Eli Lilly has introduced a half-priced generic version of its blockbuster fast-acting insulin, Humalog, amid intensifying scrutiny of drug prices.

The Indianapolis drugmaker said Wednesday that it was now selling lispro, the chemical name of Humalog, a move that the company announced in March. The generic, which is half the list price and identical to Humalog, will cost $137.35 for a vial, or $265.20 for a package of pen injectors, the Associated Press reported. Activists say the cost is still too high, especially compared with prices in other countries, as many patients need two vials a month.

People with Type 1 diabetes rely on injected insulin to regulate their blood glucose levels because their bodies do not produce insulin, and must inject the hormone to live. Many people with Type 2 diabetes, a condition in which not enough insulin is present, also rely on injected insulin. Humalog is a fast-acting insulin used by about 700,000 Americans, according to the AP.

Lilly’s decision to introduce the lower-priced generic follows congressional hearings on drug pricing and numerous reports of patients who have been hospitalized or died from rationing insulin because of its cost.

Insulin prices nearly tripled between 2002 and 2013, and have risen 10 percent or more a year since then, according to the AP.

In a statement announcing the company’s plans in March, Lilly CEO David A. Ricks said the decision followed discussions with patients who use Humalog and their caregivers, medical professionals, advocacy groups, drug wholesalers, lawmakers and academics.

“Solutions that lower the cost of insulin at the pharmacy have been introduced in recent months, but more people need help. We’re eager to bring forward a low-priced rapid-acting insulin,” Ricks said in the statement.

Patients and advocates were swift to criticize Lilly, saying that the new generic does not go far enough to address the high cost of a lifesaving drug.

“This does not get Eli Lilly off the hook for their price-gouging and it shows us that they have the power to set a price that is truly affordable at any time,” T1International, a patient advocacy group, said in a statement following the March announcement.

“While $137.35 is an improvement, it’s still an unaffordable price for so many, considering most people need at least 2 vials each month,” the group said.

According to the AP, patients who are uninsured, or who have high-deductible health plans or Medicare Part D plans will experience the biggest cost savings. Depending on their insurance plan, Humalog may still be cheaper for some patients.

Patients can find out whether the generic version is cheaper with their insurance by calling Lilly’s diabetes patient support center at 833-808-1234.