Prognostic value of t(4;14) translocation in newly diagnosed multiple myeloma patients in novel agent era

ABSTRACT Objective To evaluate the prognostic value of t(4; 14) translocation for newly diagnosed multiple myeloma (MM) patients in the novel agent era. Methods We retrospectively analyzed 606 newly diagnosed MM patients treated with novel agents. The propensity score matching technique was used to reduce the bias between groups. Results Among 606 patients, t(4; 14) was observed in 108 (17.8%) patients, among which 79 (73.1%) were accompanied by 1q21 gain and/or del 17p. Median overall survival (OS) (56.2 vs. 87.3 months) and progression-free survival (PFS) (25.7 vs. 37.6 months) were significantly shorter in patients with t(4;14) compared with patients without cytogenetic abnormalities. Univariate Cox proportional hazards regression analysis showed that the t(4;14) was not associated with shorter OS (p = 0.666) and PFS (p = 0.164). The multivariable analysis also showed t(4;14) was not a poor prognostic factor for OS and PFS of patients with newly diagnosed MM (p > 0.05). After balancing the distribution of factors between patients with and without t(4;14) by the propensity score matching technique, patients with t(4;14) had similar OS (57.6 vs. 56.5 months, p = 0.964) and PFS (26.5 vs. 28.1 months, p = 0.740) with the patients without t(4;14). Conclusions These results demonstrated that t(4; 14) alone may be not a poor prognostic factor patients with newly diagnosed MM in the novel agent era.


Introduction
Multiple myeloma (MM) is a malignant hematological disease originating from monoclonal plasma cells, mainly manifested as hypercalcemia, renal insufficiency, anemia and bone lesions [1,2].MM is a highly heterogeneous disease with significant discrepancies in survival, ranging from a few months to more than ten years.So it is very important to clarify the prognostic factors of MM patients and design personalized treatment to improve the outcome of patients.Cytogenetic abnormalities represent the biological characteristics of myeloma cells and play an important role in the prognosis of multiple myeloma patients.Fluorescence in situ hybridization (FISH) is a common method to detect cytogenetic abnormalities in MM patients.IGH gene locates at 14q32 and several cytogenetic abnormalities based on 14q32 translocations are identified which have special prognostic significance for MM patients.These translocations mainly include t(4;14)(p16;q32), t(14;16)(q32;q23), t (11;14)(q13;q32), and t(14;20)(q32;q12).In prior reports, t(4;14) translocation could be detected by FISH in 10-30% patients with newly diagnosed MM [3][4][5][6].Several studies found that the t(4;14) was a poor prognostic factor for the outcome of MM patients [7][8][9][10][11][12][13][14][15][16].However, some studies suggested that t(4;14) was not associated with the prognosis of MM patients [3,5,[17][18][19].At present, the prognostic value of t (4; 14) in newly diagnosed MM patients is still controversial.
To evaluate the prognostic value of t(4;14) in newly diagnosed MM patients in the novel agent era, we conducted this retrospective analysis of 606 newly diagnosed MM patients in Beijing Chaoyang Hospital, Capital Medical University and found that t(4; 14) alone was not significantly associated with overall survival (OS) and progression-free survival (PFS) of patients with newly diagnosed MM in the era of novel agents.

Patients
We screened newly diagnosed MM patients who received initial treatment in Beijing Chaoyang Hospital, Capital Medical University from 1 January 2010 to 1 January 2022.A total of 606 patients had available FISH results before MM treatment and received novel agent therapy and thus were included in this study.We recorded the baseline data and conducted regular follow up with the electronic medical record system.All patients were diagnosed according to the MM criteria of the International Myeloma Working Group (IMWG) [2] and followed up until 1 June 2022.FISH was used to detect cytogenetic abnormalities in myeloma cells prior to initial treatment.Before the detection of FISH, bone marrow plasma cells of patients were purified by anti-CD138 + magnetic beads (Miltenyi technology, Bergisch Gladbach, Germany).Then DNA probes were used to analyze aberrations in chromosomal regions 1q21, 17p13, 14q32(IGH),16q23(MAF), 4p16.3(FGFR3),11q13 (CCND1).A total of 200 interphase nuclei were analyzed.The technical thresholds of cytogenetic abnormalities for 1q21 gain, del17p13, t(14;16), t(4;14), and t (11;14) were set as 20%, 20%, 10%, 10% and 10%, respectively.The baseline data were collected including age, sex, hemoglobin (HGB), serum creatinine (SCr), corrected serum calcium (CsCa), lactate dehydrogenase (LDH) and types of MM.Approval for this study was obtained from the medical ethics committee at Beijing Chaoyang Hospital.

Response and outcome measures
All patients received induction regimens containing at least one novel agent (bortezomib, thalidomide, lenalidomide), including bortezomib based regimens, immunomodulatory (IMIDs) based regimens or bortezomib combined with IMIDs regimens.Responses of patients receiving autologous stem cell transplant (ASCT) were evaluated 3 months after ASCT, and maintenance therapy was performed in the non-progressive patients.When the efficacy reached a plateau, the non-ASCT patients received maintenance therapy.Bortezomib combined with lenalidomide was recommended for high-risk patients.Most patients received lenalidomide or thalidomide monotherapy, while a small number received bortezomib or ixazomib monotherapy.All patients received maintenance therapy until intolerance or disease progression.Patient responses were evaluated according to the IMWG criteria [20], including strict complete response (sCR), complete response (CR), very good partial response (VGPR), partial response (PR), stable disease (SD), and progressive disease (PD).The primary outcomes were progression-free survival (PFS) and overall survival (OS).PFS was defined as from the time of diagnosis to disease progression or death, and OS was defined as from the time of diagnosis to death from any cause or last follow-up date.Patients who cannot be followed up were censored at the last follow-up date.

Statistical analysis
SPSS 23.0 software was used for statistical analysis.The Chi-square test was used to test categorical variables.
Kaplan-Meier method was used for survival analysis, and the log-rank test was used to compare the differences between groups.The Cox proportional hazards regression analysis was used to assess prognostic factors and results were reported as hazard ratios (HRs) with 95% confidence intervals (95% CIs).In order to balance the distribution of factors between patients with and without t(4;14), the propensity score matching technique was used to match to reduce the deviation between the two groups.Patients with and without t(4;14) were matched at 1:1 with a caliper value of 0.05.A p value <0.05 was considered statistically significant.

Patient characteristics
A total of 606 patients with newly diagnosed MM were enrolled.Clinical characteristics of patients were summarized in Table 1 1).Among 606 patients, 172 (28.4%) had at least 2 cytogenetic abnormalities.The median age was 61 (30-87) years, and the male-to-female ratio was 1.24 (336/270).Of all 606 patients, IgG-type (49.2%) myeloma was the most common type, and 306 patients (50.5%) were at stage III of the International Scoring System (ISS).All patients were treated with novel agent combination induction therapy, including 319 patients (52.6%) who received bortezomib based combination therapy, 49 patients (8.1%) who received immunomodulatory (IMiD) based combination therapy, and 238 patients (39.3%) who received bortezomib and IMiD based combination therapy.After induction therapy, 180 (29.7%) patients received ASCT.Patients were divided into three groups according to cytogenetic abnormalities for further analysis: patients with no cytogenetic abnormalities, patients with t (4:14), and patients with other cytogenetic abnormalities.As shown in Table 1, there were statistically significant differences among three groups in sex, monoclonal protein type, hemoglobin, 1q21 gain, del 17p, t (14;16) and t (11;14).

Matched pairs of patients
The translocation t(4; 14) was observed in 108 (17.8%) patients, among which 79 (73.1%) were accompanied by 1q21 gain or del 17p.In order to balance the distribution of factors between patients with and without t(4;14), the propensity score matching technique was used to match to reduce the deviation between the two groups.Among 606 patients, patients with and without t(4; with and without t(4;14) with respect to these characteristics (Table 4).

Discussion
In this study, we evaluated the prognostic impact of t (4;14) on the outcome of newly diagnosed MM patients.We found that t(4;14) alone had no prognostic value for newly diagnosed MM patients in the novel agent era.MM is characterized by recurrent chromosomal translocations involving the immunoglobulin heavychain locus.These translocations are detectable in 60% of MM patients by FISH.One of these recurrent translocations was t(4;14), which could be identified by FISH in 10-30% of MM patients [3][4][5][6].Many studies have shown that t(4;14) was associated with poor outcomes in MM patients [7][8][9][10][11][12][13][14][15][16].Sato S et al. [6] retrospectively investigated 93 patients with newly diagnosed MM and found that the rate of 3year OS was lower in t(4;14) patients than those without t(4;14), and considered that t(4;14) MM still had a poor prognosis in the era of novel drugs.Gertz MA et al. [7] analyzed the prognostic value of t(4;14) in 238 patients who received high dose therapy and found that PFS and OS were significantly shorter for patients with t(4;14).A single-center retrospective longitudinal cohort study of newly diagnosed MM patients undergoing ASCT within 12 months from initial diagnosis also considered t(4;14) as a high-risk factor for patients [4].One study analyzed the data derived from four phase III trials involving patients younger than 66 years treated with novel agent-   based induction and ASCT and showed that t(4;14) was related to the risk of early MM progressionrelated death [8].Nemec P et al. [9]  This study had some limitations.One main limitation was its single-center database and retrospective nature.Another limitation was that the treatment of some patients may be transferred to other medical centers, resulting in some data loss.This may interfere with the assessment of the prognostic value of t(4;14).Finally, follow-up of patients is insufficient and further larger population studies are needed to validate the results.
In conclusion, our study demonstrated that t(4;14) lost its prognostic value for newly diagnosed MM patients in the novel agent era.Further studies are needed to confirm its prognostic value in the future.

Figure 2 .
Figure 2. Kaplan-Meier survival curves on OS of patients with newly diagnosed MM.(a) all patients.(b) matched patients.

Figure 3 .
Figure 3. Kaplan-Meier survival curves on PFS of patients with newly diagnosed MM.(a) all patients.(b) matched patients.

Table 1 .
14) were matched for age, MM subtype, ISS stage, HGB, SCr, CsCa, LDH, 1q21 gain, del(17p13), t(14; 16), t(11; 14) and ASCT.A total of 208 patients were identified by propensity score matching technique, with 104 patients in each group.It was shown that there was no significantly difference in matched patients Baseline clinical and biological characteristics of MM patients.

Table 4 .
Baseline characteristics between matched patients with and without t(4;14).

Table 3 .
Cox analysis (univariate and multivariate) of prognostic factors for PFS.

Table 5 .
Best response rate of MM patients.
Our study found that translocation t(4;14) was observed in 17.8% newly diagnosed MM patients which was similar to previous studies.In this study, patients with t(4;14) had shorter PFS and OS estimated by the Kaplan-Meier method than patients without cytogenetic abnormality.However, univariate and multivariate analysis revealed that t(4;14) was not a poor prognostic factor for PFS and OS of newly diagnosed MM patients.After balancing the distribution of factors between patients with and without t(4;14) by the propensity score matching technique, patients with t(4;14) had similar OS and PFS with the patients without t(4;14).In this study, there were 108 patients with t(4;14), more than 70% of patients had other cytogenetic abnormalities including 1q21 gain and del 17p, while less than 30% of patients had t(4;14) alone.The multivariate analysis and the propensity score matching analysis confirmed that t(4;14) alone had lost its prognostic value for newly diagnosed MM patients in the novel agent era.This may indicate that t(4;14) alone had little prognostic value for survival of patients with newly diagnosed MM, and other cytogenetic abnormalities including 1q21 gain and del 17p enhanced the poor prognostic power of t(4;14).As a result, t(4;14) alone cannot be considered a poor prognostic factor for patients with newly diagnosed MM.