Expansion Cohort Research Articles

Phase I study of the tissue factor-targeting antibody-drug conjugate XB002 among patients with advanced solid tumors (JEWEL-101): Design of expansion cohorts for endometrial, epithelial ovarian, and cervical cancers

Phase I study of the tissue factor-targeting antibody-drug conjugate XB002 among patients with advanced solid tumors (JEWEL-101): Design of expansion cohorts for endometrial, epithelial ovarian, and cervical cancers

Neoadjuvant treatment with regorafenib and capecitabine combined with radiotherapy in locally advanced rectal cancer: a multicenter phase Ib trial (RECAP)–SAKK 41/16

BackgroundThe multi tyrosine kinase inhibitor regorafenib is active in metastatic colorectal cancer. Improvement in clinical outcome by adding regorafenib to long-course chemoradiotherapy (LcCRT) was investigated in molecularly undefined LARC. MethodsPatients with T3–4 and/or N+ but M0 rectal cancer were included. Neoadjuvant LcRCT consisted in capecitabine (C) 825mg/m2 d1–d38 and 28 fractions of 1.8Gy (50.4Gy). Regorafenib was added d1–14 and d22–35 in three dose escalation (DE) cohorts (40mg/80mg/120mg). The recommended dose (RD) was used for the expansion (EXP) cohort. Primary endpoints were dose-limiting toxicity (DLT) for DE and pathological response (near-complete regression [npCR] or complete regression [pCR]) for EXP. ResultsOverall, 25 patients were included. Two DLTs occurred at the regorafenib dose level of 120 mg, thereby establishing the RD at 80mg daily. Among the 19 patients who were treated at the RD, eight (42.1%; one-sided 80% confidence interval [CI] (lower bound): 30.7%; 95% CI: 20.3%–66.5%) reached the primary endpoint (five [26.3%] had npCR and three [15.8%] pCR). One additional patient received no surgery due to clinical complete response. All patients had R0 resections and clear circumferential margins. Postoperative complications occurred in six patients (35.3%). The most common grade ≥3 treatment-related adverse event in the EXP cohort was diarrhea (two patients). ConclusionAdding regorafenib 80mg to LcCRT in LARC resulted in both primary endpoints being met and yielded an expectedpathological response rate. Toxicity was manageable, and postoperative complications were as expected. Micro AbstractThe SAKK 41/16 study investigated the addition of regorafenib to the standard neoadjvuant chemoradiation with capecitabine. We could show expected pathological response rate and manageable toxicity at the recommended dose of regorafenib. Regorafenib may be potential partner for future trials investigating treatment intensification for high-risk locally advanced rectal cancer.

503LBA LBA Orals: Results from CA240-0007, a phase 1/2 multiple expansion cohort study of BMS-986504 in patients (pts) with advanced solid tumors with homozygous MTAP deletion (MTAP-del)

503LBA LBA Orals: Results from CA240-0007, a phase 1/2 multiple expansion cohort study of BMS-986504 in patients (pts) with advanced solid tumors with homozygous MTAP deletion (MTAP-del)

235 (PB223): IND.243: a multiple expansion cohort, signal seeking and dose confirmation phase 2 trial of the PKMYT1 inhibitor lunresertib

235 (PB223): IND.243: a multiple expansion cohort, signal seeking and dose confirmation phase 2 trial of the PKMYT1 inhibitor lunresertib

A Phase II Study Assessing Long-term Response to Ibrutinib Monotherapy in Recurrent or Refractory CNS Lymphoma.

Ibrutinib is a first-in-class inhibitor of Bruton tyrosine kinase. We previously reported the safety and short-term antitumor activity of ibrutinib in 20 patients with relapsed or refractory (r/r) primary central nervous system (CNS) lymphoma (PCNSL) or secondary CNS lymphoma (SCNSL). We enrolled 26 additional patients with r/r PCNSL/SCNSL into the dose-expansion cohort of the trial into a combined cohort of 46 patients (31 with PCNSL and 15 with SCNSL). Patients received ibrutinib at 560 or 840 mg daily in the dose-escalation cohort and ibrutinib at 840 mg daily in the expansion cohort. The median follow-up was 49.9 and 62.1 months for patients with PCNSL and SCNSL, respectively. We sequenced DNA from available tumor biopsies and cerebrospinal fluid collected before and during ibrutinib therapy. Tumor responses were observed in 23/31 (74%) patients with PCNSL and 9/15 (60%) patients with SCNSL, including 12 complete responses in PCNSL and 7 in SCNSL. The median progression-free survival (PFS) for PCNSL was 4.5 months [95% confidence interval (CI), 2.8-9.2] with 1-year PFS at 23.7% (95% CI, 12.4%-45.1%). The median duration of response in the 23 PCNSL responders was 5.5 months. The median PFS in SCNSL was 5.3 months (95% CI, 1.3-14.5) with a median duration of response of 8.7 months for the 9 responders. Exploratory biomarker analysis suggests that mutations in TBL1XR1 may be associated with a long-term response to ibrutinib in PCNSL (P = 0.0075). Clearance of ctDNA from cerebrospinal fluid was associated with complete and long-term ibrutinib responses. Our study confirms single-agent activity of ibrutinib in r/r CNS lymphoma and identifies molecular determinants of response based on long-term follow-up.

A multicenter, randomized, non-comparative, phase II study of nivolumab ± ipilimumab for patients with metastatic sarcoma (Alliance A091401): expansion cohorts and correlative analyses

BackgroundIn this open-label, randomized, non-comparative, multicenter phase II study (Alliance A091401) we report on three expansion cohorts treated with nivolumab (N) with and without ipilimumab (N+I) and provide a multi-omic...

620P Efficacy, safety and PKPD of 23ME-00610, a first-in-class anti-CD200R1 antibody, in patients with tumor mutational burden-high (TMB-H) and/or microsatellite instability-high (MSI-H) cancers: Results from an expansion cohort

620P Efficacy, safety and PKPD of 23ME-00610, a first-in-class anti-CD200R1 antibody, in patients with tumor mutational burden-high (TMB-H) and/or microsatellite instability-high (MSI-H) cancers: Results from an expansion cohort

1706P Efficacy, safety and PKPD of 23ME-00610, a first-in-class anti-CD200R1 antibody, in patients with advanced or metastatic clear-cell renal cell carcinoma (ccRCC): Results from a multi-center multi-country phase I/IIa expansion cohort

1706P Efficacy, safety and PKPD of 23ME-00610, a first-in-class anti-CD200R1 antibody, in patients with advanced or metastatic clear-cell renal cell carcinoma (ccRCC): Results from a multi-center multi-country phase I/IIa expansion cohort

762P First results from phase II dose expansion cohort of transcon IL-2 β/γ in combination with standard of care chemotherapy for platinum resistant ovarian cancer (PROC) in the IL Believe trial

762P First results from phase II dose expansion cohort of transcon IL-2 β/γ in combination with standard of care chemotherapy for platinum resistant ovarian cancer (PROC) in the IL Believe trial

A Phase I Open-Label Study of Cediranib Plus Etoposide and Cisplatin as First-Line Therapy for Patients With Extensive-Stage Small-Cell Lung Cancer or Metastatic Neuroendocrine Non–Small-Cell Lung Cancer

IntroductionSmall cell lung cancer (SCLC) is known to express high levels of the proangiogenic factor vascular endothelial growth factor (VEGF). We assessed the safety and tolerability of cediranib, an oral inhibitor of VEGF receptor tyrosine kinases, in combination with etoposide and cisplatin as first-line therapy for extensive-stage (ES) SCLC or metastatic lung neuroendocrine cancer (NEC). MethodsPatients received up to six 21-day cycles of etoposide (100 mg/m2, days 1-3) and cisplatin (80 mg/m2, day 1) with once-daily cediranib until disease progression or unacceptable toxicity. Cediranib dosing started at 30 mg with de-escalation cohorts planned based on cycle 1 dose-limiting toxicities (DLTs). An expansion cohort of 12 patients was enrolled at the recommended phase II dose. ResultsTwenty-two patients (18 with ES SCLC, 4 with NEC) received treatment. Only 4 patients were enrolled at the 30 mg cediranib dose before other studies established 20 mg/day as the recommended dose with chemotherapy. Among the 18 patients enrolled at the 20-mg dose, common adverse events included nausea/vomiting, neutropenia, and diarrhea; 8 patients (44%) had grade 1 or 2 hypertension, and 2 (11%) had grade 3 hemoptysis. For all 18 patients, the objective response rate and median progression-free survival duration were 67% and 7.9 months. Plasma levels of VEGF were significantly higher, and those of soluble VEGFR2 were significantly lower, on day 22 than at baseline but were not correlated with tumor shrinkage. ConclusionsCediranib (20 mg) plus etoposide and cisplatin is well tolerated and has promising clinical activity.

1598P Xaluritamig, a STEAP1 x CD3 XmAb 2+1 immune therapy, in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC): Initial results from dose expansion cohorts in a phase I study

1598P Xaluritamig, a STEAP1 x CD3 XmAb 2+1 immune therapy, in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC): Initial results from dose expansion cohorts in a phase I study

Efficacy and safety of bintrafusp alfa in 2 phase I expansion cohorts with advanced HCC.

Simultaneous inhibition of the TGF-β and programmed cell death 1 ligand 1 pathways provides a potential novel treatment approach. Bintrafusp alfa, a first-in-class bifunctional fusion protein composed of the extracellular domain of TGF-βRII (a TGF-β "trap") fused to a human IgG1 monoclonal antibody blocking programmed cell death 1 ligand 1, was evaluated in patients with advanced HCC. In this global, open-label, phase I study (NCT02517398), patients with programmed cell death 1 ligand 1-unselected HCC who failed or were intolerant to ≥1 line of sorafenib received bintrafusp alfa 1200mg every 2 weeks in a dose-escalation (n = 38) or dose-expansion (n = 68) cohort until confirmed progression, unacceptable toxicity, or trial withdrawal. The primary endpoint was the best overall response per Response Evaluation Criteria in Solid Tumors version 1.1 by an independent review committee. Secondary endpoints included investigator-assessed best overall response, safety, and pharmacokinetics. Median follow-up times (range) were 41.4 (39.8-44.2) and 38.6 (33.5-39.7) months in the dose-escalation and dose-expansion cohorts, respectively. The objective response rate was below the prespecified 20% objective response rate threshold set to evaluate the efficacy of bintrafusp alfa in both cohorts (10.5% and 8.8%, respectively). Median overall survival and progression-free survival, respectively, were 13.8 and 1.5 months in the dose-escalation cohort and 13.5 and 1.4 months in the dose-expansion cohort. Treatment-related adverse events occurred in 78.9% and 64.7% of patients in the respective cohorts (grade ≥3 in 18.4% and 25.0% of patients). Bintrafusp alfa showed moderate clinical activity and a safety profile consistent with previous studies of bintrafusp alfa in patients with advanced HCC.

A single-arm, exploratory study of disitamab vedotin (DV) combined with camrelizumab and platinum-based chemotherapy as first-line treatment in patients with HER2 expressing locally advanced or metastatic esophageal squamous cell carcinoma (ESCC).

TPS217 Background: Esophageal cancer (EC) is one of the most common cancers worldwide with esophageal squamous cell carcinoma (ESCC) being the predominant histological subtype. PD-1 blockades combined with chemotherapy are now standard-of-care in first-line setting for patients with ESCC. HER2 expression, prevalent in an estimated 7.6% to 28.5% of ESCC cases, correlates with diminished overall survival, suggesting HER2-targeted therapy as a potential novel approach. To our knowledge, there is currently no clinical trial regarding anti-HER2 therapy in ESCC. Clinical evidence has suggested the potential synergistic anti-tumor effect of Disitamab Vedotin (DV) with PD-1 inhibitors in HER2-expressing gastric or gastroesophageal junction (G/GEJ) cancers. This single-arm, exploratory study aimed to evaluate the safety and preliminary anti-tumor activity of DV combined with camrelizumab and platinum-based chemotherapy in ESCC. Methods: This is a single-arm, exploratory study (NCT06055153). Approximately 20 patients will be enrolled in this study, phase 1 will initiate with a 3+3 dose-escalation scheme (2.5mg/kg to 2.0mg/kg) to identify dose-limiting toxicities (DLTs) and establish a safe dosage of DV. The expansion cohort will subsequently evaluate this dose for both efficacy and safety. The study population will included both male and female patients over the age of 18 with histologically confirmed ESCC, and locally advanced unresectable, recurrent unresectable or metastatic EC verified by imaging examination. This group also includes those patients who have experienced relapse or progression more than six months post the conclusion of last therapeutic regimen. Required HER2 expression levels in tumor specimens range from IHC 1+ to 3+. According to RECIST v1.1, participants must have at least one measurable lesion, an ECOG performance status of 0 or 1, and a minimum expected survival of 12 weeks with suitable organ function. Treatment protocol includes intravenous administration of DV (either 2.5 mg/kg or 2.0 mg/kg on day 1), Camrelizumab (200 mg on day 1), and Cisplatin (75mg/m2) or Nedaplatin (75mg/m2) on a 21-day cycle, continued until disease progression or the advent of unacceptable toxicity. The primary outcomes for evaluation are DLT for safety and the objective response rate (ORR) for efficacy. Adverse events will be monitored in accordance with the CTCAE 5.0 criteria. Secondary endpoints encompass progression-free survival (PFS), overall survival (OS), disease control rate (DCR), duration of response (DoR), and time to response (TTR). Clinical trial information: NCT06055153 .

A phase Ib/II study of pacritinib, an interleukin 1 receptor associated kinase 1 (IRAK1) inhibitor, in patients (pts) with solid tumors harboring the 1q21.3 copy number amplification (CNA).

43 Background: The role of IRAK1 pathway in inflammatory and immune response is established in autoimmune diseases but less well-understood in cancer. Chromosome 1q21.3 CNA detected in plasma cell-free DNA was observed in pts with advanced solid tumors, and associated with IRAK1 upregulation. In preclinical animal models, IRAK1 upregulation promoted tumorigenesis, while its inhibition led to decreased tumor growth. Pacritinib is a JAK2/FLT3 inhibitor that is FDA approved for treatment in myelofibrosis, but also have known activity against IRAK1. We hypothesize that pacritinib may be effective in disease control of pts with plasma 1q21.3 CNA. Methods: A phase Ib/II clinical trial was designed to investigate the efficacy of pacritinib in pts with treatment (rx) refractory solid tumors harboring 1q21.3 CNA. Serial pt tumor and blood samples were collected and analyzed to elucidate the effect of IRAK1 inhibition on tumor microenvironment and systemic immune modulation. Results: 330 patients were screened, 1q21.3 CNA was detected in 30.1% of pts. Highest incidence of 1q21.3 CNA positivity was detected in breast cancer (39.8%), colorectal cancer (39.7%) and lung cancer (36.1%). 12 pts were commenced on rx over 3 dose levels (DL) (DL1: n=6, DL2: n=3, DL3: n=3). At DL1 (200mg BID), no DLTs were observed, but 2 pts had G3 transaminitis attributed to drug/disease, and 1 pt had intolerable G2 rash; decision was made for dose reduction. At DL2 (200mg OM, 100mg ON), no DLTs were observed. Reescalation to 200mg BID (DL3) was carried out with no DLT observed. Pacritinib at 200mg BD was declared the recommended phase II dose in pts with solid tumors. In the dose expansion cohort, 8 pts (4 colorectal cancer, 3 hepatobiliary [HPB] cancer, 1 lung cancer) have been enrolled thus far. No objective responses were observed. Within pts with HPB tumors, 1 pt with pancreatic cancer had a progression-free survival (PFS) of 25.0 weeks, and 1 pt with cholangiocarcinoma had a PFS of 15.9 weeks. Preliminary analysis of serial tumor biopsy samples suggest an expansion of CD8+ T cell population with pacritinib rx. Serial peripheral blood mononuclear cells analysis showed no significant trend in change in CD8+ T cell population, but a predominance of PD-1+ T cells with rx, and also an increase in CD4+ T cell population. In the myeloid cell population, there appears to be decrease in dendritic cell population, but no significant change in trend of macrophage was observed. Conclusions: Pacritinib at 200mg BID is safe and tolerable in pts with solid tumors. IRAK1 inhibition appears to modulate immune cell populations both in the tumor microenvironment and systemic circulation. Dose expansion is underway, with potential signal of disease control in HPB tumors. Clinical trial information: NCT04520269 .

Anti-CD7 allogeneic WU-CART-007 in patients with relapsed/refractory T-cell acute lymphoblastic leukemia/lymphoma: a phase 1/2 trial.

Relapsed/refractory T-cell acute lymphoblastic leukemia (ALL)/lymphoma (LBL) represent a significant unmet medical need. WU-CART-007 is a CD7-targeting, allogeneic, fratricide-resistant chimeric antigen receptor T cell product generated from healthy donor T cells. WU-CART-007 was evaluated in a phase 1/2 study with a 3 + 3 dose-escalation design followed by cohort expansion in relapsed/refractory T-ALL/LBL. Patients received one infusion of WU-CART-007 after standard or enhanced lymphodepleting chemotherapy. The primary objectives, to characterize safety and assess the composite complete remission rate, were met. Of 26 patients enrolled, 13 received the recommended phase 2 dose (RP2D) of 900 million cells of WU-CART-007 with enhanced lymphodepletion. The most common treatment-related adverse event was cytokine release syndrome (88.5%; 19.2% grade 3-4). Biochemical abnormalities consistent with grade 2 hemophagocytic lymphohistiocytosis were seen in one patient (3.8%). Grade 1 immune effector cell-associated neurotoxicity syndrome events (7.7%) and one grade 2 acute graft-vs-host disease event occurred. Grade 5 events (11.5%) were due to fungal infection and multi-organ failure. The composite complete remission rate was 81.8% among 11/13 patients evaluable for response at the RP2D. WU-CART-007 at the RP2D demonstrated a high response rate in patients with relapsed/refractory T-ALL/LBL and has the potential to provide a new treatment option. ClinicalTrials.gov registration: NCT04984356.

Tocilizumab Prophylaxis Following Axicabtagene Ciloleucel in Relapsed or Refractory Large B-Cell Lymphoma

Axicabtagene ciloleucel (axi-cel) is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved in patients with relapsed/refractory (R/R) large B-cell lymphoma (LBCL). Most patients treated with axi-cel experience cytokine release syndrome (CRS) and/or adverse neurologic events (NEs). To explore potential approaches for reducing CAR T-cell-related toxicities with axi-cel, several safety expansion cohorts were added to the pivotal ZUMA-1 trial. ZUMA-1 Cohort 3 was an exploratory safety cohort that investigated the use of the IL-6 receptor-blocking antibody tocilizumab and anticonvulsant levetiracetam as prophylaxis against CRS and NEs in patients treated with axi-cel. Patients with R/R LBCL were enrolled in Cohort 3 and received conditioning chemotherapy on d -5 through -3 followed by a single infusion of axi-cel (2 × 106 cells/kg) on d 0. Prophylactic tocilizumab (8 mg/kg) was administered 48 h after axi-cel infusion. Primary endpoints were incidence and severity of CRS and NEs. Key secondary endpoints included the incidence of adverse events, objective response rate (ORR), duration of response, progression-free survival, overall survival (OS), and biomarker analyses (eg, circulating CAR T cells, cytokines, chemokines). Forty-two patients were enrolled in Cohort 3, 38 of whom received axi-cel. In the 24-month analysis, any-grade CRS and NEs occurred in 92% and 87% of patients, and Grade ≥3 CRS and NEs occurred in 3% and 42% of patients, respectively. One Grade 5 NE (cerebral edema) occurred. With 24-mo minimum follow-up, the ORR was 63%, and 39.5% of patients had ongoing response. With 48-month follow-up, median OS was 34.8 mo (95% CI, 5.4-not estimable). CAR T-cell expansion in ZUMA-1 Cohort 3 was comparable with pivotal Cohorts 1 and 2. Consistent with tocilizumab-mediated inhibition of IL-6R, serum IL-6 levels were increased relative to Cohorts 1 and 2. Grade ≥3 NEs were associated with elevated IL-6 levels, proinflammatory cytokines, and myeloid cells in the cerebrospinal fluid. Based on these findings, prophylactic tocilizumab is not recommended to prevent CAR T-cell-related adverse events, and beneficial effects of prophylactic levetiracetam remain uncertain in patients with R/R LBCL.

ENDOLUNG trial. A phase 1/2 study of the Akt/mTOR inhibitor and autophagy inducer Ibrilatazar (ABTL0812) in combination with paclitaxel/carboplatin in patients with advanced/recurrent endometrial cancer

BackgroundCarboplatin and paclitaxel (CP) have been the standard of care for advanced/recurrent endometrial cancer (EC) for many years. However, this chemotherapy combination shows limited efficacy and recurrences often occur in less than 12 months. ABTL0812 is a novel drug that selectively kill cancer cells by cytotoxic autophagy and has shown anticancer efficacy in preclinical models of EC in combination with CP.MethodsENDOLUNG was an open-label, phase 1/2 clinical trial designed to determine the safety and efficacy of Ibrilatazar (ABTL0812) with CP in patients with advanced/recurrent EC and non-irradiable stage III and IV squamous non-small cell lung cancer (sq-NSCLC). The phase 1 part consisted of a 3 + 3 de-escalation design followed by an expansion cohort with 12 patients. The primary endpoint was safety. ABTL0812 starting dose was 1300 mg tid combined with carboplatin at area under the curve (AUC) 5 and paclitaxel at 175 mg/m2 both administered every 21 days for up to 8 cycles. The phase 2 part included a total of 51 patients. The primary endpoint was overall response rate (ORR) and the secondary endpoints included duration of response (DOR), progression-free survival (PFS) and overall survival (OS).ResultsDuring the phase 1 only one dose limiting toxicity (DLT), a grade 4 neutropenia, was observed in 1 out of 6 patients, thus no de-escalation was applied. One additional DLT, a grade 3 febrile neutropenia, was observed in the expansion cohort, thus the recommended phase 2 dose (RP2D) for ABTL0812 was established at 1300 mg tid. Most frequent hematological adverse events (AE) of the combination were neutropenia (52.9%), anemia (37.3%) and thrombocytopenia (19.6%). Nausea (66.7%), asthenia (66.7%), diarrhea (54.9%) and vomiting (54.9%) were the most frequent non-hematological adverse events (AEs). The combination of ABTL0812 plus CP showed an ORR of 65.8% (13.2% complete response and 52.6% partial response) with a median DOR of 7.4 months (95% CI: 6.3–10.8 months). Median PFS was 9.8 months (95% CI: 6.6–10.6) and median OS 23.6 months (95% CI 6.4-ND). Pharmacokinetic parameters were compatible with target engagement observed in preclinical studies, and blood pharmacodynamic biomarkers indicated sustained target regulation during, at least, 28 days after starting the treatment.ConclusionsThis study suggests that the combination of ABTL0812 with CP is safe and feasible with an encouraging activity in patients with advanced/recurrent EC. Our data warrant further confirmation in prospective randomized trials.Trial registrationEU Clinical Trial Register, EudraCT number 2016-001352-21 and National Clinical Trials Number, NCT03366480. Registration on 19 September 2016.

Cohort Expansion and Genotype-Phenotype Analysis of RAB11A-Associated Neurodevelopmental Disorder

BackgroundGTPases of the Rab family are important orchestrators of membrane trafficking, and their dysregulation has been linked to a variety of neuropathologies. In 2017, we established a causal link between RAB11A variants and developmental and epileptic encephalopathy. In this study, we expand the phenotype of RAB11A-associated neurodevelopmental disorder and explore genotype-phenotype correlations. MethodsWe assessed 16 patients with pathogenic or likely pathogenic RAB11A variants, generally de novo, heterozygous missense variants. One individual had a homozygous nonsense variant, although concomitant with a pathogenic LAMA2 variant, which made their respective contributions to the phenotype difficult to discriminate. ResultsWe reinforce the finding that certain RAB11A missense variants lead to intellectual disability and developmental delays. Other clinical features might include gait disturbances, hypotonia, magnetic resonance imaging abnormalities, visual anomalies, dysmorphisms, early adrenarche, and obesity. Epilepsy seems to be less common and linked to variants outside the binding sites. Individuals with variants in the binding sites seem to have a more multisystemic, nonepileptic phenotype. ConclusionsSimilar to other Rab-related disorders, RAB11A-associated neurodevelopmental disorder can also impact gait, tonus, brain anatomy and physiology, vision, adrenarche, and body weight and structure. Epilepsy seems to affect the minority of patients with variants outside the binding sites.

Leveraging pharmacokinetic parameters as covariate in Bayesian logistic regression model to optimize dose selection in early phase oncology trial

ABSTRACT Dose selection and optimization in early phase of oncology drug development serves as the foundation for the success of late phases drug development. Bivariate Bayesian logistic regression model (BLRM) is a widely utilized model-based algorithm that has been shown to improve the accuracy for identifying recommended phase 2 dose (RP2D) based on dose-limiting-toxicity (DLT) over traditional method such as 3 + 3. However, it remains a challenge to optimize dose selection that strikes a proper balance between safety and efficacy in escalation and expansion phase of phase I trials. In this paper, we first use a phase I clinical trial to demonstrate how the variability of drug exposure related to pharmacokinetic (PK) parameters among trial participants may add to the difficulties of identifying optimal dose. We use simulation to show that concurrently or retrospectively fitting BLRM model for dose/toxicity data from escalation phase with dose-independent PK parameters as covariate lead to improved accuracy of identifying dose level at which DLT rate is within a prespecified toxicity interval. Furthermore, we proposed both model- and rule-based methods to modify dose at patient level in expansion cohorts based on their PK/exposure parameters. Simulation studies show this approach leads to higher likelihood for a dose level with a manageable toxicity and desirable efficacy margin to be advanced to late phase pipeline after being screened at expansion phase of phase I trial.

Atezolizumab combined with immunogenic salvage chemoimmunotherapy in patients with transformed diffuse large B-cell lymphoma.

Patients with relapsed/refractory (R/R) transformed diffuse large B-cell lymphoma (DLBCL) from indolent B-cell lymphomas, including Richter transformation (RT), have a poor prognosis. PD-1/PD-L1 antibodies produce modest objective and complete response rates (ORR and CRR) in B-NHL as monotherapy but may synergize with immunogenic chemotherapies like gemcitabine and oxaliplatin (GemOx). Thus, we evaluated the safety and efficacy of atezolizumab plus rituximab and GemOx (R-GemOx+Atezo) in R/R transformed DLBCL, including RT. We conducted a phase I trial including patients with transformed DLBCL after ≥1 prior therapy. Patients received up to 4 cycles of R-GemOx-+Atezo. Patients in CR could then proceed to Ratezo maintenance until progression. A safety lead-in with dose-limiting toxicity (DLT) evaluation was enrolled to confirm the recommended phase 2 dose (RP2D), followed by 2 expansion cohorts: one for transformed follicular lymphoma (FL) and another for non-FL transformed DLBCL, including RT. Twenty-seven patients were enrolled. One of the 6 safety lead-in patients had a DLT attributed to atezolizumab, a grade 4 Stevens-Johnson syndrome (SJS). The most common grade ≥3 events were neutropenia (18.5%), lymphopenia (18.5%), and thrombocytopenia (14.8%). The overall and complete response rates (ORR and CRR) were 59% and 33%, respectively. The ORR and CRR in transformed FL were 79% and 43%, and 38% and 23% in transformed non-FL, respectively. The median PFS and OS of the total population were 4.2 and 7.7 months, respectively. R-GemOx+Atezo was well tolerated and demonstrated promising preliminary efficacy in patients with R/R transformed DLBCL.