Selective Oral MEK1/2 Inhibitor Pimasertib: A Phase I Trial in Patients with Advanced Solid Tumors

BACKGROUND

The Ras/Raf/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (Ras/Raf/MEK/ERK) signaling cascade is frequently constitutively activated in human cancers. Pimasertib is a selective and potent adenosine triphosphate non-competitive MEK1/2 inhibitor.

OBJECTIVE

Our objectives were to describe the results of a phase I, first-in-human, dose-escalation trial of pimasertib that investigated the maximum tolerated dose, recommended phase II dose, and safety, as well as other endpoints.

PATIENTS AND METHODS

Four dosing schedules of pimasertib (once daily [qd], 5 days on, 2 days off; qd, 15 days on, 6 days off; continuous qd; continuous twice daily [bid]) were evaluated in patients with advanced solid tumors. Each treatment cycle lasted 21 days. The primary objective was to determine the maximum tolerated dose based on dose-limiting toxicities (DLTs) evaluated during cycle 1, and the recommended phase II dose (RP2D). Secondary objectives included safety, pharmacokinetics, pharmacodynamics, and antitumor activity.

RESULTS

Overall, 180 patients received pimasertib (dose range 1-255 mg/day). DLTs were mainly observed at doses ≥ 120 mg/day and included skin rash/acneiform dermatitis and ocular events, such as serous retinal detachment. The most common drug-related adverse events were consistent with class effects, including diarrhea, skin disorders, ocular disorders, asthenia/fatigue, and peripheral edema. The median time to maximum pimasertib concentration was 1.5 h across dosing schedules, and the apparent terminal half-life was 5 h across qd dosing schedules. Pimasertib decreased ERK phosphorylation within 2 h of administration, which was maintained for up to 8 h at higher doses and prolonged with bid dosing.

CONCLUSIONS

Based on the safety profile and efficacy signals, a continuous bid regimen was the preferred dosing schedule and the RP2D was defined as 60 mg bid.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00982865.

Phase I Study Evaluating WEE1 Inhibitor AZD1775 As Monotherapy and in Combination With Gemcitabine, Cisplatin, or Carboplatin in Patients With Advanced Solid Tumors

Purpose AZD1775 is a WEE1 kinase inhibitor targeting G2 checkpoint control, preferentially sensitizing TP53-deficient tumor cells to DNA damage. This phase I study evaluated safety, tolerability, pharmacokinetics, and pharmacodynamics of oral AZD1775 as monotherapy or in combination with chemotherapy in patients with refractory solid tumors. Patients and Methods In part 1, patients received a single dose of AZD1775 followed by 14 days of observation. In part 2, patients received AZD1775 as a single dose (part 2A) or as five twice per day doses or two once per day doses (part 2B) in combination with one of the following chemotherapy agents: gemcitabine (1,000 mg/m2), cisplatin (75 mg/m2), or carboplatin (area under the curve, 5 mg/mL⋅min). Skin biopsies were collected for pharmacodynamic assessments. TP53 status was determined retrospectively in archival tumor tissue. Results Two hundred two patients were enrolled onto the study, including nine patients in part 1, 43 in part 2A (including eight rollover patients from part 1), and 158 in part 2B. AZD1775 monotherapy given as single dose was well tolerated, and the maximum-tolerated dose was not reached. In the combination regimens, the most common adverse events consisted of fatigue, nausea and vomiting, diarrhea, and hematologic toxicity. The maximum-tolerated doses and biologically effective doses were established for each combination. Target engagement, as a predefined 50% pCDK1 reduction in surrogate tissue, was observed in combination with cisplatin and carboplatin. Of 176 patients evaluable for efficacy, 94 (53%) had stable disease as best response, and 17 (10%) achieved a partial response. The response rate in TP53-mutated patients (n = 19) was 21% compared with 12% in TP53 wild-type patients (n = 33). Conclusion AZD1775 was safe and tolerable as a single agent and in combination with chemotherapy at doses associated with target engagement.

Phase II Study of WEE1 Inhibitor AZD1775 Plus Carboplatin in Patients With TP53-Mutated Ovarian Cancer Refractory or Resistant to First-Line Therapy Within 3 Months

Purpose AZD1775 is a first-in-class, potent, and selective inhibitor of WEE1 with proof of chemopotentiation in p53-deficient tumors in preclinical models. In a phase I study, the maximum tolerated dose of AZD1775 in combination with carboplatin demonstrated target engagement. We conducted a proof-of-principle phase II study in patients with p53 tumor suppressor gene ( TP53)-mutated ovarian cancer refractory or resistant (< 3 months) to first-line platinum-based therapy to determine overall response rate, progression-free and overall survival, pharmacokinetics, and modulation of phosphorylated cyclin-dependent kinase (CDK1) in skin biopsies. Patients and Methods Patients were treated with carboplatin (area under the curve, 5 mg/mL⋅min) combined with AZD1775 225 mg orally twice daily over 2.5 days every 21-day cycle until disease progression. Results AZD1775 plus carboplatin demonstrated manageable toxicity; fatigue (87%), nausea (78%), thrombocytopenia (70%), diarrhea (70%), and vomiting (48%) were the most common adverse events. The most frequent grade 3 or 4 adverse events were thrombocytopenia (48%) and neutropenia (37%). Of 24 patients enrolled, 21 patients were evaluable for efficacy end points. The overall response rate was 43% (95% CI, 22% to 66%), including one patient (5%) with a prolonged complete response. Median progression-free and overall survival times were 5.3 months (95% CI, 2.3 to 9.0 months) and 12.6 months (95% CI, 4.9 to 19.7), respectively, with two patients with ongoing response for more than 31 and 42 months at data cutoff. Conclusion To our knowledge, this is the first report providing clinical proof that AZD1775 enhances carboplatin efficacy in TP53-mutated tumors. The encouraging antitumor activity observed in patients with TP53-mutated ovarian cancer who were refractory or resistant (< 3 months) to first-line therapy warrants further development.

Phase I/II study with ruthenium compound NAMI-A and gemcitabine in patients with non-small cell lung cancer after first line therapy

BACKGROUND

This phase I/II study determined the maximal tolerable dose, dose limiting toxicities, antitumor activity, the pharmacokinetics and pharmacodynamics of ruthenium compound NAMI-A in combination with gemcitabine in Non-Small Cell Lung Cancer patients after first line treatment.

METHODS

Initial dose escalation of NAMI-A was performed in a 28 day cycle: NAMI-A as a 3 h infusion through a port-a-cath at a starting dose of 300 mg/m(2) at day 1, 8 and 15, in combination with gemcitabine 1,000 mg/m(2) at days 2, 9 and 16. Subsequently, dose escalation of NAMI-A in a 21 day schedule was explored. At the maximal tolerable dose level of this schedule an expansion group was enrolled of which 15 patients were evaluable for response.

RESULTS

Due to frequent neutropenic dose interruptions in the third week, the 28 day schedule was amended into a 21 day schedule. The maximal tolerable dose was 300 and 450 mg/m(2) of NAMI-A (21 day schedule). Main adverse events consisted of neutropenia, anemia, elevated liver enzymes, transient creatinine elevation, nausea, vomiting, constipation, diarrhea, fatigue, and renal toxicity.

CONCLUSION

NAMI-A administered in combination with gemcitabine is only moderately tolerated and less active in NSCLC patients after first line treatment than gemcitabine alone.

Phase I dose-escalation study and population pharmacokinetic analysis of fixed dose rate gemcitabine plus carboplatin as second-line therapy in patients with ovarian cancer

OBJECTIVE

This phase I study of fixed dose rate (FDR) gemcitabine and carboplatin assessed the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), safety, pharmacokinetic (PK)/pharmacodynamic (PD) profile and preliminary anti-tumor activity in patients with recurrent ovarian cancer (OC).

METHODS

Patients with recurrent OC after first line treatment were treated with carboplatin and FDR gemcitabine (infusion speed 10mg/m(2)/min) on days 1, 8 and 15, every 28 days. Pharmacokinetics included measurement of platinum concentrations in plasma ultrafiltrate (pUF) and plasma concentrations of gemcitabine (dFdC) and metabolite dFdU. Intracellular levels of dFdC triphosphate (dFdC-TP), the most active metabolite of gemcitabine, were determined in peripheral blood mononuclear cells (PBMCs). Population pharmacokinetic modeling and simulation were performed to further investigate the optimal schedule.

RESULTS

Twenty three patients were enrolled. Initial dose escalation was performed using FDR gemcitabine 300 mg/m(2) (administered at infusion speed of 10 mg/m(2)/min) combined with carboplatin AUC 2.5 and 3. Excessive bone marrow toxicity led to a modified dose escalation schedule: carboplatin AUC 2 and dose escalation of FDR gemcitabine (300 mg/m(2), 450 mg/m(2), 600 mg/m(2) and 800 mg/m(2)). DLT criteria as defined per protocol prior to the study were not met with carboplatin AUC 2 in combination with FDR gemcitabine 300-800 mg/m(2) because of myelosuppressive dose-holds (especially thrombocytopenia and neutropenia).

CONCLUSIONS

FDR gemcitabine in combination with carboplatin administered in this 28 days schedule resulted in increased grade 3/4 toxicity compared to conventional 30-minute infused gemcitabine. A two weekly schedule (chemotherapy on days 1 and 8) would be more appropriate.

Evaluation of dried blood spot (DBS) technology versus plasma analysis for the determination of MK-1775 by HILIC-MS/MS in support of clinical studies

The collection of human blood samples as dried blood spots (DBS) for the pharmacokinetic assessment of investigational drugs in clinical trials offers a number of advantages over conventional plasma sampling, namely, small sample volume, simplified sample handling, and cost-effective shipping and storage. The use of DBS coupled with liquid chromatography-tandem mass spectrometry analysis was evaluated for the quantification of MK-1775, a Wee-1 inhibitor under development as a chemo/radio-sensitizer for the treatment of cancer. The DBS method exhibited an assay performance comparable to that of the existing plasma assay, which is currently used in support of clinical studies. Both assays used the same linear dynamic range of 2-1,000 ng/mL, with a lower limit of quantification of 2 ng/mL. Based on the intra-day assay validation results, the accuracy of the DBS method ranged from 94.0 to 105.0%, with a coefficient of variation of <4.8%. The blood-to-plasma ratio calculated from the DBS data (blood concentrations) and the plasma data (plasma concentrations) was in good agreement with the one obtained from the in vitro assessment using conventional methodology. No significant hematocrit impact on the assay was observed as hematocrit ranged from 16 to 85%. The correlation between the measured MK-1775 concentrations in plasma and that determined in dried blood spots from oncology patients during the ongoing clinical study was discussed.

Phase I dose-escalation study of the safety, pharmacokinetics, and pharmacodynamics of the MEK inhibitor RO4987655 (CH4987655) in patients with advanced solid tumors

PURPOSE

This phase I study of the mitogen-activated protein/extracellular signal-regulated kinase inhibitor RO4987655 (CH4987655) assessed its maximum tolerated dose (MTD), dose-limiting toxicities (DLT), safety, pharmacokinetic/pharmacodynamic profile, and antitumor activity in patients with advanced solid tumors.

PATIENTS AND METHODS

An initial dose escalation was conducted using a once-daily dosing schedule, with oral RO4987655 administered at doses of 1.0 to 2.5 mg once daily over 28 consecutive days in 4-week cycles. Doses were then escalated from 3.0 to 21.0 mg [total daily dose (TDD)] using a twice-daily dosing schedule.

RESULTS

Forty-nine patients were enrolled. DLTs were blurred vision (n = 1) and elevated creatine phosphokinase (n = 3). The MTD was 8.5 mg twice daily (TDD, 17.0 mg). Rash-related toxicity (91.8%) and gastrointestinal disorders (69.4%) were the most frequent adverse events. The pharmacokinetic profile of RO4987655 showed dose linearity and a half-life of approximately 4 hours. At the MTD, target inhibition, assessed by suppression of extracellular signal-regulated kinase phosphorylation in peripheral blood mononuclear cells, was high (mean 75%) and sustained (90% of time >IC(50)). Of the patients evaluable for response, clinical benefit was seen in 21.1%, including two partial responses (one confirmed and one unconfirmed). 79.4% of patients showed a reduction in fluorodeoxyglucose uptake by positron emission tomography between baseline and day 15.

CONCLUSION

In this population of heavily pretreated patients, oral RO4987655 showed manageable toxicity, a favorable pharmacokinetics/pharmacodynamics profile, and promising preliminary antitumor activity, which has been further investigated in specific populations of patients with RAS and/or RAF mutation driven tumors.

Pharmacodynamic evaluation of pCDC2 as the target engagement biomarker to assess activity of MK-1775 a Wee1 tyrosine kinase inhibitor

e13598

Background: Wee1 kinase regulates the G2 checkpoint through phosphorylation of CDC2. MK-1775 is a first-in-class inhibitor of Wee1, and thereby reduces pCDC2 levels relative to CDC2. pCDC2therefore can be used as a target engagement (TE) biomarker to assess activity of MK-1775. This was investigated in a phase I first-in-man clinical trial of MK-1775. Methods: This is a multicenter, open-label, non-randomized phase I dose escalation study in patients with locally advanced or metastatic solid tumors. MK-1775 was administered orally in escalating doses as monotherapy, and either single dose or multi-dose in combination with chemotherapy including cisplatin, carboplatin and gemcitabine. Serial skin biopsies were performed at baseline and either 8, 24 or 48 hours following MK-1775 administration and analyzed by IHC for CDC2 and pCDC2. Based on preclinical efficacy experiments, TE was defined as a decrease of pCDC2 of at least 50% (or fold change > 0.50) from pre- to post-dose MK-1775. Results: To date a total of 176 patients have received at least one dose of MK-1775 either as monotherapy or in combination (single or multi-dose MK-1775) with chemotherapy at doses ranging from 25 mg to 1300 mg to define maximum tolerated dose. Dose dependent decreases in pCDC2 were observed in skin biopsies between pre-dose and post-dose treatment in all treatment groups. TE with monotherapy was achieved at 325 mg. TE with multi-dose MK-1775 in combination with cisplatin and carboplatin were achieved at 125 mg BID and 225 mg BID. Gemcitabinecombination treatment is on-going. In contrast, chemotherapy alone resulted in an increase of pCDC2. Conclusions: Based on preclinical data, in this first-in-man clinical trial of MK-1775, we were able to demonstrate TE required for maximal efficacy at tolerable doses of MK-1775 either as a single agent or in combination with chemotherapy. [Table: see text]

A phase I, open-label, randomized crossover study to assess the effect of dosing of the MEK 1/2 inhibitor Selumetinib (AZD6244; ARRY-142866) in the presence and absence of food in patients with advanced solid tumors

Purpose

This Phase I study assessed whether food influences the rate and extent of selumetinib absorption in patients with advanced solid malignancies and determined the safety, tolerability, and pharmacokinetic (PK) profile of selumetinib and its active metabolite N-desmethyl-selumetinib in fed and fasted states.

Methods

A single dose of 75 mg selumetinib was to be taken with food on Day 1 followed by a single dose of 75 mg after fasting for at least 10 h on Day 8, or vice versa, followed by twice daily dosing of 75 mg selumetinib from Day 10. Plasma concentrations and PK parameters were determined on Days 1 and 8. Patients could continue to receive selumetinib for as long as they benefitted from treatment.

Results

In total, 31 patients were randomized to receive selumetinib; 15 to fed/fasted sequence and 16 to fasted/fed sequence. Comprehensive PK sampling was performed on 11 and 10 patients, respectively. The geometric least-squares means of C_max and AUC for selumetinib were reduced by 62% (ratio 0.38 90% CI 0.29, 0.50) and 19% (ratio 0.81 90% CI 0.74, 0.88), respectively, under fed compared with fasting conditions. The rate of absorption (t_max) of selumetinib (fed) was delayed by approximately 2.5 h (median). The food effect was also observed for the active metabolite N-desmethyl-selumetinib. Selumetinib was well tolerated.

Conclusions

The presence of food decreased the extent of absorption of selumetinib. It is recommended that for further clinical studies, selumetinib be taken on an empty stomach. Selumetinib demonstrated an acceptable safety profile in the advanced cancer population.

Abrogation of the G2 checkpoint by inhibition of Wee-1 kinase results in sensitization of p53-deficient tumor cells to DNA-damaging agents

Inducing DNA damage is a well known strategy for attacking cancer, already being used for many years by the application of a variety of anti cancer drugs. Tumor cells and other rapidly dividing cells are more sensitive to DNA damage caused by DNA damaging agents compared to normal cells. While normal cells can rely on various mechanisms for DNA repair in order to protect the integrity of the genome and to promote cell survival, most tumor cells, due to genetic changes, are more challenged when it comes to repair of DNA damage. Wee 1 is a tyrosine kinase that phosphorylates CDC2 at Tyr 15 and as such plays a pivotal role in the G2 DNA damage checkpoint. The strategy of inhibition of Wee 1 by a tyrosine kinase inhibitor is exploiting the impaired options for DNA damage repair especially in cells with deregulated p53, which results in malfunction of the G1 checkpoint. Tumor cells that are unable to rely on the G1 checkpoint are more sensitive to G2 checkpoint abrogation. Administration of DNA damaging chemotherapy in combination with a Wee 1 inhibitor may therefore selectively sensitize p53 deficient cells, while normal cells are spared from toxicity. PD-166285 has been described as a novel G2 abrogator and Wee 1 inhibitor, but has also been characterized as a broad-spectrum receptor tyrosine kinase inhibitor. MK-1775 is a specific and potent inhibitor of Wee-1 and is currently under investigation in a multi-center phase I study in combination with either gemcitabine, carboplatin or cisplatin in patients with advanced solid tumors. Preliminary results show good tolerability and promising anti-cancer activity.

A phase I and pharmacological study of MK-1775, a Wee1 tyrosine kinase inhibitor, in both monotherapy and in combination with gemcitabine, cisplatin, or carboplatin in patients with advanced solid tumors

3510

Background: MK-1775 is an inhibitor of Wee1, a kinase that phosphorylates CDC2 to inactivate the CDC2/cyclin B complex (regulating the G2 checkpoint). Since most human cancers harbor p53-dependent G1 checkpoint abnormalities, they are dependent on the G2 checkpoint. G2 checkpoint abrogation may therefore sensitize p53 deficient tumor cells to anti-cancer agents. Methods: This study is evaluating the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of MK-1775 administered as both monotherapy (MT) and combination therapy (CT) with gemcitabine (G), cisplatin (P), or carboplatin (C). PART 1 consists of a single dose of MK-1775 followed by 14 days observation. If well tolerated, the same pt continues on to one of three treatment arms in PART 2: a single lower dose of MK-1775 in combination with: 1) 1000 mg/m2 G, 2) 75 mg/m2 P or 3) C AUC 5. Maximum Tolerated Doses (MTDs) will be established for MK-1775 as both monotherapy and in combination. PD biomarkers include IHC analysis for pCDC2/CDC2 in plucked hair and skin biopsies, peripheral blood, and tumor biopsies. Wee1 gene expression signature is measured in plucked hair and tumor biopsies by qPCR. Results: To date, 37 pts (median age 61; up to 4 prior therapies) have been treated with MK-1775. 4 pts experienced DLT. One pt on G + 200mg MK-1775 had gr3 leucopenia and neutropenia; one pt on P + 200mg MK-1775 had gr3, fatigue, diarrhea and hypokalemia and another pt gr2 nausea/vomiting > 48hrs requiring hospitalization. One pt on C + 325mg MK-1775 was hospitalized for gr3 bilirubin. Linear PK was demonstrated at 100, 200, 325, 650 and 1300 mg MK-1775. Terminal T½ of MK-1775 was 7.6–12.2 hrs and Tmax was 1.0–6.0 hrs. Preliminary MTDs of MK-1775 in combination with G, C and P were 200, 325 and 200mg, respectively. Significant changes in Wee1 signature gene expression were observed in plucked hair. Of 28 evaluable pts, >50% regression of axillary lymphadenopathy was seen in 1 pt with melanoma on the P arm, and stable disease in 14 other pts (median duration). Conclusions: MK-1775 is a first in class Wee1 inhibitor that is well tolerated and shows promising anti-tumor activity in previously treated pts.

[Table: see text]

Increased expression of the tight junction molecule claudin-18 A1 in both experimental colitis and ulcerative colitis

BACKGROUND

We previously identified a major quantitative trait locus (qtl) on mouse chromosome 9 (Tnbs1) that confers resistance/susceptibility to trinitrobenzene sulfonic acid (TNBS) induced colitis. Here we wanted to identify possible candidate genes in this locus.

METHODS

We applied micro-array technology and identified claudin-18 as a plausible candidate gene in the Tnbs1 region. Subsequently we studied the expression profile of this gene by means of RT-PCR in resistant and susceptible mice as well as in human inflammatory bowel disease.

RESULTS

Expression of this gene was markedly upregulated during colitis in mice. Also in humans relative expression of claudin-18 in patients with ulcerative colitis was significantly upregulated as compared to healthy individuals undergoing surveillance endoscopy (n = 13, P < 0.0005). Expression was not related to the histological severity of the disease.

CONCLUSIONS

Claudins belong to the integral membrane proteins of the tight junction, a structure that seals off the intercellular space between adjacent epithelial cells and regulates passive diffusion of solutes and macromolecules. This study demonstrates for the first time that claudin-18 is expressed in human and mouse colon. Expression is upregulated during experimental colitis and in patients with ulcerative colitis. The observation that this is unrelated to the severity of inflammation might point to a primary defect in regulation in patients with ulcerative colitis and warrants further genetic examination.

AML1/RUNX1 increases during G1 to S cell cycle progression independent of cytokine-dependent phosphorylation and induces cyclin D3 gene expression

AML1/RUNX1, a member of the core binding factor (CBF) family stimulates myelopoiesis and lymphopoiesis by activating lineage-specific genes. In addition, AML1 induces S phase entry in 32Dcl3 myeloid or Ba/F3 lymphoid cells via transactivation. We now found that AML1 levels are regulated during the cell cycle. 32Dcl3 and Ba/F3 cell cycle fractions were prepared using elutriation. Western blotting and a gel shift/supershift assay demonstrated that endogenous CBF DNA binding and AML1 levels were increased 2-4-fold in S and G(2)/M phase cells compared with G(1) cells. In addition, G(1) arrest induced by mimosine reduced AML1 protein levels. In contrast, AML1 RNA did not vary during cell cycle progression relative to actin RNA. Analysis of exogenous Myc-AML1 or AML1-ER demonstrated a significant reduction in G(1) phase cells, whereas levels of exogenous DNA binding domain alone were constant, lending support to the conclusion that regulation of AML1 protein stability contributes to cell cycle variation in endogenous AML1. However, cytokine-dependent AML1 phosphorylation was independent of cell cycle phase, and an AML1 mutant lacking two ERK phosphorylation sites was still cell cycle-regulated. Inhibition of AML1 activity with the CBFbeta-SMMHC or AML1-ETO oncoproteins reduced cyclin D3 RNA expression, and AML1 bound and activated the cyclin D3 promoter. Signals stimulating G(1) to S cell cycle progression or entry into the cell cycle in immature hematopoietic cells might do so in part by inducing AML1 expression, and mutations altering pathways regulating variation in AML1 stability potentially contribute to leukemic transformation.