How effective and safe is ibrutinib compared to temsirolimus for relapsed or persistent mantle cell lymphoma?

This study compared the effectiveness and safety of ibrutinib (Imbruvica) versus temsirolimus (Torisel) in patients with relapsed or refractory (does not respond to treatment) mantle cell lymphoma (MCL). This study concluded that ibrutinib significantly improved survival outcomes compared to temsirolimus for these patients.

Mantle cell lymphoma (MCL) is a rare but aggressive type of non-Hodgkin’s lymphoma (NHL). This type represents about 6% of all new NHL cases in the U.S and is more common in older adults. For patients with relapsed or refractory disease, ibrutinib has become the preferred standard of care.

Ibrutinib is a targeted therapy. This type of treatment only targets cancer cells, and blocks their growth. This leads to cancer cell death. Temsirolimus is also a targeted therapy, but is used primarily for kidney cancer. Whether ibrutinib is safer and more effective than temsirolimus for mantle cell lymphoma remains under investigation.

This study involved 280 patients with relapsed or refractory MCL. 49.6% received ibrutinib and 50.4% received temsirolimus. The average follow-up period was 38.7 months.

The overall response rate (ORR; cancer shrinks or disappears after treatment) was 77% (ibrutinib) and 47% (temsirolimus). 23% (ibrutinib) versus 3% (temsirolimus) achieved a complete response (CR; complete disappearance of cancer). This difference was statistically significant.

The average progression-free survival (PFS; time from treatment before disease progression) was 15.6 months (ibrutinib) versus 6.2 months (temsirolimus). Ibrutinib reduced risk of disease progression by 55%. This difference was statistically significant.

The average overall survival (OS; time from treatment until death from any cause) was 30.3 months (ibrutinib) versus 23.5 months (temsirolimus). Ibrutinib reduced mortality risk by 26%. This difference was not statistically significant. By the end of the study, 55% (ibrutinib) and 59% (temsirolimus) of patients had died.

Overall, the ibrutinib group most commonly reported fatigue (24%) and cough (23%). The temsirolimus group most commonly reported low white blood cell count (56%) and low red blood cell count (44%). 33% (ibrutinib) and 31% (temsirolimus) also reported diarrhea.

Severe or life-threatening side effects were also reported. 13% (ibrutinib) and 17% (temsirolimus) reported low neutrophil (white blood cell) count. 9% (ibrutinib) and 20% (temsirolimus) reported low red blood cell count.

This study concluded that ibrutinib significantly improved survival outcomes compared to temsirolimus for relapsed or refractory MCL.

Some of the authors of this paper reported previous funding from the manufacturers of ibrutinib or temsirolimus. Also, three of the authors reported having stocks in the manufacturer of ibrutinib.

If you have relapsed or refractory MCL, talk to your care team about ibrutinib.