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Mobocertinib (TAK-788) is a first-in-class oral epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that received accelerated approval for the treatment of patients with non-small cell lung cancer with EGFR exon 20 insertion mutations previously treated with platinum-based chemotherapy. This phase 1, 2-period, study was conducted to assess the absolute bioavailability of mobocertinib (Period 1), as well as mass balance, pharmacokinetics, metabolism, and excretion of [14C]-mobocertinib (Period 2) in healthy adult males. In Period 1, participants received a single oral capsule dose of 160 mg mobocertinib, followed by a 15-minute intravenous infusion of 50 µg (~ 2 µCi) [14C]-mobocertinib administered from 3.75 to 4 h after the capsule dose. In Period 2, a single oral dose of 160 mg (~ 100 µCi) [14C]-mobocertinib was administered as an oral solution. The geometric mean absolute bioavailability of mobocertinib was determined to be 36.7%. After oral administration of [14C]-mobocertinib, mobocertinib and its active metabolites, AP32960 and AP32914, were minor components in plasma, accounting for only 0.275% of total plasma radioactivity as the majority of mobocertinib-related material was covalently bound to plasma proteins. The geometric mean percentage of the administered radioactive dose recovered in the urine and feces was 3.57% and 76.0%, respectively. Only 0.39% of the oral dose of [14C]-mobocertinib was recovered in the urine as mobocertinib; thus, indicating that renal excretion of unchanged drug was a very minor pathway of elimination. In both treatment periods, mobocertinib was generally safe and well-tolerated as all adverse events were Grade 1 in severity. (Trial registration number ClinicalTrials.gov NCT03811834. Registration date January 22, 2019). [ABSTRACT FROM AUTHOR]

Brigatinib is an oral anaplastic lymphoma kinase (ALK) inhibitor approved for the treatment of ALK‐positive metastatic non‐small cell lung cancer. In vitro studies indicated that brigatinib is primarily metabolized by CYP2C8 and CYP3A4 and inhibits P‐gp, BCRP, OCT1, MATE1, and MATE2K. Clinical drug–drug interaction (DDI) studies with the strong CYP3A inhibitor itraconazole or the strong CYP3A inducer rifampin demonstrated that CYP3A‐mediated metabolism was the primary contributor to overall brigatinib clearance in humans. A physiologically‐based pharmacokinetic (PBPK) model for brigatinib was developed to predict potential DDIs, including the effect of moderate CYP3A inhibitors or inducers on brigatinib pharmacokinetics (PK) and the effect of brigatinib on the PK of transporter substrates. The developed model was able to predict clinical DDIs with itraconazole (area under the plasma concentration–time curve from time 0 to infinity [AUC∞] ratio [with/without itraconazole]: predicted 1.86; observed 2.01) and rifampin (AUC∞ ratio [with/without rifampin]: predicted 0.16; observed 0.20). Simulations using the developed model predicted that moderate CYP3A inhibitors (e.g., verapamil and diltiazem) may increase brigatinib AUC∞ by ~40%, whereas moderate CYP3A inducers (e.g., efavirenz) may decrease brigatinib AUC∞ by ~50%. Simulations of potential transporter‐mediated DDIs predicted that brigatinib may increase systemic exposures (AUC∞) of P‐gp substrates (e.g., digoxin and dabigatran) by 15%–43% and MATE1 substrates (e.g., metformin) by up to 29%; however, negligible effects were predicted on BCRP‐mediated efflux and OCT1‐mediated uptake. The PBPK analysis results informed dosing recommendations for patients receiving moderate CYP3A inhibitors (40% brigatinib dose reduction) or inducers (up to 100% increase in brigatinib dose) during treatment, as reflected in the brigatinib prescribing information. [ABSTRACT FROM AUTHOR]

Epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations represent ~6%–12% of all EGFR‐mutated non‐small cell lung cancer (NSCLC) cases. First‐, second‐, and third‐generation tyrosine kinase inhibitors (TKIs) have limited clinical activity against EGFR ex20ins mutations. Mobocertinib is a first‐in‐class oral EGFR TKI that selectively targets in‐frame EGFR ex20ins mutations in NSCLC; accelerated approval in the United States was granted for the treatment of adult patients with locally advanced or metastatic NSCLC with EGFR ex20ins mutations whose disease has progressed on or after platinum‐based chemotherapy. Accelerated approval was based on the results from the three‐part, open‐label, multicenter, pivotal phase I/II nonrandomized clinical trial (NCT02716116) that enrolled 114 patients with locally advanced or metastatic EGFR ex20ins mutation–positive NSCLC who were previously treated with platinum‐based chemotherapy and received mobocertinib at the recommended dosage of 160 mg once daily. At the November 1, 2021, data cutoff date, the confirmed objective response rate per independent review committee (IRC) was 28%, median duration of response was 15.8 months, median progression‐free survival per IRC was 7.3 months, and median overall survival was 20.2 months. The most common treatment‐emergent adverse events were gastrointestinal‐ and skin‐related. The phase III EXCLAIM‐2 study evaluated mobocertinib versus chemotherapy as first‐line therapy for locally advanced or metastatic EGFR ex20ins–positive NSCLC; however, the primary end point was not met, resulting in initiating voluntary withdrawal of mobocertinib worldwide. This mini‐review article summarizes the mechanism of action, pharmacokinetic characteristics, key clinical trials, and clinical efficacy and safety data for mobocertinib. [ABSTRACT FROM AUTHOR]

Background: CREBBP and EP300 mutations occur at a frequency of 15% and 13%, respectively, in small cell lung cancer (SCLC), and preclinical models demonstrated susceptibility to targeting with HDAC inhibitors. Methods: Patients with treatment-naïve extensive-stage SCLC, ECOG ≤2 were enrolled and treated with entinostat orally weekly (4 dose levels, DL) in combination with standard dose carboplatin, etoposide, and atezolizumab. Cohort allocation was determined by Bayesian optimal interval (BOIN) design targeting an MTD with a DLT rate of 20%. Results: Three patients were enrolled and treated at DL1 with entinostat 2 mg. Patients were aged 69-83; 2 male, 1 female; 2 were ECOG 1, and 1 was ECOG 0. The most common adverse events (AEs) were anemia (3), neutropenia (3), thrombocytopenia (2), leukopenia (2), and hypocalcemia (2). Two experienced DLTs during cycle 1: (1) grade (Gr) 4 febrile neutropenia, and (1) Gr 5 sepsis. BOIN design required stopping accrual to DL1, and the trial was closed to further accrual. Entinostat and atezolizumab pharmacokinetics were both comparable to historical controls. Conclusion: Addition of entinostat to atezolizumab, carboplatin, and etoposide is unsafe and resulted in early onset and severe neutropenia, thrombocytopenia. Further exploration of entinostat with carboplatin, etoposide, and atezolizumab should not be explored. (ClinicalTrials.gov Identifier: NCT04631029). This phase I trial evaluated the safety of combining an HDAC inhibitor, entinostat, with standard of care chemotherapy and immunotherapy for small cell lung cancer. [ABSTRACT FROM AUTHOR]

Brigatinib, a next-generation anaplastic lymphoma kinase (ALK) inhibitor designed to overcome mechanisms of resistance associated with crizotinib, is approved for the treatment of ALK-positive advanced or metastatic non-small cell lung cancer. After oral administration of single doses of brigatinib 30–240 mg, the median time to reach maximum plasma concentration ranged from 1 to 4 h. In patients with advanced malignancies, brigatinib showed dose linearity over the dose range of 60–240 mg once daily. A high-fat meal had no clinically meaningful effect on systemic exposures of brigatinib (area under the plasma concentration–time curve); thus, brigatinib can be administered with or without food. In a population pharmacokinetic analysis, a three-compartment pharmacokinetic model with transit absorption compartments was found to adequately describe brigatinib pharmacokinetics. In addition, the population pharmacokinetic analyses showed that no dose adjustment is required based on body weight, age, race, sex, total bilirubin (< 1.5× upper limit of normal), and mild-to-moderate renal impairment. Data from dedicated phase I trials have indicated that no dose adjustment is required for patients with mild or moderate hepatic impairment, while a dose reduction of approximately 40% (e.g., from 180 to 120 mg) is recommended for patients with severe hepatic impairment, and a reduction of approximately 50% (e.g., from 180 to 90 mg) is recommended when administering brigatinib to patients with severe renal impairment. Brigatinib is primarily metabolized by cytochrome P450 (CYP) 3A, and results of clinical drug–drug interaction studies and physiologically based pharmacokinetic analyses have demonstrated that coadministration of strong or moderate CYP3A inhibitors or inducers with brigatinib should be avoided. If coadministration with a strong or moderate CYP3A inhibitor cannot be avoided, the dose of brigatinib should be reduced by approximately 50% (strong CYP3A inhibitor) or approximately 40% (moderate CYP3A inhibitor), respectively. Brigatinib is a weak inducer of CYP3A in vivo; data from a phase I drug–drug interaction study showed that coadministration of brigatinib 180 mg once daily reduced the oral midazolam area under the plasma concentration–time curve from time zero to infinity by approximately 26%. Brigatinib did not inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, or CYP2D6 at clinically relevant concentrations in vitro. Exposure–response analyses based on data from the ALTA (ALK in Lung Cancer Trial of AP26113) and ALTA-1L pivotal trials of brigatinib confirm the favorable benefit versus risk profile of the approved titration dosing regimen of 180 mg once daily (after a 7-day lead-in at 90 mg once daily). [ABSTRACT FROM AUTHOR]

Optimizing Ponatinib Treatment in CP‐CML (OPTIC) was a randomized, phase II dose‐optimization trial of ponatinib in chronic phase‐chronic myeloid leukemia (CP‐CML) resistant to ≥ 2 tyrosine kinase inhibitors or with T315I mutation. Patients were randomized to starting doses of 45‐, 30‐, or 15‐mg ponatinib once daily. Patients receiving 45‐ or 30‐mg reduced to 15‐mg upon achievement of ≤ 1% BCR::ABL1IS (≥ molecular response with 2‐log reduction (MR2)). The exposure‐molecular response relationship was described using a four‐state, discrete‐time Markov model. Time‐to‐event models were used to characterize the relationship between exposure and arterial occlusive events (AOEs), grade ≥ 3 neutropenia, and thrombocytopenia. Increasing systemic exposures were associated with increasing probability of transitioning from no response to ≥ MR1, and from MR1 to ≥ MR1, with odds ratios of 1.63 (95% confidence interval (CI), 1.06–2.73) and 2.05 (95% CI, 1.53–2.89) for a 15‐mg dose increase, respectively. Ponatinib exposure was a significant predictor of AOEs (hazard ratio (HR) 2.05, 95% CI, 1.43–2.93, for a 15‐mg dose increase). In the exposure‐safety models for neutropenia and thrombocytopenia, exposure was a significant predictor of grade ≥ 3 thrombocytopenia (HR 1.31, 95% CI, 1.05–1.64, for a 15‐mg dose increase). Model‐based simulations predicted a clinically meaningful higher rate of ≥ MR2 response at 12 months for the 45‐mg starting dose (40.4%) vs. 30‐mg (34%) and 15‐mg (25.2%). The exposure–response analyses supported a ponatinib starting dose of 45 mg with reduction to 15 mg at response for patients with CP‐CML. [ABSTRACT FROM AUTHOR]

Ixazomib has been approved in several countries as single‐agent maintenance therapy in newly diagnosed multiple myeloma, in both posttransplant and transplant‐ineligible settings, based on two phase III studies. In these maintenance studies, patients were initially administered 3 mg ixazomib, escalating to 4 mg if the initial dose level was well tolerated through Cycles 1–4. Here, we report the results of exposure–response analyses of TOURMALINE‐MM4, wherein relationships between exposure and clinical response, dose adjustments, and selected adverse events were evaluated. Similar progression‐free survival benefits were observed across the range of ixazomib exposures achieved in the study. Moreover, increased ixazomib exposures corresponded to a higher probability of maintaining complete response. Exposure was not a significant predictor (P > 0.05) of hematological adverse events (anemia, neutropenia, thrombocytopenia) and peripheral neuropathy; however, higher exposures did correlate to increased probabilities of experiencing diarrhea, vomiting, nausea, rash, and fatigue. While ixazomib exposure was not predictive of dose reductions, lower apparent clearance values (corresponding to higher systemic exposures) were correlated with a reduced likelihood of escalating to the 4 mg dose. Thus, the dose titration approach balanced patient benefit and risk; it ensured that only patients for whom the 3 mg dose was safe/tolerable escalated to the higher dose, while maximizing the fraction of patients (85%) who were able to derive additional clinical benefit at 4 mg. Collectively, these results highlight the value of safety‐driven personalized dosing to maximize patient benefit/risk. [ABSTRACT FROM AUTHOR]

Brigatinib is a next‐generation anaplastic lymphoma kinase (ALK) inhibitor approved for the treatment of patients with ALK‐positive (ALK+) non–small cell lung cancer (NSCLC). A phase 1 drug‐drug interaction study was conducted to evaluate the effect of multiple‐dose administration of brigatinib on the single‐dose pharmacokinetics of midazolam, a sensitive cytochrome P450 3A substrate. In cycle 1, patients with ALK+ or ROS1+ solid tumors, including NSCLC, received a single 3‐mg dose of midazolam as an oral solution alone on day 1 and then coadministered with brigatinib on day 21 (brigatinib 90 mg once daily on days 2‐8; 180 mg once daily on days 9‐28). After cycle 1, patients could continue to receive brigatinib in 28‐day treatment cycles. The primary study objective was to characterize the effect of brigatinib 180 mg once daily on midazolam pharmacokinetics. The secondary objective was to assess safety. Exploratory efficacy endpoints included objective response rate and progression‐free survival. Brigatinib was generally well tolerated, and safety data were consistent with the known safety profile. Among the 10 patients with ALK+ NSCLC, the confirmed objective response rate was 30% and median progression‐free survival was 7.2 months. Coadministration of brigatinib reduced midazolam maximum observed plasma concentration by ≈16% (geometric least‐squares mean ratio, 0.836 [90%CI, 0.662‐1.056]) and area under the plasma concentration–time curve from time 0 to infinity by ≈26% (geometric least‐squares mean ratio, 0.741 [90%CI, 0.600‐0.915]). Thus, brigatinib is a weak inducer of cytochrome P450 3A in vivo. [ABSTRACT FROM AUTHOR]

Ixazomib is an oral proteasome inhibitor approved in combination with lenalidomide and dexamethasone for the treatment of relapsed/refractory multiple myeloma (MM). Approval in the United States, Europe, and additional countries was based on results from the phase III TOURMALINE‐MM1 (C16010) study. Here, joint population pharmacokinetic/pharmacodynamic time‐to‐event (TTE) and discrete time Markov models were developed to describe key safety (rash and diarrhea events, and platelet counts) and efficacy (myeloma protein [M‐protein] and progression‐free survival [PFS]) outcomes observed in TOURMALINE‐MM1. Models reliably described observed safety and efficacy results; prior immunomodulatory drug therapy and race were significant covariates for diarrhea and rash events, respectively, whereas M‐protein dynamics were sufficiently characterized using TTE models of relapse and dropout. Moreover, baseline M‐protein was identified as a significant covariate for observed PFS. The developed framework represents an integrated approach to describing safety and efficacy with MM therapy, enabling the simulation of prospective trials and potential alternate dosing regimens. [ABSTRACT FROM AUTHOR]