Gloom Lifting as MCL Treatments Evolve

Jim Kling

October 25, 2022

An optimistic new review offers guidance about treating mantle cell lymphoma (MCL) in the new era of chimeric antigen receptor (CAR)-T cell therapy and medication choices informed by risk stratification.

Traditionally, MCL has had a notoriously poor prognosis and is still impossible to cure. But survival rates are rising thanks to better treatments, the review authors wrote, and even relapsed/refractory patients have a growing number of options that can potentially give them extra years of life.

"Prognosis has certainly changed in past 10 years. We have been able to have an excellent control of disease, and patients are living longer, even past the 8- or 10-year mark," Moffit Cancer Center/Memorial Healthcare System hematologist-oncologist Jose Sandoval‐Sus, MD, said in an interview. He is corresponding author of the review, which appeared in the October issue of Current Oncology Reports.

MCL — which affects cells in the mantle zone of lymph nodes — is rare. It usually strikes older men, often presents at an advanced stage, and accounts for 6%-8% of non-Hodgkin lymphomas in the United States.

Prognoses are improving. The review highlights a study released earlier this year that found that median 5-year overall survival has increased from 68.8% (2002-2009) to 81.6% (2010-2015).

Now, the review notes, there are several first-line chemotherapy options that combine agents with rituximab such as rituximab/bendamustine, which "has generally been established as an effective treatment for MCL at first relapse in patients who are bendamustine naive when compared to other chemotherapy agents."

Other treatments include rituximab, bortezomib, cyclophosphamide, doxorubicin, vincristine, and prednisolone; rituximab, bendamustine and cytarabine; and rituximab, gemcitabine, and oxaliplatin.

"I think of rituximab as a medication of maintenance, either after autologous stem cell transplant or even in patients who have not been through transplant," Sandoval‐Sus said. "As maintenance, it really has improved outcomes for these patients."

But the first step before treatment, he said, is to explore prognostic factors such as alterations on the TP53 gene that "really dictate a lot in terms of the prognosis of patients." As the review notes, these alterations — either bi-allelic del17p or TP53 mutations — "are associated with poor outcomes after frontline and salvage regimens, including targeted agents such as Burton's tyrosine kinase inhibitors (BTKis)."

These patients, who make up about 20% of those with MCL, also are most unlikely to benefit from autologous stem cell transplantation, Sandoval‐Sus said.

What about refracted/relapsed (R/R) cases? BTKis have been a major advance for these patients, he said. However, choosing the best drug can be a challenge. As the review notes, "all approved BTKis for R/R MCL seem to have similar clinical outcomes based on identical mechanism of action, and there are no prospective trials comparing these agents in a head-to-head fashion."

The authors added that "we wonder if AEs [adverse events] could be decreased by using combinations based on new generation BTKi, but it is still a question that needs to be resolved in the clinical trial arena."

Stem cell transplants may be an option, the review said, but "in practice the clinical benefit ... is limited to single-center series or small multi-institutional registries with few prospective studies."

Then there's CAR-T cell therapy, the game-changer. A type called brexucabtagene autoleucel (Brexu-cel) is now approved in MCL, the review authors wrote, and real-world data "serve as a platform to expand CAR-T therapy to more R/R MCL patients that do not fit the strict inclusion criteria of the studies (e.g., controlled comorbidities and worse performance status)...We strongly recommend early referral of these patients to accredited institutions with ample cellular therapy experience, including high-risk MCL patients (e.g., blastoid/pleomorphic morphology, biallelic del17p, TP53 mutations) so an appropriate bridging strategy and a CAR-T cell roadmap is planned with the patient and caretakers."

Some researchers are exploring combination treatment with both BTKis and CAR T-cell therapy, "which may be considered for patients with R/R MCL who are naive to both CAR T-cell and BTKi therapy, because combination therapy may increase treatment efficacy," wrote the authors of another review that appeared in the October issue of Current Oncology Reports. "Based on limited data in patients with CLL, BTKi therapy may be initiated as bridging therapy and continued during lymphodepletion prior to CAR T-cell infusion"

What's next? Multiple treatments are in the research stage, Sandoval‐Sus said. "There are a lot of things in development that are really incredible."

Reversible BTKis, for example, appear to be effective at controlling disease and are well-tolerated, he said. "And we are awaiting the results of clinical trials of targeted therapies."

For now, he said, the best advice for hematologists is to gain a full understanding of a patient's MCL, in order to provide the most appropriate treatment. Community oncologists should get at least one second opinion from an academic center or other clinic that treats these kinds of lymphomas, he said, and molecular tests are crucial. A discussion about stem cell transplantation after remission is a good idea, he said, and so is an exploration of clinical trials "from the get-go."

"In patients who relapse and have high-risk features, they should be started on a BTKi inhibitor for the most part," he said, "although we need to weigh risks and benefits between the side effects of different BTKi inhibitors. And they should be referred earlier to a CAR T cell therapy center, so they can discuss the benefits and see if they're an appropriate patient. I think patients are being referred a little bit too late in the second- or third-line setting."

What about CAR T therapy as a first-line therapy? It's not FDA-approved, Sandoval‐Sus said, and "definitely not a standard of care." But clinical trials are exploring the idea, he said. As for messages to patients, Sandoval-Sus said he would tell them that MCL is not yet curable, "but the future is very bright."

Sandoval-Sus declared advisory board relationships with Seagen, Incyte, Janssen, ADC Therapeutics, TG therapeutics, and Genmab. The other review authors had no disclosures.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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