A phase 1 study of veliparib (ABT-888) plus weekly carboplatin and paclitaxel in advanced solid malignancies, with an expansion cohort in triple negative breast cancer (TNBC) (ETCTN 8620)

BACKGROUND

Veliparib is a poly-ADP-ribose polymerase (PARP) inhibitor, and it has clinical activity with every 3 weeks carboplatin and paclitaxel. In breast cancer, weekly paclitaxel is associated with improved overall survival. We aimed to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of veliparib with weekly carboplatin and paclitaxel as well as safety, pharmacokinetics, and preliminary clinical activity in triple negative breast cancer (TNBC).

METHODS

Patients with locally advanced/metastatic solid tumors and adequate organ function were eligible. A standard 3 + 3 dose-escalation design was followed by a TNBC expansion cohort. Veliparib doses ranging from 50 to 200 mg orally bid were tested with carboplatin (AUC 2) and paclitaxel (80 mg/m2) given weekly in a 21-day cycle. Adverse events (AE) were evaluated by CTCAE v4.0, and objective response rate (ORR) was determined by RECIST 1.1.

RESULTS

Thirty patients were enrolled, of whom 22 had TNBC. Two dose-limiting toxicities were observed. The RP2D was determined to be 150 mg PO bid veliparib with weekly carboplatin and paclitaxel 2 weeks on, 1 week off, based on hematologic toxicity requiring dose reduction in the first 5 cycles of treatment. The most common grade 3/4 AEs included neutropenia, anemia, and thrombocytopenia. PK parameters of veliparib were comparable to single-agent veliparib. In 23 patients with evaluable disease, the ORR was 65%. In 19 patients with TNBC with evaluable disease, the ORR was 63%.

CONCLUSION

Veliparib can be safely combined with weekly paclitaxel and carboplatin, and this triplet combination has promising clinical activity.

A phase 1 and pharmacodynamic study of chronically-dosed, single-agent veliparib (ABT-888) in patients with BRCA1- or BRCA2-mutated cancer or platinum-refractory ovarian or triple-negative breast cancer

PURPOSE

BRCA1 or BRCA2 mutated cancers (BRCAmut) have intrinsic sensitivity to PARP inhibitors due to deficiency in homologous recombination-mediated DNA repair. There are similarities between BRCAmut and BRCAwt ovarian and basal-like breast cancers. This phase I study determined the recommended phase II dose (RP2D) and preliminary efficacy of the PARP inhibitor, veliparib (ABT-888), in these patients.

PATIENTS AND METHODS

Patients (n = 98) were dosed with veliparib 50-500 mg twice daily (BID). The BRCAmut cohort (n = 70) contained predominantly ovarian (53%) and breast (23%) cancers; the BRCAwt cohort (n = 28) consisted primarily of breast cancer (86%). The MTD, DLT, adverse events, PK, PD, and clinical response were assessed.

RESULTS

DLTs were grade 3 nausea/vomiting at 400 mg BID in a BRCAmut carrier, grade 2 seizure at 400 mg BID in a patient with BRCAwt cancer, and grade 2 seizure at 500 mg BID in a BRCAmut carrier. Common toxicities included nausea (65%), fatigue (45%), and lymphopenia (38%). Grade 3/4 toxicities were rare (highest lymphopenia at 15%). Overall response rate (ORR) was 23% (95% CI 13-35%) in BRCAmut overall, and 37% (95% CI 21-55%) at 400 mg BID and above. In BRCAwt, ORR was 8% (95% CI 1-26%), and clinical benefit rate was 16% (95% CI 4-36%), reflecting prolonged stable disease in some patients. PK was linear with dose and was correlated with response and nausea.

CONCLUSIONS

Continuous veliparib is safe and tolerable. The RP2D was 400 mg BID. There is evidence of clinical activity of veliparib in patients with BRCAmut and BRCAwt cancers.

Phase II study of durvalumab following neoadjuvant chemoRT in operable rectal cancer: NSABP FR-2

99

Background: Although immunotherapy shows no benefit in microsatellite stable (MSS) colorectal cancer, preclinical models suggest that radiotherapy (RT) can enhance neoantigen presentation, modulate the microenvironment, and improve the likelihood of anti-tumor activity with checkpoint inhibitor use. Using a “window-of-opportunity” study design, this prospective phase II trial will determine the safety and activity of this approach with the anti-PD-L1 agent durvalumab (MEDI4736). Methods: Stage II/III patients (pts) with MSS rectal cancer undergoing standard NCCN guideline-compliant neoadjuvant chemoradiotherapy (CRT) followed by definitive surgery were eligible. Treatment included durvalumab (750mg IV infusion once every 2 wks) for 4 total doses beginning within 3-7 days after CRT completion followed by surgery within 8-12 wks of the final CRT dose. Primary end point (EP): Improvement in modified neoadjuvant rectal cancer (mNAR) score (goal 10.6) compared to historical controls (15.6) targeting a 20% DFS RR reduction and 3-4% absolute OS improvement. Secondary EPs: toxicity, pCR, cCR, therapy completion, negative surgical margins, sphincter preservation, and exploratory assessments of tumor-infiltrating lymphocytes, tumor Immunoscore, circulating immunologic profiles, and molecular predictors of response. We test H0: mNAR ≥15.6 vs HA: mNAR <15.6 at alpha 0.10 one-sided with statistical significance defined as p<0.1. Results: From May 2018 to October 2020, 45 pts were enrolled with 40 pts evaluable for mNAR. Mean mNAR was 12.03 (80% CI: 9.29-14.97) (p=0.06 one-sided). pCR=22.2%; cCR=31.1%; R0 resection=81.0%, and sphincter preservation=71.4%. Side effects were consistent with both CRT and durvalumab safety profile. Most common grade 3 AEs included diarrhea, lymphopenia, and back pain. There was one grade 4 AE (elevated amylase/lipase) and no grade 5 AEs. Remaining secondary and correlative immunologic end points are still being assessed. Conclusions: Durvalumab immediately following CRT prior to surgery for definitive management of rectal cancer was safe and without unexpected short-term toxicities. The primary end point of mean mNAR score was significantly less than our historical control, warranting further investigation. Correlative analyses for immunologic markers of response including PD-(L)1 expression and Immunoscore are ongoing. NCT 03102047. Support: AstraZeneca-Medimmune, NSABP Foundation. Clinical trial information: NCT03102047.

Combining neoadjuvant chemoradiation with adjuvant chemotherapy in multimodality treatment for patients with potentially curable esophageal carcinoma

e15574

Background: Optimal multimodality treatment followed by surgical resection results in cure for less than half of patients with operable adenocarcinoma of the lower esophagus or GEJ. The current standard of care is either neoadjuvant chemoradiation established by the CROSS trial or perioperative chemotherapy established by MAGIC trial. We aimed to investigate whether additional treatment beyond current standards of care might improve outcomes. Methods: We performed a phase II, single center, investigator initiated study assessing the combination of neoadjuvant chemoradiation followed by esophagectomy and adjuvant chemotherapy in patients with resected esophageal/GEJ cancer. All patients received neoadjuvant infusional 5-fluorouracil at 225mg/m2 for 5 days with concurrent radiation at a dose of 4500 cGy followed by esophagectomy and 6 cycles of adjuvant paclitaxel 200mg/m2 on day 1, carboplatin AUC 6 on day 1 and infusion 5-fluorouricil 225 mg/m2 on days 1-7 (PCF) on a 28-day cycle. Results: 27 patients with stage IIA-IIIB (AJCC7) esophageal/GEJ tumors were enrolled on the protocol between 1999 and 2007. There were 23 males and 4 females with a median age at diagnosis 58 years. Twenty-five patients had adenocarcinoma, 1 had squamous and 1 had adenosquamous histology with 14 tumors located in GEJ and 11 in lower 1/3 of esophagus. The time between the surgery to start of PCF was 2.4 months. Fifteen patients (55.6%) had an R0 resection margin at the time of surgery. Only 8 (30%) patients could complete all 6 cycles of planned adjuvant chemotherapy, median number of cycles of chemotherapy administered was 1. Patients were followed for 10 years. Median progression free and overall survival was estimated to be 11.9 and 18.8 months respectively. At present time only one patient is alive and free of disease. One patient passed from an unrelated malignancy. Conclusions: Inferior survival results in this small study may be attributed to difficulty delivering adjuvant chemotherapy after prior chemoradiation, extensive surgery and delayed recovery. Total neoadjuvant therapy may overcome these obstacles in management of esophageal/GEJ cancer patients and should be explored in future studies.

Abstract P3-11-10: Response to subsequent therapies after failure to achieve pathologic complete response (pCR) after neo-adjuvant chemotherapy (NAC) in patients (pts) with triple negative breast cancer (TNBC)

Background: More than half of pts with TNBC do not achieve a pCR after NAC, which carries a poor prognosis. It is unclear whether these patients respond to subsequent therapies on relapse. We sought to determine the time to progression (TTP) on subsequent therapies for recurrent disease in TNBC patients who did not achieve pCR to neo-adjuvant therapy.

Methods: We retrospectively identified 117 TNBC pts who received NAC from 2009 through 2012 using an electronic database at the Magee Women’s Breast Cancer Program at the University of Pittsburgh. Patient records were then assessed for pts who did not achieve a pCR for time to local or distant recurrence (TTR) and time to progression (TTP) on susbequent therapies.

Results: 86 of 117 TNBC pts did not achieve pCR to NAC defined as residual disease present in either the breast and/or axilla. Median follow up was 2 yrs (range 1-4yrs). Out of these 86 pts, 21 pts(25%) had recurrence in form of distant metastasis or local recurrence. Nearly all pts(95%) received anthracycline and taxane based NAC. Median TTR was 19 months (4-29 months). Therapies received in the metastatic setting most commonly included single agent capecitabine, paclitaxel, nab-paclitaxel, and eribulin. The most commonly received doublets included carboplatin with paclitaxel or gemcitabine. Median TTP on systemic chemotherapy was 15 weeks (3 -39 weeks), 6 weeks (1-24 weeks) and 6 weeks (2-9 weeks) in first, second and third line setting, respectively. Greater than 80% pts were able to receive two lines of systemic chemotherapy but &lt;50% received third line treatment. Two pts died before initiating any systemic treatment.

Conclusions: Response to subsequent chemotherapeutic regimens in metastatic setting in TNBC pts who do not achieve pCR to anthracycline and taxane based NAC is limited. This highlights the importance of identifying new agents and targeted therapies for this poor prognosis sub-type.

Citation Format: Shalu Pahuja, Kandace McGuire, Nancy Davidson, Adam Brufsky, Priya Rastogi, Rachel Jankowitz, Barry Lembersky, Shannon Puhalla. Response to subsequent therapies after failure to achieve pathologic complete response (pCR) after neo-adjuvant chemotherapy (NAC) in patients (pts) with triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-11-10.

Preliminary activity of veliparib (V) in BRCA2-mutated metastatic castration-resistant prostate cancer (mCRPC)

170

Background: Male BRCA mutation carriers have a 2-8-fold increased risk of prostate cancer when compared to the general population, and up to 3% of patients (pts) with prostate cancer carry an inherited mutation in BRCA1 or 2. The therapeutic implications of germline BRCA mutations in prostate cancer are largely unknown. BRCA mutation enhances sensitivity to inhibition of the PARP1 and PARP2 enzymes, due to a synthetic lethal effect on DNA repair. We therefore conducted a phase 1 study of the PARP 1, 2 inhibitor, veliparib (V), in 2 cohorts of pts- BRCA germline mutated (BRCA+) and BRCA-wild type (BRCA-wt; consisting of serous ovarian cancer and triple-negative breast cancer). Methods: A 3+3 dose escalation phase I trial was performed to determine a maximum tolerated dose (MTD) and recommended phase II dose (RP2D). V was administered orally continuously on a 28-day cycle. Results: A total of98 (70 BRCA+ and 28 BRCA-wt) pts were enrolled. The maximum administered dose (MAD) was 500 mg BID and the MTD/RP2D was 400 mg BID. In BRCA+ cohort at doses ≥ 400 mg BID, overall response rate (ORR) defined as complete response (CR)+ partial response (PR) was 37%, and clinical benefit rate (CBR) defined as CR+PR+stable disease (SD) > 6 cycles was 40%. Three pts with BRCA2+ metastatic castration-resistant prostate cancer (mCRPC) were enrolled on the RP2D and were evaluable for response. In these pts, the ORR was 2/3 (66%) and CBR 3/3 (100%) (summarized in table). One pt with rapidly progressive mCRPC involving liver and bone achieved PR and undetectable serum PSA, and remains on therapy at 19+ cycles. The most common adverse effects in these pts were grade 1/2 nausea/vomiting, fatigue, and leukopenia consistent with the overall study population. Conclusions: Single-agent V demonstrates evidence of activity in BRCA2+ mCRPC. These data support the role of genotype-directed therapy in prostate cancer. Clinical trial information: NCT00892736. [Table: see text]

Outcome of BRCA 1/2-mutated (BRCA+) and triple-negative, BRCA wild type (BRCA-wt) breast cancer patients in a phase I study of single-agent veliparib (V)

135

Background: Veliparib (V) (ABT-888) is an oral, potent inhibitor of PARP 1/2. PARP inhibitors have preclinical and clinical efficacy in BRCA+ malignancies. There are genotypic and phenotypic similarities between BRCA+ cancers, serous ovarian cancer and basal-like breast cancer and we postulated that these tumors types may be similarly sensitive to single-agent PARP inhibition. This study sought to establish the maximum tolerated dose (MTD), dose -limiting toxicities (DLT), pharmacokinetic and pharmocodynamic properties, and preliminary efficacy of chronically-dosed V in 2 cohorts of patients, BRCA+ and BRCA-wt (consisting of serous ovarian cancer and triple-negative breast cancer (TNBC). Methods: A 3+3 dose escalation phase I trial was performed. Nine dose levels (DL) were planned, and dose escalation started at 50 mg BID to a maximum of 500 mg BID to determine a maximum tolerated dose (MTD) and recommended phase II dose (RP2D). V was administered orally continuously on a 28 day cycle. BRCA+ and BRCA-wt patients were enrolled in 2 separate cohorts with 2 separate escalations. Results: 98 (70 BRCA+ and 28 BRCA-wt) pts have been enrolled. The maximum administered dose (MAD) was 500mg BID and the MTD/RP2D is 400mg BID for both cohorts. 59 BRCA+ pts and 24 BRCA-wt pts (21 TNBC and 3 ovary) were evaluable for response. ORR was defined as CR+PR and clinical benefit rate (CBR) as CR+PR+SD > 6 months. Results are summarized in the table. Conclusions: There is evidence of anti-tumor activity with V comparable to that of other PARP inhibitors in the BRCA+ population. There was indication of dose responsiveness with greater activity in this population at higher doses. There is less activity in the mostly TNBC, BRCA-wt population, although there was evidence of benefit in a small number of patients. Ongoing tissue correlative studies will help to identify potential mechanisms of sensitivity and resistance. Clinical trial information: NCT00892736. [Table: see text]

Neoadjuvant therapy for high-risk bulky regional melanoma

Clinically detectable regional lymph node melanoma metastasis (AJCC stage IIIB-C) carries a risk of relapse and death that approaches 70% at 5 years. Surgical management is the cornerstone of therapy, with postoperative adjuvant therapy utilizing high-dose interferon alfa-2b (HDI). Neoadjuvant chemotherapy or immunotherapy in addition to surgery has been demonstrated to improve outcome in the management of patients with a variety of solid tumors. In patients with melanoma, the characteristics of the host immune response differ between patients with earlier stage and those with more advanced stages of disease (and particularly between those with measurable active disease and those without measurable gross disease) providing rationale for neoadjuvant approaches with immunotherapy. Host immune tolerance is now understood to impede the results of therapy for advanced disease, but appears to be less an issue for patients with microscopic high-risk operable disease, where the host may be more susceptible to immunologic interventions. Phase II studies have shown that neoadjuvant biochemotherapy has limited activity in melanoma patients with local-regional metastases, where chemotherapy may potentially alter the effects of immunotherapeutic agents. Studies of neoadjuvant HDI therapy for high-risk melanoma patients with bulky regional stage IIIB-C lymphadenopathy have shown unexpectedly high clinical and pathologic response rates, without increased morbidity. Through the design of neoadjuvant trials utilizing promising emerging melanoma therapeutics in which it is possible to obtain biopsy samples before and after therapy, a greater understanding of the dynamic interaction between tumors and the immune system is possible. This should lead to the identification of new targets for the treatment of melanoma and aid the development of new immunotherapy that may have greater specificity and less toxicity. This will simplify the evaluation of promising new combinations of agents with HDI to build on the clinical, immunologic, and molecular effect of this therapy for patients with melanoma.

Abrogation of tumor necrosis alpha (TNF-alpha) pathway by anti-TNF therapy in hematological malignancies

7093

Background: Tumor necrosis factor-alpha (TNF-alpha) enhances tumor growth and mediates cancer-related inflammatory symptoms by inducing secretion of cytokines. Anti-TNF approaches have been evaluated in pilot studies for cancer treatment and for alleviation of cancer related cachexia, fatigue, and other constitutional symptoms with conflicting results. While the incidence of malignancies with TNF alpha inhibitors (infliximab, adalimumab, etanercept) are not significantly higher than the untreated control population, their role in cancer treatment itself is unclear. We explored the activity and tolerance of TNF-alpha inhibitors in various hematological malignancies. Methods: We reviewed the English literature by conducting systematic MEDLINE using the terms TNF-, infliximab, adalimumab, etanercept, cancer therapy, hematologic malignancies, myelodysplastic syndrome (MDS), multiple myeloma (MM), myeloproliferative disease (MPD), chronic lymphocytic leukemia (CLL), and lymphoma from January 2001 to August 2008. We also performed a complete literature search of American Society of Hematology (ASH) and American Society of Clinical Oncology (ASCO) published abstracts. Studies were analyzed for observed activity of TNF alpha inhibitors and also for reported safety. Results: Overall 11 phase I and II studies (n = 237; CLL n = 44, MM n = 10, MDS n = 109, MPD n = 51, HCL n = 3, TCL 13, FL 7) that involved anti-TNF- therapy in hematological malignancies were identified. As a single agent, etanercept did not yield significant responses. In conjunction with ATG or azacitidine in low-/intermediate-risk MDS, TNF inhibitors resulted in improvement in cytopenia. Improvement in constitutional symptoms were noted in at least 50% of patients with myelofibrosis(MF)/Ph- MPD. No significant clinical benefit was seen among lymphoproliferative disorders, but treatment was well tolerated. Conclusions: Existing data suggests that anti-TNF therapy by itself does not induce a therapeutic response in hematologic malignancies. Combination strategy with TNF inhibitors has to be evaluated further to determine any anti-tumor activity and their role to alleviate constitutional symptoms particularly in MF/MPD.

No significant financial relationships to disclose.

Correlation of surface expression of CD11b or CD32 in polymorphonuclear cells (PMNs) and CD69 in natural killer cells (NK) with progression-free survival (PFS) following chemoimmunotherapy with rituximab and liposomal doxorubicin (LD) in patients (pts) with relapsed or refractory B-cell lymphoma

8583

Antibody dependent cellular citotoxicity (ADCC) play a significant role in rituximab's anti-tumor activity. FcγRIIIa polymorphisms have been associated with clinical responses to rituximab. The predictive value of FcγRIIIa polymorphisms is lost when rituximab is combined with chemotherapy. Alternative assays to assess the immune system had not been studied in patients treated with rituximab plus chemotherapy. To this end, we prospectively studied the pre-treatment quality and function of PMNs and NK cells from pts with refractory/relapsed B-cell lymphomas in a Phase I/II trial. Forty-two B-cell lymphoma patients pts completed treatment. Demographics: 22M:20F; Median age = 61.8 (range 35–83); Patients received R (375 mg/m2/dose) on day 1 and LD (30 mg/m2/dose) on day 3 q21 day × 6 cycles. Pre-treatment flow cytometry was performed to assess surface expression of CD11b, CD62, CD69, CD16, CD32 and CD64 in PMNs or NKcells was performed. Serum or PBMC's were isolated from each patient and used 51Cr release assays to study rituximab-associated complement mediated cytotoxicity (CMC) or ADCC. To correlate laboratory parameters with response rate, and PFS patients were divided in tertiles. Overall, R+LD was very well-tolerated. Overall response rate (ORR) = 68% (39% CR, 19% PR); median time-to-progression (TTP) = 12 m. Surface expression of CD32 in PMNs, and CD69 in NKcells correlated with better response rates. Surface expression of CD11b and CD32 in the PMN's correlated with a longer PFS (P = 0.040 and P = 0.015, respectively).There was a non-statistically significant trend towards an improved in PFS in those patients whom their PBMC's exhibited a higher degree of ex-vivo rituximab ADCC. Our data suggest that R+LD is a safe and effective regimen and that the quality of the immune system prior to a chemo-immunotherapy regimen may play a role in clinical outcomes, specifically the expression of CD11b and CD32 in PMNs or CD69 in NKcells. Our data supports further research in seeking ways to enhance the quality of the immune system to improve responses to rituximab ± chemotherapy.

[Table: see text]

Neuroglial cyst: a rare occurence in abdomen and pelvis

We hereby report a case of a child who presented with abdominal distension and urinary retention. Radiological investigations and exploratory laparotomy revealed a cystic mass in the sacral region pushing the urinary bladder anteriorly and upwards. Histopathological examination revealed neuroglial elements. Neuroglial cysts are uncommon outside the central nervous system and this is the first report of its occurrence in abdomen and pelvis.