibitor to allow QD dosing. EVG will soon be available in combination with tenofovir alfenamide, which is as efficacious as tenofovir disoproxil fumarate, but offers better renal and bone outcomes.DTG has a high genetic barrier to resistance and has been the subject of a number of simplification and treatment failure trials and shown promise. There are some emerging reports of neuropsychiatric and gastrointestinal side-effects associated with DTG, which were not reported in clinical trials emphasizing the importance of real-life data.Carbotegravir, a long-acting InSTI, is currently in the pipeline of development. All three InSTIs have impressive data on efficacy, tolerability and safety. The unique differences of each InSTI's pharmacokinetics and pharmacodynamics lend themselves to various clinical scenarios, enabling us as clinicians to provide better patient-centred care.

Impact of a planned dose interruption of dacomitinib in the treatment of advanced non-small-cell lung cancer (ARCHER 1042)

ObjectivesDacomitinib is a pan-HER inhibitor for advanced non-small-cell lung cancer (NSCLC). We explored the impact of a planned 4-day dacomitinib dose interruption on plasma exposure of dacomitinib and adverse events (AEs) of interest in Cohort III of the ARCHER 1042 study. Materials and methodsPatients, treatment-naïve for advanced NSCLC with EGFR activating mutations, received oral dacomitinib 45mg QD (once daily). A planned dose interruption occurred in Cycle 1 from Days 11 through 14. The primary endpoint was the pharmacokinetic (PK) characteristics of dacomitinib in Cycle 1Day 10 and during dose interruption. Secondary endpoints included safety and concomitant medications used to treat AEs of interest. ResultsCohort III enrolled 25 patients. Median plasma Cmax of dacomitinib in Cycle 1 Day 10 was 83.40ng/mL. Average median plasma dacomitinib concentration during the 4-day dose interruption was 42.63ng/mL. In the first 8 weeks of treatment 1) 80% of patients used concomitant medications for dermatologic AEs, 76% for diarrhea, and 44% for stomatitis, and 2) all patients experienced treatment-emergent AEs and 28% had all-causality Grade 3 AEs. ConclusionAt 45mg QD dosing, PK parameters of plasma dacomitinib in Cycle 1 Day 10 were comparable to that obtained in Cycle 1 Day 14 from other dacomitinib studies. Average median plasma dacomitinib concentration during the 4-day dose interruption was approximately half of the median plasma Cmax of dacomitinib observed prior to dose interruption. The toxicity profile was consistent with that from other studies of dacomitinib.