A Phase I Trial Evaluating the Addition of Lenalidomide to Patients with Relapsed/Refractory Multiple Myeloma Progressing on Ruxolitinib and Methylprednisolone

BACKGROUND

Ruxolitinib (RUX), an orally administered selective Janus kinase 1/2 inhibitor, has received approval for the treatment of myelofibrosis, polycythemia vera, and graft-versus-host disease. We have previously demonstrated the anti-multiple myeloma effects of RUX alone and in combination with the immunomodulatory agent lenalidomide (LEN) and glucocorticosteroids both pre-clinically and clinically.

OBJECTIVE

This study aims to evaluate whether LEN can achieve clinical activity among patients with multiple myeloma progressing on the combination of RUX and methylprednisolone (MP).

METHODS

In this part of a phase I, multicenter, open-label study, we evaluated the safety and efficacy of RUX and MP for patients with multiple myeloma with progressive disease who had previously received a proteasome inhibitor, LEN, glucocorticosteroids, and at least three prior regimens; we also determined the safety and efficacy of adding LEN at the time of disease progression from the initial doublet treatment. Initially, all subjects received oral RUX 15 mg twice daily and oral MP 40 mg every other day. Those patients who developed progressive disease according to the International Myeloma Working Group criteria then received LEN 10 mg once daily on days 1-21 within a 28-day cycle in addition to RUX and MP, which were administered at the same doses these patients were receiving at the time progressive disease developed.

RESULTS

Twenty-nine subjects (median age 64 years; 18 [62%] male) were enrolled in this part of the study and initially received the two-drug combination of RUX and MP. The median number of prior therapies was six (range 3-12). The overall response rate from this two-drug combination was 31% and the clinical benefit rate was 34%. The best responses were 1 very good partial response, 8 partial responses, 1 minor response, 12 stable disease, and 7 progressive disease. The median progression-free survival was 3.5 months (range  0.5-36.2 months). The median time to response was 3.0 months. The median duration of response was 12.5 months (range 2.8-36.2 months). Twenty (69%) patients who showed progressive disease had LEN added to RUX and MP; all patients had prior exposure to LEN and all but one patient was refractory to their last LEN-containing regimen. After the addition of LEN, the overall response rate was 30% and the clinical benefit rate was 40%. The best responses of patients following the addition of LEN were 2 very good partial responses, 4 partial responses, 2 minor responses, 8 stable disease, and 4 progressive disease. The median time to response was 2.6 months (range 0.7-15.0 months). The median duration of response was not reached. The median progression-free survival following the addition of LEN was 3.5 months (range 0.3-25.9 months).

CONCLUSIONS

For patients with multiple myeloma, treatment with RUX and MP is effective and well tolerated, and LEN can be used to extend the benefit of this RUX-based treatment.

CLINICAL TRIAL REGISTRATION

This study is registered with ClinicalTrials.gov, NCT03110822, and is ongoing.

Preclinical and clinical evaluation of the Janus Kinase inhibitor ruxolitinib in multiple myeloma

Multiple myeloma (MM) is the most common primary malignancy of the bone marrow. No established curative treatment is currently available for patients diagnosed with MM. In recent years, new and more effective drugs have become available for the treatment of this B-cell malignancy. These new drugs have often been evaluated together and in combination with older agents. However, even these novel combinations eventually become ineffective; and, thus, novel therapeutic approaches are necessary to help overcome resistance to these treatments. Recently, the Janus Kinase (JAK) family of tyrosine kinases, specifically JAK1 and JAK2, has been shown to have a role in the pathogenesis of MM. Preclinical studies have demonstrated a role for JAK signaling in direct and indirect growth of MM and downregulation of anti-tumor immune responses in these patients. Also, inhibition of JAK proteins enhances the anti-MM effects of other drugs used to treat MM. These findings have been confirmed in clinical studies which have further demonstrated the safety and efficacy of JAK inhibition as a means to overcome resistance to currently available anti-MM therapies. Additional studies will provide further support for this promising new therapeutic approach for treating patients with MM.

The incidence of translocation t(11;14) among patients with multiple myeloma in a single clinic

OBJECTIVES

Data regarding bone marrow (BM) sampling and cytogenetic testing rates for identification of translocation (11q13;14q32) and their changes over time in a multiple myeloma (MM) population are limited. We analyzed these metrics at a clinic specializing in the treatment of MM.

METHODS

A total of 760 BM aspirate samples from 351 patients were collected between August 2004 and October 2021. We analyzed BM sampling statistics, cytogenetic testing frequency, and the incidence rates for the t(11;14) translocation in a single clinic specializing in the treatment of MM.

RESULTS

We report that most (54.4%) patients had only 1 aspirate collected; the main reason (64.6%) for BM collection was to confirm disease progression. Less than half (47.5%) of BM samples collected for evaluation of MM disease had cytogenetic testing, but the rates have markedly increased in recent years. Our data demonstrated an incidence rate of 19.3% for t(11;14).

CONCLUSIONS

This report suggests that some patients may need to retest for this genetic aberration due to the possibility of false negatives and the potential benefit of identifying the t(11;14) marker for patients who may be candidates for a highly effective targeted therapy consisting of the BCL-2 inhibitor venetoclax.

Efficacy of isatuximab in combination with steroids for the treatment of relapsed/refractory multiple myeloma patients exhibiting only biochemical progression-A single center retrospective study

OBJECTIVES

Isatuximab is approved for treatment of relapsed/refractory multiple myeloma (RRMM) with dexamethasone and carfilzomib or pomalidomide. Patients receiving these three-drug regimens have exhibited more Grade ≥ 3 adverse events (AEs) compared to the two-drug class combination of isatuximab and steroids alone. Thus, this single-center retrospective study investigated the efficacy of isatuximab with dexamethasone and methylprednisolone (ISAdm) for RRMM patients showing only biochemical progression (BP) of their disease.

METHODS

Twenty-four RRMM patients exhibiting only BP were administered isatuximab at 10 mg/kg with dexamethasone once weekly for cycle 1 of a 28-day cycle, followed by every other week for each cycle thereafter. Starting in cycle 2, oral methylprednisolone was added every other day stopping 48 h before and starting 48 h after each dexamethasone infusion.

RESULTS

Overall response rate and clinical benefit rate were 63% and 79%, respectively. Progression free survival was 12.9 months. There were only 5 AEs of Grade ≥ 3 which included lymphocytopenia (13%), leukopenia (4%), and neutropenia (4%). No Grade ≥ 3 AE related to respiratory infection, anemia, or thrombocytopenia were reported.

CONCLUSION

This study shows that the two-drug class combination of ISAdm is an effective and well tolerated treatment option for RRMM patients exhibiting only BP.

Clinical Outcomes and Serum B-Cell Maturation Antigen Levels in a Real-World Unselected Population of Newly Diagnosed Multiple Myeloma Patients

BACKGROUND

Progression-free survival (PFS) and overall survival (OS) of newly diagnosed multiple myeloma (MM) patients have been widely published in the clinical trials setting, but data published from real-world settings are limited.

OBJECTIVE

We determined the survival and factors that predict outcomes among 161 unselected, newly diagnosed MM patients whose frontline therapy was started at a single clinic specializing in the treatment of this B-cell malignancy.

PATIENTS AND METHODS

None of these patients underwent an autologous stem cell transplantation as part of their initial therapy and the population had a high proportion (35%) of cytogenetic high-risk patients.

RESULTS

With a median follow-up of 42.7 months, the cohort had a median PFS of 22.8 months and a median OS of 136.2 months. The 1-, 3-, and 5-year survival rates were 97.5%, 85.3%, and 76.2%, respectively. These results are considerably better than those reported from patients enrolled in clinical trials and those from countries with national registries. Age <65 years predicted for a longer OS (p = 0.0004). Baseline serum B-cell maturation antigen (sBCMA) levels were also assessed and showed median and mean levels of 320.3 ng/mL and 551.1 ng/mL, respectively. Furthermore, patients with baseline sBCMA levels in the lowest quartile (≤136.2 ng/mL) showed a longer PFS (p = 0.0262).

CONCLUSION

These results provide clinicians with a real-world understanding of the survival of unselected, newly diagnosed patients initiating therapy in a clinic specializing in the care of MM patients.

Predicting outcomes and monitoring disease in patients with multiple myeloma

Multiple myeloma (MM) is a clonal plasma cell dyscrasia and the most common form of primary bone marrow cancer. Nearly 35,000 new cases of MM are diagnosed in the United States each year. MM is a slowly progressive illness that remains incurable. The median survival for patients with MM is approximately 7 years, during which these patients suffer substantial morbidity. Despite the introduction of new drugs and immune-based therapies, many patients unfortunately relapse and require further therapies. Therefore, it is becoming increasingly important to be able to accurately and quickly determine changes in a patient's clinical status. Assessments of monoclonal protein and serum free light chain levels are the most common tests now available for monitoring patients with MM; however, these assays have several drawbacks. Modern radiologic techniques such as positron emission tomography and computed tomography are better than standard radiographs but are costly and cumbersome. Serum B-cell maturation antigen is a new biomarker for both the diagnosis and prognosis of MM. Assessment of measurable residual disease is becoming an important endpoint. The creation of better ways to predict outcomes and promptly and accurately monitor changes for patients with MM should lead to improved quality of life and longer survival.

The JAK1/2 inhibitor ruxolitinib downregulates the immune checkpoint protein B7H3 in multiple myeloma

We hypothesized that ruxolitinib may inhibit the immune checkpoint protein, B7H3; and, thus, investigated its effects on this immune inhibitor using multiple myeloma (MM) cell lines, bone marrow (BM) mononuclear cells from MM patients and human MM LAGλ -1A xenografts. Ruxolitinib reduced B7H3 gene and protein expression and increased IL-2 and CD8 gene expression. These results suggest that ruxolitinib inhibition of B7H3 may restore exhausted T-cell activity in the MM BM tumor microenvironment.

Loss of anti-spike antibodies following mRNA vaccination for COVID-19 among patients with multiple myeloma

BACKGROUND

Multiple myeloma (MM) patients have variable responses to mRNA vaccination to COVID-19. Little is known regarding their vaccine-induced antibody levels over time.

METHODS

We monitored spike IgG antibody levels over 24 weeks among a subset of 18 MM patients who showed a full response after two mRNA vaccinations.

RESULTS

MM patients had a more rapid decline in antibody levels as compared to eight healthy controls, with power law half-lives of 72 days (vs. 107 days) and exponential half-lives of 37 days (vs. 51 days). The patients with longer SARS-CoV-2 antibody half-lives were more likely to have undetectable monoclonal protein than those with shorter half-lives, suggesting better disease control may correlate with longer duration of vaccine-induced antibodies. Regardless, by 16 weeks post-second dose of mRNA vaccination, the majority of patients had antibody levels below 250 binding arbitrary units per milliliter, which would be unlikely to contribute to preventing COVID-19.

CONCLUSIONS

Thus, even MM patients who respond adequately to vaccination are likely to require more frequent booster doses than the general population.

Ruxolitinib and methylprednisolone for treatment of patients with relapsed/refractory multiple myeloma

Although Janus kinase (JAK) inhibitors have demonstrated efficacy for treating autoimmune disorders and myeloproliferative neoplasms, their efficacy in treating other types of cancer has not been clearly demonstrated. We evaluated oral ruxolitinib (15 mg twice daily) with oral methylprednisolone (40 mg every other day) for multiple myeloma (MM) patients with progressive disease who had received a proteasome inhibitor, lenalidomide, glucocorticosteroids and three or more prior regimens. All of the planned 29 patients had been enrolled with follow-up until 28 April 2022. Median lines of prior therapy were 6 (range 3-12). Cytogenetics and fluorescent in situ hybridization were evaluable in 28 patients; 9 (32%) and 17 (70%) patients showed high-risk cytogenetics and/or 1q+, respectively. The overall response rate was 31%. The median duration of response was 13.1 (range 2.8-22.0) months. Median progression-free survival rate was 3.4 (range 0.5-24.6) months, Overall, the treatment was well tolerated. The combination of ruxolitinib and methylprednisolone demonstrated significant clinical activity among previously heavily-treated MM patients, and responses were achieved among patients who had high-risk cytogenetics. This is the first clinical study to show activity of JAK inhibitors in combination with steroids for MM patients and expands the potential use of these drugs to those with cancers other than myeloproliferative neoplasms.

Third dose of an mRNA COVID-19 vaccine for patients with multiple myeloma

We have reported that IgG antibody responses following two mRNA COVID-19 vaccinations are impaired among patients with multiple myeloma (MM). In the current study, sixty-seven patients with MM were tested for anti-spike IgG antibodies 0-60 days prior to their first vaccination, 14-28 days following the second dose, and both before and 14-28 days after their third dose of the mRNA-1273 or BNT162b2 vaccines. After the first two doses, most patients' (93 %) antibody levels declined to ineffective levels (<250 BAU/mL) prior to their third dose (D3). D3 elicited responses in 84 % of patients (61 % full response and 22 % partial response). The third vaccination increased antibody levels (average = 370.4 BAU/mL; range, 1.0-8977.3 BAU/mL) relative to just prior to D3 (average = 25.0 BAU/mL; range, 1.0-683.8 BAU/mL) and achieved higher levels than peak levels after the first two doses (average = 144.8 BAU/mL; range, 1.0-4,284.1 BAU/mL). D3 response positively correlated with mRNA-1273, a > 10-fold change from baseline for the two-dose series, switching from BNT162b2 to mRNA-1273 for D3, and treatment with elotuzumab and an immunomodulatory agent. Lower antibody levels prior to D3, poorer overall response to first two doses, and ruxolitinib or anti-CD38 monoclonal antibody treatment negatively correlated with D3 response. Our results show encouraging activity of the third vaccine, even among patients who failed to respond to the first two vaccinations. The finding of specific factors that predict COVID-19 antibody levels will help advise patients and healthcare professionals on the likelihood of responses to further vaccinations.

A phase 1 study of ruxolitinib, steroids and lenalidomide for relapsed/refractory multiple myeloma patients

Ruxolitinib with lenalidomide and dexamethasone shows anti-myeloma effects in vitro and in vivo. MUC1 leads to lenalidomide resistance in multiple myeloma (MM) cells, and ruxolitinib blocks its expression. Thus, ruxolitinib may restore sensitivity to lenalidomide. A phase I trial was conducted to determine the safety and efficacy of ruxolitinib with lenalidomide and methylprednisolone for patients with relapsed/refractory (RR)MM who had been treated with lenalidomide, steroids and a proteasome inhibitor and showed progressive disease at study entry. A traditional 3 + 3 dose escalation design was used to enroll subjects in four cohorts. Subjects received ruxolitinib twice daily, lenalidomide daily on days 1-21 of a 28 day cycle and methylprednisolone orally every other day. Primary endpoints were safety, clinical benefit rate (CBR) and overall response rate (ORR). Forty-nine patients were enrolled. The median age was 64 years and they had received a median of six prior treatments including lenalidomide and steroids to which 94% were refractory. No dose limiting toxicities occurred. The CBR and ORR were 49% and 36%, respectively. All responding patients were refractory to lenalidomide. Grade 3 or 4 adverse events (AEs) included anemia (17%), decreased lymphocyte count (15%), and hypophosphatemia (10%). Most common serious AEs included sepsis (9.8%) and pneumonia (7.8%). This Phase I trial demonstrates that a JAK inhibitor, ruxolitinib, can overcome refractoriness to lenalidomide and steroids for patients with RRMM. These results represent a promising novel therapeutic approach for treating MM. NCT03110822.

A Phase 1/2 Study of the Oral Janus Kinase 1 Inhibitors INCB052793 and Itacitinib Alone or in Combination With Standard Therapies for Advanced Hematologic Malignancies

BACKGROUND

The Janus kinase (JAK)/signal transducers and activators of transcription pathway has been implicated in the pathogenesis and progression of various hematologic malignancies. JAK1-regulated cytokines stimulate proliferation and growth of malignant cells and resistance to certain therapies.

PATIENTS AND METHODS

This phase 1/2 study evaluated 2 oral, novel JAK1 inhibitors (INCB052793 and itacitinib) in advanced hematologic malignancies. Phase 1a assessed dose escalation and expansion of INCB052793 monotherapy. Phase 1b evaluated INCB052793 plus standard therapy in relapsed/refractory multiple myeloma, acute myeloid leukemia (AML), or myelodysplastic syndrome (MDS). Phase 2 evaluated INCB052793 or itacitinib plus azacitidine in DNA methyltransferase inhibitor (DNMTi)-refractory AML or MDS. Primary endpoints included safety and tolerability for phase 1, and objective response rate for phase 2.

RESULTS

Fifty-eight patients were enrolled, all received study treatment and discontinued either treatment or participation in the study. The most common reasons for treatment discontinuation were progressive disease (35.4% and 50.0%) and adverse events (22.9% and 20.0%) for INCB052793 and itacitinib plus azacitidine, respectively. In phase 1, 12 of 39 patients (31%) achieved an objective response; 35 mg once daily was selected as the phase 2 dose. Two patients with DNMTi-refractory disease had an objective response in phase 2. The study was terminated for lack of efficacy.

CONCLUSION

Inhibition of JAK1 with INCB052793 (monotherapy or combination therapy) or itacitinib plus azacitidine did not demonstrate clinically meaningful responses in these patients with hematopoietic malignancies.

Serum B-Cell Maturation Antigen is an Independent Prognostic Marker in Previously Untreated Chronic Lymphocytic Leukemia

B-cell maturation antigen (BCMA) is a cell membrane receptor expressed on mature B lymphocytes with elevated serum levels found among patients with B-cell malignancies, including chronic lymphocytic leukemia (CLL). Serum BCMA (sBCMA) levels were measured in 331 untreated, newly diagnosed CLL patients using an ELISA with a polyclonal anti-BCMA antibody. Elevated sBCMA was found among patients with CLL compared to age- and sex-matched healthy controls and those with more active CLL based on prognostic factors. The relationships between sBCMA, time to first treatment (TTFT), overall survival (OS) and multiple prognostic factors were compared using Mann Whitney and Kruskal-Wallis tests. The median sBCMA level in the CLL cohort (48.6 ng/mL) was significantly higher (p < 0.001) compared to age- and sex-matched healthy subjects (n = 100; 37.8 ng/mL). sBCMA correlated with TTFT (hazard ratio [HR] 2.9, 95% confidence interval [CI] 2.0-4.2, p < 0.001) and OS (HR 2.5, 95% CI 1.5-4.0, p < 0.001). Multiple models were utilized to test the predictive effects of sBCMA, sex, CLL-IPI and IPS-E on TTFT and OS. The addition of sBCMA to CLL-IPI and IPS-E improved their prognostic ability to predict TTFT and OS. Thus, serum BCMA is a new promising prognostic biomarker for CLL.

Use of serum B-cell maturation antigen levels to predict outcomes for myeloma patients treated with ruxolitinib, lenalidomide and methylprednisolone

Previous retrospective studies have shown that serum B-cell maturation antigen (sBCMA) levels predict outcomes among patients with multiple myeloma (MM) undergoing new treatments. Specifically, baseline levels and changes during treatment of this protein predict both progression free survival (PFS) and overall survival. However, prospective studies are lacking evaluating sBCMA for determining outcomes among MM patients undergoing new treatments. Thus, we evaluated whether its baseline levels and changes during treatment in the amount of this serum marker predict outcomes among 38 relapsed/refractory MM patients treated with ruxolitinib, lenalidomide and methylprednisolone in a phase 1 trial. Patients with baseline sBCMA levels in the lowest three quartiles had longer PFS (median PFS 136 vs. 28 days; p < 0.0001). This was also shown for patients with baseline levels below the median (median PFS 140 vs. 77 days; p = 0.0225). PFS was shorter for patients whose sBCMA levels increased ≥25% through their first cycle (median PFS: 50 vs. 134 days, p = 0.0022), second cycle (median PFS: 50 vs. 141 days, p = 0.0273), and during the first three cycles of study treatment (median PFS: 50 vs. 220 days, p < 0.0001). No patient whose sBCMA increased ≥25% during cycle 1 responded whereas the majority (58%) of patients whose level increased <25% responded. This is the first prospective study to determine whether sBCMA levels predict outcomes for MM patients undergoing a non-BCMA directed treatment regimen and demonstrates that baseline levels and its changes during treatment predict PFS and the likelihood of responding to their treatment. These results add to the growing literature suggesting that this serum marker will be useful for determining outcomes for patients undergoing treatment for MM.

Severe breakthrough COVID-19 with a heavily mutated variant in a multiple myeloma patient 10 weeks after vaccination

Background

Patients with multiple myeloma have unpredictable responses to vaccination for COVID-19. Anti-spike antibody levels can determine which patients develop antibodies at levels similar to healthy controls, and are a known correlate of protection.

Case report

A multiple myeloma patient developed protective anti-spike antibodies after vaccination (608 IU/mL), but nonetheless developed severe breakthrough COVID-19 just 10 weeks following his second vaccination with mRNA-1273.

Results

Sequencing of the viral isolate revealed an extensively mutated variant with 10 spike protein mutations, including E484Q and N440K. Serology testing showed a dramatic decline in anti-spike antibodies immediately prior to virus exposure.

Conclusions

Multiple myeloma patients who do develop detectable antibody responses to vaccination may be at increased risk for breakthrough infections due to rapid decline in antibody levels. Viral variants with immune escape mutations such as N440K, also seen independently in the SARS-CoV-2 Omicron variant (B.1.1.529) and in viral passaging experiments, likely require a higher level of anti-spike antibodies to prevent severe COVID-19.

A phase 2 trial of the efficacy and safety of elotuzumab in combination with pomalidomide, carfilzomib and dexamethasone for high-risk relapsed/refractory multiple myeloma

High-risk multiple myeloma (MM) continues to have a poor prognosis and remains a therapeutic challenge. This phase 2 study evaluated the efficacy and safety of elotuzumab in combination with pomalidomide, carfilzomib, and low-dose dexamethasone for patients with high-risk relapsed/refractory (RR)MM (NCT03104270). Of 13 enrolled patients, 11 were evaluable for efficacy. Overall response rate and clinical benefit rate were 45.4% and 54.5%, respectively. Deep responses were observed including two complete responses. The novel quadruplet combination was overall well-tolerated, with clinically manageable adverse events. Common adverse events of ≥ grade 3 included lymphopenia (15%), anemia (15%), sepsis (15%), pneumonia (15%), and hypophosphatemia (15%). The novel combination showed promising efficacy and was well tolerated in this heavily pretreated MM population. Even though the study was terminated early prior to completion of enrollment, the results indicate that this may be a promising therapeutic approach for high-risk RRMM patients, which warrants further study.

Response to mRNA vaccination for COVID-19 among patients with multiple myeloma

Multiple myeloma (MM) patients are at higher risk for severe COVID-19. Their mRNA vaccination response against SARS-CoV-2 is unknown. Thus, we analyzed responses to mRNA vaccination against COVID-19 among these patients. Using an ELISA-based assay that detects IgG antibodies to SARS-CoV-2 spike protein, we determined serum antibody levels prior to immunization and 12–21 and 14–21 days following the first and second vaccinations, respectively, with mRNA-1273 (Moderna) or BNT162b2 (Pfizer/BioNTech) among 103 MM patients (96 and 7 with active and smoldering disease, respectively). We stratified patients into clinically relevant responders (>250 IU/mL), partial responders (50–250 IU/mL, which was above pre-COVID-19 background), and nonresponders (<50 IU/mL). Smoldering MM patients responded better than those with active disease. Only 45% of active MM patients developed an adequate response, while 22% had a partial response. Lower spike antibody levels were associated with older age, impaired renal function, low lymphocyte counts, reduced uninvolved immunoglobulin levels, > second line of treatment, and among those not in complete remission. Patients who received mRNA-1273 vaccine had higher anti-spike antibody levels than those who were vaccinated with BNT162b2. Thus, most MM patients have impaired responses to mRNA vaccination against COVID-19, and specific clinical and myeloma-related characteristics predict vaccine responsiveness.

Serum BCMA levels predict outcomes in MGUS and smoldering myeloma patients

Soluble BCMA (sBCMA) levels are elevated in monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM). However, the association between sBCMA levels and prognosis in MGUS and SMM has not been studied. We retrospectively analyzed sBCMA levels in stored samples from 99 MGUS and 184 SMM patients. Baseline sBCMA levels were significantly higher in MGUS and SMM patients progressing to MM during clinical follow up. When stratified according to the median baseline sBCMA level for each cohort, higher levels were associated with a shorter PFS for MGUS (HR 3.44 comparing sBCMA ≥77 vs <77 ng/mL [95% CI 2.07-5.73, p < 0.001] and SMM (HR 2.0 comparing sBCMA ≥128 vs <128 ng/mL, 95% 1.45-2.76, p < 0.001) patients. The effect of sBCMA on PFS was similar even after adjusting for the baseline MGUS or SMM risk stratification. We evaluated paired serum samples and found that sBCMA increased significantly in MGUS and SMM patients who eventually progressed to MM, whereas among MGUS non-progressors the sBCMA level remained stable. While our results require independent validation, they suggest that sBCMA may be a useful biomarker to identify MGUS and SMM patients at increased risk of progression to MM independent of the established risk models.

Baseline serum B-cell maturation antigen levels predict time to disease progression for patients with smoldering multiple myeloma

Multiple myeloma (MM) patients with smoldering (S) disease are defined by a lack of CRAB/SLiM criteria but may transform into disease requiring treatment. The International Myeloma Working Group risk stratification model for SMM uses serum M-protein, serum-free light chain ratio, and bone marrow plasma cell percentage. We investigated whether baseline serum B-cell maturation antigen (sBCMA) levels are predictive of disease progression among 65 patients with SMM. A receiver operating characteristic curve was used to establish a definition for high-risk baseline sBCMA. Mantel Byar analysis was used to examine whether high-risk sBCMA was correlated with shorter time to transformation, and a time-dependent cox proportional hazard was used to determine whether it is independent of other risk factors. A z test for proportions was used to compare the percentage of patients that progressed among high-risk versus low-risk sBCMA patients. A baseline sBCMA level ≥137.5 mg/ml was found to be the optimal cutoff between high- and low-risk SMM patients. Patients with high-risk sBCMA levels had a shorter time to transformation (P = .000332). sBCMA was also higher at the time of transformation than baseline levels (P = .0116). sBCMA was the only variable found to be significantly predictive of time to transformation and additionally was found to be independent of other risk factors. In this study, we have shown for the first time that sBCMA levels predict transformation of SMM to active disease and that these levels increase at the time of transformation. These results are consistent with other studies showing that active MM patients undergoing therapy with higher baseline sBCMA levels are more likely to progress early and its levels increase at the time of disease progression.

Baseline and Changes in Serum B-Cell Maturation Antigen Levels Rapidly Indicate Changes in Clinical Status Among Patients with Relapsed/Refractory Multiple Myeloma Starting New Therapy

BACKGROUND

B-cell maturation antigen (BCMA) is expressed on malignant plasma cells from patients with multiple myeloma (MM). These patients have higher levels of serum (s)BCMA than healthy subjects, and levels correlate with disease status. The half-life of sBCMA is only 24-36 h, and levels are independent of renal function.

OBJECTIVE

We determined whether baseline sBCMA values, a ≥ 25% increase, and a ≥ 50% decrease during treatment predicted progression-free survival (PFS) and overall survival (OS) among 81 patients with relapsed/refractory MM (RRMM) starting new treatments.

METHODS

Serum was obtained on day 22 of each patient's 28-day cycle of new therapy. Kaplan-Meier survival analysis and log-rank comparison tests were used to determine the effect of baseline sBCMA. The effect of percentage change in sBCMA was investigated using time-dependent Cox proportional hazard models.

RESULTS

Patients with baseline sBCMA levels above the median had a shorter PFS (p = 0.0077), and those in the highest quartile had a shorter PFS (p = 0.0012) and OS (p = 0.0022). A ≥ 25% increase at week 4, week 8, and anytime through week 12 predicted a shorter PFS (p = 0.0011, p = 0.0005, and p < 0.0001, respectively). A ≥ 50% decrease at week 4, week 8, and anytime through week 12 predicted a longer PFS (p = 0.0045, p = 0.029, p = 0.0055, respectively). A ≥ 25% increase in sBCMA occurred before progression according to International Myeloma Working Group criteria in 67.5% of patients.

CONCLUSIONS

Our results indicate the potential for the use of sBCMA as a new biomarker for monitoring patients with RRMM.

Low dose venetoclax in combination with bortezomib, daratumumab, and dexamethasone for the treatment of relapsed/refractory multiple myeloma patients-a single-center retrospective study

Venetoclax is a BCL-2 inhibitor currently indicated for use in treating hematologic malignancies with recommended doses ranging from 400 to 600 mg/day. Although currently not FDA-approved to treat multiple myeloma (MM) patients, there is a growing number of reports indicating its efficacy as a salvage therapy for these patients, especially for those with the t(11;14) chromosomal marker. These studies, however, have also indicated that venetoclax given at doses ≥ 400 mg/day can cause serious adverse events (SAEs) especially when administered with bortezomib, commonly related to infections. The purpose of this single-center retrospective study was to determine the efficacy of low dose venetoclax (defined as ≤ 250 mg/day) in combination with low dose bortezomib (defined as 1.0 mg/m² per dose), daratumumab, and dexamethasone (Dvvd) as a salvage therapy for relapsed/refractory myeloma (RRMM) patients. Twenty-two RRMM patients were given venetoclax orally at doses ranging from 100 to 250 mg daily using this four-drug regimen. While the low doses resulted in reduced venetoclax efficacy among those lacking t(11;14) (overall response rate [ORR] = 31%), those harboring the t(11;14) marker exhibited an ORR of 80%. Notably, this response was without frequent infection-related SAEs as reported in previous studies. Together, the results of this study demonstrate that treatment of t(11;14) positive RRMM patients with Dvvd is both effective and well-tolerated.

Ruxolitinib reverses checkpoint inhibition by reducing programmed cell death ligand-1 (PD-L1) expression and increases anti-tumour effects of T cells in multiple myeloma

Multiple myeloma (MM) tumour cells evade host immunity through a variety of mechanisms, which may potentially include the programmed cell death ligand-1 (PD-L1):programmed cell death protein-1 (PD-1) axis. This interaction contributes to the immunosuppressive bone marrow (BM) microenvironment, ultimately leading to reduced effector cell function. PD-L1 is overexpressed in MMBM and is associated with the resistance to immune-based approaches for treating MM. Ruxolitinib (RUX), an inhibitor of the Janus kinase (JAK) family of protein tyrosine kinases, is approved for myeloproliferative diseases. We investigated the effects of RUX alone or in combination with anti-MM agents on the expression of PD-L1 and T-cell cytotoxicity in MM. We showed that the expression of the PD-L1 gene was markedly increased in BM mononuclear cells from patients with MM with progressive disease versus those in complete remission. Furthermore, RUX treatment resulted in a concentration-dependent reduction of PD-L1 gene expression in the MM tumour cells cultured alone or co-cultured with stromal cells compared with untreated cells. The results also demonstrated that RUX increased MM cell apoptosis in the presence of interleukin-2-stimulated T cells to a similar degree as the treatment with anti-PD-1 or anti-PD-L1 antibodies. In summary, these results indicate that RUX can block PD-L1 expression resulting in augmentation of anti-MM effects of T cells.

Removal of a Silicone Gel Breast Implant in a Multiple Myeloma Patient Improved Disease Status: A Case Report

A 52-year-old African-American woman with a prior history of monoclonal gammopathy of undetermined significance (MGUS) developed infiltrating ductal carcinoma of the left breast. Following a mastectomy, she underwent reconstruction with a silicone gel breast implant. Three years later, her MGUS had progressed to active multiple myeloma (MM). She had a minimal response after two different regimens of bortezomib-based treatments and monthly zoledronic acid, and was placed on maintenance therapy with bortezomib, intravenous dexamethasone, and oral methylprednisolone, as well as ongoing monthly zoledronic acid. After 1 year of this maintenance therapy, during which her myeloma markers remained unchanged, she had her silicone implant replaced with saline. Despite no change in her myeloma treatment, her laboratory values began to steadily improve following removal of the silicone implant. Her M-protein decreased from 2.14 to 0.83 g/dL and her IgG levels from 3,330 to 1,210 mg/dL following replacement of her silicone implant with saline. To our knowledge, this is the first report in which removal of silicone implants improved the clinical status of a patient with MM following a year of maintenance therapy during which the patient's myeloma laboratory values remained unchanged. Further studies are warranted to determine if silicone breast implant removal can, in fact, improve MM patients' disease status.

Normalization of serum B-cell maturation antigen levels predicts overall survival among multiple myeloma patients starting treatment

Serum B-cell maturation antigen (sBCMA) is a novel biomarker for B-cell malignancies. A normal reference range (<82·59 ng/ml) has been recently established but the impact of achieving normal levels to outcomes for patients receiving treatment for B-cell malignancies has not been studied. We first found that among multiple myeloma (MM) patients starting a new treatment, those who begin treatment within normal sBCMA limits (<82·59 ng/ml) have improved progression-free survival (PFS; P = 0·0398) and overall survival (OS; P = 0·0217) than those who do not. Furthermore, among patients who begin treatment with elevated (≥82·59 ng/ml) sBCMA levels, we assessed the relationship of a decrease in sBCMA to the normal range to OS and found that those who normalize sBCMA demonstrated improved OS (P = 0·0078). Normalizing patients also experienced a markedly improved overall response rate (P < 0·0001). Moreover, all patients who achieved complete remission (CR) showed normalization of sBCMA, and time to normalization (median 0·9 months) was faster than time to CR (5·0 months; P = 0·0036) for these patients. These results suggest that normalization of sBCMA may be an accurate predictor of OS for MM patients during treatment and predict for a higher likelihood of response.

Estimating a normal reference range for serum B-cell maturation antigen levels for multiple myeloma patients

The serum B-cell maturation antigen (sBCMA) has been identified as a novel serum biomarker for patients with multiple myeloma. However, no study has yet established a reference range for sBCMA levels. Its levels were determined in 196 healthy subjects and showed a right-tailed distribution with a median value of 37·51 ng/ml with a standard deviation of 22·54 ng/ml (range 18·78-180·39 ng/ml). Partitioning of subgroup reference ranges was considered but determined to be irrelevant. A non-parametric method using the median ± 2 standard deviations suggests using a universal reference interval of <82·59 ng/ml.

A Phase I Study of Ruxolitinib, Lenalidomide, and Steroids for Patients with Relapsed/Refractory Multiple Myeloma

PURPOSE

Ruxolitinib with lenalidomide and dexamethasone shows antimyeloma effects in vitro and in vivo. MUC1 leads to lenalidomide resistance in multiple myeloma cells, and ruxolitinib blocks its expression. Thus, ruxolitinib may restore sensitivity to lenalidomide. Therefore, a phase I trial was conducted to determine the safety and efficacy of ruxolitinib with lenalidomide and methylprednisolone for patients with relapsed/refractory multiple myeloma (RRMM) who had been treated with lenalidomide/steroids and a proteasome inhibitor and showed progressive disease at study entry.

PATIENTS AND METHODS

A traditional 3+3 dose escalation design was used to enroll subjects in four cohorts with planned total enrollment of 28 patients. Subjects received ruxolitinib twice daily, lenalidomide daily on days 1-21 of a 28-day cycle, and methylprednisolone orally every other day. Primary endpoints were safety, clinical benefit rate (CBR), and overall response rate (ORR).

RESULTS

Twenty-eight patients were enrolled. The median age was 67 years and received a median of six prior treatments including lenalidomide and steroids to which 93% were refractory. No dose-limiting toxicities occurred. The CBR and ORR were 46% and 38%, respectively. All 12 responding patients were refractory to lenalidomide. Grade 3 or grade 4 adverse events (AE) included anemia (18%), thrombocytopenia (14%), and lymphopenia (14%). Most common serious AEs included sepsis (11%) and pneumonia (11%).

CONCLUSIONS

This phase I trial demonstrates that a JAK inhibitor, ruxolitinib, can overcome refractoriness to lenalidomide and steroids for patients with RRMM. These results represent a promising novel therapeutic approach for treating multiple myeloma (ClinicalTrials.gov number, NCT03110822).

The Role of B-Cell Maturation Antigen in the Biology and Management of, and as a Potential Therapeutic Target in, Multiple Myeloma

B-cell maturation antigen (BCMA) was originally identified as a cell membrane receptor, expressed exclusively on late stage B-cells and plasma cells (PCs). Investigations of BCMA as a target for therapeutic intervention in multiple myeloma (MM) were initiated in 2007, using cSG1 as a naked antibody (Ab) as well as an Ab-drug conjugate (ADC) targeting BCMA, ultimately leading to ongoing clinical studies for previously treated MM patients. Since then, multiple companies have developed anti-BCMA-directed ADCs. Additionally, there are now three bispecific antibodies in development, which bind to both BCMA and CD3ε on T-cells. This latter binding results in T-cell recruitment and activation, causing target cell lysis. More recently, T-cells have been genetically engineered to recognize BCMA-expressing cells and, in 2013, the first report of anti-BCMA-chimeric antigen receptor T-cells showed that these killed MM cell lines and human MM xenografts in mice. BCMA is also solubilized in the blood (soluble BCMA [sBCMA]) and MM patients with progressive disease have significantly higher sBCMA levels than those responding to treatment. sBCMA circulating in the blood may limit the efficacy of these anti-BCMA-directed therapies. When sBCMA binds to B-cell activating factor (BAFF), BAFF is unable to perform its major biological function of inducing B-cell proliferation and differentiation into Ab-secreting PC. However, the use of γ-secretase inhibitors, which prevent shedding of BCMA from PCs, may improve the efficacy of these BCMA-directed therapies.

The role of JAK inhibitors in multiple myeloma

Multiple myeloma (MM) is the most common primary malignancy of the bone marrow. No established curative treatment is currently available for patients diagnosed with MM. In recent years, new and more effective drugs have become available for the treatment of MM. Many newer drugs have been evaluated together and in combination with older agents. However, even in combination with other active MM agents, the responses are transient, and; thus, therapeutic approaches to help overcome resistance to these drugs are necessary. Recently, the Janus kinase (JAK) family of tyrosine kinases, including JAK1 and JAK2, has been shown to play a role in the pathogenesis of MM. Preclinical studies have demonstrated that the JAK1/2 inhibitor ruxolitinib, in combination with lenalidomide and dexamethasone, reduces proliferation of the MM cell lines and primary tumor cells derived from MM patients, and this inhibition is greater when these drugs are combined than with single agents. Clinically, early results from the oral treatment regimen of ruxolitinib, corticosteroids (methylprednisolone), and lenalidomide for patients with relapsed/refractory disease are encouraging in terms of safety and efficacy, and additional studies will provide further support for this promising new therapeutic approach for patients with MM.

JAK1/2 pathway inhibition suppresses M2 polarization and overcomes resistance of myeloma to lenalidomide by reducing TRIB1, MUC1, CD44, CXCL12, and CXCR4 expression

Monocytes polarize into pro-inflammatory macrophage-1 (M1) or alternative macrophage-2 (M2) states with distinct phenotypes and physiological functions. M2 cells promote tumour growth and metastasis whereas M1 macrophages show anti-tumour effects. We found that M2 cells were increased whereas M1 cells were decreased in bone marrow (BM) from multiple myeloma (MM) patients with progressive disease (PD) compared to those in complete remission (CR). Gene expression of Tribbles homolog 1 (TRIB1) protein kinase, an inducer of M2 polarization, was increased in BM from MM patients with PD compared to those in CR. Ruxolitinib (RUX) is an inhibitor of the Janus kinase family of protein tyrosine kinases (JAKs) and is effective for treating patients with myeloproliferative disorders. RUX markedly reduces both M2 polarization and TRIB1 gene expression in MM both in vitro and in vivo in human MM xenografts in severe combined immunodeficient mice. RUX also downregulates the expression of CXCL12, CXCR4, MUC1, and CD44 in MM cells and monocytes co-cultured with MM tumour cells; overexpression of these genes is associated with resistance of MM cells to the immunomodulatory agent lenalidomide. These results provide the rationale for evaluation of JAK inhibitors, including MM BM in combination with lenalidomide, for the treatment of MM patients.

A phase I trial of ruxolitinib, lenalidomide, and methylprednisolone for patients with relapsed/refractory multiple myeloma (MM)

8048

Background: Preclinical studies from our laboratory have demonstrated that ruxolitinib (RUX) in combination with lenalidomide (LEN) and dexamethasone shows marked anti-myeloma effects both in vitro and in vivo. Furthermore, MUC1 is responsible for LEN resistance in MM cells, and RUX blocks its expression in MM cells. Thus, RUX may restore sensitivity to LEN. Therefore, a phase 1 trial was conducted to determine the safety and efficacy of RUX in combination with LEN and methylprednisolone (MP) for relapsed/refractory (RR) MM patients (pts) who had previously been treated with LEN/steroids and a proteasome inhibitor (PI) and showed progressive disease at study entry. Methods: A traditional 3+3 dose escalation design was used to enroll subjects in four cohorts with planned total enrollment to be 49 pts. Subjects received RUX twice daily continuously, LEN daily on d1-21 of a 28-d cycle and MP orally every other day. In DL0, pts received RUX 5 mg, LEN 5 mg, and MP 40 mg. In DL+1 and +2, both doses of LEN and MP remained unchanged and RUX was escalated to 10 and 15 mg, respectively. DL+3 escalated LEN to 10 mg with MP unchanged and RUX at 15 mg. Primary endpoints were safety, clinical benefit rate (CBR) and overall response rate (ORR). Results: As of September 1, 2018, 36 pts were enrolled, and 32 were evaluable for efficacy. The median age was 66 years (range, 46-81), and 21 (58%) were male. Pts received a median of 6 prior treatments including LEN and steroids to which they were all refractory and a proteasome inhibitor. No DLTs occurred, and DL+3 was expanded. Among evaluable pts, the CBR and ORR were 47% and 41%, respectively (1 CR, 2 VGPR, 10 PR and 2 MR), and 14 and 3 pts showed SD and PD. All 15 responding pts were refractory to LEN. G3 AEs included anemia (17%), neutropenia (14%), sepsis (14%), lymphocytopenia (11%), thrombocytopenia (11%), and pneumonia (11%). Most common SAEs included sepsis (14%) and pneumonia (11%). Conclusions: This Ph 1 trial demonstrates for the first time that a JAK inhibitor, RUX, can overcome refractoriness to LEN and steroids for RR MM pts. These promising results are leading to expansion of the current clinical trial to 78 pts, and represents a novel therapeutic approach for treating MM. Clinical trial information: NCT03110822.

Serum BCMA levels to predict outcomes for patients with MGUS and smoldering multiple myeloma (SMM)

8020

Background: BCMA (B-cell maturation antigen) is a TNF receptor family member found on normal and malignant B-cells, including multiple myeloma (MM). It plays a role in proliferation and antiapoptotic pathways. Levels of serum (s)BMCA are elevated in patients (pts) with plasma cell disorders (PCD) and increase with each stage of disease: healthy donor< MGUS<SMM< active untreated MM. The purpose of this study was to test whether sBCMA levels predict progression of MGUS or SMM to MM. Methods: There were 3 cohorts in this retrospective study: MGUS progressing to MM (n=42); MGUS not progressing to MM (n=49); SMM progressing to MM (n=32). sBCMA levels were measured using an ELISA-based assay with a polyclonal anti-BCMA antibody from R&D Systems (Minneapolis, MN). The Kruskal-Wallis analysis was used to assess differences. The relationships between sBCMA and both time to progression and overall survival were also assessed using Cox proportional hazard models. Results: The highest values of sBCMA were seen among pts with more advanced PCD (Table). The lowest baseline levels were seen in pts with MGUS who did not progress; the change of sBCMA over time was lowest in the MGUS non-progressors. ROC analysis identified a cutoff of 74.4 ng/mL to be predictive of progression at 5 years. This cut-point was associated with a risk ratio of progression of 5.8 (95%CI 3.2, 11.3) for all comers, a risk ratio of death for all comers of 2.5 (95%CI 1.5, 4.2), and a risk ratio of death for MGUS pts of 3.3 (95%CI 1.9, 5.7). Conclusions: Serum BCMA levels were predictive of diagnosis, progression and death among pts with MGUS or SMM. Limitations of the current study are that only a minority of pts had baseline bone marrow exams or serum FLCs to place sBCMA risk in the context of other previously described risk factors. Serum FLC is now being determined on all patients. [Table: see text]

Serum B-cell maturation antigen as a prognostic marker for untreated chronic lymphocytic leukemia

7525

Background: New prognostic markers in chronic lymphocytic leukemia (CLL) are in demand. Different groups have developed models which combine multiple prognostic markers into a single index to classify CLL patients (pts). The CLL-International Prognostic Index (CLL-IPI) combines five parameters: age, clinical stage, TP53 status, IGHV mutational status, and serum β2 microglobulin levels. B-cell maturation antigen (BCMA) is a cell membrane receptor expressed exclusively on late stage B-cells and plasma cells with elevated serum (s) levels found in B-cell malignancies, such as multiple myeloma (MM). In MM, sBCMA levels can be used to monitor disease status and predict overall survival (OS). To further evaluate this biomarker in other hematologic malignancies, we studied it in CLL. Methods: Untreated (UNTX) CLL pts seen and consented at Mayo Clinic were identified. sBCMA levels were measured on stored sera of 331 UNTX CLL pts using an ELISA-based assay with a polyclonal anti-BCMA antibody from R&D Systems (Minneapolis, MN). The Mann-Whitney analysis was used to assess differences between CLL pts and healthy controls. The relationships between sBCMA and both time to first treatment (TFT) and OS were also assessed using Cox Regression models with an optimal sBCMA cutoff of 40.9 ng/mL. Results: The median age of pts was 61 years, and 71% were male. The distribution of CLL-IPI risk groups was as follows: 135 (41%) Low; 114 (34%) Intermediate; 67 (20%) High; 15 (5%) Very High. The median level of sBCMA in CLL pts (48.6 ng/mL) was higher (P <0.0001) than those of healthy controls (n = 104; 36.03 ng/mL). In CLL pts, sBCMA is significant in univariable analyses of TFT (HR 2.9 (95%CI, 2.0-4.2); P < 0.0001) and OS (HR 2.5 (95%CI, 1.5-4.0); P < 0.0003), and remains significant when adjusting for sex and CLL-IPI factors (HR 2.3 (95%CI, 1.6-3.3), P < 0.0001; HR 1.9 (95%CI 1.1-3.1), P = 0.01, respectively). Conclusions: sBCMA is elevated in CLL pts compared to healthy controls. After adjusting for CLL-IPI and sex, sBCMA levels provided independent prognostic value in predicting TFT and OS in this cohort. Measuring sBCMA with a readily accessible ELISA-based test, provides incremental value over the current CLL-IPI model in predicting prognosis of CLL.

Once-weekly (70 mg/m2) versus twice-weekly (56 mg/m2) dosing of carfilzomib (CFZ) for patients (pts) with relapsed and/or refractory multiple myeloma (RRMM)

e19505

Background: CFZ combined with dexamethasone is approved to treat pts with RRMM, with CFZ given once-weekly at 70 mg/m2 (Kd70 QW) or twice-weekly at 56 mg/m2 (Kd56 BIW). No randomized trials have directly compared Kd70 QW with Kd56 BIW. We performed a post hoc comparison between pts who received Kd56 BIW in the ENDEAVOR trial and pts who received Kd70 QW in the A.R.R.O.W. or CHAMPION-1 trials. Methods: Data were analyzed from 3 trials of CFZ in RRMM: A.R.R.O.W. (240 pts in Kd70 QW arm; 2–3 prior therapies and refractory to most recent therapy), CHAMPION-1 (104 pts received Kd70 QW; 1–3 prior therapies), and ENDEAVOR (464 pts in Kd56 BIW arm; 1–3 prior therapies). Pts who received Kd70 QW in A.R.R.O.W. and CHAMPION-1 were pooled and compared with pts who received Kd56 BIW in ENDEAVOR. As study populations slightly varied among the 3 trials, an analysis of safety and efficacy was performed in a subgroup of pts who received 2–3 prior therapy lines and were not refractory to bortezomib (BTZ). Also, we performed regression analyses (controlling for age, ISS stage, BTZ and lenalidomide refractory status, and number of prior regimens) among all pts in the trials who received Kd70 QW or Kd56 BIW. Results: Among BTZ non-refractory pts with 2–3 lines of prior therapy, median progression-free survival (PFS) was 12.1 months (95% CI 8.4–14.3) for Kd70 QW (n = 146) and 14.5 months (95% CI 10.2–NE) for Kd56 BIW (n = 217), and the overall response rate (ORR) was 69.9% (95% CI 61.7–77.2) for Kd70 QW and 72.4% (95% CI 65.9–78.2) for Kd56 BIW. The rate of grade ≥3 adverse events (Kd70 QW vs Kd56 BIW) was 67.6% and 85.3%; among adverse events of interest, the grade ≥3 rate was 1.4% and 5.1% for cardiac failure, 3.4% and 6.0% for renal failure, and 5.5% and 15.7% for hypertension. Kd70 QW represents a convenient and well-tolerated treatment modality for pts with RRMM. In a Cox proportional hazards model, the hazard ratio for PFS (Kd70 QW vs Kd56 BIW) was 0.91 (95% CI 0.69–1.19), and in a logistic regression model the odds ratio for ORR (Kd70 QW vs Kd56 BIW) was 1.12 (95% CI 0.74–1.69). Conclusions: This post hoc analysis suggests that once-weekly Kd70 has a comparable benefit-risk profile to twice-weekly Kd56. Clinical trial information: NCT02412878, NCT01677858, NCT01568866.

Safety and tolerability of BION-1301 in adults with relapsed or refractory multiple myeloma

8012

Background: BION-1301 (BION) is first in class humanized monoclonal antibody directed against a proliferation-inducing ligand (APRIL) for treatment of relapsed/refractory (R/R) multiple myeloma (MM). APRIL secreted by cells in the bone marrow (BM) niche binds to BCMA (B-Cell maturation antigen) and TACI (transmembrane activator and CAML interactor) expressed on human MM cells to drive their proliferation and survival. In patients (pts) with MM, serum APRIL levels are elevated and are correlated with promotion of malignancy, chemo- and immune-resistance. This study evaluated tolerability and clinical activity of BION monotherapy in R/R MM pts. Methods: Adults with MM, progression after ≥3 systemic therapies, and ECOG 0-1 were enrolled in this phase 1/2, open-label study. The phase 1 study is evaluating 6 cohorts with increasing BION doses of 50, 150, 450, 1350, and 2700 mg administered Q2W intravenously (cohort 6 - 1350 mg dose given QW and Q2W). Response was assessed by investigators Q4W. Serum was analyzed for BION, anti-drug antibodies (ADA), and soluble unbound “free APRIL” (fAPRIL) and evaluated by PK-PD modeling. Results: As of 7Dec2018, 15 pts were enrolled in 4 cohorts at doses between 50-1350 mg given Q2W. 5/15 (33%) had ECOG 0 and pts received median of 6 prior systemic therapies (range: 4-17). Related treatment emergent adverse events (TEAE) were reported in 8/15 (36%); most common related TEAE included anemia (n=3), arthralgia (n=2), and dysgeusia (n=2). 1 subject receiving 4th dose of BION experienced grade 3 wheezing considered infusion-related and serious. No dose-limiting toxicities were observed. Of 14/15 evaluable for response, no objective response was observed and 5/14 (36%) had stable disease. Median time on treatment was 2 months (range: 0.9-4.9+) and median of 3 doses of BION (range: 2-11) were administered. BION exposure increased dose proportionally from 50-1350 mg, and half-life (T1/2) and clearance (CL) did not differ significantly (median T1/2 = 9.0 days [range: 3.9-20], median CL = 0.52 L/day [range: 0.32-0.72]). Levels of fAPRIL in serum and BM decreased with increasing BION doses. By 450 mg, 95% target engagement (TG) was achieved around peak exposure levels. Non-neutralizing ADA was detected in 1/15 pts. Conclusions: BION, at doses 50-1350 mg given Q2W, was well-tolerated and dose-dependently reduces serum levels of fAPRIL. To date, objective responses have not been observed. The study is ongoing with pts exposed to higher and/or more frequent doses with the objective of achieving accelerated and sustained APRIL TG. Clinical trial information: NCT03340883.

Elotuzumab and dexamethasone for relapsed or refractory multiple myeloma patients: A retrospective study

OBJECTIVE

To evaluate the efficacy and safety of elotuzumab and dexamethasone (Ed) for relapsed or refractory multiple myeloma (RRMM) patients.

METHOD

This retrospective study evaluated the efficacy and safety of Ed treatment for 21 RRMM patients, 11 of whom were considered lenalidomide-refractory, and all of whom had progressed on at least 1 prior steroid-containing regimen. We also evaluated the efficacy of adding lenalidomide to a subset of patients following progression from Ed.

RESULTS

The overall response rate (ORR) and clinical benefit rate (CBR) of Ed were 10% and 19%, respectively. An additional 52% of patients demonstrated stable disease as their best response. The median PFS was 1.8 months on Ed for all patients. Fifteen patients received ERd following progression on Ed, and 60% of these patients were lenalidomide-refractory. The ORR and CBR were 20% and 33%, respectively, and the median PFS was 3.4 months.

CONCLUSION

Our results suggest that some patients can benefit from Ed without an accompanying immunomodulatory agent and that efficacy can be achieved with the addition of lenalidomide at the time of progression. No new safety signals were detected, except for thrombocytopenia in 1 patient on Ed.