Keytruda drug ef­fec­tive against 3 can­cers: stud­ies

The China Post - - LIFE - BY LINDA A. JOHN­SON

One of the hot new can­cer im­munother­apy drugs, Merck & Co.’s Keytruda, strongly ben­e­fited pa­tients with melanoma, lung can­cer and mesothe­lioma, ac­cord­ing to three stud­ies pre­sented Sun­day at the Amer­i­can As­so­ci­a­tion for Can­cer Re­search con­fer­ence in Philadel­phia.

One study, com­par­ing Keytruda to Bris­tol- My­ers Squibb Co.’s Yer­voy, could give Merck a tem­po­rary ad­van­tage as the ri­vals battle for mar­ket supremacy and bil­lions of dol­lars in an­nual sales from this new gen­er­a­tion of drugs, which help the im­mune sys­tem de­stroy can­cer cells. While re­search con­tin­ues, the pace is quick­en­ing and big im­prove­ments in pa­tient care reg­i­mens are likely fairly soon.

Here’s a look at the stud­ies:

Melanoma

Merck ran the first head-to­head com­par­i­son of two ap­proved “im­mune check­point in­hibitors,” its Keytruda and Yer­voy, as ini­tial ther­apy for pa­tients with ad­vanced melanoma. Of 834 par­tic­i­pants, one-third each got Keytruda ev­ery two weeks, Keytruda ev­ery three weeks or Yer­voy ev­ery three weeks.

Con­firm­ing par­tial re­sults dis­closed pre­vi­ously, com­pared to Yer­voy, Keytruda boosted sur­vival with­out can­cer wors­en­ing by 42 per­cent af­ter 6 months and boosted over­all sur­vival more than 30 per­cent af­ter a year. About 33 per­cent of pa­tients on Keytruda re­sponded, mean­ing their tu­mors shrank or dis­ap­peared, ver­sus 12 per­cent get­ting Yer­voy. Se­ri­ous side ef­fects oc­curred a bit sooner and more com­monly in the Yer­voy group.

Dr. Michael Pos­tow, a melanoma and im­munother­a­peu­tics spe­cial­ist at Me­mo­rial Sloan-Ket­ter­ing Can­cer Cen­ter in New York, said Keytruda was clearly bet­ter.

“I don’t think there’s much de­bate,” Pos­tow said, adding doc­tors ex­pect “this sur­vival ben­e­fit will be con­tin­ued over the long haul.”

Longer fol­low-up of pa­tients is needed to con­firm that, he stressed. Some Yer­voy stud­ies have fol­lowed pa­tients for five years, find­ing the Bris­tol-My­ers drug, com­bined with stan­dard chemo­ther­apy, in­creased sur­vival about 18 per­cent over chemo­ther­apy alone.

Melanoma is the dead­li­est skin can­cer, each year killing about 10,000 Amer­i­cans and strik­ing about 73,000. Yer­voy, from a class of im­munother­apy drugs called CTLA-4 in­hibitors, is ap­proved as ini­tial treat­ment for ad­vanced melanoma. Keytruda, from the PD-1 in­hibitors class, is ap­proved as sec­ond-line treat­ment, for use af­ter Yer­voy or an­other drug. Based on th­ese re­sults, Merck will seek FDA ap­proval of Keytruda as ini­tial ther­apy. Pos­tow said the study shows PD-1 in­hibitors should be an ini­tial treat­ment.

Keytruda costs US$ 12,500 (NT$387,273) per month, and Yer­voy about US$11,000.

Lung Can­cer

In an early-stage study, Merck tested Keytruda in pa­tients with ad­vanced non-small cell lung can­cer, on Sun­day re­port­ing re­sults for all 495 pa­tients for the first time.

On av­er­age, pa­tients sur­vived for 12 months, in­clud­ing nearly 4 months with­out the can­cer wors­en­ing, and 20 per­cent re­sponded, mean­ing their tu­mors shrank or dis­ap­peared. Among the sub­set of pa­tients who had a pro­tein called PD-L1 on at least half their tu­mor cells, re­sults were stronger be­cause Keytruda tar­gets PD-L1. On av­er­age 45 per­cent re­sponded, they sur­vived more than six months with­out tu­mors wors­en­ing, and they’re living long enough that av­er­age over­all sur­vival hasn’t been reached yet. There was no com­par­i­son group get­ting a dif­fer­ent treat­ment or placebo.

Dr. Hos­sein Borghaei, a lung can­cer and mesothe­lioma spe­cial­ist at Fox Chase Can­cer Cen­ter in Philadel­phia, called the re­sults “great news.” He noted it’s im­por­tant to find “pa­tients that have the best chance of re­spond­ing to a drug,” to help them — and to spare oth­ers the side ef­fects and ex­pense of a treat­ment less likely to work. Still, he noted even in pa­tients with PD-L1 on fewer tu­mor cells, Keytruda ex­tended sur­vival about as much as stan­dard chemo­ther­apy.

This is a much big­ger mar­ket than melanoma, so more money is at stake. Non-small cell lung can­cer causes about 85 per­cent of lung can­cer, killing about 158,000 Amer­i­cans and strik­ing about 221,000 each year. On Sun­day, Merck said it ap­plied to the FDA for Keytruda’s ap­proval in this use. Bris­tol-My­ers al­ready has run four non-small cell lung can­cer stud­ies of its own PD-L1 in­hibitor, Op­divo. Op­divo costs US$12,500 per month.

Mesothe­lioma

Merck for the first time re­ported re­sults of Keytruda treat­ment for mesothe­lioma, a rare but tough-totreat can­cer caused by as­bestos ex­po­sure that mainly af­fects the lungs.

In a study of 25 pa­tients not helped by chemo­ther­apy — a group for whom there’s no ap­proved sec­ond-line treat­ment — af­ter 5 months’ treat­ment on av­er­age, 76 per­cent were helped. The pa­tients all had tu­mors with the PD-L1 pro­tein. Al­to­gether, 28 per­cent had tu­mors shrink and 48 per­cent had tu­mors stop grow­ing, though 10 pa­tients were still tak­ing the drug and two haven’t been as­sessed yet.

Nor­mally, only 10 per­cent of mesothe­lioma pa­tients who have re­lapsed af­ter ini­tial treat­ment re­spond to a sec­ond type of chemo­ther­apy.

“For an early-stage in­ves­ti­ga­tion into this ter­ri­ble dis­ease, it’s very en­cour­ag­ing to have the kind of re­sults that the in­ves­ti­ga­tors are re­port­ing,” said Fox Chase’s Borghaei, adding that Keytruda’s side ef­fects were more tol­er­a­ble than those of chemo­ther­apy.

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