Phase III randomized study of taselisib or placebo with fulvestrant in estrogen receptor-positive, PIK3CA-mutant, HER2-negative, advanced breast cancer: the SANDPIPER trial.

BACKGROUND: The phase III SANDPIPER study assessed taselisib (GDC-0032), a potent, selective PI3K inhibitor, plus fulvestrant in estrogen receptor-positive, HER2-negative, PIK3CA-mutant locally advanced or metastatic breast cancer. PATIENTS AND METHODS: Postmenopausal women with disease recurrence/progression during/after an aromatase inhibitor were randomized 2 : 1 to receive taselisib (4 mg; taselisib arm) or placebo (placebo arm) plus fulvestrant (500 mg). Stratification factors were visceral disease, endocrine sensitivity, and geographic region. Patients with PIK3CA-mutant tumors (central cobas® PIK3CA Mutation Test) were randomized separately from those without detectable mutations. The primary endpoint was investigator-assessed progression-free survival (INV-PFS) in patients with PIK3CA-mutant tumors. Secondary endpoints included objective response rate, overall survival, clinical benefit rate, duration of objective response, PFS by blinded independent central review (BICR-PFS), safety, and time to deterioration in health-related quality of life. RESULTS: The PIK3CA-mutant intention-to-treat population comprised 516 patients (placebo arm: n = 176; taselisib arm: n = 340). INV-PFS was significantly improved in the taselisib {7.4 months [95% confidence interval (CI), 7.26-9.07]} versus placebo arm (5.4 months [95% CI, 3.68-7.29]) (stratified hazard ratio [HR] 0.70; 95% CI, 0.56-0.89; P = 0.0037) and confirmed by BICR-PFS (HR 0.66). Secondary endpoints, including objective response rate, clinical benefit rate, and duration of objective response, showed consistent improvements in the taselisib arm. Safety was assessed in all randomized patients who received at least one dose of taselisib/placebo or fulvestrant regardless of PIK3CA-mutation status (n = 629). Serious adverse events were lower in the placebo versus taselisib arm (8.9% versus 32.0%). There were more discontinuations (placebo arm: 2.3%; taselisib arm: 16.8%) and dose reductions (placebo arm: 2.3%; taselisib arm: 36.5%) in the taselisib arm. CONCLUSION: SANDPIPER met its primary endpoint; however, the combination of taselisib plus fulvestrant has no clinical utility given its safety profile and modest clinical benefit.

Weekly paclitaxel with trastuzumab and pertuzumab in patients with HER2-overexpressing metastatic breast cancer: overall survival and updated progression-free survival results from a phase II study.

We previously reported progression-free survival (PFS) results on a phase II trial of weekly paclitaxel, trastuzumab, and pertuzumab in patients with human epidermal growth factor receptor 2(HER2)-positive metastatic breast cancer (MBC) treated in the first- and second-line setting. Here, we report results for overall survival (OS) and updated PFS after an additional year of follow-up. Patients with HER2-positive MBC with 0-1 prior treatment were eligible. Treatment consisted of paclitaxel (80 mg/m(2)) weekly, and trastuzumab (loading dose 8 mg/kg â†’ 6 mg/kg) and pertuzumab (loading dose 840 mg â†’ 420 mg) every 3 weeks, all given intravenously. Primary endpoint was 6-month PFS. Secondary endpoints included median PFS, 6-month and median OS. Evaluable patients received at least one full dose of treatment. From January 2011 to December 2013, 69 patients were enrolled: 51 (74 %) and 18 (26 %) treated in first- and second-line metastatic settings, respectively. As of July 1, 2015, the median follow-up was 33 months (range 3-49 months; 67 patients were evaluable for efficacy). The median OS was 44 months (95 % CI 37.5-NR) overall and 44 months (95 % CI 38.3-NR) and 37.5 months (95 % CI 30.3-NR) for patients with 0 and 1 prior metastatic treatment, respectively; 6-month OS was 98 % (95 % CI 90-1). The 6-month PFS was 86 % (95 % CI 75-93) overall and 89 % (95 % CI 76-95) and 78 % (95 % CI 51-91) for patients with 0 and 1 prior therapy, respectively; and median PFS was 21.4 months (95 % CI 14.1-NR) overall and 25.7 months (95 % CI 14.1-NR) and 16.9 months (95 % CI 8.5-NR) for patients with 0-1 prior treatment, respectively. Treatment was well tolerated. Updated analysis demonstrates that weekly paclitaxel, when added to trastuzumab and pertuzumab, is associated with a favorable OS and PFS and offers an alternative to docetaxel-based therapy. http://www.ClinicalTrials.gov NCT0127604.

Telomerase activity and telomere length in acute and chronic leukemia, pre- and post-ex vivo culture.

We studied telomerase regulation and telomere length in hematopoietic progenitor cells from peripheral blood and bone marrow from patients with acute and chronic leukemia and myeloproliferative diseases. CD34+ cells from a total of 93 patients with either acute myeloid leukemia (AML; n = 25), chronic myeloid leukemia (CML; n = 21), chronic lymphocytic leukemia (CLL; n = 18), polycythemia vera (PV; n = 16), or myelodysplastic syndromes (MDS; n = 13) were analyzed before and in 19 patients after ex vivo expansion in the presence of multiple cytokines (kit ligand, interleukin-3, interleukin-6, and granulocyte colony-stimulating factor plus erythropoietin). Compared with hematopoietic progenitor cells from normal donors (n = 108), telomerase activity (TA) was increased 2- to 5-fold in chronic phase (CP)-CML, CLL, PV, and MDS. In AML, accelerated phase (AP) and blastic phase (BP)-CML, basal TA was 10- to 50-fold higher than normal. TA of CP-CML CD34+ cells was up-regulated within 72 h of ex vivo culture, peaked after 1 week, and decreased below detection after 2 weeks. In contrast, TA in AP/BP-CML and AML CD34+ cells was down-regulated after 1 week of culture and decreased further thereafter. The expansion potential of CD34+ cells from patients with leukemia was considerably decreased compared with CD34+ cells from normal donors. The average expansion of cells from leukemic individuals was 6.5-, 2.3-, 0.6-, and 0.2-fold in weeks 1, 2, 3, and 4, respectively, whereas expansion of normal cells was 5- to 15-fold higher. In serial expansion culture, a median telomeric loss of 0.7 kbp was observed during 3-4 weeks of expansion. Our results demonstrate that up-regulation of telomerase is similar in CD34+ cells from CP-CML, CLL, PV, and MDS patients and in normal hematopoietic cells during the first week of culture, whereas in AML and AP/BP-CML, telomerase is high at baseline and down-regulated during expansion culture. High levels of telomerase in leukemic progenitors at baseline may be a feature of both the malignant phenotype and rapid cycling. Telomerase down-regulation during culture of leukemic cells may be due to the decreased expansion potential or repression of normal hematopoiesis, or in AML it may be due to the partial differentiation of AML cells, shown previously to be associated with loss of TA. Telomere shortening during ex vivo expansion correlated with low levels of TA, particularly in chronic leukemic and MDS progenitors where telomerase was insufficient to protect against telomere bp loss during intense proliferation.

A phase I trial of a single high dose of idarubicin combined with high-dose cytarabine as induction therapy in relapsed or refractory adult patients with acute lymphoblastic leukemia.

Relapsed or refractory adult acute lymphoblastic leukemia (ALL) carries a grave prognosis. The most promising strategy for curing these patients is through re-induction chemotherapy followed by successful allogeneic transplant. We studied a new high-dose induction regimen in order to improve the outcome for these patients. Eighteen adult patients with relapsed/refractory ALL were treated on a phase I study of high-dose cytarabine combined with a single escalating dose of idarubicin. Five patients had primary refractory disease and 13 were treated in refractory relapse. Nine patients (50%) had Ph+ ALL. The induction regimen was cytarabine 3 g/m2/day intravenously days 1-5 and idarubicin as a single intravenous dose on day 3. G-CSF 5 microg/kg subcutaneously every 12 h was started on day 7. The initial idarubicin dose was 20 mg/m2 with dose escalations of 10 mg m2. Cohorts of three patients were treated at each idarubicin dose level. Unacceptable toxicity was encountered at 50 mg/m2 with one death from infection and one death from cardiotoxicity in a patient with significant prior anthracycline exposure. There were no instances of grade 4 non-hematologic toxicity encountered at idarubicin doses of 20 mg/m2, 30 mg/m2, or 40 mg/m2. The data suggest a dose-response relationship for increasing doses of idarubicin with 0/3 complete responses (CR) at 20 mg/m2, 1/3 CR at 30 mg/m2, and 7/12 (58%) CR at idarubicin doses > or = 40 mg/m2. We conclude that concomitant administration of cytarabine 3 g/m2/day x 5 and high-dose idarubicin at 40 mg/m2 as a single dose on day 3 can be administered safely to patients with refractory and relapsed ALL.

Telomerase activity and telomere length in pediatric patients with malignancies undergoing chemotherapy.

Telomerase activity and telomere length in mononuclear cells (MNCs) and granulocytes from peripheral blood (PB) and bone marrow (BM) specimens were studied in pediatric acute leukemia (ALL, n = 15; AML, n = 11) and pediatric solid tumor (ST) patients (n = 9) at diagnosis, during and after chemotherapy. In four ST patients, tumor tissue was also available. For comparative analysis, MNCs from healthy donors (n = 53) were analyzed. Telomerase was evaluated using a modified telomeric repeat amplification protocol (TRAP) assay, and telomere length by terminal restriction fragment (TRF) analysis. At diagnosis, high telomerase activity was detected in MNCs from all leukemia patients, which was similar to the activity from ST biopsy specimens. This exceeded by 10- to 20-fold the activity in PB MNCs from ST patients and healthy donors (P < 0.05). Granulocyte fractions lacked telomerase activity in all groups. BM MNCs in leukemia patients revealed a four-fold higher telomerase activity than PB (P = 0.005). After induction chemotherapy and response to treatment, telomerase activity decreased to borderline or undetectable levels in PB MNCs in leukemia (P < 0.01). Average telomeres in PB MNCs from pediatric patients were significantly longer (n = 25; 10.9 kbp) than telomeres in PB and BM MNCs from adult healthy donors (7.45 kbp) (P < 0.0001). At diagnosis, telomeres were shorter from BM compared to PB specimens in leukemia (P < 0.05), and two peak TRFs were observed corresponding to the malignant and normal cell clones. With the attainment of remission, the lower TRF peak, reflecting the leukemic population, was lost. In leukemia patients, mean TRFs increased on average 2.2 kbp after induction chemotherapy, but decreased thereafter on consolidation and maintenance chemotherapy (1 kbp). This was comparable to an average telomere loss of 1.2 kbp in PB specimens from ST patients after chemotherapy. In all patients, telomere loss in granulocytes as compared to MNCs was more pronounced with 1.8 vs 1 kbp, respectively (P = 0.014). Our results demonstrate that at diagnosis, telomerase was consistently and highly upregulated in BM and PB specimens in leukemia, decreased after induction therapy, and correlated with remission. BM specimens in leukemia had higher telomerase activity, probably due to the greater leukemic burden than in PB. Telomeres were significantly longer in children than in adults, but shortened as a consequence of chemotherapy with repeated cycles of hematopoietic regeneration. In acute leukemia, with the loss of the leukemic burden after induction chemotherapy, longer mean TRFs were found, a reflection of the repopulation with normal cells. Our findings suggest that telomerase activity may be useful in the management of childhood malignancies. The significance of telomere length shortening in pediatric patients undergoing chemotherapy and possible telomere regeneration after myelosuppressive treatment remain to be determined.

Relative contribution of normal and neoplastic cells determines telomerase activity and telomere length in primary cancers of the prostate, colon, and sarcoma.

Telomerase and telomere length are increasingly investigated as potential diagnostic and prognostic markers in human tumors. Among other factors, telomerase and telomere length may be influenced by the degree of tumor cell content in tumor specimens. We studied telomerase activity and telomere length with concomitant integration of histopathological data to determine whether both were influenced by the amount of tumor cells. We measured telomerase in 153 specimens: in 51 solid tumor blocks; in 51 cryostat sections; and in 51 adjacent normal tissues from patients with sarcoma (n = 10) and colorectal (n = 11) and prostate cancer (n = 30) using the sensitive and rapid detection telomeric repeat amplification protocol assay. Telomere length was determined by telomere restriction fragment Southern blot analysis. From cryostat sections, tumor cell infiltration was assessed. Telomerase activity was detected in all colorectal tumors and sarcomas, as expected. In primary prostate cancer, however, telomerase activity was less frequently observed (14 of 30, 47%). Moreover, a decreased intensity compared to colon cancer and sarcoma was evident (P < 0.001). The median tumor cell infiltration was significantly higher in sarcoma (65%) and colon (30%) compared to prostate cancer (5%; P < 0.001). There was a positive correlation between tumor cell infiltration and telomerase activity (r = 0.89; P < 0.001). Telomere restriction fragments in tumors were shorter compared to the normal tissues with peak differences in colon, sarcoma, and prostate of 1.8, 2.8, and 1 kilobase pairs, respectively (P < 0.002). Our data suggest the presence of a positive correlation between the degree of tumor cell content in human solid tumors and the level of telomerase activity detected. We demonstrated that the amount of tumor cells also affects telomere restriction fragment analysis. Therefore, with the predominance of normal cells in tumor specimens, telomerase activity measured may not reflect the malignant phenotype, and telomere loss may be underestimated. This phenomenon was most evident in prostate cancer. Our results will have implications for the future when telomerase activity and telomere lengths may be used for early screening, diagnosis, and prognosis determinations and when telomerase inhibitors are applied to clinical practice.

Telomerase and telomere length in the development and progression of premalignant lesions to colorectal cancer.

Telomerase and telomere length are increasingly studied as prognostic markers in malignancy. Telomerase is also known to be expressed in certain nonmalignant cells, although generally at low levels. We investigated telomerase activity and telomere length in premalignant, malignant, inflammatory, and normal colon specimens to determine whether significant differences exist and whether telomerase may serve as a marker for early- or late-stage colorectal cancer. Telomerase activity was evaluated in 130 frozen specimens from human colon cancer (n = 50), adjacent normal colon tissue (n = 50), colon polyps (n = 20), and colitis (n = 10) using a modified telomeric repeat amplification protocol assay, and telomere length was assessed by terminal restriction fragment analysis. High to moderate levels of telomerase activity were detected in 90% of colorectal tumors. Weakly positive activity was detected in 10%. None of the normal tissues exhibited telomerase activity. In polyps and colitis, telomerase activity was found in 60% (12 of 20) and 40% (4 of 10), respectively. Telomerase activity in both nonmalignant lesions was 25- to 54-fold lower than that detected in colon cancer (P < 0.001). We found a positive correlation between tumor cell infiltration determined in cryostat sections and telomerase activity (r = 0.886; P > 0.0001). Late-stage tumors (Dukes C + D) demonstrated increased telomerase activity compared to early-stage tumors (Dukes A + B). Telomere restriction fragments in colon tumors had peak values of 4.8 +/- 1 kbp that were significantly and consistently shorter than those of the adjacent normal tissues (7.54 +/- 1.3 kbp), polyps (7.5 +/- 0.7 kbp), and colitis specimens (7.7 +/- 0.5kbp; P < 0.0001). Telomeres were 0.6 kbp longer in tumors with high telomerase activity and in late-stage cancers (Dukes C + D) compared to those in tumors with low telomerase activity and in early-stage cancers (Dukes A + B). Our data demonstrate that telomerase in colon cancer was commonly acquired, and activity was higher than that in polyps and colitis. However, weak telomerase activity was detected in premalignant and inflammatory lesions. Telomeres in colon cancer were considerably shorter, an indication of extensive cell proliferation and population divisions, whereas adjacent normal colon specimens, polyps, and colitis had comparable telomere lengths. Our results indicate that increased telomerase activity occurs in colon cancer cells that have undergone extensive telomere shortening relative to surrounding normal tissues and in which telomerase-induced stabilization of telomeres may be critical for the continued proliferation of the malignant clone. The link between telomerase activity and stage suggests that telomerase is up-regulated as a function of increased tumor cell invasion, tumor progression, and metastatic potential in colon cancer.