The following article features coverage from the American Society of Hematology 2019 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Results of a retrospective study presented at the 61st American Society of Hematology (ASH) Annual Meeting and Exposition highlighted evolving diagnostic and treatment approaches in Waldenström macroglobulinemia (WM).

Tracking trends in the diagnosis and treatment of patients with WM, an indolent B-cell lymphoproliferative disease that is a subtype of non-Hodgkin lymphoma (NHL), can be challenging due to the rarity of the disease.

This study used the UK Rory Morrison Registry to evaluate the patient- and disease-related characteristics, as well as treatment history, of patients diagnosed with WM in the UK between 1978 and 2019.

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Of the 671 patients included in the study, the median age at diagnosis was 64 years, and approximately 90% were Caucasian. While only 7 patients in the dataset were diagnosed with WM prior to 1990, this number increased by a factor of more than 60 (433 individuals) since 2010, according to the abstract.


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Disease-related characteristics included a median hemoglobin level (112 g/L), median platelet count (242), median beta2 microglobulin (3 ug/mL), and median M-protein (17 g/L).

Peripheral neuropathy, cryoglobulinemia, amyloidosis, and Schnitzler’s syndrome were reported in 74, 26, 12, and 7 patients, respectively. Notably, the rate of CNS involvement was very low in this dataset, with only 1.5%. The rate of high-grade transformation was also 1.5%.

Genetic testing for mutations in MYD88 L265P and CXCR4 was performed for 190 and 76 patients, respectively, with MYD88 L265P and CXCR4 mutations found in 84.2% and 26.3% of patients, respectively.

“There was a trend towards difference in OS rates (P =.095) according to MYD88 status, with somewhat poorer OS rate amongst MYD88 wild-type patients. CXCR4 status did not impact the OS rate in this cohort (P =.93),” the researchers wrote on their poster. However, they added, “The lower-than-average MYD88 L265P incidence likely reflects earlier methodology for detection, which was less sensitive; CXCR4 is not routinely commissioned in the U.K. until it influences treatment choices.”

At diagnosis, the International Prognostic Scoring System for WM (IPSSWM) score was available for 352 patients, with 34.7%, 29.3%, and 45% classified as low-risk, intermediate-risk, and high-risk.

Of the 440 (65.6%) patients in this analysis who received treatment for WM, some of the rationales for initiating first-line therapy were hyperviscosity (24.8%), fatigue (21.6%) and peripheral neuropathy (9.8%). The number of lines of therapy received was 1, 2, 3, 4, and 5 or more in 43.6%, 24.1%, 4.8%, 6.6%, and 10.9%, respectively.

Since 2010, the most frequently used first-line treatments were rituximab-based, including dexamethasone, rituximab, and cyclophosphamide (DRC), rituximab plus bendamustine (R-bendamustine), single-agent rituximab, and R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone).

In addition, Bruton tyrosine kinase (BTK) inhibitors were administered to 23% of patients receiving second-line therapy.

There were 118 deaths reported among the patients included in the dataset, although cause of death was available for only 30 patients, of which 7 patients were reported to have died from progressive disease. One patient died from WM central nervous system relapse.

Five- and 10-year rates of OS were 90.5% and 79.4%, respectively, with higher rates observed in patients with low and intermediate IPSSWM scores compared with high IPSSWM scores (P <.001).

In commenting on these results, the study authors noted that “OS rates are high and correlate with IPSSWM risk, but a majority of patients had received multiple lines of therapy reflecting the chronically relapsing nature of WM.”

“Treatment practices are clearly evolving, with increasing first-line use of DRC and R-bendamustine, as well as BTK inhibitors for relapsed disease.”

Read more of Cancer Therapy Advisor‘s coverage of ASH’s annual meeting by visiting the conference page.

Reference

Tomkins O, Bomsztyk J, McCarthy H, et al. An analysis from the WM Rory Morrison Registry: Waldenstrom’s macroglobulinaemia patient demographics, disease characteristics and evolving treatment choices. Presented at: 61st American Society of Hematology (ASH) Annual Meeting and Exposition; December 7-10, 2019; Orlando, FL. Abstract 4016.