Phase I/II trial of palbociclib, pembrolizumab and letrozole in patients with hormone receptor-positive metastatic breast cancer

BACKGROUND

CDK4/6 inhibitors modulate immune response in breast cancer. This phase I/II trial was designed to test the safety and efficacy of palbociclib, pembrolizumab and letrozole in women with hormone receptor positive (HR⁺) human epidermal growth factor receptor 2 negative (HER2^-) metastatic breast cancer (MBC).

PATIENTS AND METHODS

Women with stage IV HR⁺ HER2^- MBC were enrolled and treated with palbociclib, pembrolizumab and letrozole. Primary end-points were safety, tolerability and efficacy.

RESULTS

Between November 2016 and July 2020, 23 patients were enrolled with 20 evaluable for response, including 4 patients in cohort 1 and 16 patients in cohort 2. Cohort 1 median age was 48 years (33-70) and cohort 2 median age was 55 (37-75). Cohort 1 closed early due to limited accrual. Grade III-IV adverse events were neutropenia (83%), leucopaenia (65%), thrombocytopenia (17%) and elevated liver enzymes (17%). In cohort 1, 50% achieved a partial response (PR) and 50% had stable disease (SD). In cohort 2, 31% achieved complete response (CR), 25% had PR and 31% had SD by Response Evaluation Criteria in Solid Tumours version 1.1. Median progression-free survival was 25.2 months (95% confidence interval [CI] 5.3, not reached) and median overall survival was 36.9 months (95% CI 36.9, not reached) in cohort 2 with a median follow-up of 24.8 months (95% CI 17.1, not reached). A correlative immune biomarker analysis was published separately.

CONCLUSION

The combination of palbociclib, pembrolizumab and letrozole is well tolerated, and a complete response rate of 31% was identified in HR⁺ MBC patients who received this combination as front-line therapy. Confirmatory trials are required to better understand the immune-priming effects of CDK4/6 inhibitors.

Phase 1 study of the Aurora kinase A inhibitor alisertib (MLN8237) combined with the histone deacetylase inhibitor vorinostat in lymphoid malignancies

Alisertib, an Aurora kinase A inhibitor, was evaluated in a Phase 1 study in combination with the histone deacetylase inhibitor vorinostat, in patients with relapsed/refractory lymphoid malignancies (N = 34; NCT01567709). Patients received alisertib plus vorinostat in 21-day treatment cycles with escalating doses of alisertib following a continuous or an intermittent schedule. All dose-limiting toxicities (DLTs) were hematologic and there were no study-related deaths. The recommended phase 2 dose (RP2D) of the combination was 20 mg bid of alisertib and 200 mg bid of vorinostat on the intermittent schedule. A 13-patient expansion cohort was treated for a total of 18 patients at the RP2D. There were no DLTs at the RP2D, and toxicities were mainly hematologic. Two patients with DLBCL achieved a durable complete response, and two patients with HL achieved partial response. Alisertib plus vorinostat showed encouraging clinical activity with a manageable safety profile in heavily pretreated patients with advanced disease.

Results of a prospective phase 2 study of pazopanib in patients with surgically unresectable or metastatic chondrosarcoma

BACKGROUND

This single-arm, multicenter, phase 2 study evaluated the safety and antitumor activity of pazopanib in patients with unresectable or metastatic conventional chondrosarcoma.

METHODS

Eligible patients had conventional chondrosarcoma of any grade with measurable tumors that were unresectable or metastatic. Patients with mesenchymal, dedifferentiated, and extraskeletal myxoid chondrosarcoma subtypes and patients who received prior tyrosine kinase inhibitor therapy were excluded. Pazopanib at 800 mg once daily was administered for 28-day cycles. Tumor responses were evaluated by local radiology assessments every 2 cycles. The primary endpoint was the disease control rate (DCR) at week 16 (4 cycles).

RESULTS

Forty-seven patients were enrolled. The DCR at 16 weeks was 43% (95% confidence interval [CI], 28%-58%), which was superior to the null hypothesis rate of 30%, but the 2-sided P value (exact test) was .09 (1-sided P = .045). One patient had a partial response. The median overall survival was 17.6 months (95% CI, 11.3-35.0 months), and the median progression-free survival was 7.9 months (95% CI, 3.7-12.6 months). Grade 3 or higher adverse events were infrequent; hypertension (26%) and elevated alanine aminotransferase (9%) were most common.

CONCLUSIONS

This study provides evidence of positive drug activity for pazopanib in conventional chondrosarcoma.

Phase I study of the halichondrin B analogue eribulin mesylate in combination with cisplatin in advanced solid tumors

BACKGROUND

Eribulin mesylate is a synthetic macrocyclic ketone analogue of Halichondrin B that has demonstrated high antitumor activity in preclinical and clinical settings. This phase I study aimed to determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), and pharmacokinetics in combination with cisplatin (CP) in patients with advanced solid tumours.

METHODS

Thirty-six patients with advanced solid tumours received eribulin mesylate 0.7-1.4 mg m(-2) and CP 60-75 mg m(-2). Eribulin mesylate was administered on days 1, 8, and 15 in combination with CP day 1 every 28-day cycle. The protocol was amended after dose level 4 (eribulin mesylate 1.4 mg m(-2), CP 60 mg m(-2)) when it was not feasible to administer eribulin mesylate on day 15 because of neutropenia; the treatment schedule was changed to eribulin mesylate on days 1 and 8 and CP on day 1 every 21 days.

RESULTS

On the 28-day schedule, three patients had DLT during the first cycle: grade (G) 4 febrile neutropenia (1.0 mg m(-2), 60 mg m(-2)); G 3 anorexia/fatigue/hypokalemia (1.2 mg m(-2), 60 mg m(-2)); and G 3 stomatitis/nausea/vomiting/fatigue (1.4 mg m(-2), 60 mg m(-2)). On the 21-day schedule, three patients had DLT during the first cycle: G 3 hypokalemia/hyponatremia (1.4 mg m(-2), 60 mg m(-2)); G 4 mucositis (1.4 mg m(-2), 60 mg m(-2)); and G 3 hypokalemia (1.2 mg m(-2), 75 mg m(-2)). The MTD and recommended phase II dose was determined as eribulin mesylate 1.2 mg m(-2) (days 1, 8) and CP 75 mg m(-2) (day 1), on a 21-day cycle. Two patients had unconfirmed partial responses (PR) (pancreatic and breast cancers) and two had PR (oesophageal and bladder cancers).

CONCLUSIONS

On the 21-day cycle, eribulin mesylate 1.2 mg m(-2), administered on days 1 and 8, in combination with CP 75 mg m(-2), administered on day 1 is well tolerated and showed preliminary anticancer activity.

Facultative use of thelytokous parthenogenesis for queen production in the polyandrous ant Cataglyphis cursor

The evolutionary paradox of sex remains one of the major debates in evolutionary biology. The study of species capable of both sexual and asexual reproduction can elucidate factors important in the evolution of sex. One such species is the ant Cataglyphis cursor, where the queen maximizes the transmission of her genes by producing new queens (gynes) asexually while simultaneously maintaining a genetically diverse workforce via the sexual production of workers. We show that the queen can also produce gynes sexually and may do so to offset the costs of asexual reproduction. We genotyped 235 gynes from 18 colonies and found that half were sexually produced. A few colonies contained both sexually and asexually produced gynes. Although workers in this species can also use thelytoky, we found no evidence of worker production of gynes based on genotypes of 471 workers from the six colonies producing sexual gynes. Gynes are thus mainly, and potentially exclusively, produced by the queen. Simulations of gynes inbreeding level following one to ten generations of automictic thelytoky suggest that the queen switches between or combines thelytoky and sex, which may reduce the costs of inbreeding. This is supported by the relatively small size of inbred gynes in one colony, although we found no relationship between the level of inbreeding and immune parameters. Such facultative use of sex and thelytoky by individual queens contrasts with other known forms of parthenogenesis in ants, which are typically characterized by distinct lineages specializing in one strategy or the other.

A phase I/II prospective, single arm trial of gefitinib, trastuzumab, and docetaxel in patients with stage IV HER-2 positive metastatic breast cancer

Inhibition of the HER-2 pathway via the monoclonal antibody trastuzumab has had a major impact in treatment of HER-2 positive breast cancer, but de novo or acquired resistance may reduce its effectiveness. The known interplay between the epidermal growth factor receptor (EGFR) and HER-2 receptors and pathways creates a rationale for combined anti-EGFR and anti-HER-2 therapy in HER-2 positive metastatic breast cancer (MBC), and toxicities associated with the use of multiple chemotherapeutic agents together with biological therapies may also be reduced. We conducted a prospective, single arm, phase I/II trial to determine the efficacy and toxicity of the combination of trastuzumab with the EGFR inhibitor gefitinib and docetaxel, in patients with HER-2 positive MBC. The maximum tolerated dose (MTD) was determined in the phase I portion. The primary end point of the phase II portion was progression-free survival (PFS). Immunohistochemical analysis of biomarker expression of the PKA-related proteins cAMP response element-binding protein (CREB), phospho-CREB and DARPP-32 (dopamine and cAMP-regulated phosphoprotein of 32 kDa) plus t-DARPP (the truncated isoform of DARPP-32); PTEN; p-p70 S6K; and EGFR was conducted on tissue from metastatic sites. Nine patients were treated in the phase I portion of the study and 22 in the phase II portion. The MTD was gefitinib 250 mg on days 2-14, trastuzumab 6 mg/kg, and docetaxel 60 mg/m(2) every 21 days. For the 29 patients treated at the MTD, median PFS was 12.7 months, with complete and partial response rates of 18 and 46%, and a stable disease rate of 29%. No statistically significant correlation was found between response and expression of any biomarkers. We conclude that the combination of gefitinib, trastuzumab, and docetaxel is feasible and effective. Expression of the biomarkers examined did not predict outcome in this sample of HER-2 overexpressing metastatic breast cancer.

Phase II study of aflibercept (VEGF-Trap) in patients (pts) with recurrent or metastatic transitional cell carcinoma (TCC) of the urothelium: A California Cancer Consortium trial

e16030

Background: The role and efficacy of subsequent systemic therapies for advanced TCC following failure of frontline platinum-based chemotherapy is unclear. There is evidence that vascular endothelial growth factor (VEGF) is important in the pathophysiology of TCC. Aflibercept is a recombinant fusion protein that binds and neutralizes multiple VEGF isoforms. Methods: Pts with measurable, metastatic or locally advanced urothelial TCC previously treated with one platinum-containing regimen were entered. Aflibercept was given at 4 mg/kg IV q 2 weeks. Response rate (RR) and progression free survival (PFS) were assessed in a 2-stage accrual design (22+18). A maximum of 40 pts were to be accrued to rule out a null hypothesized RR of 4% and PFS of 3 months versus alternative of 15% RR and 5.4 months PFS with α=0.12 and β=0.19. Results: 22 pts were accrued between 11/06–2/08. Pt characteristics: M/F 15/7; Median age 67 years (45–79); 18 had bladder primary. One partial response (4.5% RR) was seen in a pt with nodal metastasis. Median PFS was 3.5 months (95% CI: 1.8–4.1). Attributable grade 3 toxicities included: hypertension (2), proteinuria (1), pulmonary hemorrhage (1), back pain (1), upper GI bleed (1), hyponatremia (1), anorexia (1) and fatigue (1). There were no attributable grade 4+ toxicities Conclusions: Aflibercept was well tolerated with toxicities similar to those seen with other VEGF pathway inhibitors, however it has limited single agent activity in platinum-pretreated TCC pts.

[Table: see text]

Phase II study of aflibercept (VEGF trap) in recurrent inoperable stage III or stage IV melanoma of cutaneous or ocular origin

9028

Background: Aflibercept is a fusion protein combining the Fc portion of human IgG1with the extracellular ligand-binding domains of human VEGFR1 and VEGFR2, acting as a high-affinity soluble VEGF receptor and potent angiogenesis inhibitor. Methods: Phase II study of aflibercept in patients with inoperable stage III or IV melanoma who had received no prior chemotherapy or hormonal therapy. A 2-stage design was adopted focusing upon response rate (RECIST) and 4-month PFS rate. First stage accrual of 21 patients was specified, while final accrual of 41 is planned, with adequate response/4 month PFSR. Aflibercept was given at 4 mg/kg IV every 2 weeks. Response was assessed every 8 weeks. Results: Twenty seven patients (16 male, 11 female), age 23–83 (median 58) have been enrolled to date. All had AJCC stage IV melanoma (3M1a, 3M1b, 21M1c). Karnofsky PS: 100 (13), 90 (11) or 80 (3). Nine patients had primary ocular melanoma, 16 cutaneous and 2 unknown primary site. A total of 160 cycles have been administered (median 4; range 1–18). Grade 3/4 toxicities included cerebral ischemia (1 patient; 4%), confusion (1; 4%), thrombocytopenia (1; 4%), hypertension (7; 26%), hypotension (1; 4%), left ventricular diastolic dysfunction (1; 4%), fatigue (1; 4%), proteinuria (4; 15%), extraocular muscle paresis (1; 4%), renal failure (1; 4%), back pain (1; 4%), headache (1; 4%). Interim analysis was conducted after the first 21 patients (stage 1). Eight (1 M1a, 1M1b, 6M1c; 4 ocular, 3 cutaneous, 1 unknown primary) of the first 21 patients had at least 4 months of PFS (10 out of 27; 2 additional patients with cutaneous melanoma had SD: 1M1a and 1M1c). One patient (23rd; cutaneous, M1c) had a confirmed complete remission. Four patients were taken off study prior to response evaluation for toxicity (3) or treatment refusal (1). One patient is currently disease free who was not evaluable for response (previous surgery and radiofrequency ablation of measurable disease site). Eleven patients had progression. Conclusions: Aflibercept can be administered with acceptable toxicity, and exhibits promising antitumor efficacy against advanced melanoma. This study continues second stage accrual with anticipated closure before June 2009.

[Table: see text]

Phase II study of hydroxyurea and gemcitabine in recurrent or persistent squamous cell cancer of the head and neck

15524

Background: Preclinical studies demonstrate increased activity when hydroxyurea (HU) is given prior to gemcitabine (G). Clinical feasibility was demonstrated in a phase I trial (Yen, et. al. Cancer Chemother Pharmacol. 2002 ). We performed a phase II trial treating patients (pts) with squamous cell head and neck cancers (SCCHN). Methods: Pts had metastatic or incurable locally recurrent SCCHN. Prior chemotherapy was allowed, but not required. Serum creatinine ≤2.0 mg/dl, bilirubin <3.0 gm/dl, AST/ALT <5× ULN and KPS ≥60% were required. HU 500 mg orally every 6 hours for 4 doses was given on day 1 of a 21-day cycle. On day 2, 6 hours after HU, G 750 mg/m2 was given over 30 minutes. This sequence was repeated on day 8 and 9. After 8 pts, G was given at 500 mg/m2. G-CSF was given on day 10 and until the WBC count was >10k/μl. The primary endpoint was response rate (RR), with an early stopping rule for <3 objective responders among the first 18 pts. Results: 22 pts (17 M) were accrued, 16 with prior chemotherapy and 19 with prior radiation. The first 8 pts received G 750 mg/m2. Two pts died of neutropenic fever (NF) during course 1. Subsequently 14 pts received G 500 mg/m2. 18 pts were evaluable for response, with 1 still in follow-up. Partial response was seen in 1 pt, stable disease in 9, and progressive disease in 8. The overall median survival of the 22 pts was 6 months and the median progression free survival (PFS) was 2 months. The primary toxicity was hematologic. Grade 4 neutropenia was seen in 7/22 pts during the 1st cycle (5 at G 750 mg/m2) with 5 cases of NF. Grade 4 thrombocytopenia occurred in 1 pt at G 750 mg/m2. Conclusions: The RR and PFS of treated pts treated were not promising and further accrual is not planned. Analysis of biopsy materials is planned to see if responsive pts can be selected. (Supported by NCI Grant CA33572).

No significant financial relationships to disclose.

Maintenance thalidomide following single cycle autologous peripheral blood stem cell transplant in patients with multiple myeloma

Although autologous stem cell transplant is an effective therapy for patients with multiple myeloma and extends progression-free survival (PFS) and overall survival (OS), patients show a continued pattern of recurrent disease. Twenty-nine patients were enrolled in a phase II study investigating the tolerability and efficacy of maintenance thalidomide following single autologous peripheral blood stem cell transplant. Six to eight weeks after transplant, patients were started on maintenance thalidomide at 50 mg a day. The dose was gradually escalated to a target dose of 400 mg a day and continued until disease progression or 6 months after achieving complete remission (CR) for a maximum total duration of 18 months. At 6 months, 13 patients (45%) achieved CR or near complete remission (positive immunofixation without any evidence of disease). The estimated 2-year OS was 83% and PFS was 49%. Median tolerated dose of thalidomide was 200 mg a day. In conclusion, thalidomide as maintenance therapy is feasible and may improve outcome after single autologous stem cell transplant.

Predictors of survival after coronary bypass grafting in patients with total occlusion of the left main coronary artery

Twenty-three patients with angiographically documented total occlusion of the left main coronary artery were retrospectively identified. Statistical analysis suggests that poor right-to-left collaterals and the presence of concurrent significant right coronary artery disease were weakly associated with decreased survival after bypass surgery.