By Bill Berkrot
Dec 8 (Reuters) - A closely watched leukemia drug developedby Johnson & Johnson and Pharmacyclics Inc maintained its effectiveness in keeping the disease at bay formost patients, according to long-term follow-up data from amidstage study being presented at a major medical meeting.
The oral drug, ibrutinib, last month won U.S. approval totreat a rare and aggressive form of non-Hodgkin lymphoma knownas mantle cell lymphoma. It is awaiting a Food and DrugAdministration decision on treating chronic lymphocytic leukemia(CLL), a slowly progressing form of blood cancer that primarilyaffects people aged 65 and older.
Some industry analysts had expected the CLL approval to comeat the same time as the lymphoma decision. Data from this andother studies being presented at the American Society ofHematology (ASH) meeting in New Orleans could give regulatorsadditional comfort about the medicine's safety and effectivenessin treating CLL.
"Patients receiving ibrutinib are doing much better thanhistorically what we're used to seeing with CLL," Dr John Byrd,a co-leader of the study, said in a telephone interview.
The 148-patient ibrutinib extension study looked at bothpreviously untreated CLL patients and those who had relapsed orstopped responding following prior therapies.
With a median follow-up of more than 27 months of treatment,nearly all of the previously untreated, or treatment-naive,patients and almost three quarters of the relapsed andrefractory patients had no evidence of the disease progressing.
"With extended follow-up the remissions with ibrutinibappear to be continuing and the safety of this long-term isbeing maintained," said Byrd, professor of internal medicine anddirector of hematology at the Ohio State UniversityComprehensive Cancer Center in Columbus.
"There has not been an increase of infections or otherlate-term complications, suggesting that it's going to be a drugthat patients can take for a continued, extended period of timewithout it being a detriment," he added.
Researchers had not yet been able to determine medianprogression-free survival - the point at which the diseasebegins to worsen for half the patients in a study.
Among previously untreated patients, about 96 percent hadnot yet experienced disease progression, with just one of 31patients in that group relapsing so far, researchers said.
Typically you would expect about 50 percent to see diseaseprogression at two years, Byrd explained.
"You don't even need a statistician to see the difference.The data are better," he said.
Of the 117 previously treated patients in the extensionstudy, 21 had experienced disease progression and 11 had diedwithin 30 days of receiving their last dose of the drug. Thatleft more than 70 percent whose disease remained in check.
"Ibrutinib is the single most active drug that's come intothe clinic for CLL in terms of the durability of remissioninduced with it, so it's going to be a game-changer in CLL,"Byrd predicted.
"A lot of the patients from the initial phase II study havebeen on drug for two to three years," he added.
Serious adverse side effects, such as pneumonia, declinedafter the first year of treatment, researchers said. Theincidence of serious side effects was twice as high in patientswho had received prior therapies, which may have had more to dowith the state of their disease than a reaction to ibrutinib,they said.
"Long term follow-up has only shown a low risk of infectionthat you would expect to see in this patient population," saidByrd. "Otherwise the safety has been very favorable relative toother things that have been used in this patient population."
RBC Capital Markets analyst Michael Yee is forecastingeventual annual worldwide sales of $5 billion for the medicine,now being sold for lymphoma under the brand name Imbruvica.
About 15,000 Americans are diagnosed with CLL each year,according to ASH. While there are effective treatments for thedisease, such as chemotherapy combined with Roche's Rituxan, current therapies can be highly toxic.
Ibrutinib is one of several new medicines for CLL -including one in late stage development from Gilead Sciences Inc - that have fewer toxicities and safety issues and maylead to better quality of life for patients being treated.
"The future will hold combining this with some of the othernew targeted therapies that we have coming forward to getcomplete remissions and hopefully get us onto the path of cure,"Byrd said.
- Health Care Industry
- chronic lymphocytic leukemia