The approval of Calquence (acalabrutinib) for patients with chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) is good news for patients as well as oncologists and hematologists, two physicians told MD Alert.
Acalabrutinib is a second-generation BTK inhibitor, making it similar to ibrutinib, which is already being used to treat patients with these conditions. While there are similarities, Rajat Bannerji, MD, PHD, of the Rutgers Cancer Institute of New Jersey said there are also distinct differences that will have a positive effect on patient care. One of the most significant differences, Bannerji said, is that acalabrutinib did not show the same side effects as the older drug in clinical trials prior to its approval.
“Because acalabrutinib seems to be more selective, it seems to have less what we call off-target effects and may be to some extent better tolerated than the ibrutinib,” Bannerji said.
Bannerji said a study published in Blood Advances showed that the newer medication is a viable option for people who were intolerant to ibrutinib. Among the most commonly cited reasons patients gave for stopping ibrutinib was rash, body ache, diarrhea, bleeding, and even atrial fibrillation.
The addition of acalabrutinib to the treatment options continues a trend of moving away from chemotherapy for most patients, Bannerji said.
The dosage of the two drugs is also different, according to Brian Hill, MD, PHD, of the Cleveland Clinic. While ibrutinib is typically taken once per day, acalabrutinib is taken twice a day. Hill said patients taking acalabrutinib have seen conditions like atrial fibrillation occur at a lower rate.
Even with the approval, both doctors said there is still a lot to learn about acalabrutinib. Bannerji said one area doctors are interested in is whether the drug is as effective if it is only prescribed for a limited amount of time.
“Both ibrutinib and acalabrutinib are approved and would be routinely used with what we call ‘indefinite treatment,’” Bannerji said. “Patients would be prescribed the medication to treat their CLL, and they would stay on the medication until the CLL came back or they had side effects that caused them to want to stop taking the medicine.”
Studies currently underway are looking at what happens if patients stop taking acalabrutinib after a set period between six months and two years.
“I think that will be a major advance because I think patients are intimidated by the idea of being on one of these medicines ‘forever,” Bannerji said. “To know that ‘yes, I’m going to take these drugs but only for a year or two years, and then I’ll be stopping’ I think makes it much more palatable.”
Hill said the treatment of CLL and SLL can be challenging for even the most seasoned oncologists because of the way it reacts to medication and its extended duration. The approval of acalabrutinib, including its usage as a combination therapy could change that discussion drastically.
“We don’t get very deep or complete remissions, but we get prolonged disease control, and generally toxicities are manageable enough to maintain the treatment for long-term use.”
Whether acalabrutinib becomes the new first-line treatment for CLL or SLL remains to be seen, but with good results so far and more research expected Bannerji said there is reason for patients to be optimistic after diagnosis. He said the results with obinutuzumab could be especially good for patients.
“These combinations, even with a limited period of treatment, tend to have very high rates of patients becoming minimal residual disease negative, and the feeling is that the patients who become MRD- will have a longer period of progression-free survival,” he said.
“It will be interesting to see if the achievement of MRD-status really predicts for someone who doesn’t need to be treated for their CLL for years, decades, some people maybe never again.”
More information about recent studies is expected to be presented at the upcoming American Society of Hematology conference in Orlando.