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Karyopharm Shares Data at ASH 2023 Showing Strong SVR and TSS Durability Observed from Phase 1 Study of Selinexor 60mg and Ruxolitinib in JAK Inhibitor (JAKi)-Naïve Myelofibrosis Patients, with no SVR or TSS Progressions Observed As of the Data Cutoff

On December 10, 2023 Karyopharm Therapeutics Inc. (Nasdaq: KPTI), a commercial-stage pharmaceutical company pioneering novel cancer therapies, reported long-term follow up of treatment-naïve patients with myelofibrosis (MF) who participated in the Phase 1 portion of its study evaluating once-weekly selinexor in combination with ruxolitinib (NCT04562389) (Press release, Karyopharm, DEC 10, 2023, View Source,-with-no-SVR-or-TSS-Progressions-Observed-As-of-the-Data-C [SID1234638381]). The data, featured in an oral presentation at the 65th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition (ASH 2023), show patients treated with 60mg selinexor, and who achieved ≥35% reduction in spleen volume (SVR35) at week 24, continued to remain in radiographic response. In addition, all patients who achieved TSS50 at Week 24 remained in response as of the data cut-off.

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The data included in the oral presentation for ASH (Free ASH Whitepaper) 2023 were based on the Phase 1 portion of the Phase 1/3 study evaluating the safety and efficacy of once-weekly selinexor in combination with ruxolitinib in patients with treatment-naïve MF (NCT04562389). As of August 1, 2023, 24 patients had been assigned to either selinexor 40mg (N= 10) or 60mg (N=14), in combination with ruxolitinib. The maximum duration of follow-up was 78 weeks with a median duration of 32 weeks for SVR35 durability, and a maximum duration of follow-up was 64 weeks with a median duration of 51 weeks for TSS50 durability.

An exploratory biomarker analysis showed a reduction of variant allele frequency (VAF) at week 24 for all three MF driver genes (CALR, MPL, and JAK2) and rapid and sustained reduction of pro-inflammatory cytokine production. Early cytokine reduction at Week 4 was associated with spleen volume reduction (SVR) at Week 24 and was sustained until the end of treatment. The clinical efficacy associated with biomarkers impacting MF biological hallmarks may suggest disease modification.

"The growing body of data from this study suggests that selinexor in combination with ruxolitinib may provide spleen reduction, symptom improvement, long-term durability and disease modification, expanding the benefit this combination may provide to patients with treatment-naïve myelofibrosis, " said Reshma Rangwala, MD, PhD, Chief Medical Officer of Karyopharm. "We’re excited about the potential to change treatment paradigms for these patients – and expand the number of patients who benefit from first-line therapy."

The safety profile was consistent with previous data cuts with no new safety signals observed as of Aug 1st.

"The current standard of care is not associated with consistent molecular or pathologic responses," said Dr. Sri Tantravahi, University of Utah. "The long-term findings are very exciting as they underscore the potential for durable, clinically relevant responses and modification of disease course. The wait for new options has been long and difficult for the myelofibrosis community, and we welcome this important research to help advance the understanding of XPO1 and JAK inhibitor combinations as a meaningful treatment option for patients."

"We are encouraged by the attention MPNs (Myeloproliferative Neoplasms) are getting in recent years from companies like Karyopharm," said Kapila Viges, Chief Executive Officer of MPN Research Foundation. "With patients waiting for more answers to these chronic yet serious blood cancers, we look forward to the data readouts at ASH (Free ASH Whitepaper) this year. Efforts to develop better therapies and now combinations of therapies bring hope to the myelofibrosis community and open the potential for more options in the treatment paradigm. For patients, options matter."

About XPOVIO (selinexor)

XPOVIO is a first-in-class, oral exportin 1 (XPO1) inhibitor and the first of Karyopharm’s Selective Inhibitor of Nuclear Export (SINE) compounds to be approved for the treatment of cancer. XPOVIO functions by selectively binding to and inhibiting the nuclear export protein XPO1. XPOVIO is approved in the U.S. and marketed by Karyopharm in multiple oncology indications, including: (i) in combination with Velcade (bortezomib) and dexamethasone (XVd) in patients with multiple myeloma after at least one prior therapy; (ii) in combination with dexamethasone in patients with heavily pre-treated multiple myeloma; and (iii) in patients with diffuse large B-cell lymphoma (DLBCL), including DLBCL arising from follicular lymphoma, after at least two lines of systemic therapy. XPOVIO (also known as NEXPOVIO in certain countries) has received regulatory approvals in various indications in a growing number of ex-U.S. territories and countries, including but not limited to the European Union, the United Kingdom, China, South Korea, Canada, Israel and Taiwan. XPOVIO and NEXPOVIO is marketed by Karyopharm’s partners, Antengene, Menarini, Neopharm and FORUS in China, South Korea, Singapore, Australia, Hong Kong, Germany, Austria, Israel and Canada.

Please refer to the local Prescribing Information for full details.

Selinexor is also being investigated in several other mid- and late-stage clinical trials across multiple high unmet need cancer indications, including in endometrial cancer and myelofibrosis.

For more information about Karyopharm’s products or clinical trials, please contact the Medical Information department at:

Tel: +1 (888) 209-9326
Email: [email protected]

SELECT IMPORTANT SAFETY INFORMATION

Warnings and Precautions

Thrombocytopenia: Monitor platelet counts throughout treatment. Manage with dose interruption and/or reduction and supportive care.
Neutropenia: Monitor neutrophil counts throughout treatment. Manage with dose interruption and/or reduction and granulocyte colony‐stimulating factors.
Gastrointestinal Toxicity: Nausea, vomiting, diarrhea, anorexia, and weight loss may occur. Provide antiemetic prophylaxis. Manage with dose interruption and/or reduction, antiemetics, and supportive care.
Hyponatremia: Monitor serum sodium levels throughout treatment. Correct for concurrent hyperglycemia and high serum paraprotein levels. Manage with dose interruption, reduction, or discontinuation, and supportive care.
Serious Infection: Monitor for infection and treat promptly.
Neurological Toxicity: Advise patients to refrain from driving and engaging in hazardous occupations or activities until neurological toxicity resolves. Optimize hydration status and concomitant medications to avoid dizziness or mental status changes.
Embryo‐Fetal Toxicity: Can cause fetal harm. Advise females of reproductive potential and males with a female partner of reproductive potential, of the potential risk to a fetus and use of effective contraception.
Cataract: Cataracts may develop or progress. Treatment of cataracts usually requires surgical removal of the cataract.
Adverse Reactions

The most common adverse reactions (≥20%) in patients with multiple myeloma who receive XVd are fatigue, nausea, decreased appetite, diarrhea, peripheral neuropathy, upper respiratory tract infection, decreased weight, cataract and vomiting. Grade 3‐4 laboratory abnormalities (≥10%) are thrombocytopenia, lymphopenia, hypophosphatemia, anemia, hyponatremia and neutropenia. In the BOSTON trial, fatal adverse reactions occurred in 6% of patients within 30 days of last treatment. Serious adverse reactions occurred in 52% of patients. Treatment discontinuation rate due to adverse reactions was 19%.
The most common adverse reactions (≥20%) in patients with multiple myeloma who receive Xd are thrombocytopenia, fatigue, nausea, anemia, decreased appetite, decreased weight, diarrhea, vomiting, hyponatremia, neutropenia, leukopenia, constipation, dyspnea and upper respiratory tract infection. In the STORM trial, fatal adverse reactions occurred in 9% of patients. Serious adverse reactions occurred in 58% of patients. Treatment discontinuation rate due to adverse reactions was 27%.
The most common adverse reactions (incidence ≥20%) in patients with DLBCL, excluding laboratory abnormalities, are fatigue, nausea, diarrhea, appetite decrease, weight decrease, constipation, vomiting, and pyrexia. Grade 3‐4 laboratory abnormalities (≥15%) are thrombocytopenia, lymphopenia, neutropenia, anemia, and hyponatremia. In the SADAL trial, fatal adverse reactions occurred in 3.7% of patients within 30 days, and 5% of patients within 60 days of last treatment; the most frequent fatal adverse reactions was infection (4.5% of patients). Serious adverse reactions occurred in 46% of patients; the most frequent serious adverse reaction was infection (21% of patients). Discontinuation due to adverse reactions occurred in 17% of patients.
Use In Specific Populations

Lactation: Advise not to breastfeed.

For additional product information, including full prescribing information, please visit www.XPOVIO.com.

To report SUSPECTED ADVERSE REACTIONS, contact Karyopharm Therapeutics Inc. at 1‐888‐209‐9326 or FDA at 1‐800‐FDA‐1088 or www.fda.gov/medwatch.

New Data Reinforce the Benefit of Early Preventative Treatment with Chugai’s Hemlibra for Babies with Severe Hemophilia A

On December 10, 2023 Chugai Pharmaceutical Co., Ltd. (TOKYO: 4519) reported that the primary analysis of the Phase III HAVEN 7 study reinforced the efficacy and safety of Hemlibra (generic name: emicizumab) in previously untreated or minimally treated infants with severe hemophilia A without factor VIII inhibitors (Press release, Chugai, DEC 10, 2023, View Source;category= [SID1234638380]). Results showed that Hemlibra achieved meaningful bleed control in babies up to 12 months of age, and was well tolerated.1 The new data were presented at the 65th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition taking place 9-12 December 2023, in San Diego, California, and included in the press program.

"Hemlibra, which can be administered subcutaneously, is an option to reduce the treatment burden for infants who have difficulty with intravenous administration in the treatment of severe hemophilia A to prevent bleeding. In this study, Hemlibra demonstrated effective bleeding control in infants for the first time. This complements data across a wide range of ages shown in previous clinical trials and supports earlier initiation of Hemlibra treatment aimed at preventing bleeding in infants. We remain committed to building evidence including long-term data to support the safe use of this drug for those who need it," said Dr. Osamu Okuda, Chugai’s President and CEO.

The burden of severe hemophilia A in babies and on their parents and caregivers is significant. The World Federation of Hemophilia treatment guidelines consider the standard of care in hemophilia to be regular prophylaxis initiated at a young age, as studies have shown this improves long-term outcomes, while reducing the risk of intracranial hemorrhage.2-4 However, for many babies with hemophilia A, prophylaxis is not started until after the first year of life.5-8 Hemlibra, which is already approved and being used to treat babies with hemophilia A, provides a flexible treatment option that can be administered subcutaneously from birth at different dosing frequencies for maintenance dosing.9

The HAVEN 7 study is a Phase III, descriptive, single-arm study, set up in collaboration with the hemophilia A community to evaluate the efficacy, safety, pharmacokinetics and pharmacodynamics of subcutaneous Hemlibra in infants with severe hemophilia A without factor VIII inhibitors. These results, which included data from 55 participants, showed that at 101.9 weeks median follow-up, 54.5% of participants (n=30) did not have any bleeds that required treatment, while 16.4% (n=9) did not have any treated or untreated bleeds at all. There were no spontaneous bleeds requiring treatment in any participant, and all treated bleeds were as a result of trauma. A total of 207 bleeds occurred in 46 participants (83.6%); 87.9% of these were as a result of trauma. Model-based annualized bleeding rate (95% CI) was 0.4 (0.30-0.63) for treated bleeds. No new safety signals were observed and there were no treatment-related serious adverse events, intracranial hemorrhages or deaths reported. 3.6% of participants (n=2) tested positive for factor VIII inhibitors which may be a consequence of reduced factor VIII usage in participants treated with Hemlibra, and no participant tested positive for anti-drug antibodies.1 Results were consistent with positive results from the interim analysis and from previous Phase III HAVEN studies.10-14

The results of additional research on biomarkers in the HAVEN 7 study were also presented at ASH (Free ASH Whitepaper), and were supportive of the study’s primary efficacy analysis. This additional research showed that the pharmacodynamic profiles of Hemlibra in babies were consistent with those previously observed in older children and adults with hemophilia A. The data showed that Hemlibra exhibits the expected pharmacodynamic response, despite the reduced presence of the clotting factors that Hemlibra binds to in this age group.15

The HAVEN 7 study results complement data from the broader, pivotal HAVEN clinical program, providing insights into the evolution of hemophilia A in babies, and the impact of initiating preventative treatment from birth. The primary analysis is being followed by a seven year extension period.1

About Hemlibra
Hemlibra is a bispecific monoclonal antibody created with Chugai’s proprietary antibody engineering technologies. The drug is designed to bind factor IXa and factor X. In doing so, Hemlibra provides the cofactor function of factor VIII in people with hemophilia A, who either lack or have impaired coagulation function of factor VIII.16,17 The product was approved by the U.S. Food and Drug Administration (FDA) in November 2017, for the first time in the world, for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adult and pediatric patients with hemophilia A (congenital factor VIII deficiency) with factor VIII inhibitors. Hemlibra has been approved in more than 115 countries for congenital hemophilia A with and without factor VIII inhibitors. In Japan, it was first approved in March 2018 for congenital hemophilia A with factor VIII inhibitors, and its indication was later expanded to include congenital hemophilia A without factor VIII inhibitors, and acquired hemophilia A.

MorphoSys’ Pelabresib Improves All Four Hallmarks of Myelofibrosis in Phase 3 MANIFEST-2 Study

On December 10, 2023 MorphoSys AG (FSE: MOR; NASDAQ: MOR) reported comprehensive results from the Phase 3 MANIFEST-2 study investigating pelabresib, an investigational BET inhibitor, in combination with the JAK inhibitor ruxolitinib in JAK inhibitor-naïve patients with myelofibrosis (Press release, MorphoSys, DEC 10, 2023, View Source [SID1234638379]). These findings were presented in an oral presentation at the 65th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition in San Diego, California.

Myelofibrosis is characterized by four hallmarks: an enlarged spleen, anemia, bone marrow fibrosis and disease-associated symptoms. In MANIFEST-2, all hallmarks were improved with the pelabresib and ruxolitinib combination versus placebo plus ruxolitinib, which is the standard of care in myelofibrosis. Ruxolitinib dosing was similar in both arms of the study and was determined based on its approved myelofibrosis indication.

"The MANIFEST-2 results demonstrated clear benefits across the four hallmarks of myelofibrosis, including a significant reduction in spleen size – a key finding given the known association between spleen volume reduction and patient survival," said Raajit K. Rampal, M.D., Ph.D., Director, Center for Hematologic Malignancies, and Director, Myeloproliferative Neoplasms Program, Memorial Sloan Kettering Cancer Center. "The comprehensive results presented at ASH (Free ASH Whitepaper) also show that the pelabresib combination improves anemia, disease-associated symptoms and bone marrow fibrosis, and that it is well-tolerated. These findings point to pelabresib and ruxolitinib as a potential paradigm-shifting first-line treatment of this debilitating disease."

MANIFEST-2 Comprehensive Findings

MANIFEST-2 is a global, multicenter, double-blind, Phase 3 study of 430 JAK inhibitor-naïve adults with myelofibrosis, randomized 1:1 to receive the pelabresib and ruxolitinib combination or placebo plus ruxolitinib. MANIFEST-2 is one of the largest studies in this disease to date.

Strong Reductions in Spleen Size and Symptoms

In the MANIFEST-2 study, pelabresib and ruxolitinib demonstrated a near doubling in the proportion of patients achieving a ≥35% reduction in spleen volume (SVR35) at 24 weeks, the primary endpoint, versus placebo plus ruxolitinib (p<0.001).

For the first key secondary endpoint assessing symptom reduction, absolute change in total symptom score (TSS) at 24 weeks, there was a strong numerical improvement for patients receiving pelabresib and ruxolitinib versus placebo plus ruxolitinib. The response rate for the second key secondary endpoint, proportion of patients achieving ≥50% reduction in symptom score (TSS50) at 24 weeks, was also numerically greater for patients receiving pelabresib and ruxolitinib. Significant improvements in both key secondary endpoints were observed with the pelabresib combination for patients classified as intermediate-risk (Dynamic International Prognostic Scoring System [DIPSS] Int-1 and Int-2), who account for over 90% of the MANIFEST-2 population.

The proportion of patients achieving both SVR35 and TSS50 at 24 weeks was doubled with pelabresib and ruxolitinib versus placebo plus ruxolitinib (40.2% vs. 18.5%, respectively).

Details are included in the table below.

Endpoint Pelabresib + Ruxolitinib
(N=214) Placebo +
Ruxolitinib
(N=216) Difference
SVR35 65.9% 35.2% 30.4%*
P-value: p<0.001
Absolute Change in TSS -15.99
(Mean Baseline: 28.26)
-14.05
(Mean Baseline: 27.36) -1.94**
P-value: 0.0545
TSS50 52.3% 46.3% 6.0%*
P-value: 0.216
*Difference calculated using Cochran–Mantel–Haenszel (CMH) common risk difference

**Least square mean estimate

Improvement in Anemia

Patients receiving pelabresib in combination with ruxolitinib reported fewer anemia adverse events (43.9%, grade ≥3: 23.1%) compared with placebo plus ruxolitinib (55.6%, grade ≥3: 36.4%). Additionally, by week 24, fewer patients in the pelabresib and ruxolitinib arm required red blood cell transfusions compared with the placebo arm (30.8% vs. 41.2%, respectively).

A greater proportion of patients achieved a hemoglobin response — defined as a ≥1.5 g/dL mean increase in hemoglobin levels over baseline in the absence of transfusions during the previous 12 weeks — with pelabresib and ruxolitinib versus placebo plus ruxolitinib (9.3% vs. 5.6%, respectively). Average hemoglobin levels were greater in patients receiving pelabresib and ruxolitinib than in those receiving placebo plus ruxolitinib, starting at week 9 and continuing to week 24. Anemia benefits were observed across all studied patient risk groups.

"Anemia can reduce patients’ quality of life by causing severe fatigue and necessitating blood transfusions," said Professor Claire Harrison, Guy’s and St. Thomas’ NHS Foundation Trust, London, United Kingdom. "In MANIFEST-2, patients receiving the combination therapy showed clear benefits on anemia, including greater hemoglobin levels, fewer red blood cell transfusions and fewer anemia and fatigue adverse events. Given its strong efficacy, safety profile and signs of disease modification, the pelabresib and ruxolitinib combination has the potential to become the new standard of care in the first-line treatment of myelofibrosis."

Improvement in Bone Marrow Fibrosis

Bone marrow fibrosis, or the replacement of bone marrow with fibrous scar tissue, is a central pathological feature of myelofibrosis. In MANIFEST-2, fibrosis was improved by at least one grade in a greater proportion of patients receiving pelabresib and ruxolitinib (38.5% vs. 24.2% with placebo plus ruxolitinib) and worsened by at least one grade in a smaller proportion of patients receiving pelabresib and ruxolitinib (16.3% vs. 28.3% with placebo plus ruxolitinib) at 24 weeks. Bone marrow fibrosis is graded on a scale from 0 (normal) to 3 (most severe) based on fiber density; studies suggest a correlation between the grade of bone marrow fibrosis and patient prognosis.

Biomarker Analysis Suggests Disease Modification

In a biomarker analysis, average plasma levels of inflammatory cytokines (IL-8, IL-6, TNF-α and NF-κB-regulated cytokines) were reduced in patients receiving pelabresib and ruxolitinib compared with placebo plus ruxolitinib at 24 weeks. Increased cytokine levels are associated with all four disease hallmarks; increased IL-8 levels are also associated with worse survival outcomes. These biomolecular improvements suggest early evidence of a disease-modifying effect.

Well-Tolerated Safety Profile

Overall, grade ≥3 treatment-emergent adverse events (TEAEs) were reported less frequently with pelabresib and ruxolitinib than with placebo plus ruxolitinib (49.1% vs. 57.5%, respectively).

In the pelabresib and ruxolitinib arm, the most common (≥10%) hematologic TEAEs were anemia (43.9%; grade ≥3: 23.1%), thrombocytopenia (32.1%; grade ≥3: 9.0%) and platelet count decrease (20.8%; grade ≥3: 4.2%). In the placebo plus ruxolitinib arm, the most common hematologic TEAEs were anemia (55.6%; grade ≥3: 36.4%), thrombocytopenia (23.4%; grade ≥3: 5.6%) and platelet count decrease (15.9%; grade ≥3: 0.9%).

The most common (≥10%) nonhematologic TEAEs in the pelabresib and ruxolitinib arm were diarrhea (23.1%; grade ≥3: 0.5%), dysgeusia (18.4%; grade ≥3: 0.5%), constipation (18.4%; grade ≥3: 0%), nausea (14.2%; grade ≥3: 0.5%), cough (12.7% grade ≥3: 0), asthenia (11.8% grade ≥3: 0.5%), fatigue (11.8%; grade ≥3: 0.5%), dizziness (11.3%; grade ≥3: 0%), headache (11.3% grade ≥3: 0.5%) and COVID-19 (11.3%; grade ≥3: 0%). The most common nonhematologic TEAEs in the placebo plus ruxolitinib arm were constipation (24.3%; grade ≥3: 0%), diarrhea (18.7%; grade ≥3: 1.4%), fatigue (16.8%; grade ≥3: 0.9%), COVID-19 (15.9%; grade ≥3: 1.9%), nausea (15.0%; grade ≥3: 0%), asthenia (13.6%; grade ≥3: 0%), dyspnea (13.1%; grade ≥3: 0.9%), cough (11.2%; grade ≥3: 0%) and headache (10.7%; grade ≥3: 0%). Discontinuation rates due to adverse events were 10.7% with pelabresib and ruxolitinib and 6.5% with placebo plus ruxolitinib.

The safety profile of the pelabresib and ruxolitinib combination therapy was consistent with previous clinical studies. No new safety signals were observed.

"The four hallmarks of myelofibrosis – enlarged spleen, anemia, bone marrow fibrosis and disease-associated symptoms – have a strong impact on a patient’s life. In MANIFEST-2, the combination of JAK and BET inhibition addressed all four of these hallmarks with the potential to modify the course of the disease," said Tim Demuth, M.D., Ph.D., MorphoSys Chief Research and Development Officer. "We are confident that the comprehensive data package will provide impactful insights into the promising and well-tolerated combination of pelabresib and ruxolitinib. Our goal now is to bring this first-line therapy to patients with intermediate- and high-risk myelofibrosis as quickly as possible. We look forward to meeting with regulatory agencies regarding these data and are diligently preparing regulatory filings with the intention of submitting applications to the U.S. Food and Drug Administration and the European Medicines Agency in the middle of 2024."

Investor Event at ASH (Free ASH Whitepaper) 2023

MorphoSys will host an in-person investor event to review these detailed findings and address questions with the company’s management team and medical experts, including Professor Claire Harrison, Guy’s and St. Thomas’ NHS Foundation Trust, London, United Kingdom, and Ruben Mesa, M.D., FACP, President and Executive Director, Atrium Health Levine Cancer Center and Atrium Health Wake Forest Baptist Comprehensive Cancer Center.

The event, taking place on Monday, December 11 at the Hilton San Diego Bayfront Hotel, will start with a networking breakfast at 6:30 a.m. PST and continue with a formal presentation at 7:00 a.m. PST (4:00 p.m. CET / 3:00 p.m. GMT / 10:00 a.m. EST). A webcast will also be available for those not attending ASH (Free ASH Whitepaper) 2023 in person.

Webcast participants may pre-register and will receive dial-in details to access the call easily and quickly: View Source;linkSecurityString=c1a71840b. Please dial in 10 minutes before the beginning of the conference.

The live webcast (audio and presentation) can be directly accessed via View Source or via the Investors section under "Events & Conferences" on the MorphoSys website, www.morphosys.com; after the call, a slide-synchronized audio replay of the conference call will be available at the same location.

Poseida Therapeutics Presents Positive Early Results from its Phase 1 Trial of Allogeneic CAR-T P-BCMA-ALLO1 in Relapsed-Refractory Multiple Myeloma at the 65th American Society of Hematology (ASH) Annual Meeting

On December 10, 2023 Poseida Therapeutics, Inc. (Nasdaq: PSTX), a clinical-stage cell and gene therapy company advancing a new class of treatments for patients with cancer and rare diseases, reported early efficacy and safety results from its Phase 1 study of P-BCMA-ALLO1, its BCMA-targeted allogeneic, T stem cell memory (TSCM)-rich chimeric antigen receptor (CAR)-T therapy candidate (Press release, Poseida Therapeutics, DEC 10, 2023, View Source [SID1234638378]). The Company is investigating P-BCMA-ALLO1 in partnership with Roche for the treatment of relapsed/refractory multiple myeloma (RRMM). Detailed study findings, along with two additional Company poster presentations in cell and gene therapy, are being featured at the 65th ASH (Free ASH Whitepaper) Annual Meeting and Exposition being held in San Diego on December 9-12, 2023.

"Today, far too many patients are unable to benefit from autologous CAR-T therapy due to its limited supply, lengthy timelines, complex logistics, and cost," said Kristin Yarema, Ph.D., President, Cell Therapy at Poseida. "We have long believed that readily produced, off-the-shelf allogeneic, TSCM-rich CAR-T products have the potential to offer a compelling efficacy and safety profile while also supporting patient access. TSCM-rich CAR-T products can be difficult to produce with older virus-based technology, but we are able to create a portfolio of such products using Poseida’s unique, non-viral set of technologies. We see these early P-BCMA-ALLO1 results in multiple myeloma, in which all enrolled patients received CAR-T therapy and most patients receiving adequate lymphodepletion achieved a stringent complete response (sCR) or very good partial response (VGPR), as validating our vision and eagerly await additional data yet to come from this study. This is also the first known publicly presented data set that provides clear clinical evidence supporting the hypothesis that TSCM cells are the ideal cell type for allogeneic CAR-T, extending our previous findings with autologous TSCM cells to the allogeneic setting. We hope that TSCM-rich allogeneic CAR-T therapies may potentially offer the optimal combination of clinical results, on-demand availability and high-volume production, while supporting broader access to CAR-T therapies. We are excited to have taken this first step with our early P-BCMA-ALLO1 clinical results. They inspire us to further develop P-BCMA-ALLO1 in partnership with Roche, and to continue advancing our entire allogeneic TSCM cell-based CAR-T portfolio."

P-BCMA-ALLO1 program data presentations

At the time of the October 23, 2023 data cut off, 39 patients were enrolled as an intent-to-treat (ITT) population in the ongoing Phase 1 multicenter, open-label dose-escalation study (NCT04960579). Enrolled patients had previously failed protease inhibitor, immunomodulatory drug (IMiD), and anti-CD38 antibody treatments or were otherwise triple-refractory. Previous treatment with B cell maturation antigen (BCMA)-targeted therapy was allowed including autologous BCMA CAR-T and bispecific T cell-engaging (TCE) antibodies. All enrolled patients completed lymphodepletion and went on to receive P-BCMA-ALLO1 a median of 7 days after enrollment for a 100% ITT treatment rate with no use of bridging therapy. Six patient cohorts varying in size (n=1 to n=6) received one of three fludarabine/cyclophosphamide (flu/cy) lymphodepleting conditioning regimens including 3 days of fludarabine at 30 mg/m2/day for all patients and, depending upon the patient cohort, 3 days of cyclophosphamide at 300, 500, or 1,000 mg/m2/day followed by infusion of P-BCMA-ALLO1 cells at cell doses varying by cohort up to 6×106 cells/kg to date.

Evaluable patients with at least 4 weeks of follow up (n=33) were heavily pretreated with a median of 7 prior lines of therapy. Additionally, 30% of these patients had high risk disease by cytogenetics and nearly 2 in 5 (39%) had received previous BCMA-targeted therapy. 11 of the 33 evaluable patients were in the two cohorts receiving 2×106 cells/kg of P-BCMA-ALLO1 and higher cyclophosphamide preconditioning doses at either 500 mg/m2 (‘P1 arm’; n=5) or 1,000 mg/m2 (‘P2 arm’; n=6).

An overall objective response rate (ORR) of 82% (9/11 total patients) was reached among patients in the pooled P1 and P2 arms. ORR in the P2 arm was 83% (5/6) with 100% (5/5) of the responding P2 patients achieving a VGPR or better and 40% (2/5) achieving sCR. 80% ORR was obtained in the P1 arm (4/5) with 50% of responding patients achieving VGPR. Both nonresponding patients, one in each of the P1 and P2 arms, had received and not achieved clinical response with the BCMAxCD3 bispecific TCE antibody therapy teclistamab prior to receiving P-BCMA-ALLO1.

A 100% ORR (9/9) was achieved among patients in P1 and P2 arms who had not received a prior BCMA-targeting bispecific TCE antibody as well as 100% ORR (2/2) in patients who had received prior autologous CAR-T BCMA targeted therapy.

P-BCMA-ALLO1 was very well tolerated, with no graft-vs-host disease (GvHD) at any dose and low rates of cytokine release syndrome (CRS) and neurotoxicity, all Grade 2 or less, found among all evaluable patients.

Expansion and persistence of the CAR-T cells in patients after infusion was found to be highly dependent upon the conditioning dose of cyclophosphamide, with P-BCMA-ALLO1 levels measured in the blood much higher in patient cohorts in the P1 and P2 arms receiving the 500 mg/m2 and 1,000 mg/m2 conditioning doses than in any of the 300 mg/m2 (arm ‘S’, n=20) cohorts. Clinical responses in patients receiving arm S conditioning treatment were inferior to those achieved by patients in P1 or P2.

Analysis of P-BCMA-ALLO1 cellular kinetics in two patients with high CAR-T expansion showed CAR-T cells persisted and were measurable in the peripheral blood of one patient for at least 4 weeks and engrafted and persisted at a high level in the bone marrow of the other for at least 6 weeks. Moreover, in both cases cells in the TSCM-rich CAR-T infused drug product underwent differentiation after infusion to generate a much more effector T cell-rich population, particularly among the important CD8+ ‘killer T cell’ subpopulation. These findings are the first known direct clinical evidence supporting the theory that allogeneic TSCM-based CAR-T cells can act as effective prodrugs because they can expand, traffic to the relevant tissues, differentiate into effector cells and persist, all of which may contribute to driving deep clinical responses in patients while also being well-tolerated.

"Despite the emergence of autologous BCMA-targeted therapies, multiple myeloma remains an incurable malignancy. Autologous CAR-T therapies may be associated with numerous challenges for patients and physicians, including prolonged manufacturing times, inconsistent drug quality and serious safety issues," said Bhagirathbhai Dholaria, M.D., Associate Professor of Medicine (Hematology/Oncology) at the Vanderbilt-Ingram Cancer Center. "Allogeneic CAR-T therapies have the potential to overcome many of these challenges. Today’s data demonstrate that P-BCMA-ALLO1 is a well-tolerated off-the-shelf therapy with a favorable emerging safety profile and encouraging evidence of early clinical activity. In addition, the data show that P-BCMA-ALLO1 can achieve deep clinical responses in patients with high-risk disease and those who have previously received BCMA targeting therapies. Importantly, P-BCMA-ALLO1 was delivered to all patients in the ITT population with all drug product meeting all quality specifications. We look forward to continuing to enroll patients in this study."

Enrollment is ongoing including additional exploration of dose regimens and lymphodepleting conditioning regimens. While still early to assess durability, at the time of the data cut off 8 of the 9 responding patients in P1 and P2 arms remained in response. The Company, together with Roche, plans to present additional clinical data updates for P-BCMA-ALLO1 at scientific meetings in 2024, subject to coordination with Roche.

A second Poseida-sponsored poster highlights the development of an in vivo bioassay for assessing BCMA CAR-T final product potency and presents data suggesting P-BCMA-ALLO1 drug product may have greater potency than drug products produced in the Company’s earlier, autologous P-BCMA-101 CAR-T program.

P-FVIII-101 program data presentation

The Company has also presented a third poster describing P-FVIII-101, a fully non-viral liver-directed gene therapy combining Poseida’s proprietary piggyBac DNA Delivery System with nanoparticle delivery for the treatment of Hemophilia A. This poster demonstrates the capabilities of the piggyBac DNA insertion system and non-viral approach in providing stable Factor VIII (FVIII) transgene expression through genomic integration, along with the potential for redosing. The poster highlights 52-week durability in an adult Hemophilia A model along with a favorable tolerability profile of Poseida’s liver-targeted non-viral delivery platform providing further proof-of-principle toward developing an effective and durable treatment for Hemophilia A.

Company-Hosted Webcast and Conference Call Information:

Poseida will host a webcast and conference call today, December 10th at 11:00 AM PST / 2:00 PM EST. The conference call can be accessed by dialing 800-225-9448 (United States) or 203-518-9708 (International) with the conference ID PSTX23. A live webcast may be accessed using the link here, or by visiting the Events and Presentations section of the Poseida website at investors.poseida.com. After the live webcast, the event will remain archived on the Poseida site for 90 days.

Poster Presentation Details:

Title: Early Safety Results of P-BCMA-ALLO1, a Fully Allogeneic Chimeric Antigen Receptor T-Cell (CAR-T), in Patients with Relapsed/Refractory Multiple Myeloma (RRMM)

Presenting Author: Bhagirathbhai Dholaria, M.D., Associate Professor of Medicine (Hematology/Oncology) at the Vanderbilt-Ingram Cancer Center
Session Date & Time: Sunday, December 10, 2023, at 6:00 – 8:00 PM PT
Publication Number: 3479
Session Title: 704. Cellular Immunotherapies: Early Phase and Investigational Therapies: Poster II
Location: Halls G-H
Title: A Tumor-Bearing Murine Xenograft Model as a Bioassay for Assessing CAR-T Product Potency Shows Positive Predictive Value for Clinical Performance

Presenting Author: Stacey Cranert, Ph.D., Poseida Therapeutics
Session Date & Time: Saturday, December 9, 2023, at 5:30 – 7:30 PM PT
Publication Number: 2293
Session Title: 803. Emerging Tools, Techniques and Artificial Intelligence in Hematology: Poster I
Location: Halls G-H
Title: Effective Gene Therapy for Hemophilia A: Novel Re-Dosable Non-Viral Formulation That Provides Stable, and Durable FVIII Expression with Improved Tolerability

Presenting Author: Brian Truong, Ph.D., Poseida Therapeutics
Session Date & Time: Saturday, December 9, 2023, at 5:30 – 7:30 PM PT
Publication Number: 1232
Session Title: 321. Coagulation and Fibrinolysis: Basic and Translational: Poster I
Location: Halls G-H
About P-BCMA-ALLO1

P-BCMA-ALLO1 is an allogeneic CAR-T product candidate licensed to Roche targeting B-cell maturation antigen (BCMA) for the treatment of relapsed/refractory multiple myeloma in Phase 1 development. This allogeneic program includes a VH-based binder that targets BCMA and has shown early evidence of encouraging safety and efficacy. Additional information about the Phase 1 study is available at www.clinicaltrials.gov using identifier: NCT04960579.

About P-FVIII-101

P-FVIII-101 is a liver-directed gene therapy combining Poseida’s non-viral piggyBac platform and nanoparticle delivery technologies for the in vivo treatment of Hemophilia A. Hemophilia A is a bleeding disorder caused by a deficiency in Factor VIII production with a high unmet need. P-FVIII-101 utilizes the piggyBac gene integration system delivered via lipid nanoparticle, which has demonstrated stable and sustained Factor VIII expression in juvenile and adult animal models.

Vincerx Pharma Presents Preclinical VIP943 and VIP924 Posters at ASH 2023

On December 10, 2023 Vincerx Pharma, Inc. (Nasdaq: VINC)("Vincerx"), a biopharmaceutical company aspiring to address the unmet medical needs of patients with cancer through paradigm-shifting therapeutics, reported the presentation of two preclinical posters at the 65th Annual Meeting of the American Society for Hematology (ASH 2023) for VIP943, for leukemias and myelodysplastic syndrome, and VIP924, for B-cell malignancies (Press release, Vincerx Pharma, DEC 10, 2023, View Source [SID1234638377]).

"We are excited to share new preclinical data for VIP943 and VIP94 with our stakeholders," said Ahmed Hamdy, M.D., Chief Executive Officer of Vincerx. "The compelling data from these studies underscore the differentiation of our next-generation ADCs and the power of VersAptx, our versatile and adaptable bioconjugation platform used to develop these ADCs."

"The preclinical data from the VIP943 poster highlight the on-target selectivity and activity of VIP943 in acute myeloid leukemia (AML) cell lines, including those with common AML mutations such as TP53. We also show that repeat dosing of VIP943 in cynomolgus monkeys has good overall tolerability without the myelosuppression and hepatotoxicity typically associated with ADCs, which is consistent with the favorable safety profile seen to date in our VIP943 Phase 1 dose-escalation trial. The first dosing cohort enrolled rapidly and completed the 28-day safety evaluation without evidence of drug-related adverse events. One of the three patients from this cohort continues treatment, and the second cohort is enrolling."

"The preclinical data from the VIP924 poster highlight the superior efficacy of VIP924 when compared with two commercially available ADCs, Polivy and Zynlonta, in a mouse model of mantle cell lymphoma. In this study, VIP924 shows significant efficacy (i.e., significant tumor growth inhibition and increased survival) with no substantial change in body weight, an indication of safety, while Polivy and Zynlonta show no improvement in tumor growth inhibition or survival. Based on the side-effect profile of current ADC and CAR-T therapies for B-cell malignancies, we believe VIP924 may have the potential to be used in earlier lines of therapy, either as a monotherapy or in combination with other targeted drugs (e.g., BTK or BCL2 inhibitors), to improve efficacy and safety," concluded Dr. Hamdy.

Poster Highlights

VIP943: CD123-KSPi ADC for leukemias and myelodysplastic syndrome

Poster #1435: Selectivity and Safety of VIP943: A novel CD123 Targeting Antibody-Drug Conjugate (ADC) Using a Proprietary Linker and Payload Class.

Objective: The poster outlines a series of assays used to characterize the preclinical properties of VIP943, including biochemistry, pharmacology, on-target selectivity and activity, safety, and toxicokinetics.

Results:

On-target selectivity and activity show that VIP943 is highly selective for the kinesin spindle protein (KSP) target, aka EG5, versus other members of the related KIF super family. This on-target activity translates to cell cycle arrest at the G2/M phase of mitosis, resulting in apoptosis in AML cell lines.
In vitro cytotoxicity assays show that most hematologic cell lines (n=56) are sensitive to VIP943’s payload and that DNA alterations (including common AML mutations such as TP53) did not reduce its cytotoxicity.
Nonhuman primate safety and toxicokinetic studies show that repeat dosing of VIP943 in cynomolgus monkeys has good overall tolerability without the myelosuppression and hepatotoxicity seen with other ADCs. This is consistent with the favorable safety profile seen to date in the VIP943 Phase 1 dose-escalation trial.
VIP924: CXCR5-KSPi ADC for B-cell malignancies

Poster #2809: Comparison of the CXCR5-Antibody Drug Conjugate (ADC; VIP924) to a CD19-ADC and a CD79b-ADC in a Humanized REC-1 Mantle Cell Lymphoma (MCL) Mouse Model.

Objective: To evaluate target expression (CXCR5, CD19, and CD79b) in human patient samples and to compare the activity of VIP924 to two commercially available, B-cell targeted ADCs, Polivy (a CD19-ADC, polatuzumab vedotin) and Zynlonta (CD79b-ADC, loncastuximab tesirine), in a humanized mouse model of MCL by evaluating in vivo activity, immunophenotyping of key tissues, and complete blood counts. VIP924 data are based on a dose level of 10 mg/kg compared with 3 mg/kg for Polivy and 0.66 mg/kg for Zynlonta. Doses were selected based on the literature as effective doses in mouse xenograft experiments and higher doses lead to toxicity in these models. Tumor growth was measured at day 25; blood work was assessed at days 0, 5, and 18.

Results:

Target expression analysis in a panel of 20 human MCL samples shows that CXCR5 and CD19 expression was medium to high in all samples, while CD79b showed slightly lower expression.
In vivo activity in a humanized mouse model shows that VIP924 demonstrates significant efficacy (i.e., tumor growth inhibition and increased survival) with no substantial change in body weight (an indication of safety). In comparison, the commercially available ADCs, Polivy and Zynlonta, show no improvement in tumor growth inhibition or survival in this setting.
Immunophenotyping of key immune tissues show that:
VIP924 treatment yielded no difference in the percent of CD45+ cells versus the control, while the other two ADCs showed a clear reduction in CD45+ cells.
VIP924 treatment reduced T-follicular helper cells (Tfhs) in the blood, tumor and spleen; significantly increased T-regs; and had no meaningful impact on myeloid-derived suppressor cells (MDSCs) compared with controls. Zynlonta also reduced peripheral blood Tfhs and significantly increased MDSCs compared with control.
Complete blood counts (CBCs) show that VIP924 had minimal impact on the six elements of the CBC reported in these studies. Zynlonta reduced the levels of all cell populations in the CBC, except for platelets.
About VIP943

VIP943, the first ADC from our VersAptx platform, consists of an anti-CD123 antibody, a unique linker cleaved intracellularly by legumain, and a novel kinesin spindle protein inhibitor (KSPi) payload enhanced with our CellTrapper technology. Our proprietary effector chemistry (linker + payload) was designed to reduce non-specific release of the payload and ensure payload accumulation in cancer cells versus healthy cells. The increased therapeutic index has the potential to address challenges associated with many ADCs by improving efficacy and reducing severe toxicities. VIP943 is in a Phase 1 dose-escalation trial evaluating patients with relapsed/refractory acute myeloid leukemia, myelodysplastic syndrome, and B-cell acute lymphoblastic leukemia who have exhausted standard therapeutic options (NCT06034275). We expect to expand into these CD123-positive indications, including TP53 mutated AML both as monotherapy and in combination, as safety and efficacy data are generated. Preliminary Phase 1 data are expected in mid-2024.

About VIP924

VIP924, the second ADC from our VersAptx Platform, consists of an anti-CXCR5 antibody, a unique linker cleaved intracellularly by legumain, and a novel KSPi payload enhanced with our CellTrapper technology. Our proprietary effector chemistry (linker + payload) was designed to reduce non-specific release of the payload and ensure payload accumulation in cancer cells versus healthy cells. The increased therapeutic index has the potential to address challenges associated with many ADCs by improving efficacy and reducing severe toxicities. VIP924 has the potential to be evaluated in B-cell malignancies, such as mantle cell lymphoma, follicular lymphoma, diffuse large B-cell lymphoma (DLBCL), and chronic lymphocytic leukemia, both as monotherapy and in combination. We continue to judiciously pace our investment in VIP924 to focus resources on VIP236 and VIP943.

About VersAptx Platform

VersAptx is our versatile and adaptable, next-generation bioconjugation platform. The modular nature of this innovative platform allows us to combine different targeting, linker, and payload technologies to develop bespoke bioconjugates to address different cancer biologies. With this platform (i) antibodies and small molecules can be used to target different tumor antigens (ii) linkers can be designed to reduce non-specific release of the payload, cleave intracellularly or extracellularly, and conjugate to single or multiple payloads, and (iii) payloads can be designed with reduced permeability using our CellTrapper technology to ensure accumulation in cancer cells or to be permeable for release in the tumor microenvironment. The VersAptx platform allows us to optimize these technologies to a specific target and develop bioconjugates designed to address the safety and efficacy challenges of many ADCs and the needs of cancer patients.

About Enitociclib

Enitociclib is a highly selective CDK9 inhibitor that prevents activation of RNA polymerase II, resulting in reduction of known oncogenes MYC and MCL1. It is currently in a dose-escalation Phase 1 trial (NTC05371054) in collaboration with the National Institutes of Health evaluating the combination of enitociclib, venetoclax, and prednisone in DLBCL and peripheral T-cell lymphoma (PTCL). The first dose level completed enrollment with no drug-related safety signal (n=3; 1=DLBCL, 2=PTCL). The first patient on the second dose level (n=1; 1=PTCL) remains on study with a partial response due to an 80% reduction in the pulmonary lesion on computerized tomography (CT) scan and resolved skin lesions. Investigators are pleased with the safety profile of this novel combination and continue with enrollment. Early-stage clinical studies in patients with hematologic malignancies and solid tumors provided monotherapy proof-of-concept. Additional combination studies will be determined based on financing/partnering support.