Ponatinib is a potent oral tyrosine kinase inhibitor (TKI) approved for patients with refractory CML/Ph+ ALL, or with T315I. In first- and second-line settings with other TKIs, landmark responses have been correlated with positive long-term outcomes; data are limited for heavily pretreated populations.

BACKGROUND Ponatinib is a potent oral tyrosine kinase inhibitor of unmutated and mutated BCR-ABL, including BCR-ABL with the tyrosine kinase inhibitor-refractory threonine-to-isoleucine mutation at position 315 (T315I). We conducted a phase 2 trial of ponatinib in patients with chronic myeloid leukemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL). METHODS We enrolled 449 heavily pretreated patients who had CML or Ph-positive ALL with resistance to or unacceptable side effects from dasatinib or nilotinib or who had the BCR-ABL T315I mutation. Ponatinib was administered at an initial dose of 45 mg once daily. The median follow-up was 15 months. RESULTS Among 267 patients with chronic-phase CML, 56% had a major cytogenetic response (51% of patients with resistance to or unacceptable side effects from dasatinib or nilotinib and 70% of patients with the T315I mutation), 46% had a complete cytogenetic response (40% and 66% in the two subgroups, respectively), and 34% had a major molecular response (27% and 56% in the two subgroups, respectively). Responses were observed regardless of the baseline BCR-ABL kinase domain mutation status and were durable; the estimated rate of a sustained major cytogenetic response of at least 12 months was 91%. No single BCR-ABL mutation conferring resistance to ponatinib was detected. Among 83 patients with accelerated-phase CML, 55% had a major hematologic response and 39% had a major cytogenetic response. Among 62 patients with blast-phase CML, 31% had a major hematologic response and 23% had a major cytogenetic response. Among 32 patients with Ph-positive ALL, 41% had a major hematologic response and 47% had a major cytogenetic response. Common adverse events were thrombocytopenia (in 37% of patients), rash (in 34%), dry skin (in 32%), and abdominal pain (in 22%). Serious arterial thrombotic events were observed in 9% of patients; these events were considered to be treatment-related in 3%. A total of 12% of patients discontinued treatment because of an adverse event. CONCLUSIONS Ponatinib had significant antileukemic activity across categories of disease stage and mutation status. (Funded by Ariad Pharmaceuticals and others; PACE ClinicalTrials.gov number, NCT01207440 .).

ABSTRACT Disclosure G.J. Weiss: GJW has received funds and other support related to participation in this clinical trial from ARIAD Pharmaceuticals, Inc. through his employer, Scottsdale Healthcare. GJW has served on Speakers Bureaus for Genentech, Pfizer, and Eli Lilly. N.I. Narasimhan: NIN is an employee of ARIAD Pharmaceuticals, Inc. D.J. Dorer: DJD is an employee of ARIAD Pharmaceuticals, Inc. V.M. Rivera: VMR is an employee of ARIAD Pharmaceuticals, Inc. J. Zhang: JZ is an employee of ARIAD Pharmaceuticals, Inc. T. Clackson: TC is an employee of ARIAD Pharmaceuticals, Inc. F. Haluska: FH is an employee of and owns stock/stock options in ARIAD Pharmaceuticals, Inc. A.T. Shaw: ATS has received consulting fees/honorarium from ARIAD, Pfizer, Chugai, and Daiichi. ATS has received support in the form of grants paid to her employer by Novartis and AstraZeneca. D.R. Camidge: DRC has received consulting fees/honorarium from ARIAD and has served on advisory boards for Pfizer, Chugai, Novartis, and ARIAD. All other authors have declared no conflicts of interest. AP26113 is a novel, synthetic, orally-active tyrosine kinase inhibitor (TKI) that potently inhibits mutant activated forms of anaplastic lymphoma kinase (ALK+) and epidermal growth factor receptor (EGFRm), as well as TKI-resistant forms including L1196M (ALK) and T790M (EGFR). AP26113 does not inhibit native EGFR. This is the initial report of a phase 1/2 open-label, multicenter study of AP26113. The dose finding phase (3 + 3 design) is ongoing in patients (pts) with advanced malignancies (except leukemia) refractory to available therapies or for whom no standard treatment exists. Initial dosing is once daily. As of 07 May 2012, 15 pts were enrolled: 30 mg n = 3, 60 mg n = 3, 90 mg n = 5, 120 mg n = 4; 67% female, median age 65 (41–77) yrs. Diagnoses were: 11 non-small cell lung cancer (NSCLC), 4 other (1 pancreatic, 1 colon, 1 cholangiocarcinoma, 1 adenocarcinoma of unknown primary [ACUP]). Ten pts had a documented history of ALK+ (n = 5; 4 NSCLC, 1 ACUP) or EGFRm (n = 5; all NSCLC). Pts were heavily pretreated. Four ALK+ NSCLC pts failed prior crizotinib therapy. Four pts with EGFRm failed prior EGFR-targeted therapy. Eight pts discontinued (7 disease progression, 1 investigator decision). The most common adverse events (AEs; >3 patients) were: fatigue (n = 4; 3 grade 1/2, 1 grade 3), nausea (n = 4; grade 1). No treatment-related serious AEs were observed. No DLTs were observed; the 120 mg dose level remains under evaluation. At 90 mg (n = 3), Day 29 geometric mean Cmax, Ctrough, AUC(0-24hr), and t1/2 were: 402 ng/mL, 170 ng/mL, 6130 ng*hr/mL, 29 hr, respectively. At the time of analysis, 8 pts had ≥1 set of tumor response measurements starting ≥8 weeks after first dose. Partial responses were observed in 4 of 4 ALK+ pts (60 mg n = 1; 90 mg n = 3, including the crizotinib-naive ACUP pt). Anti-tumor activity at 120 mg remains to be evaluated. In summary, AP26113 was well tolerated with preliminary anti-cancer activity in ALK+ pts naive to or failing prior crizotinib. The phase 2 expansion will include 4 cohorts: ALK+ NSCLC that is 1) naive or 2) resistant to prior ALK-targeted therapy; 3) EGFRm NSCLC that is resistant to EGFR-targeted therapy; 4) other cancers with abnormalities in ALK or other AP26113 targets. ClinicalTrials.gov: NCT01449461.

Members of the fibroblast growth factor receptor family of kinases (FGFR1–4) are dysregulated in multiple cancers. Ponatinib (AP24534) is an oral multitargeted tyrosine kinase inhibitor being explored in a pivotal phase II trial in patients with chronic myelogenous leukemia due to its potent activity against BCR-ABL. Ponatinib has also been shown to inhibit the in vitro kinase activity of all four FGFRs, prompting us to examine its potential as an FGFR inhibitor. In Ba/F3 cells engineered to express activated FGFR1–4, ponatinib potently inhibited FGFR-mediated signaling and viability with IC50 values <40 nmol/L, with substantial selectivity over parental Ba/F3 cells. In a panel of 14 cell lines representing multiple tumor types (endometrial, bladder, gastric, breast, lung, and colon) and containing FGFRs dysregulated by a variety of mechanisms, ponatinib inhibited FGFR-mediated signaling with IC50 values <40 nmol/L and inhibited cell growth with GI50 (concentration needed to reduce the growth of treated cells to half that of untreated cells) values of 7 to 181 nmol/L. Daily oral dosing of ponatinib (10–30 mg/kg) to mice reduced tumor growth and inhibited signaling in all three tumormodels examined. Importantly, the potency of ponatinib in thesemodels is similar to that previously observed in BCR-ABL–driven models and plasma levels of ponatinib that exceed the IC50 values for FGFR1–4 inhibition can be sustained in patients. These results show that ponatinib is a potent pan-FGFR inhibitor and provide strong rationale for its evaluation in patients with FGFR-driven cancers. Mol Cancer Ther; 11(3); 1–10. 2012 AACR.

6518 Background: Ponatinib is an oral multiple tyrosine kinase inhibitor and potent pan-BCR-ABL inhibitor. Preliminary phase 1 results suggest substantial activity in BCR-ABL+ patients (pts). In preclinical models, ponatinib also inhibits the FLT3/ITD mutant prevalent in AML with potency similar to that of BCR-ABL (IC50 2 nM). A cohort of pts with AML was enrolled in a phase 1 trial of ponatinib to assess safety and preliminary efficacy in this population. Methods: Pts (≥18 years) with relapsed or refractory AML were enrolled after the recommended phase 2 dose of ponatinib was established in pts with chronic myeloid leukemia (CML). Pts received 45 mg ponatinib orally once daily: trough plasma concentrations are known to exceed the target for inhibition of FLT3/ITD activity (IC50) in cells at this dose. FLT3/ITD mutation status was determined at a central laboratory. Results: Of 81 total pts in this study, 12 were included in the AML cohort. The median age of AML pts was 49 (range 30-72) years. At the time of analysis (Dec 15, 2010), 4 (33%) AML pts remained on study (range 77-143 days) and 8 (67%) discontinued (range 10-97 days) (no discontinuations were treatment related). Seven AML pts had documented FLT3/ITD at baseline, 2 did not carry FLT3 alterations, and 3 pts had inadequate samples for testing; however, these 3 pts had a positive FLT3 status reported by investigative sites. Overall, 7 pts with the FLT3/ITD mutation were FLT3 inhibitor naïve. All pts had treatment emergent AEs consistent with those expected in refractory AML. Three pts had treatment related grade 2 pancreatitis: 1 pt subsequently discontinued due to investigator decision; 2 had the event resolve and continued therapy at a reduced dose. The overall response rate in the AML cohort was 25% (3/12): 2 pts (29%) had CRi and 1 (14%) had PR. All responses observed were in the subset of pts with the FLT3/ITD mutation who were naïve to FLT3 inhibitors: 3/7 (43%). Conclusions: Ponatinib was well‐tolerated in this small group of AML patients; the safety profile was similar to that observed in CML. Evidence of activity in pts with the FLT3/ITD mutation was observed, with a response rate of 43% (3/7) in FLT3 inhibitor naïve pts.

In the treatment of chronic myeloid leukemia (CML) with BCR-ABL kinase inhibitors, the T315I gatekeeper mutant has emerged as resistant to all currently approved agents. This report describes the structure-guided design of a novel series of potent pan-inhibitors of BCR-ABL, including the T315I mutation. A key structural feature is the carbon-carbon triple bond linker which skirts the increased bulk of Ile315 side chain. Extensive SAR studies led to the discovery of development candidate 20g (AP24534), which inhibited the kinase activity of both native BCR-ABL and the T315I mutant with low nM IC(50)s, and potently inhibited proliferation of corresponding Ba/F3-derived cell lines. Daily oral administration of 20g significantly prolonged survival of mice injected intravenously with BCR-ABL(T315I) expressing Ba/F3 cells. These data, coupled with a favorable ADME profile, support the potential of 20g to be an effective treatment for CML, including patients refractory to all currently approved therapies.

In the treatment of chronic myeloid leukemia (CML) with BCR-ABL kinase inhibitors, the T315I gatekeeper mutant has emerged as resistant to all currently approved agents. This report describes the structure-guided design of a novel series of potent pan-inhibitors of BCR-ABL, including the T315I mutation. A key structural feature is the carbon-carbon triple bond linker which skirts the increased bulk of Ile315 side chain. Extensive SAR studies led to the discovery of development candidate 20g (AP24534), which inhibited the kinase activity of both native BCR-ABL and the T315I mutant with low nM IC(50)s, and potently inhibited proliferation of corresponding Ba/F3-derived cell lines. Daily oral administration of 20g significantly prolonged survival of mice injected intravenously with BCR-ABL(T315I) expressing Ba/F3 cells. These data, coupled with a favorable ADME profile, support the potential of 20g to be an effective treatment for CML, including patients refractory to all currently approved therapies.

OBJECTIVES Salivary glands are useful target organs for local and systemic gene therapeutics. For such applications, the regulation of transgene expression is important. Previous studies by us in murine submandibular glands showed that a rapamycin transcriptional regulation system in a single serotype 2, adeno-associated viral (AAV2) vector was effective for this purpose. This study evaluated if such a vector was similarly useful in rhesus macaque parotid glands. METHODS A recombinant AAV2 vector (AAV-TF-RhEpo-2.3w), encoding rhesus erythropoietin (RhEpo) and a rapamycin-inducible promoter, was constructed. The vector was administered to macaques at either of two doses [1.5 x 10(11) (low dose) or 1.5 x 10(12) (high dose) vector genomes] via cannulation of Stensen's duct. Animals were followed up for 12-14 weeks and treated at intervals with rapamycin (0.1 or 0.5 mg kg(-1)) to induce gene expression. Serum chemistry, hematology, and RhEpo levels were measured at interval. RESULTS AAV-TF-RhEpo-2.3w administration led to low levels of rapamycin-inducible RhEpo expression in the serum of most macaques. In five animals, no significant changes were seen in serum chemistry and hematology values over the study. One macaque, however, developed pneumonia, became anemic and subsequently required euthanasia. After the onset of anemia, a single administration of rapamycin led to significant RhEpo production in this animal. CONCLUSION Administration of AAV-TF-RhEpo-2.3w to macaque parotid glands was generally safe, but led only to low levels of serum RhEpo in healthy animals following rapamycin treatment.