Phase I study of continuous olaparib capsule dosing in combination with carboplatin and/or paclitaxel (Part 1)

Background The PARP inhibitor olaparib has shown acceptable toxicity at doses of up to 400 mg twice daily (bid; capsule formulation) with encouraging signs of antitumor activity. Based on its mode of action, olaparib may sensitize tumor cells to DNA-damaging agents. This Phase I trial (NCT00516724) evaluated the safety, pharmacokinetics (PK) and preliminary efficacy of olaparib combined with carboplatin and/or paclitaxel. Methods Patients with advanced solid tumors received olaparib (capsule bid) plus carboplatin (Part A), carboplatin and paclitaxel (Part B), or paclitaxel (Part C). In each part of the study, different drug doses were given to define the most appropriate dose/drug combination to use in further studies. Safety assessments included evaluation of dose-limiting toxicities (DLTs; cycle 1 only), adverse events (AEs) and physical examinations. PK assessments of olaparib, carboplatin and paclitaxel were performed. Tumor responses (RECIST) were assessed every two cycles. Results Fifty-seven patients received treatment. DLTs were reported in two patients (both receiving olaparib 100 mg bid and carboplatin AUC 4; Part A, cohort 2): grade 1 thrombocytopenia with grade 2 neutropenia lasting for 16 days, and grade 2 neutropenia lasting for 7 days. Non-hematologic AEs were predominantly grade 1-2 and included fatigue (70%) and nausea (40%). Bone marrow suppression, mainly neutropenia (51%) and thrombocytopenia (25%), frequently led to dose modifications. Conclusions Olaparib in combination with carboplatin and/or paclitaxel resulted in increased hematologic toxicities, making it challenging to establish a dosing regimen that could be tolerated for multiple cycles without dose modifications.

Phase I study of intermittent olaparib capsule or tablet dosing in combination with carboplatin and paclitaxel (part 2)

Background In the first part of this extensive phase I study (NCT00516724), continuous olaparib twice daily (bid) with carboplatin and/or paclitaxel resulted in myelosuppression and dose modifications. Here, we report the safety, tolerability, and efficacy of intermittent olaparib dosing combined with carboplatin and paclitaxel. Methods Patients with advanced solid tumors (part D) and enriched for ovarian and breast cancer (part E) received olaparib (capsule and tablet formulations) using intermittent schedules (2 to 10 days of a 21-day cycle) combined with carboplatin/paclitaxel. Safety assessments included evaluation of dose-limiting toxicities (DLTs; cycle 1 only), adverse events (AEs), and physical examinations. Pharmacokinetic assessments of olaparib capsule and tablet combined with carboplatin/paclitaxel were performed. Tumor responses (RECIST) were assessed every 2 cycles. Results In total, 132 heavily pre-treated patients were included. One DLT of grade 3 elevated alanine aminotransferase lasting for 8 days was reported (olaparib tablet 100 mg bid days 3-12, carboplatin area under the curve 4 and paclitaxel 175 mg/m²). The most common hematological AEs were neutropenia (47%) and thrombocytopenia (39%), which frequently led to dose modifications. Non-hematological AEs were predominantly grade 1-2, including alopecia (89%) and fatigue (84%). Overall objective response rate was 46%. Conclusions Discontinuous dosing of olaparib resulted in significant myelosuppression leading to dose interruptions and/or delays. Anti-tumor activity was encouraging in patients enriched with BRCA-mutated breast and ovarian cancer. The most appropriate olaparib tablet dose for use in further studies evaluating olaparib in combination with carboplatin and paclitaxel is 50 mg bid (days 1-5).

Basket of baskets (BoB): A modular, open label, phase II, multicenter study to evaluate targeted agents in molecularly selected populations with advanced solid tumors

TPS3151

Background: Basket trials with targeted agents can show high response rates for tumors with specific molecular profiles, granting extension of the label of some drugs. In other cases, study results were disappointing, likely due to the rarity of molecular alterations, limits in trial design and the difficulties in applying molecular tumor profiling in the clinical setting. Methods: Basket of Baskets (BoB), NCT03767075, aims to bridge the gap between Academic Genomics and clinical applications (ready-to market multi-marker Companion Diagnostics) by providing a sustainable and adaptable (to new technologies, markers, and therapeutic agents) platform for co-development of drug/companion diagnostic. BoB is a novel platform trial from Cancer Core Europe, a recently established sustainable European network for innovative cancer research. This protocol has two parts: (1) Part A includes a molecular profiling program for subjects with advanced solid tumors (iPROFILER), a variant annotation tool, and a molecular tumor board to select the most appropriate treatment. It also enables testing/developing companion diagnostics linked with the therapeutic part (part B). (2) Part B includes iBASKET, a modular multi-arm basket trial for subjects with tumors harboing selected molecular alterations. Each module is focused on a certain molecular pathway or on certain molecular alterations that may confer sensitivity to the study drug or study drug combination evaluated in that module/arm. The current version of iBASKET (Module 1- Atezolizumab in genomically-selected patients) is open for enrollment for patients with advanced neoplasms bearing one of the following alterations: Arm 1A: BRCA1 or BRCA2; Arm 1B: MLH1, MSH2, MSH6, PMS2; Arm 1C: POLE, POLD1 mutations; Arm 1D: hypermutated tumors; Arm 1E: other mutations in DNA-repair genes; Arm 1F: PDL1 gene amplification. All patients enrolled in Module 1 will receive single-agent atezolizumab. New Modules for genomically selected populations can be added through amendments. Our final aim is to achieve drug repurposing of treatments, co-develop multi-marker companion diagnostics and a large database of knowledge in Precision Medicine. Clinical trial information: NCT03767075.

A Phase I Dose-Escalation Study of the Safety and Pharmacokinetics of Pictilisib in Combination with Erlotinib in Patients with Advanced Solid Tumors

BACKGROUND

Epidermal growth factor receptor (EGFR) and phosphatidylinositol 3-kinase (PI3K) are involved in the proliferation and survival of many cancer types. Enhanced antitumor activity may be achieved through combined inhibition of these pathways. We report results for pictilisib (GDC-0941, a class I pan-PI3K inhibitor) plus erlotinib (an EGFR tyrosine kinase inhibitor) in patients with advanced solid tumors.

MATERIALS AND METHODS

A 3 + 3 dose-escalation study was carried out at a starting daily dose of 60 mg pictilisib on days 1-21 of a 28-day cycle and 150 mg erlotinib from day 2 of cycle 1. The primary objectives of the study were to assess safety and tolerability, identify dose-limiting toxicities (DLTs), estimate the maximum tolerated dose, and identify the recommended phase II dose (RP2D). Evaluation of a dose-expansion cohort at the RP2D was performed.

RESULTS

Fifty-seven patients were treated in the study. All patients experienced at least one adverse event (AE). Grade ≥3 AEs, serious AEs, and deaths were reported in 38 (66.7%), 19 (33.3%), and 4 (7.0%) patients, respectively. DLTs occurred in nine patients across eight cohorts and the RP2D was determined to be 340 mg pictilisib on a "5 days on, 2 days off" schedule plus 100 mg erlotinib. Two patients (3.5%) experienced partial response and 19 (33.3%) had stable disease.

CONCLUSION

Combining pictilisib with erlotinib in patients with advanced solid tumors is feasible; however, antitumor activity is limited. Additional studies may identify patients likely to benefit from combined inhibition of EGFR and PI3K pathways.

IMPLICATIONS FOR PRACTICE

Combining drugs targeting different signaling pathways in cancer growth and survival could overcome drug resistance and improve antitumor activity. In this first-in-human study for the combination, addition of the PI3K inhibitor pictilisib to the EGFR tyrosine kinase inhibitor erlotinib resulted in toxicity that led to dose and schedule modifications to identify a tolerable recommended phase II dose of 340 mg pictilisib on a "5 days on, 2 days off" schedule plus 100 mg erlotinib daily. The limited antitumor activity observed, however, suggests that additional studies are needed to identify patients most likely to benefit from combined EGFR and PI3K inhibition.

First-in-Human Phase I Study of GSK2126458, an Oral Pan-Class I Phosphatidylinositol-3-Kinase Inhibitor, in Patients with Advanced Solid Tumor Malignancies

PURPOSE

GSK2126458 (GSK458) is a potent inhibitor of PI3K (α, β, γ, and δ), with preclinical studies demonstrating broad antitumor activity. We performed a first-in-human phase I study in patients with advanced solid tumors.

MATERIALS AND METHODS

Patients received oral GSK458 once or twice daily in a dose-escalation design to define the maximum tolerated dose (MTD). Expansion cohorts evaluated pharmacodynamics, pharmacokinetics, and clinical activity in histologically and molecularly defined cohorts.

RESULTS

One hundred and seventy patients received doses ranging from 0.1 to 3 mg once or twice daily. Dose-limiting toxicities (grade 3 diarrhea,n= 4; fatigue and rash,n= 1) occurred in 5 patients (n= 3 at 3 mg/day). The MTD was 2.5 mg/day (MTD with twice daily dosing undefined). The most common grade ≥3 treatment-related adverse events included diarrhea (8%) and skin rash (5%). Pharmacokinetic analyses demonstrated increased duration of drug exposure above target level with twice daily dosing. Fasting insulin and glucose levels increased with dose and exposure of GSK458. Durable objective responses (ORs) were observed across multiple tumor types (sarcoma, kidney, breast, endometrial, oropharyngeal, and bladder cancer). Responses were not associated withPIK3CAmutations (OR rate: 5% wild-type vs. 6% mutant).

CONCLUSIONS

Although the MTD of GSK458 was 2.5 mg once daily, twice-daily dosing may increase duration of target inhibition. Fasting insulin and glucose levels served as pharmacodynamic markers of drug exposure. Select patients achieved durable responses; however,PIK3CAmutations were neither necessary nor predictive of response. Combination treatment strategies and novel biomarkers may be needed to optimally target PI3K.

Long-term safety and anti-tumour activity of olaparib monotherapy after combination with carboplatin and paclitaxel in patients with advanced breast, ovarian or fallopian tube cancer

BACKGROUND

Olaparib (AZD2281), a PARP-1/2 inhibitor, has been extensively investigated in clinical trials. However, limited clinical data are available about its long-term safety and anti-tumour activity.

METHODS

Patients had first participated in a phase I study of olaparib combined with carboplatin and/or paclitaxel. They continued with olaparib monotherapy in their best interest if they failed to tolerate the combination due to the treatment-related adverse events (TRAEs). Safety data were collected by physical examination and regular laboratory evaluations. Disease evaluations were performed by CT scan.

RESULTS

At data cutoff, 21 patients were included; 10 with breast, 9 with ovarian and 2 with fallopian tube cancer of whom 16 patients had a BRCA mutation (13 BRCA1; 3 BRCA2). TRAEs were mostly haematological and most prominent shortly after switching from combination to monotherapy, probably due to carry-over effects of chemotherapy. Over time, both severity and frequency of TRAEs decreased. Responses to olaparib were durable with a median treatment duration of 52 (range 7-183) weeks. In total, nine (43%) patients were still on study at data cutoff.

CONCLUSION

Continued long-term daily olaparib was found to be safe and tolerable. Encouragingly, patients who showed a favourable response on earlier combination therapy maintained this response on olaparib monotherapy.

A first-in-human study of the oral selective androgen receptor down-regulating drug (SARD) AZD3514 in patients with castration-resistant prostate cancer (CRPC)

4511

Background: AZD3514 is a first in class, orally bio-available drug that inhibits androgen-dependent and –independent androgen receptor (AR) signaling through two distinct mechanisms; inhibition of ligand-driven nuclear AR translocation and down-regulation of AR levels. Methods: A rolling six design was employed initially using a once a day (QD) schedule (A). PK assessments led to a change to twice daily (BD) dosing (B) to increase exposure. PK profiles were studied over 96 hours after a single dose and over 24 hours at start of/following 21 days continuous dosing. PD analyses included PSA and CTC quantification. Results: 49 CRPC patients (pts) have been treated with escalating doses of AZD3514 (A 35 pts, B 14 pts). Starting doses were 100 mg (A) and 1000 mg (B). The AZD3514 formulation was switched from capsules to tablets at 1000mg (QD). 2000mg BD was considered non-tolerable due to multiple grade 2 toxicities (nausea [N], vomiting [V], fatigue). No adverse events (AEs) met the DLT definition. The most frequent drug-related AE’s were N; G1/2 36/49 (73%), G3 2/49 (4%) and V; G1/2 24/49 (49%) & G3 3/49 (6%). N/V were managed with oral anti-emetics. Dose proportional increases in plasma concentrations were observed following a single dose. Geometric mean (%CV) Cmax and AUC at MTD were 9,608 (38.5) ng/mL and 61,734 (40.6) ng.hr/mL, respectively. Compared with single dose continuous dosing led to a mean decrease of 26% in exposure. Maximum PSA and CTC declines are summarized below. Objective soft tissue responses per RECIST1.1 were observed in 2/26 (8%) pts. One pt with abiraterone resistant disease remained on study for 19 months. At 6 and 12 months 21 (43%) and 8 (16%) pts remained on study without evidence of bone or soft tissue progression, respectively. Conclusions: AZD3514 has antitumor activity in patients with advanced CRPC. Clinical trial information: NCT01162395. [Table: see text]

Phase I study of olaparib in combination with carboplatin and/or paclitaxel in patients with advanced solid tumors

2579

Background: This three-center phase I study evaluated the PARP1/2 inhibitor olaparib (O) in combination with carboplatin (C), paclitaxel (Pa) or both (CPa) in patients (pts) with advanced solid tumors refractory to standard therapies (NCT00516724). Methods: This ongoing study consists of multiple parts (P) in which escalating doses of O capsule and tablet formulations were studied. Capsule formulation data are presented; continuous O with C (P1; 21 day cycle), CPa (P2a; 21 day cycle) and weekly Pa (P2b; 28 day cycle) or intermittent O with CPa (P3; 21 day cycle). Primary and secondary objectives were safety/tolerability and antitumor activity (RECIST), respectively. Results: This analysis (non validated data) included 87 enrolled pts (P1 [n=25] P2a [n=20] P2b [n=12] and P3 [n=30]). Most common tumor types were breast (26%), melanoma (10%) and ovarian (7%). 12 pts had known gBRCA1/2 mutations. A tolerable continuous dosing schedule of O with CPa was not determined. Most common AEs (all grades) were myelosuppression (71%) notably neutropenia (54%) and thrombocytopenia (26%), and fatigue (77%). Excessive treatment cycle delays due to hematologic toxicity occurred with continuous O combined with standard doses of C or CPa. Two doses were identified as tolerable: continuous O 100 mg bd with weekly Pa 80 mg/m2 and intermittent O 200 mg bd (d1–10) with CPa AUC4/175 mg/m2 q 3 weeks. 14/87 pts (16%) had an objective response (complete response [CR] 5%; partial response [PR] 11%); 28% had stable disease for ≥4 months. Activity appeared greater in pts with BRCA1/2 mutations (CR 17%; PR 33%). Conclusions: Continuous O in combination with CPa exacerbated hematologic toxicities leading to schedule delays. Tolerability improved with intermittent O. Antitumor activity was highest in pts with a BRCA1/2 mutation. This study identified two tolerable O capsule treatment schedules for further development. Clinical trial information: NCT00516724. [Table: see text]