Two 70-Year-Olds Will Start the Same $12,272 Keytruda Qlex Cancer Injections. One With Medigap Plan G Will Owe $0 in Coinsurance After the Part B Deductible, While the Other Will Owe 20% With No Annual Cap

Two hypothetical 70-year-old cancer patients are about to start the same treatment. Their oncologists recommend Keytruda Qlex, an injection given under the skin in about one minute. The manufacturer’s list price for each three-week dose is $12,272.

Both have Original Medicare. One also carries Medigap Plan G, which covers his Part B coinsurance after the deductible. The other never bought supplemental insurance. He will owe 20% of Medicare’s approved treatment cost each time, with no annual limit on what he can pay.

Merck (NYSE:MRK | MRK Price Prediction) reported $830 million in Q3 2026 Keytruda Qlex sales. The treatment is gaining traction, but the two men’s Medicare bills will look very different.

$12,272 List Price Differs From His Medicare Bill

Merck lists the three-week dose at $12,272 before discounts. Medicare pays its own approved amount for drugs that doctors give, and it ties that payment to the drug’s billing code. Qlex now has a permanent code. Merck’s oncology chief Jannie Oosthuizen said on the Q3 earnings call: “Since we received the permanent J-code on April 1, it has been a really positive trajectory.” His coinsurance comes from Medicare’s approved amount, so taking 20% of the list price gives the wrong number. Keytruda Qlex was not among the drugs selected for Medicare price negotiations taking effect in 2028.

What Original Medicare Charges

Part B generally covers medically necessary cancer drugs administered in a doctor’s office, clinic or hospital outpatient department. Once he meets the $283 Part B deductible for 2026, he typically pays 20% of the Medicare-approved amount. A full year on the three-week schedule would mean about 17 injections. Each one produces its own 20% bill, and the office visits, scans and lab work around it carry coinsurance too.

Original Medicare has no annual out-of-pocket cap. One limit applies to most hospital outpatient services: a single copayment generally cannot exceed the Part A inpatient deductible, which is $1,736 in 2026. That doesn’t cap his total annual spending, so the treatment setting still matters.

Same Treatment, Three Different Bills

Plan G covers his Part B coinsurance after the deductible. That means the injections, scans and covered visits generally add no further coinsurance, although he still pays his monthly premiums. Medicare Advantage caps in-network costs, and plans may set that cap as high as $9,850 for 2027. But an Advantage plan can require approval before the first dose, it limits him to its network, and the cap leaves out Part D drugs and out-of-network care.

A bigger risk sits behind the table. At 70, his one-time Medigap open enrollment window closed years ago. In most states, insurers can now review his health history, and a cancer diagnosis can lead to a denial or a higher premium. Leaving an Advantage plan for Original Medicare plus Plan G mid-treatment may not be an option. Connecticut, New York, Massachusetts and Maine give wider access, so check your own state’s rules. Coinsurance on a drug like Qlex is only one of the surprises Medicare hands retirees (we mapped out the IRMAA surcharges, coverage gaps and premium traps in a free Medicare guide).

What the Faster Injection Changes

IV Keytruda runs as a 30-minute infusion. Qlex takes about 1 minute every three weeks or 2 minutes every six weeks. That saves chair time, parking and long afternoons in an infusion center. Whether it also saves him money depends on how Medicare pays for the drug and for giving it, which gets its own billing code. A shorter appointment does not guarantee a smaller bill.

Three Moves Before the First Injection

• Request a written estimate. Ask the oncology billing office to price Qlex using the Medicare-approved amount, with the drug and the administration fee listed separately, and to say whether an office or a hospital outpatient department will bill.
• Check Medigap eligibility before you assume you can’t get it. If he has Original Medicare alone, he should check his state’s Medigap rules and ask whether he qualifies for Plan G. Without supplemental coverage, he faces 20% coinsurance on every injection.
• Confirm Advantage rules in writing. If he is in an Advantage plan, he should confirm his oncologist is in-network and that prior authorization covers Qlex by name. He should also compare each plan’s 2027 out-of-pocket cap before open enrollment closes on December 7.

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