Venetoclax is a selective, first-in-class, B-cell lymphoma-2 inhibitor that has demonstrated clinical efficacy in several hematological malignancies. Two studies evaluated the relative bioavailability of venetoclax in healthy subjects: (1) a bioequivalence study to compare the bioavailability of the film-coated tablet with that of an earlier uncoated tablet and (2) a food effect study to evaluate the effect of food on venetoclax pharmacokinetics. Both studies were open-label, single-dose, crossover studies. In the bioequivalence study, 15 subjects received a single dose of venetoclax 50 mg under nonfasting conditions, in each of 2 periods; one period used the uncoated tablet, and the other used the film-coated tablet. In the food effect study, 24 subjects received a single dose of venetoclax film-coated 100-mg tablet under fasting conditions, after a low-fat breakfast or after a high-fat breakfast in different periods. The venetoclax film-coated tablet was bioequivalent to the uncoated tablet, which indicates that the film coating does not affect bioavailability. The median T of venetoclax was delayed by about 2 hours when administered with food. Compared with fasting conditions, C and AUC increased by approximately 3.4-fold following a low-fat breakfast. High-fat meals increased C and AUC by approximately 50% relative to low-fat meals. The mean terminal half-life was comparable between the high-fat meal and fasting conditions (19.1 versus 16.1 hours). Based on these results and the venetoclax exposure-response profile, venetoclax should be administered with food and without specific recommendations for fat content to ensure adequate and consistent bioavailability.

PURPOSE Targeting the BCL-XL pathway has demonstrated the ability to overcome Janus kinase inhibitor resistance in preclinical models. This phase II trial investigated the efficacy and safety of adding BCL-XL/BCL-2 inhibitor navitoclax to ruxolitinib therapy in patients with myelofibrosis with progression or suboptimal response to ruxolitinib monotherapy ( NCT03222609 ). METHODS Thirty-four adult patients with intermediate-/high-risk myelofibrosis who had progression or suboptimal response on stable ruxolitinib dose (≥ 10 mg twice daily) were administered navitoclax at 50 mg once daily starting dose, followed by escalation to a maximum of 300 mg once daily in once in weekly increments (if platelets were ≥ 75 × 109/L). The primary end point was ≥ 35% spleen volume reduction (SVR35) from baseline at week 24. Secondary end points included ≥ 50% reduction in total symptom score (TSS50) from baseline at week 24, hemoglobin improvement, change in bone marrow fibrosis (BMF) grade, and safety. RESULTS High molecular risk mutations were identified in 58% of patients, and 52% harbored ≥ 3 mutations. SVR35 was achieved by 26.5% of patients at week 24, and by 41%, at any time on study, with an estimated median duration of SVR35 of 13.8 months. TSS50 was achieved by 30% (6 of 20) of patients at week 24, and BMF improved by 1-2 grades in 33% (11 of 33) of evaluable patients. Anemia response was achieved by 64% (7 of 11), including one patient with baseline transfusion dependence. Median overall survival was not reached with a median follow-up of 21.6 months. The most common adverse event was reversible thrombocytopenia without clinically significant bleeding (88%). CONCLUSION The addition of navitoclax to ruxolitinib in patients with persistent or progressive myelofibrosis resulted in durable SVR35, improved TSS, hemoglobin response, and BMF. Further investigation is underway to qualify the potential for disease modification.

Metronomic dosed (MD) chemotherapy as opposed to conventional dosed (CD) chemotherapy is considered an alternate strategy to target angiogenesis and limit host toxicity. Although this approach is promising, there has not been any attempt to define optimal metronomic dosing regimens by integrating pharmacokinetic (PK) with pharmacodynamic (PD) measurements. The aim of this study was to compare the pharmacokinetics and pharmacodynamics of temozolomide [TMZ, 8-carbamoyl-3-methylidazo(5,1-d)-1,2,3,5-terrazin-4(3H)-one] after MD and CD regimens. In vivo studies were carried out in xenografted athymic rats treated with either 18 mg/kg/day TMZ for 5 days or 3.23 mg/kg/day TMZ for 28 days. PK studies were performed on the first and last days of dosing. PD measurements consisted of gene and protein expression of various angiogenic markers, tumor size, tumor pH, and interstitial fluid pressure (IFP). The results demonstrated that the PK parameters (total clearance, volume of distribution, and tumor/plasma accumulation) were quite similar for MD and CD groups, consistent with the linear PK properties of TMZ. Both TMZ treatment schedules caused a significant decrease in IFP and tumor size compared with vehicle control treatment, demonstrating comparable effectiveness of MD and CD regimens. Using real-time polymerase chain reaction and Western blot analyses, some differences were noted in expression levels of vascular endothelial growth factor and hypoxia inducible factor-1␣, suggesting that the MD regimen may be superior to the CD regimen by preventing tumors from progressing to a proangiogenic state. In conclusion, several PK/PD factors contributing to the antitumor activity of the MD TMZ therapy have been identified and form a foundation for further investigations of low-dose TMZ regimens.

Purpose: This study examined safety, pharmacokinetics, and efficacy of veliparib, a PARP inhibitor, combined with carboplatin and etoposide in patients with extensive-stage (ED) small cell lung cancer (SCLC) and other solid tumors. Patients and Methods: The 3 þ 3 design was used for dose escalation of oral veliparib in combination with carboplatin (AUC 5 on day 1) and etoposide (100 mg/m 2 on days 1-3) in 21-day cycles. Veliparib dose was explored from 80 to 240 mg b.i.d. on 7-day, 14-day, or continuous schedules. Patients without disease progression continued on maintenance monotherapy (veliparib 400 mg b.i.d.) until disease progression or unacceptable toxicity. Results: Thirty-nine patients were enrolled to determine the recommended phase II dose of 240 mg veliparib for 14 days combined with carboplatin and etoposide based on long-term tolerability. Dose-limiting toxicity occurred in 1 patient (grade 2 toxic motor polyneuropathy) at veliparib 240 mg b.i.d. for 7 days. Most common adverse events related to veliparib were nausea (39%), fatigue (39%), and hematologic toxicities. Continuous dosing of veliparib 240 mg b.i.d. with carboplatin and etoposide resulted in excessive chemotherapy dose delays due to hematologic toxicity (grade 3/4 neutropenia/thrombocytopenia). Etoposide pharmacokinetics was not affected by veliparib. Confirmed responses occurred in 17 of 39 (44%) and 16 of 25 (64%) of all enrolled and ED SCLC patients, respectively. At the RP2D, confirmed responses occurred in 6 of 13 (46%) and 5 of 6 (83%) of all enrolled and ED SCLC patients, respectively. Conclusions: Veliparib (240 mg b.i.d. 14 days) plus carboplatin/etoposide can be safely combined. Phase II of this study is ongoing in first-line patients with ED SCLC.

Veliparib (ABT‐888) is a potent, orally bioavailable poly(ADP‐ribose) polymerase‐1 and ‐2 inhibitor. This phase 1 study evaluated the tolerability, pharmacokinetic profile, safety, and preliminary antitumor activity of single‐agent veliparib in Japanese patients with advanced solid tumors. Eligible patients were assigned to treatment with veliparib at 200 or 400 mg dose; veliparib was self‐administered orally twice daily on days 1–28 of 28‐day cycles. Dose escalation, following a 3 + 3 design, defined dose‐limiting toxicities, the maximum tolerated dose, and the recommended phase 2 dose. Sixteen patients were enrolled (median age, 59 years). Fourteen patients had high‐grade serous ovarian cancer, one had primary peritoneal cancer, and one had BRCA‐mutated breast cancer. The most frequent treatment‐emergent adverse events were nausea and vomiting (93.8% each), decreased appetite (62.5%), abdominal pain, diarrhea, and malaise (31.3% each). A grade ≥3 toxicity was observed in 50% of patients; one patient each in the 200 mg (n = 4) and 400 mg (n = 12) cohorts experienced serious adverse events. Dose‐limiting toxicities were observed for one patient at the 400 mg dose. No toxicities leading to death were reported. The recommended phase 2 dose was defined as 400 mg twice daily. The veliparib pharmacokinetic profile was consistent with that reported for the Western population. Two patients, both with ovarian cancer, had a RECIST partial response. Veliparib monotherapy showed manageable tolerability and safety profiles and a predictable pharmacokinetic profile at a 400 mg twice‐daily dose, and supports the inclusion of Japanese patients in the multinational phase 3 study (NCT02470585).