Phosphatidylinositol 3-Kinase Inhibition by Copanlisib in Relapsed or Refractory Indolent Lymphoma

Purpose:Phosphatidylinositol 3-kinase (PI3K) signaling is critical for the proliferation and survival of malignant B cells. Copanlisib, a pan-class I PI3K inhibitor with predominant activity against PI3K-a and -d isoforms, has demonstrated efficacy and a manageable safety profile in patients with indolent lymphoma.In this phase II study, 142 patients with relapsed or refractory indolent lymphoma after two or more lines of therapy were enrolled to receive copanlisib 60 mg intravenously on days 1, 8, and 15 of a 28- day cycle. The primary end point was objective response rate; secondary end points included duration of response, progression-free survival, and overall survival. In addition, safety and gene expression were evaluated.Median age was 63 years (range, 25 to 82 years), and patients had received a median of three (range, two to nine) prior regimens. The objective response rate was 59% (84 of 142 patients); 12% of patients achieved a complete response. Median time to response was 53 days. Median duration of response was 22.6 months, median progression-free survival was 11.2 months, and median overall survival had not yet been reached. The most frequent treatment-emergent adverse events were transient hyperglycemia (all grades, 50%; grade 3 or 4, 41%) and transient hypertension (all grades, 30%; grade 3, 24%). Other grade $3 events included decreased neutrophil count (24%) and lung infection (15%). High response rates to copanlisib were associated with high expression of PI3K/B-cell receptor signaling pathway genes.PI3K-a and -d inhibition by copanlisib demonstrated significant efficacy and a manageable safety profile in heavily pretreated patients with relapsed or refractory indolent lymphoma.

Malignant lymphomas comprise a heterogeneous group of lymphoproliferative malignancies for which approximately 72,000 new cases and 20,000 deaths were estimated in 2016 in the United States alone.1 For patients with indolent B-cell lym- phoma, first-line therapy usually entails ritux- imab immunotherapy either alone or combined with chemotherapy such as the alkylating agent bendamustine.2,3 However, indolent lymphomas generally are incurable despite initial response to first-line therapy, which commonly precedes relapse and the development of refractory disease for which limited treatment options exist.Targeted inhibition of phosphatidylinositol 3-kinase (PI3K) has emerged as a therapeutic strategy for patients with relapsed or refractory indolent B-cell lymphoma,4-6 with the oral PI3K-d isoform inhibitor idelalisib approved in 2014 for third-line treatment of patients with relapsed or refractory follicular lymphoma or small lym- phocytic lymphoma.7 The PI3K-a isoform is expressed to a lesser extent than PI3K-d in various forms of lymphoma, but upregulation of alternative isoforms over time in response to selective PI3K-d inhibition may be a resistance mechanism.8-10 Notwithstanding the clinical validation of PI3K-d as a therapeutic target, concerns have emerged about the identified risk of infections, noninfectious pneumonitis, and colitis with oral PI3K-d–targeting agents, such as idelalisib,11,12 which highlights the unmet need for active and safe treatment options in patients with relapsed or refractory lymphoma.Copanlisib (BAY 80-6946; Bayer AG, Berlin, Germany) is an intravenous pan-class I PI3K inhibitor with predominant and potent activity against the PI3K-a and PI3K-d isoforms13,14 and has recently been approved by the US Food and Drug Administration for the treatment of patients with relapsed follicular lymphoma who have received at least two prior systemic therapies. Intermittent copanlisib treatment has demonstrated durable responses and a manageable toxicity profile in phase I15 and phase II16 studies in patients with relapsed or refractory indolent B-cell lymphoma. In addition, in the previous phase II lymphoma study, a gene ex- pression profile possibly associated with greater response to copanlisib was identified through archival tumor tissues.16 On the basis of these results, we conducted an open-label phase II study to evaluate the efficacy and safety of copanlisib in patients with re- lapsed or refractory indolent B-cell lymphoma.

This single-arm, phase II study ( identifier: NCT01660451 part B; CHRONOS-1 [Open-Label, Uncontrolled Phase II Trial of Intravenous PI3K Inhibitor BAY80-6946 in Patients With Relapsed, Indolent or Aggressive Non-Hodgkin’s Lymphomas]) was conducted at 81 sites across Europe, Asia, the United States, Australia, and New Zealand. Patients received copanlisib 60 mg as a 1-hour infusion on days 1, 8, and 15 of a 28-day cycle. Treatment continued until progression or unacceptable toxicity. The protocol was approved by each study site’s independent ethics committee or institutional review board. The study was conducted in accordance with the updated Declaration of Helsinki. All patients provided written informed consent.Eligible patients had a histologically confirmed diagnosis of indolent B-cell lymphoma (with histologic subtype that included follicular lym- phoma grades 1 to 3a, marginal zone lymphoma [splenic, nodal, or extranodal], small lymphocytic lymphoma [with absolute lymphocyte count , 5 3 109/L], or lymphoplasmacytoid lymphoma/Waldenstro¨m macroglobulinemia [with immunoglobulin M paraprotein or . 10% of lymphoplasmacytic cells in bone marrow]). Eligible patients also had relapsed or refractory disease after two or more lines of therapy and had received rituximab and alkylating agents. Additional eligibility criteria included age $ 18 years, one bidimensionally measurable lesion (that was not previously irradiated),17 and an Eastern Cooperative Oncology Group performance status18 of 2 or better. Patients were excluded if they had received prior treatment with PI3K inhibitors or a prior allogeneic bone marrow transplant.The primary efficacy end point was objective tumor response rate, which was defined as the proportion of patients who achieved a complete or partial response per central radiologic review. Additional key efficacy end points included duration of response, progression-free survival, overall survival, disease control rate, and best change in target lesions.

Tumors were assessed by computed tomography scan or magnetic resonance imaging performed at screening and then every two cycles during year 1, every three cycles during year 2, and every six cycles during year 3. Response was determined by a blinded independent review committee in accordance with the revised International Working Group response criteria for malignant lymphoma.17 For patients with Waldenstro¨m macroglobulinemia, instead of using the response categories published by the Sixth International Workshop on Waldenstro¨m’s Macroglobulinemia, very good partial response and minor response categories were omitted.19 A separate secondary analysis
also was performed by using the investigator assessments of response.Clinic visits were scheduled weekly for the first cycle and then weekly for the first 3 weeks of the next cycles, with safety follow-up within 30 to 35 days after the last study treatment; visits were then scheduled every 3 months (6 14 days). Clinic visits included assessment of adverse events (graded by using the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.03]),20 review of concomitant med- ications, and physical examination. Noninfectious pneumonitis was captured as a diagnosis for all clinically relevant respiratory events or symptoms, including lung infection and cough, where an infectious etiology could not be clearly identified. Patients were not required to receive prophylaxis for Pneumocystis jirovecii.Archival formalin-fixed paraffin-embedded tumor tissues were used for mRNA extraction and gene expression profiling with Affymetrix GeneChip Human Gene 1.0 ST Arrays (AltheaDx, San Diego, CA). The Appendix (online only) provides a complete description of gene expression profiling.

Prespecified evaluation of the primary variable was to reject the null hypothesis of an objective response rate of # 40% by using a one-sided exact binomial test with a = 2.5%. Estimates, along with exact 95% CIs after Clopper-Pearson method, were calculated. Time-to-event variables were described by using Kaplan-Meier method. Duration of response was defined as the time from the first observed objective response to first subsequent disease progression or death as a result of disease progression. Progression-free survival was defined as the time from the first admin- istration of study treatment to first disease progression or death as a result of any cause. Patients with no disease progression or who had died were censored at the date of their last tumor assessment. Overall survival was defined as the time from the first administration of study treatment to death as a result of any cause. Overall survival times were censored at the date of the last contact if a patient was lost to follow-up or withdrew consent from the study and follow-up.Analyses were performed for all patients who received treatment (full analysis set), unless stated otherwise. Statistical analyses were conducted by or under the supervision of the sponsor’s study statistician, statistical biomarker expert, and study statistical analyst. Statistical evaluation was performed by using SAS 9.2 software (SAS Institute, Cary, NC) and R version 3.2.3/3.3.0 (The R Foundation, Vienna, Austria).21 Gene set enrichment analysis (GSEA) was performed in all patients with available gene expression data by using gene-specific logistic regression to identify and rank associations with objective response and to develop normalized enrichment scores.22 Weighted gene expression scores (WGSs) that integrated the overall expression level of each gene signature with its association with objective response to copanlisib were generated per tumor sample by using logistic regression models. The Appendix provides a complete description of the statistical analysis by GSEA and WGS.

Between November 2013 and February 2016, 142 patients were enrolled and started treatment (Appendix Fig A1, online only). The median age of patients was 63 years; 50% were male, and 85% were white (Table 1). The majority of patients had follicular lymphoma (73%; n = 104). Most patients (80%; n = 114) had stage III or IV lymphoma, with a median time of 8 weeks since the most recent progression. Patients had received a median of three prior regimens; 86 (61%) had refractory disease after their last regimen. All patients had received prior rituximab and alkylating agents of whom 80 (56%) and 60 (42%), respectively, had refractory disease. One patient with follicular lymphoma who received treatment was later confirmed by the local investigator to have diffuse large B-cell lymphoma.On the basis of independent blinded central review, the study met its predefined end point with an objective response rate of 59%, which exceeded the prespecified threshold of 40% (95% CI, 51% to 67%; P , .001). Seventeen patients (12%) achieved a com- plete response and 67 (47%) achieved a partial response (Table 2). Median time to response was 53 days (range, 41 to 296 days; 95% CI, 51 to 56 days). Forty-three patients (30%) had stable disease, one of whom (1%) had unconfirmed stable disease, and three patients (2%) had progressive disease. Data were not available for 11 patients (8%) and one patient (1%) was not evaluable.In the 104 patients with follicular lymphoma, the objective re- sponse rate was 59%, including 15 patients (14%) with a complete response and 46 (44%) with a partial response (Table 2). The objective response rate was 70% in the 23 patients with marginal zone lym- phoma, including two (9%) with a complete response and 14 (61%) with a partial response. Objective response rates of 60% and 57%, respectively, were recorded in patients whose disease was refractory (52 of 86) or responsive (32 of 56) to the last therapy. A waterfall plot of best response in target lesions on the basis of investigator assessment showed that 74 (59%) of the 125 patients assessed had at least a 50% reduction in lesions after treatment with copanlisib (Fig 1).Median duration of response was 22.6 months (range, 0 to 22.6 months; Fig 2A), and responses were rapid and durable during copanlisib treatment (Fig 2B). Patients with follicular lymphoma had a median duration of response of 12.2 months (range, 0 to 22.6 months; 95% CI, 6.9 to 22.6 months; n = 61). Median progression-free survival was 11.2 months (range, 0.2 to 24.0 months; Fig 2C), and median overall survival had not yet been reached (Fig 2D).

At the time of the database cutoff, median duration of copanlisib treatment was 22 weeks (range, 1 to 105 weeks), with a median duration of safety follow-up of 24 weeks (range, 1 to 104 weeks). Forty-six patients (32%) continued with treatment. Patients received a median of 96% of the planned dose (range, 51 to 103 patients).Dose delays were experienced in 74% of patients (n = 105), 91% of which were due to adverse events, the majority of which were transient hyperglycemia and transient hypertension and neutropenia. Fifty-five percent of the delays lasted , 1 week (median, 1 week; range, 0 to 3 weeks). Thirty-seven patients (26%) had dose reductions to 45 mg and eight (7%) had dose reductions to 30 mg.Overall, 140 (99%) of the 142 patients experienced treatment- emergent adverse events of which 53% were grade 3 and 27% were grade 4 (Table 3). Treatment-related adverse events are summa- rized in Appendix Table A1 (online only). With the exclusion of transient infusion-related events post hoc, 137 patients (97%) experienced treatment-emergent adverse events of whom 58 (41%) experienced grade 3 events; 29 (20%), grade 4 events; and six (4%), grade 5 events. The most common treatment-emergent adverse events (which occurred in $ 25% of patients) were transient hyperglycemia, transient hypertension, diarrhea, fatigue, decreased neutrophil count, and fever. The highest incidences of grade 3 or 4 events (other than hyperglycemia or hypertension) were decreased neutrophil count (8% for grade 3; 16% for grade 4) and lung infection (13% for grade 3; 2% for grade 4).

Eleven patients (8%) had noninfectious pneumonitis, with two (1%) experiencing grade 3 events. Serious adverse events of grade $ 3 in three or more patients included lung infection (13%), hyperglycemia (5%), decreased neutrophil count (4%), fever (3%), and diarrhea (2%); two patients had grade 3 pneumonitis, and one patient with a medical history of diverticulosis had grade 4 colitis. Six patients (4%) had grade 5 events during treatment or within 35 days after permanent treatment discontinuation. Three events were con- sidered treatment-related, including lung infection (in one patient with a history of bronchiectasis), respiratory failure (reported to be of multifactorial etiology, including preexisting chronic obstructive pulmonary disease, cardiac failure, and pneumonia), and a cerebral thromboembolic event (in one patient with concurrent atrial fibrillation), and three events were deemed unrelated, including lung infection (in one patient with pneumonia and pleural effu- sion), acute kidney injury (hydronephrosis secondary to disease progression), and renal failure (secondary to dehydration and contrast dye nephropathy).During the study, three nonfatal opportunistic infections occurred: two P jirovecii infections and one bronchopulmonary aspergillosis infection. Eighteen patients received prophylaxis with sulfamethoxazole and trimethoprim.Adverse events led to treatment discontinuation in 36 patients (25%) and were considered drug-related in 23 patients (16%), including noninfectious pneumonitis in five (grade 2 or 3, 4%), lung infection in four (grade 2 or 3, 3%), and hyperglycemia in three (grade 4, 2%). Abnormal safety laboratory tests of interest included increased ALT levels (overall, 23%; grade 1, 19%) and Fig 1. B

est response in target lesions. The percentage best change in the sum of the diameters of all target lesions from baseline as assessed by the investigator is shown. Of the full analysis set of 142 patients, the best change in target lesions for the investigator onsite assessment could not be determined in 15 (11%). In addition, for one patient with follicular lymphoma (with a best response of partial response), best change in target lesions had not been calculated. For one patient classified by the investigator as having follicular lymphoma but who was reclassified by independent assessment as having diffuse large B-cell lymphoma, the change in lesions (increase of 250%) is not shown. (*) Patient was assessed by independent review as having stable disease. Fig 2. Secondary efficacy end points. Data are shown for (A) duration of response, (B) change in the sum of longest diameter of target lesions over time for patients with at least partial response as the best response, (C) progression-free survival, and (D) overall survival as assessed by independent review for the full analysis set. (*) Not evaluable. (†) Censored observation increased AST levels (overall, 28%; grade 1, 25%), which were grade $ 3 in two patients each (Table 3).

Gene expression profiling was performed successfully in 71 patients with indolent lymphoma, including 54 with follicular lymphoma, who were evaluable for response. GSEA showed that upregulation of all five gene sets that reflected PI3K/B-cell receptor (BCR) pathway signaling components (with signatures ranging from 15 to 68 genes) were top-ranked for association with higher response rates in patients with indolent lymphoma and follicular lymphoma, with normalized enrichment scores of 1.93 to 3.09 and 1.52 to 2.64 and false discovery Q = 0 to .003 and 0 to .007, re- spectively. Higher gene expression levels of PI3K and BCR path- ways as assessed by WGS also were associated with higher response rates to copanlisib treatment in patients with indolent lymphoma and follicular lymphoma, with logistic regression nominal P = .009 to .035 and .003 to .229 and areas under the curve of and .61 to .77, respectively (Fig 3). A lower macrophage gene expression profile WGS may be associated with higher response rates in indolent lymphoma and follicular lymphoma, with lo- gistic regression nominal P = .098 and .011 and areas under the curve of .62 and .72, respectively. By using the median WGS of the PI3K/BCR pathway gene sets as a cutoff to define elevated ex- pression levels of these pathways, 75% (33 of 44) of patients with indolent lymphoma achieved an objective response, and 86% (six of seven) of those with complete response had elevated PI3K/ BCR profiles. Similarly, 76% (25 of 33) of patients with follicular lymphoma who achieved an objective response and 83% (five of six) of those with a complete response had elevated PI3K/BCR profiles.

In this study, treatment with copanlisib showed significant efficacy in heavily pretreated patients with indolent B-cell lymphoma relapsed or refractory to prior therapy with rituximab and alkylating agents. Overall, 59% of patients achieved an objective response. Responses were rapid and durable, with a median time to re- sponse of 53 days and a median duration of response of 22.6 months. Median progression-free survival was 11.2 months, with 46 patients still receiving treatment at the time of database closure. The overall rate of progressive disease as best response was low (2%). Objective responses were observed in 59% of patients with follicular lymphoma and 70% of patients with marginal zone lymphoma, with complete responses observed in both subgroups (14% and 9%, respectively).These findings are consistent with previous reports of copanlisib in patients with relapsed or refractory indolent B-cell lymphoma.15,16 The current efficacy data for copanlisib also are consistent with those reported for the PI3K-d–selective inhibitor idelalisib, which has a demonstrated objective response rate of 57% in patients with relapsed indolent lymphoma and 56% in a follicular lymphoma subset (median duration of response, 12.5 and 10.8 months, respectively) and overall progression-free survival of 11.0 months.4,23 The PI3K-d and -g dual inhibitor duvelisib has been reported to show an objective response rate of 46% and median progression-free survival of 8.4 months.24 The response rate of copanlisib was also greater than that reported in small cohorts of patients with relapsed or refractory indolent lymphoma for the pan-PI3K inhibitor pilaralisib25 and the Bruton’s tyrosine kinase inhibitor ibrutinib.26 However, because of differences between trials, response rates should be interpreted with caution. The pan-PI3K inhibitors buparlisib and pictilisib have not been evaluated beyond phase I in patients with indolent B-cell lymphoma.

Durable responses were observed in patients who had received multiple prior lines of therapy, including rituximab and alkylating agents, which suggests that PI3K activation may play a critical oncogenic role in malignant B-cell lymphoma. These results also are consistent with the identification of a gene expression profile first observed in a small number of patients with indolent and aggressive lymphomas,16 are validated in the current study, and show that patients with indolent lymphoma with activated PI3K/ BCR signaling and low stromal/macrophage gene activity are more likely to respond to copanlisib.Transient hyperglycemia was the most common treatment- related adverse event, which occurred in 49% of patients, with 41% grade 3 (. 250 mg/dL) or 4, although it was largely self-limiting and did not lead to significant treatment discontinuation. Hy- perglycemia is a recognized on-target effect of PI3K-a inhibition that is related to insulin receptor signaling and results in transiently reduced use of tissue glucose and/or insulin resistance.29,30 The incidence of hyperglycemia reported here was consistent with previous reports of copanlisib15,16 and other pan-PI3K inhibitors.25,27,28 However, only a few cases of hyperglycemia re- quired more intensive management, such as in patients who ex- perienced symptoms or who were diabetic for whom short-acting (regular) insulin was recommended. General recommendations for the management of treatment-related hyperglycemia are provided in the

Transient hypertension occurred in 30% of patients, with 24% grade 3 (. 160 mm Hg). However, as with hyperglycemia, this was not a significant cause for treatment discontinuation.A lower incidence of severe GI toxicities, such as hepatic transaminitis, diarrhea, colitis, or colonic perforations (none observed), were seen with intermittent intravenous copanlisib treatment compared with previous reports with continuous oral idelalisib treatment,4 which suggests that both route of admin- istration and dosing schedule may be important. More recently, increased rates of infectious and autoimmune toxicities, in- cluding deaths, in trials that combined idelalisib with other agents led to the termination of clinical studies and recom- mendations for careful monitoring of patients.11,12 In the current study, fewer such adverse events were observed with copanlisib monotherapy. Studies that combine copanlisib with standard immunochemotherapy in patients with indolent lymphoma are ongoing ( identifiers: NCT02367040 and NCT02626455).

In conclusion, treatment with copanlisib results in sig- nificant and durable responses in heavily pretreated patients with relapsed or refractory indolent lymphoma. In addition, copanlisib has a manageable safety profile in this population, with low rates of severe hepatic transaminitis, diarrhea, colitis, and noninfectious pneumonitis. Opportunistic infections, fatal infections, and other fatal adverse events were infrequent. Taken together, the results indicate a favorable risk-benefit profile that supports the use of copanlisib treatment in this clinical setting.Fig 3. Association of gene expression profiles with best response. Weighted gene expression scores (WGSs) that reflect the overall expression levels for each gene set per archival tumor sample are displayed. Color coding is used to show the association patterns of best response status in all patients with evaluable biomarker samples and response data, with corresponding tumor baseline gene expression levels of gene sets involved in phosphatidylinositol 3-kinase (PI3K)/B-cell receptor (BCR) signaling, as well as with a macrophage gene expression signature. Activation of PI3K/BCR signaling pathways (high WGSs) was associated with enhanced copanlisib response rates in patients with indolent lymphoma (n = 71). (*) Patient experienced a complete response (CR). (†) Low PI3K/BCR gene expression refers to a WGS of all gene sets of the PI3K/BCR pathways lower than the median value. (‡) High PI3K/BCR gene expression refers to a WGS of one or more gene sets of the PI3K/BCR pathways higher than the median value. (§) Tumor types were based on investigator assessment. FL, follicular lymphoma; LPL/WM, lymphoplasmacytoid lymphoma/Waldenstro¨ m macroglobulinemia; MZL, Samotolisib marginal zone lymphoma; NE, not evaluable; PD, progressive disease; PR, partial response; SD, stable disease; SLL, small lymphocytic lymphoma.