Wu, Christina

Abstract Importance The addition of agents targeting critical signal mediators of cancer cell proliferation such as cyclin-dependent kinases (CDK) potentiates the efficacy of platinum chemotherapy. Objective To determine the safety and efficacy of palbociclib combined with cisplatin (cis) or carboplatin (carbo) in advanced solid malignancies Design Enrollment on dose escalation (part I) proceeded using the Bayesian adaptive design Escalation with Overdose Control (EWOC). Setting Single institution investigator initiated trial. Participants Patients with any advanced cancer after at least one prior therapy were enrolled on dose escalation to determine recommended phase II doses (RP2D). Expansion cohorts were then opened for pancreaticobiliary tract cancers. Intervention Escalating doses of palbociclib in combination with different doses of cisplatin or carboplatin. Main Outcomes and Measures Primary endpoint was objective response rate (ORR). Secondary endpoints included safety, overall survival (OS), and progression-free survival (PFS). Results We enrolled 39 patients on dose escalation (part I) and 32 additional patients on dose expansion (part II). RP2D of palbociclib 100 mg on Day 2-22 + Cisplatin (cis) 60 mg/m2 IV on Day 1 Q4W (Arm A); and palbociclib 75 mg on Day 2-22 + Carboplatin (carbo) AUC 6 IV on Day 1 Q4W (Arm B). ORR for Part I were 12.5% (Arm A) and 25% (Arm B). Median PFS and OS for dose expansion were 2.1 and 4.9 months, respectively. For PDAC, mPFS was 1.9 months (95% CI: 1.7, 2.4), and OS was 3.7 months (95% CI: 2.7, 5.7). Most common treatment-related adverse events (TRAEs—all grade %): Arm A—neutropenia (66%), thrombocytopenia (26%), nausea, fatigue, and anemia (20% each); Arm B—neutropenia (64.7%), thrombocytopenia (53%), and anemia (29%). There were no grade 4-5 TRAEs. Conclusions and Relevance The combination of palbociclib with cisplatin or carboplatin had an acceptable safety profile and clinical responses in some treatment refractory advanced cancers. There was no objective response, but about half of PDAC patients had disease stabilization. Additional efforts are needed to exploit CDK abnormalities in these patients. Clinical trial registration number: NCT02897375

e16265 Background: The pivotal TOPAZ-1 trial established durvalumab plus gemcitabine and cisplatin (GC) as a new first-line standard of care for advanced biliary tract cancer (ABTC). However, weekly administration of GC can lead to significant toxicity limiting its tolerability in clinical practice. Based on previous studies, we implemented biweekly regimen of GC on days 1 and 15 together with durvalumab on day 1 of each 28-day cycle to optimize the treatment delivery and improve tolerability. Here, we report the Mayo Clinic experience with biweekly GC with monthly durvalumab in patients with ABTC. Methods: At our three-site institution, we retrospectively identified patients with ABTC between January 2021 and August 2024, who received biweekly GC with monthly durvalumab. Patient demographics, tumor characteristics, treatment details - treatment related adverse events (trAEs) graded according to the NCTCAE V5.0 were collected. Outcomes included median progression-free survival (mPFS), median overall survival (mOS) and clinically assessed overall response rate (ORR) and disease control rate (DCR). Results: 57 patients were included in our analysis, median age was 68 years (range 35-90), and 57.9% were females. 91.2% of patients had ECOG performance status of 0-1. 71.9% had intrahepatic cholangiocarcinoma, 19.3% extrahepatic cholangiocarcinoma and 8.7% gallbladder carcinoma. 70.2% had metastatic disease, 21 % locally advanced unresectable disease and 8.7% recurrent metastatic disease. Patients were followed for a median of 9.1 months (2.3-28.5). 91.2% of the patients received biweekly GC plus monthly durvalumab while 8.8% switched from weekly to biweekly GC plus monthly durvalumab due to treatment toxicities. Median number of treatment cycles was 5. Maintenance regimens included durvalumab (19.3%), gemcitabine/durvalumab (8.8%) and GC/durvalumab (8.8%). Median duration of follow up was 9.1 months (range 2.3 – 28.5). ORR was 36.9% and DCR was 72% (complete response 5.3%, partial response 31.6% and stable disease 35.1%). mPFS was 7.2 months, while mOS was 16 months. Grade(G) 3 or 4 trAEs included abnormal liver function tests (15.7%), infections (11.5%), anemia (8.7%), thrombocytopenia (5.2%), peripheral neuropathy (1.7%), acute kidney injury (1.7%). Immune-related AEs were noted in 6 patients (10.5%) including colitis, gastritis, hepatitis, myocarditis and hypothyroidism. There was no patient with severe neutropenia or febrile neutropenia. Only 5 patients (8.8%) stopped treatment due to trAEs. Conclusions: Biweekly GC on days 1 and 15 plus durvalumab on day 1 of each 28-day cycle is associated with a more favorable toxicity profile while maintaining efficacy similar to that observed in the TOPAZ-1 trial indicating that a de-escalation strategy is feasible with improvement in patient centered outcomes.

Background: Treatment with nab-paclitaxel with gemcitabine demonstrates a survival advantage when compared with single-agent gemcitabine. However, the combination is associated with significant toxicities, leading to a high rate of drug discontinuation. We implemented a modified regimen of gemcitabine and nab-paclitaxel (mGNabP) in an attempt to minimize toxicities while maintaining efficacy. Methods: A total of 79 evaluable patients with metastatic pancreatic adenocarcinoma (mPC) treated with a modified regimen of gemcitabine (1000 mg/m 2 ) and nab-paclitaxel (125 mg/m 2 ) on days 1, 15 of every 28-day cycle were identified from our prospective database. A total of 57 patients received this regimen as first-line treatment and were evaluated for toxicities, progression-free survival (PFS), and overall survival (OS). Overall, 22 patients with advanced or metastatic PC treated with the modified regimen outside the first-line setting were only evaluated for toxicities. Results: The median OS and PFS were 10 months [95% confidence interval (CI) 5.9–13 months] and 5.4 months (95% CI 4.1–7.4 months) for patients that received the modified regimen as first-line therapy. Neurotoxicity occurred in 27% with only 1.6% of patients experiencing grade ⩾3 toxicity. The incidence of grade ⩾3 neutropenia was 19%, resulting in growth factor support in 12% of patients. This rate was similar in patients who received the modified regimen for first-line treatment of mPC versus the overall group. Conclusions: A modified regimen of biweekly nab-paclitaxel with gemcitabine is associated with a lower cost, acceptable toxicity profile and appears to be relatively effective in pancreatic cancer. Prospective randomized studies confirming its potential benefits compared with standard weekly mGNabP are warranted.