PHASE 2 STUDY OF PONATINIB IN ADVANCED GASTROINTESTINAL STROMAL TUMORS: EFFICACY, SAFETY, AND IMPACT OF LIQUID BIOPSY AND OTHER BIOMARKERS

PURPOSE

Evaluate ponatinib for advanced gastrointestinal stromal tumors (GIST).

PATIENTS AND METHODS

This single-arm phase 2 trial enrolled patients with metastatic and/or unresectable GIST with failure of prior tyrosine kinase inhibitor (TKI) treatment into two cohorts based on presence or absence of KIT exon 11 (ex11) primary mutations. Patients initially received ponatinib 45 mg once daily. Following a temporary clinical hold in October 2013, dose reductions were implemented to reduce risk of arterial occlusive events (AOEs). Primary endpoint was 16-week clinical benefit rate (CBR) in KIT ex11-positive cohort. KIT mutations in circulating tumor DNA (ctDNA) were assessed.

RESULTS

Forty-five patients enrolled (30 KIT ex11-positive and 15 KIT ex11-negative); median follow-up was 14.7 and 13.6 months, respectively, as of August 1, 2016. Sixteen-week CBR was 36% (KIT ex11-positive; primary endpoint) and 20% (KIT ex11-negative). ctDNA analyses (n = 37) demonstrated strong concordance of primary KIT mutations between plasma and tumor. At least two secondary mutations were detected in 35% of patients overall and 54% of KIT ex11-positive patients. Changes from baseline in mutated ctDNA levels were consistent with clinical activity. Ponatinib was ineffective in patients with KIT exon 9 primary mutations. Resistance was associated with emergence of V654A. AOEs and venous thromboembolic events occurred in three and two patients, respectively. Six patients died; two deaths (pneumonia and pulmonary embolism) were considered possibly ponatinib-related.

CONCLUSION

Ponatinib demonstrated activity in advanced GIST, particularly in KIT ex11-positive disease. ctDNA analysis confirmed heterogeneous resistance mutations in TKI-pretreated advanced GIST. Safety was consistent with previous studies.

A phase 1 study of oral ridaforolimus in pediatric patients with advanced solid tumors

Purpose

Ridaforolimus is an investigational, potent, selective mTOR inhibitor. This study was conducted to determine the recommended phase 2 dose (RP2D), maximum tolerated dose, safety, pharmacokinetics, and antitumor activity of oral ridaforolimus in children with advanced solid tumors.

Experimental Design

In this phase 1, multicenter, open-label study in children aged 6 to <18 years with advanced solid tumors, ridaforolimus was administered orally for 5 consecutive days/week in 28-day cycles until progression, unacceptable toxicity, or consent withdrawal. Dose started at 22 mg/m² and increased to 28 mg/m² and 33 mg/m², followed by expansion at the RP2D.

Results

Twenty patients were treated; 18 were evaluable for dose-limiting toxicities. One dose-limiting toxicity (grade 3 increased alanine aminotransferase) occurred in 1 patient at 33 mg/m². Dose escalation concluded at 33 mg/m²; the maximum tolerated dose was not determined. The most common treatment-related adverse events (frequency ≥40%) were manageable grade 1–2 stomatitis, thrombocytopenia, hypertriglyceridemia, increased alanine aminotransferase, fatigue, hypercholesterolemia, anemia, and increased aspartate aminotransferase. Ridaforolimus exposure at 28 mg/m² and 33 mg/m² exceeded adult target levels. The RP2D for oral ridaforolimus in children was defined as 33 mg/m². Four patients received at least 4 cycles; 2 with pineoblastoma and diffuse intrinsic pontine glioma had stable disease for 12 and 46 cycles, respectively.

Conclusions

Ridaforolimus is orally bioavailable and well tolerated in children with advanced solid tumors. The RP2D (33 mg/m², 5 days/week) exceeds the adult RP2D. The favorable toxicity and pharmacokinetic profiles may allow for combination therapy, a promising therapeutic option in pediatric malignancies.

Brigatinib in Patients With Crizotinib-Refractory Anaplastic Lymphoma Kinase-Positive Non-Small-Cell Lung Cancer: A Randomized, Multicenter Phase II Trial

Purpose Most crizotinib-treated patients with anaplastic lymphoma kinase gene ( ALK)-rearranged non-small-cell lung cancer (ALK-positive NSCLC) eventually experience disease progression. We evaluated two regimens of brigatinib, an investigational next-generation ALK inhibitor, in crizotinib-refractory ALK-positive NSCLC. Patients and Methods Patients were stratified by brain metastases and best response to crizotinib. They were randomly assigned (1:1) to oral brigatinib 90 mg once daily (arm A) or 180 mg once daily with a 7-day lead-in at 90 mg (180 mg once daily [with lead-in]; arm B). Investigator-assessed confirmed objective response rate (ORR) was the primary end point. Results Of 222 patients enrolled (arm A: n = 112, 109 treated; arm B: n = 110, 110 treated), 154 (69%) had baseline brain metastases and 164 of 222 (74%) had received prior chemotherapy. With 8.0-month median follow-up, investigator-assessed confirmed ORR was 45% (97.5% CI, 34% to 56%) in arm A and 54% (97.5% CI, 43% to 65%) in arm B. Investigator-assessed median progression-free survival was 9.2 months (95% CI, 7.4 to 15.6) and 12.9 months (95% CI, 11.1 to not reached) in arms A and B, respectively. Independent review committee-assessed intracranial ORR in patients with measurable brain metastases at baseline was 42% (11 of 26 patients) in arm A and 67% (12 of 18 patients) in arm B. Common treatment-emergent adverse events were nausea (arm A/B, 33%/40%), diarrhea (arm A/B, 19%/38%), headache (arm A/B, 28%/27%), and cough (arm A/B, 18%/34%), and were mainly grades 1 to 2. A subset of pulmonary adverse events with early onset (median onset: day 2) occurred in 14 of 219 treated patients (all grades, 6%; grade ≥ 3, 3%); none occurred after escalation to 180 mg in arm B. Seven of 14 patients were successfully retreated with brigatinib. Conclusion Brigatinib yielded substantial whole-body and intracranial responses as well as robust progression-free survival; 180 mg (with lead-in) showed consistently better efficacy than 90 mg, with acceptable safety.

Activity and safety of brigatinib in ALK-rearranged non-small-cell lung cancer and other malignancies: a single-arm, open-label, phase 1/2 trial

BACKGROUND

Anaplastic lymphoma kinase (ALK) gene rearrangements are oncogenic drivers of non-small-cell lung cancer (NSCLC). Brigatinib (AP26113) is an investigational ALK inhibitor with potent preclinical activity against ALK mutants resistant to crizotinib and other ALK inhibitors. We aimed to assess brigatinib in patients with advanced malignancies, particularly ALK-rearranged NSCLC.

METHODS

In this ongoing, single-arm, open-label, phase 1/2 trial, we recruited patients from nine academic hospitals or cancer centres in the USA and Spain. Eligible patients were at least 18 years of age and had advanced malignancies, including ALK-rearranged NSCLC, and disease that was refractory to available therapies or for which no curative treatments existed. In the initial dose-escalation phase 1 stage of the trial, patients received oral brigatinib at total daily doses of 30-300 mg (according to a standard 3 + 3 design). The phase 1 primary endpoint was establishment of the recommended phase 2 dose. In the phase 2 expansion stage, we assessed three oral once-daily regimens: 90 mg, 180 mg, and 180 mg with a 7 day lead-in at 90 mg; one patient received 90 mg twice daily. We enrolled patients in phase 2 into five cohorts: ALK inhibitor-naive ALK-rearranged NSCLC (cohort 1), crizotinib-treated ALK-rearranged NSCLC (cohort 2), EGFR^T790M-positive NSCLC and resistance to one previous EGFR tyrosine kinase inhibitor (cohort 3), other cancers with abnormalities in brigatinib targets (cohort 4), and crizotinib-naive or crizotinib-treated ALK-rearranged NSCLC with active, measurable, intracranial CNS metastases (cohort 5). The phase 2 primary endpoint was the proportion of patients with an objective response. Safety and activity of brigatinib were analysed in all patients in both phases of the trial who had received at least one dose of treatment. This trial is registered with ClinicalTrials.gov, number NCT01449461.

FINDINGS

Between Sept 20, 2011, and July 8, 2014, we enrolled 137 patients (79 [58%] with ALK-rearranged NSCLC), all of whom were treated. Dose-limiting toxicities observed during dose escalation included grade 3 increased alanine aminotransferase (240 mg daily) and grade 4 dyspnoea (300 mg daily). We initially chose a dose of 180 mg once daily as the recommended phase 2 dose; however, we also assessed two additional regimens (90 mg once daily and 180 mg once daily with a 7 day lead-in at 90 mg) in the phase 2 stage. four (100% [95% CI 40-100]) of four patients in cohort 1 had an objective response, 31 (74% [58-86]) of 42 did in cohort 2, none (of one) did in cohort 3, three (17% [4-41]) of 18 did in cohort 4, and five (83% [36-100]) of six did in cohort 5. 51 (72% [60-82]) of 71 patients with ALK-rearranged NSCLC with previous crizotinib treatment had an objective response (44 [62% (50-73)] had a confirmed objective response). All eight crizotinib-naive patients with ALK-rearranged NSCLC had a confirmed objective response (100% [63-100]). Three (50% [95% CI 12-88]) of six patients in cohort 5 had an intracranial response. The most common grade 3-4 treatment-emergent adverse events across all doses were increased lipase concentration (12 [9%] of 137), dyspnoea (eight [6%]), and hypertension (seven [5%]). Serious treatment-emergent adverse events (excluding neoplasm progression) reported in at least 5% of all patients were dyspnoea (ten [7%]), pneumonia (nine [7%]), and hypoxia (seven [5%]). 16 (12%) patients died during treatment or within 31 days of the last dose of brigatinib, including eight patients who died from neoplasm progression.

INTERPRETATION

Brigatinib shows promising clinical activity and has an acceptable safety profile in patients with crizotinib-treated and crizotinib-naive ALK-rearranged NSCLC. These results support its further development as a potential new treatment option for patients with advanced ALK-rearranged NSCLC. A randomised phase 2 trial in patients with crizotinib-resistant ALK-rearranged NSCLC is prospectively assessing the safety and efficacy of two regimens assessed in the phase 2 portion of this trial (90 mg once daily and 180 mg once daily with a 7 day lead-in at 90 mg).

FUNDING

ARIAD Pharmaceuticals.

Randomized Phase II Trial of Ridaforolimus in Advanced Endometrial Carcinoma

PURPOSE

The prognosis for women with recurrent and metastatic endometrial cancer is poor, and improved therapies are needed. The mammalian target of rapamycin (mTOR) pathway is an important target, and mTOR inhibitors show clinical activity in endometrial cancer.

PATIENTS AND METHODS

An open-label, multicenter, randomized, phase II trial of oral ridaforolimus compared with progestin or investigator choice chemotherapy (comparator) was undertaken in women with metastatic or recurrent endometrial cancer who had progressive disease following one or two lines of chemotherapy and no hormonal therapy. The primary end point was progression-free survival (PFS) assessed by independent radiologic review.

RESULTS

One hundred thirty patients were enrolled (64 received ridaforolimus and 66 received the comparator), and median age was 66 years. Treatment discontinuation as a result of adverse events was 33% with ridaforolimus versus 6% with the comparator, with common (> 10%) grade 3 toxicities being hyperglycemia, anemia, and diarrhea. Thirty-eight percent (ridaforolimus) versus 71% (comparator) of patients discontinued treatment as a result of disease progression. Median PFS at the protocol prespecified interim analysis with 58 PFS events (primary end point) was 3.6 months (95% CI, 2.7 to 7.3 months) for ridaforolimus and 1.9 months (95% CI, 1.9 to 2.3 months) for the comparator (hazard ratio, 0.53; 95% CI, 0.31 to 0.90; P = .008). PFS rate for ridaforolimus versus comparator was 48% versus 18% at 16 weeks and 38% versus 15% at 24 weeks. Objective response rate for ridaforolimus versus comparator was 0% versus 4% (P = .925), and stable disease was achieved in 35% versus 17% of patients (P = .021).

CONCLUSION

Oral ridaforolimus shows encouraging activity in advanced endometrial cancer but is associated with significant toxicity. Inhibition of the PI3K/Akt/mTOR pathway may be a viable therapeutic target.

Southwest Oncology Group S0008: a phase III trial of high-dose interferon Alfa-2b versus cisplatin, vinblastine, and dacarbazine, plus interleukin-2 and interferon in patients with high-risk melanoma--an intergroup study of cancer and leukemia Group B, Children's Oncology Group, Eastern Cooperative Oncology Group, and Southwest Oncology Group

PURPOSE

High-dose interferon (IFN) for 1 year (HDI) is the US Food and Drug Administration-approved adjuvant therapy for patients with high-risk melanoma. Efforts to modify IFN dose and schedule have not improved efficacy. We sought to determine whether a shorter course of biochemotherapy would be more effective.

PATIENTS AND METHODS

S0008 (S0008: Chemotherapy Plus Biological Therapy in Treating Patients With Melanoma) was an Intergroup phase III trial that enrolled high-risk patients (stage IIIA-N2a through IIIC-N3), randomly assigning them to receive either HDI or biochemotherapy consisting of dacarbazine, cisplatin, vinblastine, interleukin-2, IFN alfa-2b (IFN-α-2b) and granulocyte colony-stimulating factor given every 21 days for three cycles. Coprimary end points were relapse-free survival (RFS) and overall survival (OS).

RESULTS

In all, 432 patients were enrolled. Grade 3 and 4 adverse events occurred in 57% and 7% of HDI patients and 36% and 40% of biochemotherapy patients, respectively. At a median follow-up of 7.2 years, biochemotherapy improved RFS (hazard ratio [HR], 0.75; 95% CI, 0.58 to 0.97; P = .015), with a median RFS of 4.0 years (95% CI, 1.9 years to not reached [NR]) versus 1.9 years for HDI (95% CI, 1.2 to 2.8 years) and a 5-year RFS of 48% versus 39%. Median OS was not different (HR, 0.98; 95% CI, 0.74 to 1.31; P = .55), with a median OS of 9.9 years (95% CI, 4.62 years to NR) for biochemotherapy versus 6.7 years (95% CI, 4.5 years to NR) for HDI and a 5-year OS of 56% for both arms.

CONCLUSION

Biochemotherapy is a shorter, alternative adjuvant treatment for patients with high-risk melanoma that provides statistically significant improvement in RFS but no difference in OS and more toxicity compared with HDI.

A phase 2 trial of ponatinib in Philadelphia chromosome-positive leukemias

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 .).

Results of an international randomized phase III trial of the mammalian target of rapamycin inhibitor ridaforolimus versus placebo to control metastatic sarcomas in patients after benefit from prior chemotherapy

PURPOSE

Aberrant mammalian target of rapamycin (mTOR) signaling is common in sarcomas and other malignancies. Drug resistance and toxicities often limit benefits of systemic chemotherapy used to treat metastatic sarcomas. This large randomized placebo-controlled phase III trial evaluated the mTOR inhibitor ridaforolimus to assess maintenance of disease control in advanced sarcomas.

PATIENTS AND METHODS

Patients with metastatic soft tissue or bone sarcomas who achieved objective response or stable disease with prior chemotherapy were randomly assigned to receive ridaforolimus 40 mg or placebo once per day for 5 days every week. Primary end point was progression-free survival (PFS); secondary end points included overall survival (OS), best target lesion response, safety, and tolerability.

RESULTS

A total of 711 patients were enrolled, and 702 received blinded study drug. Ridaforolimus treatment led to a modest, although significant, improvement in PFS per independent review compared with placebo (hazard ratio [HR], 0.72; 95% CI, 0.61 to 0.85; P = .001; median PFS, 17.7 v 14.6 weeks). Ridaforolimus induced a mean 1.3% decrease in target lesion size versus a 10.3% increase with placebo (P < .001). Median OS with ridaforolimus was 90.6 weeks versus 85.3 weeks with placebo (HR, 0.93; 95% CI, 0.78 to 1.12; P = .46). Adverse events (AEs) more common with ridaforolimus included stomatitis, infections, fatigue, thrombocytopenia, noninfectious pneumonitis, hyperglycemia, and rash. Grade ≥ 3 AEs were more common with ridaforolimus than placebo (64.1% v 25.6%).

CONCLUSION

Ridaforolimus delayed tumor progression to a small statistically significant degree in patients with metastatic sarcoma who experienced benefit with prior chemotherapy. Toxicities were observed with ridaforolimus, as expected with mTOR inhibition. These data provide a foundation on which to further improve control of sarcomas.

EPIC: A phase III randomized, open-label study of ponatinib versus imatinib in adult patients with newly diagnosed chronic myeloid leukemia in chronic phase

TPS7129

Background: The hallmark genetic abnormality of chronic myeloid leukemia (CML), known as the Philadelphia chromosome, generates the BCR-ABL fusion gene; expression of BCR-ABL in hematopoietic stem cells gives rise to CML. Ponatinib is a potent oral pan–BCR-ABL tyrosine kinase inhibitor (TKI) that is active against native and mutated forms of BCR-ABL, including the T315I gatekeeper mutant. Results from the phase 1 and phase 2 studies of ponatinib demonstrated that ponatinib is generally well tolerated and has substantial anti-leukemic activity in patients with CML who are resistant or intolerant to prior TKI therapy, regardless of baseline mutation status. In addition, multivariate analyses suggest that ponatinib has greater activity in younger patients who are less heavily pretreated and have a shorter time since diagnosis. The phase 3 EPIC (Evaluation of Ponatinib vs Imatinib in CML) study is testing the hypothesis that ponatinib is an effective treatment for newly diagnosed chronic phase (CP) CML patients when compared with standard imatinib therapy. Methods: EPIC is a multicenter, international, phase 3, two-arm, open-label trial of ponatinib (45 mg once daily) versus imatinib (400 mg once daily) in patients with newly diagnosed CP-CML. Patients ≥18 years of age with CP-CML (diagnosed within 6 months prior to study entry) and adequate renal, hepatic, and pancreatic function are eligible for enrollment. Enrolled patients are assigned to receive ponatinib or imatinib in a 1:1 fashion, stratified by Sokal Risk score (low vs intermediate vs high). The primary efficacy endpoint for this trial is major molecular response (MMR) rate at 12 months. Secondary endpoints include MMR rate at 5 years, BCR-ABLIS<10% rate at 3 months, CCyR rate at 12 months, progression-free survival, overall survival, and safety. A sample size consisting of 480 patients will provide 90% power to detect a 15% absolute increase in MMR rate at 12 months using an unstratified Fisher exact 2-sided test at an alpha level of 0.05. Assuming a 10% dropout rate, approximately 528 patients will be enrolled. The first patient was enrolled in August 2012. Clinical trial information: NCT01650805.

Safety and durability of ponatinib in patients with Philadelphia chromosome-positive (Ph+) leukemia: Long-term follow-up of an ongoing phase I study

7063

Background: Ponatinib is a potent oral pan–BCR-ABL tyrosine kinase inhibitor (TKI) that is active against native and mutated forms of BCR-ABL. The safety and anti-leukemic activity of ponatinib in patients (pts) with chronic myeloid leukemia (CML) or Ph+ acute lymphoblastic leukemia (ALL) were evaluated in a phase I clinical trial. Methods: Pts (N=81) with resistant/refractory hematologic malignancies were enrolled in this ongoing, open-label, dose escalation, phase I study. Ponatinib was dosed once daily (2–60 mg). 65 pts had Ph+ leukemia and are included in the present analysis (data as of 9 Nov 2012). Median follow-up was 25 (0.5–44) mos. Results: The median age of pts was 55 yrs; median time since diagnosis was 6.5 yrs. Pts were heavily pretreated (94% had received ≥2 prior TKIs, 62% ≥3). 65% had baseline BCR-ABL mutations. 46% (67% chronic phase [CP] CML) of pts remained on study. Progression and adverse events (AEs) were the most common reasons for discontinuation (17% each). The most common treatment-related AEs were rash (42%), thrombocytopenia (34%), arthralgia (20%), and increased lipase (20%). Significant anti-leukemic activity was observed (Table). Responses (major cytogenetic response [MCyR] for CP-CML or major hematologic response [MaHR] for accelerated phase [AP] CML, blast phase [BP] CML, or Ph+ ALL) were observed against the following mutations detected in >1 pt at baseline: 14/19 T315I, 4/7 F317L, 2/4 G250E, 2/2 M244V, 2/2 M35IT, and 1/2 F359V. Among CP-CML pts, 73% with complete cytogenetic response (CCyR) and 63% with major molecular response (MMR) are estimated to maintain response at 2 yrs (Kaplan-Meier). Of 28 CP-CML pts with CCyR, 25 remained on study (19 with continuous CCyR); of 22 pts with MMR, 21 remained on study (15 with continuous MMR). Updated data will be presented. Conclusions: Significant and durable responses were observed in heavily pretreated CP-CML pts, regardless of mutation status, and ponatinib was generally well tolerated. Clinical trial information: NCT00660920. [Table: see text]

First-in-human dose-finding study of the ALK/EGFR inhibitor AP26113 in patients with advanced malignancies: Updated results

8031

Background: AP26113 is a novel tyrosine kinase inhibitor (TKI) that potently inhibits mutant activated forms of anaplastic lymphoma kinase (ALK+) and epidermal growth factor receptor (EGFRm), and TKI-resistant forms including L1196M (ALK) and T790M (EGFR). AP26113 does not inhibit native EGFR. Methods: The dose finding phase (3+3 design) of this phase I/II open-label, multicenter study is ongoing in pts with advanced malignancies (except leukemia) refractory to available therapies or for whom no standard treatment exists. Initial dosing is orally once daily. Results: As of 14 Jan 2013, 44 pts were enrolled: 30 mg n=3, 60 mg n=3, 90 mg n=8, 120 mg n=8, 180 mg n=11, 240 mg n=9, 300 mg n=2; 64% female, median age 60 yrs; diagnoses: non-small cell lung cancer (NSCLC, n=37), other (n=7). 26 pts discontinued: 18 disease progression, 6 adverse event (AE), 2 deaths (sudden death, hypoxia; both possibly related). Most common AEs: nausea (45%), fatigue (39%), diarrhea (27%); most common grade 3/4 treatment-related AE: diarrhea (5%). 2 dose limiting toxicities observed: grade 3 ALT increase, 240 mg; grade 4 dyspnea, 300 mg. Doses <300 mg are being explored further. 21 pts had ALK+ history (18 NSCLC, 3 other). Among 18 evaluable ALK+ pts, 10 responded. 15 ALK+ pts had 0 (n=3) or 1 (n=12) prior ALK TKI (crizotinib); of these, 2/3 and 8/12 pts (67%) responded, including 2 complete responses. The longest response is 40 wks (ongoing). 4 of 5 ALK+ pts with untreated or progressing CNS lesions at baseline and with follow-up scans had evidence of radiographic improvement in CNS, including 1 pt resistant to crizotinib and LDK378 (overall response = stable disease). 16 pts had EGFRm history (15 NSCLC, 1 SCLC); 14 pts had ≥1 prior EGFR TKI. Of 12 EGFRm pts with a follow-up scan, 1 pt (prior erlotinib) responded at 120 mg (duration 21 wks, ongoing), 6 pts had stable disease (2 ongoing, duration 7-31 wks). Conclusions: AP26113 has promising anti-tumor activity in ALK+ pts, with initial evidence of activity in EGFRm pts, and is generally well tolerated. Phase II will begin after the recommended phase II dose is determined, with 4 cohorts: crizotinib-naïve NSCLC; crizotinib-resistant NSCLC; EGFR TKI-resistant NSCLC; other tumors. NCT01449461. Clinical trial information: NCT01449461.

Impact of baseline mutations on response to ponatinib and end of treatment mutation analysis in patients with chronic myeloid leukemia

7001

Background: BCR-ABL kinase domain mutations frequently cause tyrosine kinase inhibitor (TKI) failure in chronic myeloid leukemia (CML). Ponatinib, a potent oral pan-BCR-ABL TKI, has shown preclinical activity against all single mutants tested, including T315I. The impact of baseline (BL) mutations on response to ponatinib (45 mg once daily) and end of treatment (EOT) mutations in pts discontinuing treatment were evaluated in the phase II PACE trial. Methods: Heavily pretreated chronic phase (CP) CML pts (93% received ≥2 prior TKIs, 60% ≥3) resistant or intolerant to dasatinib or nilotinib (N=203) or with T315I confirmed at BL (N=64) were enrolled. The primary endpt was major cytogenetic response (MCyR). Min follow up at analysis (9 Nov 2012) was 12 mos (median 15 [0.1-25]). Sanger sequencing was done at one central laboratory. Results: At BL, no mutations were detected in 51% of pts, 1 mutation in 39%, and ≥2 mutations in 10%; 26 unique mutations were observed. Responses were observed regardless of BL mutation status. MCyR rates were: 56% overall, 49% in pts with no mutations, 64% 1 mutation, 62% ≥2 mutations; 57% in pts with mutation(s) other than T315I, 74% T315I only, 57% T315I + other mutation(s). Responses were seen against each of the 15 mutations present in >1 pt at BL, including T315I, E255V, F359V, Y253H. 99 pts discontinued, 56 had EOT mutations assessed. 5 pts lost a mutation, 46 had no change, 5 gained mutations (Table). 11 pts lost MCyR (none with T315I); of the 6 discontinuing, 4 had EOT mutations assessed and no changes from BL were seen. Conclusions: Responses to ponatinib were observed regardless of BL mutation status. No single mutation conferring resistance to ponatinib in CP-CML has been observed to date. Data with a minimum follow up of 18 mos, including pts with advanced disease, will be presented. Clinical trial information: NCT01207440. [Table: see text]

Loss of ARF sensitizes transgenic BRAFV600E mice to UV-induced melanoma via suppression of XPC

Both genetic mutations and UV irradiation (UVR) can predispose individuals to melanoma. Although BRAF(V600E) is the most prevalent oncogene in melanoma, the BRAF(V600E) mutant is not sufficient to induce tumors in vivo. Mutation at the CDKN2A locus is another melanoma-predisposing event that can disrupt the function of both p16(INK4a) and ARF. Numerous studies have focused on the role of p16(INK4a) in melanoma, but the involvement of ARF, a well-known p53 activator, is still controversial. Using a transgenic BRAF(V600E) mouse model previously generated in our laboratory, we report that loss of ARF is able to enhance spontaneous melanoma formation and cause profound sensitivity to neonatal UVB exposure. Mechanistically, BRAF(V600E) and ARF deletion synergize to inhibit nucleotide excision repair by epigenetically repressing XPC and inhibiting the E2F4/DP1 complex. We suggest that the deletion of ARF promotes melanomagenesis not by abrogating p53 activation but by acting in concert with BRAF(V600E) to increase the load of DNA damage caused by UVR.

Analysis of the potential effect of ponatinib on the QTc interval in patients with refractory hematological malignancies

Purpose

Cardiac dysfunction, particularly QT interval prolongation, has been observed with tyrosine kinase inhibitors approved to treat chronic myeloid leukemia. This study examines the effects of ponatinib on cardiac repolarization in patients with refractory hematological malignancies enrolled in a phase 1 trial.

Methods

Electrocardiograms (ECGs) were collected at 3 dose levels (30, 45, and 60 mg) at 6 time points. Electrocardiographic parameters, including QTc interval, were measured, and 11 morphological analyses were conducted. Central tendency analyses of ECG parameters were performed using time-point and time-averaged approaches. All patients with at least 2 baseline ECGs and 1 on-treatment ECG were included in the analyses. Patients with paired ECGs and plasma samples were included in the pharmacokinetic/pharmacodynamic analysis to examine the relationship between ponatinib plasma concentration and change from baseline in QT intervals.

Results

Thirty-nine patients at the 30-, 45-, and 60-mg dose levels were included in the central tendency and morphological analyses. There was no significant effect on cardiac repolarization, as evidenced by non-clinically significant mean QTcF changes from baseline of −10.9, −3.6, and −5.0 ms for the 30-, 45-, and 60-mg dose levels, respectively. The morphological analysis revealed 2 patients with atrial fibrillation and 2 with T wave inversion. Seventy-five patients were included in the pharmacokinetic/pharmacodynamic analysis across all dose levels. The slope of the relationship for QTcF versus plasma ponatinib concentration was not positive (−0.0171), indicating no exposure–effect relationship.

Conclusions

Ponatinib is associated with a low risk of QTc prolongation in patients with refractory hematological malignancies.

Ponatinib in refractory Philadelphia chromosome-positive leukemias

BACKGROUND

Resistance to tyrosine kinase inhibitors in patients with chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL) is frequently caused by mutations in the BCR-ABL kinase domain. Ponatinib (AP24534) is a potent oral tyrosine kinase inhibitor that blocks native and mutated BCR-ABL, including the gatekeeper mutant T315I, which is uniformly resistant to tyrosine kinase inhibitors.

METHODS

In this phase 1 dose-escalation study, we enrolled 81 patients with resistant hematologic cancers, including 60 with CML and 5 with Ph-positive ALL. Ponatinib was administered once daily at doses ranging from 2 to 60 mg. Median follow-up was 56 weeks (range, 2 to 140).

RESULTS

Dose-limiting toxic effects included elevated lipase or amylase levels and pancreatitis. Common adverse events were rash, myelosuppression, and constitutional symptoms. Among Ph-positive patients, 91% had received two or more approved tyrosine kinase inhibitors, and 51% had received all three approved tyrosine kinase inhibitors. Of 43 patients with chronic-phase CML, 98% had a complete hematologic response, 72% had a major cytogenetic response, and 44% had a major molecular response. Of 12 patients who had chronic-phase CML with the T315I mutation, 100% had a complete hematologic response and 92% had a major cytogenetic response. Of 13 patients with chronic-phase CML without detectable mutations, 100% had a complete hematologic response and 62% had a major cytogenetic response. Responses among patients with chronic-phase CML were durable. Of 22 patients with accelerated-phase or blast-phase CML or Ph-positive ALL, 36% had a major hematologic response and 32% had a major cytogenetic response.

CONCLUSIONS

Ponatinib was highly active in heavily pretreated patients with Ph-positive leukemias with resistance to tyrosine kinase inhibitors, including patients with the BCR-ABL T315I mutation, other mutations, or no mutations. (Funded by Ariad Pharmaceuticals and others; ClinicalTrials.gov number, NCT00660920.).

Phase III, placebo-controlled trial (SUCCEED) evaluating ridaforolimus as maintenance therapy in advanced sarcoma patients following clinical benefit from prior standard cytotoxic chemotherapy: Long-term (≥ 24 months) overall survival results

10010

Background: The mammalian target of rapamycin (mTOR) regulates cell growth and proliferation and is abnormally activated in many sarcomas. Ridaforolimus, an oral mTOR inhibitor, demonstrated clinical activity in previous nonrandomized trials in advanced sarcomas following failure of prior chemotherapy. Methods: An international, multicenter, placebo-controlled, phase 3 trial was conducted to evaluate maintenance therapy with ridaforolimus in patients with metastatic soft-tissue or bone sarcomas who achieved disease control from prior chemotherapy. Patients were randomized (1:1) to receive oral ridaforolimus (40 mg) or placebo once daily for 5 days each week. The primary endpoint was progression-free survival (PFS); secondary endpoints included overall survival (OS) and safety and tolerability. For OS, patients were to be followed at 3-month intervals for at least 24 months and up to 60 months after randomization. Results: 702 of 711 randomized patients received treatment. At the time of the data cutoff for OS (386 deaths), patients in the study population had been followed for at least 15 months. Median OS was 93.3 weeks with ridaforolimus vs 83.4 weeks with placebo (hazard ratio [HR]=0.88; 95% confidence interval [CI]: 0.72, 1.08; P=0.23). Ridaforolimus significantly improved PFS vs placebo (HR=0.72; 95% CI: 0.61, 0.85; P=0.0001; median PFS: 17.7 weeks vs 14.6 weeks); PFS improved across all prespecified baseline characteristics. As expected from the class of mTOR inhibitors, the most common adverse events with ridaforolimus were stomatitis, thrombocytopenia, noninfectious pneumonitis, hypertriglyceridemia, hyperglycemia, infections, and rash. Conclusions: Oral ridaforolimus was generally well-tolerated and significantly improved PFS in metastatic sarcoma patients with benefit from prior chemotherapy, offering an effective treatment alternative to surveillance alone. Results of a long-term OS analysis (prespecified to occur at 67% mortality, 24 months minimum follow-up) in the intent-to-treat population will be available in early 2012.

PACE: A pivotal phase II trial of ponatinib in patients with CML and Ph+ALL resistant or intolerant to dasatinib or nilotinib, or with the T315I mutation

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Background: Ponatinib is a potent, oral, pan-BCR-ABL inhibitor active against the native enzyme and all tested resistant mutants, including the uniformly resistant T315I mutation. Methods: The PACE (Ponatinib Ph+ALL and CML Evaluation) trial started Sept 2010. Pts with refractory CML (CP, AP or BP) or Ph+ALL resistant or intolerant (R/I) to dasatinib or nilotinib or with T315I received 45 mg ponatinib once daily. The trial is ongoing; enrollment completed Sept 2011. Data as of 17 Jan 2012 are reported. Results: 449 pts were enrolled, 5 of whom were ineligible (post-imatinib, non-T315I) but treated. Median age was 59 (18-94) yrs; 53% male. Diagnoses were: 271 CP-CML (R/I=207; T315I=64); 79 AP-CML (R/I=60; T315I=19); 94 BP/ALL (R/I=48; T315I=46). Median time from diagnosis to ponatinib was 6 yrs. Prior TKIs included imatinib (96%), dasatinib (85%), nilotinib (66%), bosutinib (7%); 94% failed ≥2 prior TKIs, 59% failed ≥3 prior TKIs. 83% had a history of resistance to dasatinib or nilotinib; 12% were purely intolerant. In CP, best response to most recent dasatinib or nilotinib was MCyR 25%. Frequent mutations confirmed at entry: 29% T315I, 8% F317L, 4% E255K, 4 % F359V, 3% G250E. Median follow-up was 6.6 months. Response rates are presented in the table. Overall, 64% remained on therapy (77% CP). Most frequent reasons for discontinuation were progression (12%) and AE (10%). Most common drug‑related AEs were thrombocytopenia (33%), rash (33%), dry skin (26%). Conclusions: Ponatinib has substantial activity in heavily pretreated pts and those with refractory T315I. Response rates continue to improve with longer follow-up. Multivariate analyses of predictors of outcome will be presented. [Table: see text]

Phase III trial of high-dose interferon alpha-2b versus cisplatin, vinblastine, DTIC plus IL-2 and interferon in patients with high-risk melanoma (SWOG S0008): An intergroup study of CALGB, COG, ECOG, and SWOG

8504

Background: High-dose interferon for one year (HDI) is the FDA approved adjuvant therapy for patients (pts) with high-risk melanoma (HRM). Efforts to modify IFN dose or schedule have not improved efficacy. A meta-analysis demonstrated that biochemotherapy (BCT) produced superior response rates compared with chemotherapy in pts with stage IV melanoma (Wheatley et al J Clin Oncol 25:5426, 2007). We sought to determine whether a short course of BCT would be more effective than HDI as adjuvant treatment in pts with HRM. Methods: S-0008 (an Intergroup Phase III trial) enrolled pts who were high risk (Stage III A-N2a thru Stage III C N3) and randomized them to receive either HDI or BCT consisting of dacarbazine 800 mg/m2 day 1, cisplatin 20 mg/m2/ days 1-4, vinblastine 1.2 mg/m2 days 1-4, IL-2 9 MIU/m2/day continuous IV days 1-4, IFN 5 MU/m2/day sc days 1-4, 8,10,12, and G-CSF 5 ug/kg/day sc days 7-16. BCT cycles were given every 21 days x 3 cycles (9 weeks total). Pts were stratified for number of involved nodes (1-3 v ≥4), micro v macro metastasis, and ulceration of the primary. Co-primary endpoints were relapse free survival (RFS) and overall survival (OS) using a one-sided log rank test at p= 0.05. Results: 432 pts were enrolled between 8/2000 and 11/2007: 30 were ineligible or withdrew consent. Grade 3 and 4 adverse events occurred in 57% and 7% respectively of HDI pts and 36% and 40% of BCT pts. At a median f/up of 6 yrs, BCT improved RFS (p = 0.02, HR 0.77 [90% CI: 0.62 – 0.96]) with median RFS for BCT of 4.0 yrs (90% CI:1.9 – 5.9) v 1.9 yrs (90% CI: 1.4 – 2.5) and 5 yr RFS of 47% v 39%. Median OS was not different between the two arms (p = 0.49 HR 1.0 [90% CI: 0.78 – 1.27]) with median OS not yet reached for BCT v 8.4 yrs (90% CI: 4.5 – 9.3) for HDI and 5 yr survival 56% for both arms. Conclusions: In HRM pts, BCT provides a statistically significant improvement in RFS compared to HDI, but no discernable difference in OS and more grade IV toxicity. BCT represents a shorter, alternative treatment for pts with HRM, and a potential control arm and basis for future combinations in the adjuvant setting.

Phase II study of the mammalian target of rapamycin inhibitor ridaforolimus in patients with advanced bone and soft tissue sarcomas

PURPOSE

Ridaforolimus is an inhibitor of mammalian target of rapamycin, an integral component of the phosphatidyl 3-kinase/AKT signaling pathway, with early evidence of activity in sarcomas. This multicenter, open-label, single-arm, phase II trial was conducted to assess the antitumor activity of ridaforolimus in patients with distinct subtypes of advanced sarcomas.

PATIENTS AND METHODS

Patients with metastatic or unresectable soft tissue or bone sarcomas received ridaforolimus 12.5 mg administered as a 30-minute intravenous infusion once daily for 5 days every 2 weeks. The primary end point was clinical benefit response (CBR) rate (complete response or partial response [PR] or stable disease ≥ 16 weeks). Safety, progression-free survival (PFS), overall survival (OS), time to progression, and duration of response were also evaluated.

RESULTS

A total of 212 patients were treated in four separate histologic cohorts. In this heavily pretreated population, 61 patients (28.8%) achieved CBR. Median PFS was 15.3 weeks; median OS was 40 weeks. Response Evaluation Criteria in Solid Tumors (RECIST) confirmed response rate was 1.9%, with four patients achieving confirmed PR (two with osteosarcoma, one with spindle cell sarcoma, and one with malignant fibrous histiocytoma). Archival tumor protein markers analyzed were not correlated with CBR. Related adverse events were generally mild or moderate and consisted primarily of stomatitis, mucosal inflammation, mouth ulceration, rash, and fatigue.

CONCLUSION

Single-agent ridaforolimus in patients with advanced and pretreated sarcomas led to PFS results that compare favorably with historical metrics. A phase III trial based on these data will further define ridaforolimus activity in sarcomas.

Molecular pathogenesis of cutaneous melanocytic neoplasms

Melanoma is the deadliest form of skin cancer without an effective treatment. An understanding of the genetic basis of melanoma has recently shed light on some of the mechanisms of melanomagenesis. This review explores the major genes involved in familial and sporadic cutaneous melanoma with an emphasis on CDKN2A, CDK4, MC1R, and MAPK pathway targets (e.g., RAS and BRAF), apoptosis regulators (e.g., BCL-2, AKT, and APAF-1), and the tumor-suppressor genes TP53 and PTEN. New directions for therapeutics based on our current knowledge of the genes implicated in melanoma are also discussed.

Immunologic and clinical effects of antibody blockade of cytotoxic T lymphocyte-associated antigen 4 in previously vaccinated cancer patients

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) functions as a negative regulator of endogenous and vaccine-induced antitumor immunity. The administration of fully human anti-CTLA-4 blocking monoclonal antibodies to advanced-cancer patients increases immune-mediated tumor destruction in some subjects. Nonetheless, patients that respond also frequently manifest serious inflammatory pathologies, raising the possibility that the therapeutic and toxic effects of CTLA-4 blockade might be linked. Here we show that periodic infusions of anti-CTLA-4 antibodies after vaccination with irradiated, autologous tumor cells engineered to secrete GM-CSF (GVAX) generate clinically meaningful antitumor immunity without grade 3 or 4 toxicity in a majority of metastatic melanoma patients. The application of this sequential immunotherapy to advanced ovarian carcinoma patients also revealed that tumor destruction and severe inflammatory pathology could be dissociated, although further refinements are required to increase clinical responses and to minimize toxicity in this population. The extent of therapy-induced tumor necrosis was linearly related to the natural logarithm of the ratio of intratumoral CD8(+) effector T cells to FoxP3(+) regulatory T cells (Tregs) in posttreatment biopsies. Together, these findings help clarify the immunologic and clinical effects of CTLA-4 antibody blockade in previously vaccinated patients and raise the possibility that selective targeting of antitumor Tregs may constitute a complementary strategy for combination therapy.

Randomized Trial of an Allogeneic Melanoma Lysate Vaccine With Low-Dose Interferon Alfa-2b Compared With High-Dose Interferon Alfa-2b for Resected Stage III Cutaneous Melanoma

Purpose

To compare the overall survival (OS) of patients with resected stage III melanoma administered active specific immunotherapy and low-dose interferon alfa-2b (IFN-α-2b) with the OS achieved using high-dose IFN-α-2b.

Patients and Methods

An Ad Hoc Melanoma Working Group of 25 investigators treated 604 patients from April 1997 to January 2003. Patients were stratified by sex and number of nodes and were randomly assigned to receive either 2 years of treatment with active specific immunotherapy with allogeneic melanoma lysates and low-dose IFN-α-2b (arm 1) or high-dose IFN-α-2b alone for 1 year (arm 2). Active specific immunotherapy was injected subcutaneously (SC) weekly for 4 weeks, at week 8, and bimonthly thereafter. IFN-α-2b SC was begun on week 4 and continued thrice weekly at 5 MU/m2 for 2 years. IFN-α-2b in arm 2 was administered according to the Eastern Cooperative Oncology Group 1684 study regimen.

Results

Median follow-up time was 32 months for all patients and 42 months for surviving patients. Median OS time exceeds 84 months in arm 1 and is 83 months in arm 2 (P = .56). Five-year OS rate is 61% in arm 1 and 57% in arm 2. Estimated 5-year relapse-free survival (RFS) rate is 50% in arm 1 and 48% in arm 2, with median RFS times of 58 and 50 months, respectively. The incidence of serious adverse events as a result of treatment was the same in both arms, but more severe neuropsychiatric toxicity was seen in arm 2.

Conclusion

OS and RFS achieved by active specific immunotherapy and low-dose IFN-α-2b were indistinguishable from those achieved by high-dose IFN-α-2b. Long RFS and OS times were observed in both treatment arms.

Novel inhibitors in the treatment of metastatic melanoma

Metastatic melanoma continues to be a difficult disease to treat. Recent efforts have focused on developing novel, target-directed therapeutic agents. In this review, we discuss the RAS-RAF-MAP kinase and the RAS-PI3K-AKT pathway in detail, as up to 80% of cutaneous melanomas exhibit a BRAF mutation. The preclinical and clinical data regarding BRAF inhibition is reviewed. Other potential targets in these pathways are also discussed. Preclinical data have recently emerged, suggesting that the following subsets of patients have a lower frequency of BRAF mutations: acral, mucosal and cutaneous melanomas with chronic sun-induced damage. These lesions have a higher frequency of KIT mutations. However, cutaneous melanomas without chronic sun damage have a higher frequency of BRAF mutations and are not noted to have KIT mutations. It is possible that the appropriate subset of patients may respond differently to available targeted therapies and clinical trials are in development to assess the utility of KIT inhibition in these patients.

Melanoma in the young: Differences and similarities with adult melanoma

BACKGROUND

Melanoma in the first 2 decades of life is rare and is less well characterized than melanoma in adults. Previously published comparisons of melanoma of the young (age <or=20 years) and in adults have been biased by the observation that primary melanomas of the young are significantly thicker on average than adult melanomas. In this study, the use of an adult control group that was matched for tumor thickness adjusted for this bias and allowed for a comparison of the biology of pediatric melanoma and adult melanoma.

METHODS

The authors identified young patients with melanoma who were treated at their institution between 1971 and 2002, and matched each patient by thickness and year of diagnosis to 2 adult control patients with melanoma. The study group of 73 young patients with melanoma (aged <or=20 years) was compared with to 146 adult case-matched control patients for clinical presentation, treatment, and clinically relevant outcome parameters, including disease-free and cause-specific survival. A subset of pediatric patients aged <or=13 years also was analyzed against case-matched adult controls.

RESULTS

The demographics and clinical presentation of the 2 groups were similar. Of the young patients with melanoma who underwent pathologic staging of clinically negative lymph nodes by either elective lymph node dissection or lymphatic mapping/sentinel lymph node biopsy, 11 of 25 patients (44%) had positive lymph nodes compared with 11 of 46 patients (23.9%) among the adults. The overall incidence of positive lymph nodes was 17.8% in young melanoma patients and 9.6% in thickness-matched adult control patients. Nonetheless, 10-year cause-specific survival was similar between young melanoma patients and adult melanoma patients (89.4% and 79.3%, respectively). No significant differences were observed comparing young patients with melanoma aged <13 years versus age >13 years.

CONCLUSIONS

Melanoma of the young had some important differences and similarities relative to adult melanoma. Lymph node metastases were more prevalent in young patients with melanoma compared with adult (thickness-matched) control patients; however, the 5- and 10-year survival rates were similar.

Phase II study of temozolomide and thalidomide in patients with metastatic melanoma in the brain: high rate of thromboembolic events (CALGB 500102)

BACKGROUND

Preliminary studies suggesting that extended-dose temozolomide with thalidomide is safe and active in patients with metastatic melanoma have led to frequent use of this oral regimen. To confirm these observations the combination was tested in a multicenter Phase II trial in patients with melanoma brain metastases.

METHODS

Eligible patients had melanoma brain metastases, with or without systemic metastases. The primary endpoint was response rate in brain metastases. Patients received temozolomide at a dose of 75 mg/m2/day for 6 weeks with a 2-week rest between cycles, and thalidomide (escalated to 400 mg/day for patients age < 70 years or to 200 mg/day for patients age > or = 70 years). A 2-stage design required > or = 3 responses in the first 21 patients before enrolling 29 additional patients in the second stage.

RESULTS

Sixteen eligible patients were enrolled. No objective responses were observed. The median survival was 23.9 weeks. Seven patients withdrew because of tumor progression; 7 were removed during Cycle 1 because of adverse events, including allergic reaction (1 patient), severe fatigue (1 patient), sudden death (1 patient), and thromboembolic events (pulmonary embolism in 3 patients and deep vein thrombosis in 1 patient); 2 patients withdrew when the study was suspended and subsequently closed. No associations could be established between baseline characteristics and toxicity.

CONCLUSIONS

The proportion of patients with lethal or potentially life-threatening adverse events was high (0.31, 95% confidence interval, 0.11-0.59), and the absence of objective responses made it unlikely that further accrual would demonstrate the efficacy of the regimen. These observations provide little support for the use of this combination for melanoma brain metastases unless safe and effective methods to prevent thrombosis are developed.

Therapeutic targets in melanoma: MAPKinase pathway

Recent progress in our understanding of the genetic alterations that occur in the pathogenesis of melanoma provides exciting opportunities for therapy. The most important signaling pathways in melanoma lie downstream of NRAS: the RAS-BRAF-MAPK pathway. A great deal of attention has been focused on the high mutation rate in the BRAF oncogene, which approaches 60%, because BRAF itself is an appealing drug substrate and because of the central contribution of BRAF function to melanoma development that the mutation rate signifies. Agents that specifically target BRAF, such as sorafenib, as well as new molecules that function both upstream and downstream of BRAF, are being actively investigated.

Bcl-2 antisense (oblimersen sodium) plus dacarbazine in patients with advanced melanoma: the Oblimersen Melanoma Study Group

PURPOSE

Chemotherapy resistance in melanoma has been linked to antiapoptotic effects mediated by Bcl-2 protein. We evaluated whether targeting Bcl-2 using an antisense oligonucleotide (oblimersen sodium) could improve the efficacy of systemic chemotherapy in patients with advanced melanoma.

PATIENTS AND METHODS

We randomly assigned chemotherapy-naïve patients with advanced melanoma to treatment with dacarbazine (1,000 mg/m2) alone or preceded by a 5-day continuous intravenous infusion of oblimersen sodium (7 mg/kg/d) every 3 weeks for up to eight cycles. Patients were stratified by Eastern Cooperative Oncology Group performance status, liver metastases, disease site, and serum lactate dehydrogenase (LDH). The primary efficacy end point was overall survival.

RESULTS

Among 771 patients randomly assigned, the addition of oblimersen to dacarbazine yielded a trend toward improved survival at 24-month minimum follow-up (median, 9.0 v 7.8 months; P = .077) and significant increases in progression-free survival (median, 2.6 v 1.6 months; P < .001), overall response (13.5% v 7.5%; P = .007), complete response (2.8% v 0.8%), and durable response (7.3% v 3.6%; P = .03). A significant interaction between baseline serum LDH and treatment was observed; oblimersen significantly increased survival in patients whose baseline serum LDH was not elevated (median overall survival, 11.4 v 9.7 months; P = .02). Neutropenia and thrombocytopenia were increased in the oblimersen-dacarbazine group; however, there was no increase in serious infections or bleeding events.

CONCLUSION

The addition of oblimersen to dacarbazine significantly improved multiple clinical outcomes in patients with advanced melanoma and increased overall survival in patients without an elevated baseline serum LDH.

Genetic alterations in signaling pathways in melanoma

Alterations in the RAS signaling cascade are almost uniformly present in melanoma. RAS itself is only infrequently mutated in melanoma although downstream of RAS lie BRAF on the mitogen-activated protein kinase pathway and PTEN on the protein kinase B/Akt pathway. These genes are often altered in melanomas; indeed, the most frequent target of mutation in melanomas is BRAF, which is mutated in approximately 60% to 70% of superficial spreading melanomas. These mutations occur in a background that is not normal, with the CDKN2A locus also typically being mutated. We review herein the data that suggest that the distribution of the signaling mutations is important. In general, melanomas carry a mutated NRAS, a mutated BRAF, or concurrent BRAF and PTEN mutations. These data support the hypothesis that the biochemical functions of RAS are portioned by mutations in the pathways lying downstream. Moreover, these mutations have no apparent relationship to the patterns of alteration of CDKN2A and its downstream effectors. Thus, the data also suggest that successful exploitation of mutations in melanoma will be dependent on understanding not only mutations and their frequency but their genetic context as well.

Innovations and Challenges in Melanoma: Summary Statement from the First Cambridge Conference

Innovations and Challenges in Melanoma, chaired by Michael Atkins and cochaired by Ulrich Keilholz, John Kirkwood, and Jeffrey Sosman, was held July 15 to 16, 2005, in Cambridge, Massachusetts. The conference brought together leading experts in the fields of cancer research, medical oncology, surgical oncology, anatomic pathology, dermatology, and immunotherapy who wished to advance the field of melanoma treatment by exchanging information and perspectives regarding recent advances and recommendations for further study. The conference proceedings published in this educational supplement to Clinical Cancer Research are intended to provide timely information and recommendations on how genetics, biology, and data information can enhance our understanding of melanoma biology and help inform the use of therapies for this disease.

Immunization using autologous dendritic cells pulsed with the melanoma-associated antigen gp100-derived G280-9V peptide elicits CD8+ immunity

PURPOSE

To determine the toxicity, maximal tolerated dose, and clinical and immunologic response to autologous dendritic cells pulsed with melanoma-associated antigen gp100-derived G280-9V peptide.

PATIENTS AND METHODS

Twelve HLA-A*0201(+) patients with advanced melanoma were administered dendritic cells pulsed with G280-9V peptide. Cohorts of three patients were administered 5 x 10(6), 15 x 10(6), and 50 x 10(6) cells i.v. every 3 weeks for six doses according to a dose escalation scheme. Three additional patients were treated at the highest dose. No additional cytokines or therapies were coadministered. The immunogenicity of G280-9V-pulsed dendritic cells was measured by IFN-gamma ELISPOT assay, tetramer assay, and (51)Cr release assay comparing prevaccination to postvaccination blood samples. Response to treatment was assessed by Response Evaluation Criteria in Solid Tumors.

RESULTS

CD8(+) immunity to the native G280 was observed in 8 (67%) patients as measured by ELISPOT and in 12 (100%) patients as measured by tetramer assay. Of the 9 patients tested, 9 (100%) had measurable high-avidity CTL activity as defined by lysis of allogeneic melanoma lines, which coexpress HLA-A*0201 and gp100. The median follow-up of the entire cohort is 43.8 months. Two (17%) partial responses were observed and 3 (25%) patients had stable disease. The median survival of the treated population was 37.6 months. At this time, three patients are alive, including one patient who continues to respond without additional treatment.

CONCLUSION

The high rate of immunization as measured by three independent assays and the occurrence of clinical regression support continued investigation of G280-9V peptide as a candidate epitope in melanoma vaccine formulations.

Examination of mutations in BRAF, NRAS, and PTEN in primary cutaneous melanoma

Frequent somatic mutation of v-raf murine sarcoma viral oncogene homolog B (BRAF), a downstream effector of the rat sarcoma oncogene (RAS) signaling pathway, is described in melanoma and other tumors. Our analysis of melanoma cell lines suggests that activating mutations in BRAF can occur simultaneously with inactivation of phosphatase and tensin homolog (PTEN), but neuroblastoma RAS (NRAS) mutations are not coincident. We determined the concurrent prevalence of mutations in BRAF and NRAS, and alteration of PTEN expression in 69 primary cutaneous melanomas. BRAF mutations were seen in 57% of cases. NRAS was mutated in 17% of samples, exclusively in exon 2. Two cases showed concurrent BRAF and NRAS mutations. Using immunohistochemistry, PTEN protein expression was lost or greatly reduced in 19% of tumors. Seven tumors with reduced PTEN yielded DNA amenable to sequencing, and three also showed mutation in BRAF but none in NRAS. In all, 11 (85%) of 13 tumors showing reduced PTEN expression were greater than 3.5 mm thick, and the association of increasing Breslow thickness and loss or reduction of PTEN expression was statistically significant (P<0.0001). Mutations in NRAS were not coincident with reduced PTEN expression, and the concurrent mutation of NRAS and BRAF was rare.

Phase 2 Study of the g209-2M Melanoma Peptide Vaccine and Low-Dose Interleukin-2 in Advanced Melanoma

High-dose interleukin-2 (IL-2) is the only approved immunologic therapy for advanced melanoma, but response rates are low and significant toxicities limit treatment to otherwise healthy patients. g209-2M is a nanopeptide engineered to mimic an epitope of the gp100 melanocyte differentiation protein that is recognized in a human leukocyte antigen (HLA)-restricted manner by melanoma tumor-infiltrating lymphocytes in some patients. Previous reports indicated that administration of the g209-2M peptide could induce g209-reactive circulating T cells in patients with melanoma and that the combination of g209-2M and high-dose IL-2 might be a more active treatment than high-dose IL-2 alone. Low-dose IL-2 is not active but has significant biologic effects, and because of a different toxicity profile, it can be offered to most patients. The primary objective of this cooperative group phase 2 study was to determine the activity of the combination of g209-2M and low-dose IL-2 in advanced melanoma. Twenty-six HLA appropriate patients with advanced melanoma received subcutaneous g209-2M peptide once every 3 weeks and subcutaneous IL-2 (5 million IU/m) daily for 5 days during the first and second weeks. Patients were monitored for tumor response, toxicity, and induction of g209-reactive circulating T cells. There were no objective responses. There were no toxic deaths and no grade 4 toxicities. More than half of the patients experienced some grade 2 toxicity and one quarter experienced grade 3 toxicity. There was no convincing evidence by enzyme-linked immunospot or tetramer analysis of induction of g209-reactive circulating T cells. The combination of g209-2M and low-dose IL-2 is safe and tolerable but inactive against advanced melanoma. Absence of evidence of immunization raises concerns for peptide-based immunization strategies with concurrent IL-2.

Melanoma of unknown primary: experience at Massachusetts General Hospital and Dana-Farber Cancer Institute

Melanoma may present metastatically without an identifiable primary lesion. To further characterize the epidemiology of melanoma of unknown primary (MUP), we report our experience with a cohort of MUP patients. We retrospectively reviewed patients seen at the Massachusetts General Hospital (MGH) and the Dana-Farber Cancer Institute (DFCI) between 1986 and 1996 with follow-up to 2002. Data were analysed using log-rank and proportional hazards analyses, with death from any cause as the main outcome measure. Of the 2485 melanoma patients seen, 65 (2.6%) had MUP; 41 patients were male [63.1%; 95% confidence interval (CI), 50.2%, 74.7%]. The median age at diagnosis was 54.1 years (interquartile range, 39.4-67.1 years). Thirty patients had lymph node metastases, 12 cutaneous or subcutaneous metastases and 23 visceral metastases. Of the 62 patients (95.4%) with at least some follow-up, there were 42 deaths from any cause. Patients with lymph node metastases survived significantly longer than patients with other metastases [5-year survival 38.7% (95% CI, 18.1%, 59.1%) vs. 13.9% (95% CI, 4.4%, 28.6%); P<0.01]. After adjusting for stage and age at diagnosis, there was some evidence that men survived longer than women [hazard ratio (HR)=0.55; 95% CI, 0.28, 1.09]. Survival did not differ amongst patients with different types of non-lymph node metastases. The 5-year survival rates in this cohort did not differ from those of historical controls with known primaries. The demographic and survival characteristics of this MUP cohort mirrored those found in previous studies. More studies of MUP patients, as well as a standardized definition of MUP, may shed light on the pathogenesis and prognosis of MUP.