Extranodal natural killer (NK)/T-cell lymphoma, nasal type, is a rare peripheral T-cell lymphoma associated with Epstein-Barr virus. It most often presents as limited-stage disease in patients of East Asian descent with a palatal deformity caused by erosion of the tumor through the hard palate. Limited-stage disease is often curable with the use of l-asparaginase–based chemotherapy and high-dose radiation therapy. Obtaining an accurate diagnosis is essential, because treatment with standard lymphoma regimens and omission of radiation severely compromise the likelihood of long-term survival. Conversely, patients with advanced disease have a poor prognosis and are recommended for asparaginase-based chemotherapy followed by consolidation with autologous transplantation as a potentially curative approach. Progress often has been hampered by the rarity of this disease. However, discovery of common genetic alterations in pathways that promote growth and inhibit apoptosis, and actionable markers such as CD30 (among others), have begun to broaden the availability of novel drugs (eg, targeted therapies). There is also cautious optimism about immunotherapies, such as checkpoint blockade and novel cellular therapies that target Epstein-Barr virus. Advances in treatment and understanding of the genetic landscape of this disease offer hope for improved treatment outcomes.

Hepatosplenic T-cell lymphoma (HSTCL) is a rare T-cell neoplasm that most commonly arises from a small subset of γ/δ T-cell receptor-expressing lymphocytes. HSTCL is more common in adolescent and young adults and has a rapidly progressive clinical course and poor outcome due to its refractoriness to conventional chemotherapy regimens. Approximately 20% of the cases arise in the background of chronic immunosuppression or immune dysregulation. Patients commonly present with constitutional symptoms, hepatic and liver enlargement, and cytopenias; hematophagocytic syndrome can also occur. The most frequent chromosomal aberrations associated with HSTCL are isochromosome 7q and trisomy 8, and most cases harbor mutations in genes involved in chromatin modification or the JAK/STAT pathway. The rarity of this disease, along with lack of nodal involvement and presenting symptoms that mimic different entities including infectious etiologies, makes this lymphoma a significant diagnostic challenge. In this review, we highlight the clinical and pathologic features of HSTCL. Moreover, we summarize the results of recent molecular studies suggesting potential targets for novel therapeutics strategies.

Pembrolizumab, a humanized IgG4 monoclonal antibody targeting programmed death-1 protein, has demonstrated efficacy in relapsed/refractory classical Hodgkin lymphoma (cHL). To assess the complete metabolic response (CMR) rate and safety of pembrolizumab monotherapy in newly diagnosed cHL, we conducted a multicenter, single-arm, phase II investigator-initiated trial of sequential pembrolizumab and doxorubicin, vinblastine, and dacarbazine (AVD) chemotherapy. Patients > 18 years of age with untreated early unfavorable or advanced stage disease were eligible for treatment. Thirty patients with either early unfavorable (n=12) or advanced (n=18) stage cHL were treated with 3 cycles of pembrolizumab monotherapy followed by AVD for 4-6 cycles depending on stage and bulk. Twelve had either large mediastinal masses and/or bulky disease (>10 cm). Following pembrolizumab monotherapy, 11 patients (37%) demonstrated CMR's, and an additional 7 of 28 (25%) patients with quantifiable positron emission tomography/computed tomography scanning (PET-CT) had >90% reductions in metabolic tumor volume. All patients achieved CMR following 2 cycles of AVD and maintained their responses at end of treatment. With a median follow-up of 22.5 months (range: 14.2-30.6) there have been no changes in therapy, progressions, or deaths. No patients received consolidation radiotherapy, including those with bulky disease. Therapy was well-tolerated. The most common immune-related adverse events were grade 1 rash (n=6), and grade 2 infusion reactions (n=4). One patient had a reversible grade 4 transaminitis and a second had a reversible Bell's palsy. Brief pembrolizumab monotherapy followed by AVD proved both highly effective and safe in newly diagnosed cHL patients including those with bulky disease. This trial was registered at www.clinicaltrials.gov as #NCT03226249.

Here we describe KT-413, a novel IRAKIMiD development candidate. KT-413 is a potent and selective degrader of IRAK4 (DC50 6nM) and IMiD substrates (Ikaros/Aiolos DC50 2nM), that induces rapid and potent cell killing in MYD88 MT DLBCL cell lines in vitro. This activity is superior to both IRAK4-selective degraders and inhibitors (such as CA-4948) and the IMiD CC220, which has similar potency against IMiD substrates (Ikaros/Aiolos DC50 1 nM). The combined activity of these two mechanisms drives a synergistic effect on NFkB and IRF4 signaling with greater downstream effect on NFkB, type 1 interferon (IFN) signaling, apoptosis pathways and cell cycle gene expression than can be achieved with either CC220 or IRAK4 degraders and inhibitors alone. These data support the hypothesis that simultaneous targeting of both NFkB and type 1 IFN signaling leads to the rapid antiproliferative and cell killing activity of KT-413 in MYD88 MT cells.In MYD88 MT DLBCL xenograft models, a single IV dose of KT-413 showed significant and sustained degradation of both IRAK4 and the IMiD substrates, Ikaros/Aiolos, supporting the potential for intermittent dosing to drive cell kill and tumor regressions. To assess this, we have explored the antitumor efficacy of KT-413 in intermittent dosing schedules in MYD88 WT and MYD88 MT cell line models in vivo. KT-413 was well tolerated and showed potent antitumor activity in multiple models of MYD88 MT DLBCL irrespective of the presence of comutations in CD79B, TNFAIP3, or IRF4, but substantially lower activity in MYD88 WT models. Regressions were observed on intermittent dosing schedules ranging from QW to Q3W, supporting the clinical investigation of KT-413 as monotherapy in patients with MYD88 MT DLBCL. KT-413 also showed strongly additive activity in combination with rituximab or BTK inhibitors in MYD88 MT OCI-Ly10 xenografts in vivo, suggesting the potential for therapeutically relevant drug combinations in MYD88 MT DLBCL.Collectively, these data demonstrate the synergistic activity of combined IRAK4 degradation and IMiD activity with KT-413 that is superior to either mechanism alone. Based on these results, we propose KT-413 has the potential to be effective both as a single agent and in combination with other agents in patients with MYD88 MT lymphomas.

Introduction: Approximately 30-35% of patients with classic Hodgkin Lymphoma will prove refractory to frontline therapy or relapse subsequently. Traditional second-line chemotherapy regimens including ifosfamide, carboplatin, and etoposide (ICE) result in complete response rates of ~50%. Achievement of complete metabolic response (CMR) assessed by PET/CT imaging prior to autologous hematopoietic stem cell transplant (AHSCT) predicts favorable progression free survival (PFS) and overall survival (OS). PD-1 blockade is a well-established therapeutic strategy for the treatment of cHL. Pembrolizumab (PEM) is a checkpoint inhibitor targeting PD-1 currently FDA approved as monotherapy in relapsed cHL. We hypothesized that PEM in combination with ICE (PEM-ICE) chemotherapy would be a safe and effective regimen that would yield high CMR rates prior to AHSCT. Methods: This single arm, phase II, multi-institutional clinical trial evaluated the addition of PEM to ICE chemotherapy in AHSCT eligible patients with relapsed and refractory cHL (NCT03077828). The regimen consisted of 21 day cycles of PEM 200 mg IV on day 1 with standard ICE including ifosfamide 5 g/m2 with MESNA as a 24hr continuous infusion on day 2, carboplatin AUC 5 IV (max 800 mg) on day 2, and etoposide 100 mg/m2/day IV on days 1 to 3. Two cycles of PEM-ICE were followed by stem cell mobilization/collection. One cycle of PEM 200 mg IV monotherapy was then administered. Our primary endpoint was the rate of CMR on PET/CT (PET2) imaging defined as a Deauville score of ≤ 3. Images were reviewed centrally. An optional third cycle of PEM-ICE was permitted for patients achieving CMR to allow for appropriate timing of AHSCT. Secondary objectives included clinical outcomes (PFS and OS), safety and tolerability, and transplantation related metrics including ability to collect stem cells and time to engraftment. Results: A total of 42 patients were enrolled with 37 patients evaluable for the primary endpoint. Median age was 34 (19-70) with female predominance (n=27, 64%). 16 patients had primary refractory disease. The CMR rate assessed by PET/CT imaging following 2 cycles of PEM-ICE was 86.5% (95% CI, 71.2-95%), meeting our primary endpoint of improvement over historical outcomes to 70%. The PET2 ORR was 97.3% with 11% PR and 2.7% PD. PET2 scores were Deauville 1 in 45% (n=17), Deauville 2 in 27.0% (n=10), Deauville 3 in 8.1% (n=3), Deauville 4 in 13.5% (n=5), and Deauville 5 in 5.4% (n=2). New areas of PET-positivity in two cases were biopsied showing noncaseating granuloma in one case and EBV but no cHL in another. Five patients received the optional third cycle of PEM-ICE chemotherapy with 35 of the 37 evaluable patients proceeding to AHSCT. Seven patients had radiation as part of the conditioning regimen with an additional 4 patients receiving consolidative radiation following transplant. After a median follow up of 27 months, the median PFS was 26.9 months with survival probability at 24 months of 88.2% (Figure 1). Median OS was not reached with too few events but remained 95.1% at 27 months. The addition of PEM to ICE did not impair stem cell mobilization and all patients successfully collected, with 35 (87%) within 2 apheresis sessions (range 1-7). No patients had engraftment delays or failure. Of the 42 patients, all received at least one dose of PEM and were therefore eligible for toxicity analyses. 34 patients (81%) experienced adverse events (AEs) attributed to PEM and 22 patients (52.3%) had grade 3-4 AEs comprised of cytopenias, elevated AST/ALT, hyponatremia, hypophosphatemia, and fatigue. Five patients had severe AEs attributed to PEM which included anemia, back pain, decreased EF, fever, and thrombocytopenia. There were no significant PEM-related autoimmune events that delayed a patient's treatment on protocol. There were two grade 5 toxicities on the protocol including a patient with cardiac arrest during stem cell collection and a patient with acute respiratory distress syndrome attributed to engraftment syndrome. Both were judged "possibly" related to PEM. Conclusions: Pembrolizumab with ICE chemotherapy is a tolerable and efficacious regimen with high CMR rate as assessed by PET/CT. Despite short follow up, patients had excellent PFS and OS in the post-transplant setting. The results support further investigation of PEM-ICE as second-line treatment for AHSCT eligible patients with relapsed and refractory classical Hodgkin lymphoma. Figure 1 Figure 1. Disclosures Casulo: BMS: Research Funding; Verastem: Research Funding; Genentech: Research Funding; Gilead: Research Funding. Allen: Kyowa Kirin: Consultancy, Honoraria, Research Funding; Daichii Sankyo: Consultancy, Honoraria; Secure Bio: Consultancy, Honoraria. Karmali: Epizyme: Consultancy; AstraZeneca: Speakers Bureau; Roche: Consultancy; Genentech: Consultancy; EUSA: Consultancy; Janssen/Pharmacyclics: Consultancy; Karyopharm: Consultancy; Morphosys: Consultancy, Speakers Bureau; BeiGene: Consultancy, Speakers Bureau; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau; BMS/Celgene/Juno: Consultancy, Research Funding; Takeda: Research Funding. Gordon: Zylem Biosciences: Patents & Royalties: Patents, No royalties; Bristol Myers Squibb: Honoraria, Research Funding. Winter: Actinium Pharma: Consultancy; BMS: Other: Husband: Data and Safety Monitoring Board; Karyopharm (Curio Science): Honoraria; Novartis: Other: Husband: Consultancy, Data and Safety Monitoring Board; Merck: Consultancy, Honoraria, Research Funding; Ariad/Takeda: Other: Husband: Data and Safety Monitoring Board; Epizyme: Other: Husband: Data and Safety Monitoring Board; Agios: Other: Husband: Consultancy; Gilead: Other: Husband: Consultancy; Janssen: Other: Husband: Consultancy. OffLabel Disclosure: new combination of study agent with standard of care chemotherapy regimen