Abstract P4-16-11: Phase I trial of afatinib plus vinorelbine in Japanese patients with advanced solid tumors including breast cancer

Background: Afatinib, a potent irreversible ErbB Family Blocker, inhibits signaling from HER1, HER2 and HER4 dimers, and transphosphorylation of HER3. A Phase I trial was conducted to assess if afatinib 40 mg/day in combination with vinorelbine (VNR) 25 mg/m2 i.v. weekly could be safely administered to Japanese patients (pts).

Patients and methods: The safety, tolerability and pharmacokinetics (PK) of daily oral afatinib plus weekly i.v. VNR in a 28-day cycle in Japanese pts was assessed using a 3+3 design. The primary endpoint was to determine the maximum tolerated dose (MTD), based on dose-limiting toxicities (DLTs) in Cycle 1 (see Table; dose Levels 1 and 2). When the MTD was exceeded, dose Levels 2a and 3 allowed modifications of VNR dosing as used in clinical practice. Eligible pts were ≥20 years old with histologically confirmed refractory advanced/metastatic solid tumours, and an ECOG performance status (PS) 0-1. Adverse events (AEs) were documented as per NCI CTCAE v3.0. Response was assessed using RECIST 1.1, and PK parameters for both drugs were analyzed by intra-individual comparison, based on frequent blood sampling.

Results: Seventeen pts were recruited. Median age was 60 (range 40-68) years, all pts had received previous chemotherapy, and 7/9 pts with BC had received HER2-targeted therapy. No DLTs were observed at dose Level 1. When 3/5 pts developed DLTs in Cycle 1 at an afatinib dose of 40 mg in Level 2 (see Table), an intermediate cohort 2a was introduced at 20 mg/m2 VNR i.v. weekly. Tolerability at Level 2a was confirmed. With afatinib dose modification permitted, and VNR dose skipping allowed for ANC <1500/mm3, dose re-escalation to VNR 25mg/m2 i.v. weekly at Level 3 was performed to establish a recommended phase II dose. At Level 3, 7/24 planned doses of VNR were skipped due to Grade 2 and 3 neutropenia, not qualifying as DLTs. One DLT occurred in a pt with Grade 2 epigastralgia in Course 1, who required afatinib dose reduction. Overall, the most frequent drug-related AEs were leukopenia, neutropenia (100% each), diarrhea (94%), anemia (70%), stomatitis (64%) and rash (41%). Nine BC pts were treated in cohorts 2a and 3, and all experienced diarrhea, leukopenia and neutropenia. No PK drug-drug interactions between afatinib and VNR were observed. Safety and PK profiles did not appear to differ between Japanese pts and Caucasian pts in a previous Phase I study. Two pts with BC and prior trastuzumab treatment had partial responses. Tumor shrinkage was observed in four of six evaluable BC pts, but not in other tumor types.

Conclusions: Afatinib 40 mg/day plus vinorelbine 25 mg/m2/week was tolerable and showed early signs of clinical activity in Japanese pts. AEs were as expected and were managed by dose modifications of both compounds. Final data will be presented at this congress.

Dose LevelsAfatinibVinorelbineN treatedDLTs (n)120 mg/day25 mg/m2/week3None240 mg/day25 mg/m2/week5Grade 4 neutropenia for 7 days (1); Grade 3 febrile neutropenia (1); Grade 3 pharyngeal infection with Grade 4 lipase and amylase elevations (1)2a40 mg/day20 mg/m2/week3 (all BC)None340 mg/day25 mg/m2/week6 (all BC)Grade 2 epigastralgia (1)

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-16-11.

Phase I study of pulsatile 3-day administration of afatinib (BIBW 2992) in combination with docetaxel in advanced solid tumors

BACKGROUND

A phase I study to assess the maximum tolerated dose (MTD) of a short course of afatinib in combination with docetaxel for the treatment of solid tumors.

METHODS

Patients with advanced solid malignancies received docetaxel 75 mg/m(2) intravenously on day 1 and oral afatinib once daily on days 2-4, in 3-week treatment cycles. The afatinib dose was escalated in successive cohorts of 3-6 patients until dose-limiting toxicity (DLT). The MTD cohort was expanded to 13 patients. Pharmacokinetic parameters were assessed.

RESULTS

Forty patients were treated. Afatinib doses were escalated to 160 mg/day in combination with 75 mg/m(2) docetaxel. Three patients had drug-related DLTs during cycle 1. The MTD was defined as 90 mg/day afatinib (days 2-4) with docetaxel 75 mg/m(2). The most frequent drug-related adverse events (all grades) were alopecia, diarrhea, stomatitis (all 50 %) and rash (40 %, all grade ≤ 2). Three patients had confirmed responses, two patients had unconfirmed responses and nine patients had durable stable disease >6 cycles. No pharmacokinetic interaction was observed.

CONCLUSION

Afatinib 90 mg administered for 3 days after docetaxel 75 mg/m(2) is the MTD for this treatment schedule and the recommended phase II/phase III dose. This combination showed anti-tumor activity in phase I, with a manageable adverse-event profile.

Abstract OT1-1-17: LUX-Breast 2: Phase II, open-label study of oral afatinib in HER2-overexpressing metastatic breast cancer (MBC) patients (pts) who progressed on prior trastuzumab and/or lapatinib*

Background: Management of HER2-overexpressing MBC has improved over the past decade. However, pts still develop resistance to currently available HER2-targeted therapies and novel effective treatments are increasingly required as dual targeted combinations are given in early treatment lines already. Current therapies focus on targeting HER2 and do not inhibit all relevant ErbB Family dimers. Afatinib is an oral, irreversible ErbB Family Blocker that inhibits signaling through activated EGFR (ErbB1), HER2 (ErbB2) and ErbB4 receptors and transphosphorylation of ErbB3. Preclinical studies have demonstrated efficacy in trastuzumab-sensitive, and trastuzumab-resistant human BC xenograft models dependent on ErbB signaling. Efficacy of afatinib in a trastuzumab-resistant SUM190 xenograft model has been shown to be increased by addition of intravenous (i.v.) vinorelbine. Afatinib monotherapy has shown promising clinical benefit in 46% of HER2-overexpressing MBC pts who progressed on prior trastuzumab, with 10% of pts achieving a partial response.1

Methods: This open-label Phase II trial (NCT01271725) investigates efficacy and safety of afatinib alone (40 mg/day) followed by afatinib ‘beyond progression’ in combination with chemotherapy in 120 pts with HER2-overexpressing MBC, who progressed on prior neoadjuvant and/or adjuvant trastuzumab and/or lapatinib. Pts who progress on afatinib monotherapy receive afatinib + either weekly paclitaxel 80 mg/m2 or vinorelbine i.v. 25 mg/m2. Eligible pts have confirmed HER2-overexpressing BC, Stage IV disease measurable by RECIST 1.1, progressed on trastuzumab and/or lapatinib therapy in either neoadjuvant and/or adjuvant setting, are eligible for retreatment with paclitaxel (i.e. should not have been pretreated with paclitaxel within the past 12 months), or are eligible for treatment with vinorelbine (i.e. should not have been pretreated with vinorelbine). Exclusion criteria include inadequate cardiac, renal, hepatic and hematological function, pre-existing gastrointestinal dysfunction, rapidly progressing visceral MBC, interstitial lung disease, and active brain metastases. The primary endpoint is objective response (OR) and secondary endpoints include best overall response, duration of OR, progression-free survival (PFS) and safety. PFS and safety will be assessed separately for afatinib mono- and combination therapy. An early stopping rule was deployed to minimize the number of pts treated should afatinib be ineffective; once 20 evaluable pts (according to RECIST 1.1) completed at least two courses of afatinib (or progressed during the first course), a meeting was held to evaluate the objective tumor response rate and to decide whether to proceed with the trial or stop due to futility. If at least one unconfirmed OR had been witnessed from all available information at the time, then the trial was to continue to full accrual. This early stopping rule for futility has been passed and the trial will continue to full accrual. Pt enrollment began in May 2011 in ∼40 sites and five countries.

1. Lin NU, et al. Breast Cancer Res Treat 2012. DOI: 10.1007/s10549-012-2003-y.

*Updated abstract from ASCO 2012.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT1-1-17.

Use of BIBW 2992, a novel irreversible EGFR/HER2 tyrosine kinase inhibitor (TKI), to treat patients with HER2-positive metastatic breast cancer after failure of treatment with trastuzumab

1023

Background: BIBW 2992 (Tovok) is an oral, novel, and potent, irreversible dual epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor-2 (HER2) inhibitor, with preclinical activity in trastuzumab-resistant cell lines overexpressing HER2 and phase I clinical activity. A phase II study of BIBW 2992 in patients with HER2-positive breast cancer who have failed treatment with trastuzumab is currently being conducted in the US and the UK. Methods: This is a multi-institutional open label single arm phase II study, planning to recruit 40 patients. Eligibility criteria include stage IIIB or IV HER2-positive metastatic breast cancer, progression following receipt of trastuzumab or intolerance of trastuzumab, measurable disease, Eastern Cooperative Oncology Group (ECOG) performance status of 0–2 and adequate organ function. Patients receive 50 mg BIBW 2992 once daily until disease progression. Tumor assessments are performed every two courses (one course = 28 days). The primary endpoint is objective response rate (RECIST criteria). Safety data are also collected. Results: To date, 40 patients have started treatment on the trial. Patients had received a median of three lines of prior therapy. Nine patients discontinued treatment prior to the first assessment at 8 weeks; four due to disease progression, four due to adverse events and one due to withdrawal of consent. Twenty-one patients have had tumor assessment after 8 weeks of treatment. Of these, four patients had a partial response (PR) and 10 patients had stable disease (SD). The PR has been confirmed at 16 weeks in one patient. The most frequently observed side effects to date are rash (Common Toxicity Criteria for Adverse Events [CTCAE] grade 3 in 4 patients) and diarrhea (CTCAE grade 3 in 8 patients). There were 20 dose reductions in 17 patients. Conclusions: BIBW 2992 at 50 mg/day induced responses and seems promising in HER2-positive breast cancer patients who have failed treatment with trastuzumab. Manageable cutaneous adverse events and diarrhea were the main side effects.

[Table: see text]

A phase I dose finding study of the 3-day administration of BIBW 2992, an irreversible dual EGFR/HER-2 inhibitor, in combination with three-weekly docetaxel in patients with advanced solid tumors

3556

Background: BIBW 2992 (Tovok) is a potent, irreversible, new generation TKI, an inhibitor of EGFR and HER-2 (IC50 0.5 and 14 nM, respectively). A Phase I dose finding study of BIBW 2992 with docetaxel is reported. Methods: Patients (pts) had advanced solid malignancies and received docetaxel 75 mg/m2 i.v. on Day 1 and oral BIBW 2992 once daily on Days 2–4, in 3-week cycles. The BIBW 2992 dose was doubled in successive cohorts of 3–6 pts until ≥Grade 2 CTC, after which dose escalation occurred in increments of ≤50%. The MTD cohort expanded to 12 pts. PK profiles were taken on Days 1 and 2 of treatment cycles 1 and 2. Results: 40 evaluable pts (17 male) were treated at the following doses of BIBW 2992: 10 mg (6), 20mg (3), 40 mg (6), 60 mg (4), 90 mg (13), 120 mg (5) and 160 mg (3). Common adverse events (AEs) (% of patients) were fatigue (62.5%), diarrhea (57.5%), anorexia and stomatitis (52.5%), alopecia (50%), rash (42.5%), nausea and pyrexia (40%), vomiting (35%), general physical health deterioration (32.5%), and peripheral sensory neuropathy (30%). Two DLTs occurred: one pt had Grade 4 neutropenia (a DLT if complicated or lasting >5 or 7 days) and one had Grade 3 nausea, vomiting and diarrhea (BIBW 2992 120 mg). Both fully recovered upon treatment interruption/dose reduction (docetaxel 60 mg/m2/BIBW 2992 90 mg). The MTD was 90 mg BIBW 2992 with docetaxel 75 mg/m2. Four pts (breast cancer [2], thymoma [1], oesophageal carcinoma [1]) had a PR. One breast cancer pt had a confirmed CR. Two of these pts had prior taxane treatment. Ten pts had SD and received treatment for ≥6 courses with 4 receiving treatment for ≥9 courses. There was no deviation from dose-linearity of BIBW 2992 and docetaxel. Docetaxel (75 mg/m2) plasma concentration-time profiles, Cmax and AUC0-∞ before and after BIBW 2992 dosing were comparable. Conclusions: BIBW 2992 90mg administered for 3 days after docetaxel 75 mg/m2 is well tolerated and is the recommended dose for further trials. Objective responses or durable SD (≥6 months) were seen in 15 (39%) pts. No PK interaction was observed between BIBW 2992 and docetaxel.

[Table: see text]