Shortage of cancer drugs having devastating effects on patients, veterinarians

Cisplatin and carboplatin, popular chemotherapy medications, are difficult to obtain and increasingly expensive

Dr. Terry Hamilton was a veterinary oncologist at Georgia Veterinary Specialists in Atlanta for 16 years until retiring in December 2022. The stress of cancer drug shortages was one of the reasons he retired early.

The dilemma of reserving drugs for patients with a worse prognosis, and constantly picking and choosing which patient to treat was “hugely stressful” for Dr. Hamilton.

“It’s something that kind of eats away at you a little bit,” he said. “That you know you’re not doing what you could because of conditions outside of your control. It’s burning veterinarians out. I can only imagine the same thing is happening in human medicine.”

Dog receiving chemotherapy
During drug shortages, all staff members work hand-in-hand to address the issue. Administrative tasks such as calling drug providers and tracking potential leads take up valuable time from clinicians, who are already spending additional time with clients if they’re worried about a drug not being available to finish a treatment.

As of mid-September, there were 27 oncology medicines on the official Food and Drug Administration (FDA) shortage list. Widely used chemotherapy drugs cisplatin and carboplatin have been in short supply for months, forcing human doctors and veterinarians to make challenging treatment decisions. Supply chain disruptions affecting the few pharmaceutical companies producing these drugs have meant a recent dramatic reduction in the available supply.

Intas, an India-based pharmaceutical company, made about half of the key cancer drugs used in the U.S. until late last year. The company's production of key cancer drugs was suddenly halted after the FDA found evidence of safety and quality violations at the company’s plant in Gujarat, India, last fall. Analysts now project that the shortage may persist through the fall and possibly longer.

Richard Pazdur, director of the FDA Oncology Center of Excellence, said the current critical shortage of cisplatin and carboplatin occurred because manufacturers failed to invest in enhancing production capacity, according to an interview with The Cancer Letter.

“We don’t have the redundancy we really need with most of our medications,” Dr. Hamilton said. “In spite of how expensive everything is, it’s not as profitable as the pharmaceutical companies would like it to be.”

Hard decisions and finding alternatives

In human medicine, cisplatin and other platinum-based cancer drugs, including carboplatin and oxaliplatin, are prescribed for 10% to 20% of all cancer patients, according to the National Cancer Institute.

Dr. Karen Oberthaler is a medical oncologist and owner of Treeline Veterinary Cancer Care, a cancer treatment center in Boulder, Colorado. She explained that both carboplatin and cisplatin are the treatment of choice for dogs with osteosarcoma. Carboplatin is also commonly given for many other carcinomas in dogs and cats such as anal sac adenocarcinomas, pulmonary adenocarcinomas, and transitional cell carcinoma. The drug is well-studied and well-tolerated, and until recently, was well-priced and easy to obtain, Dr. Oberthaler said.

“The carboplatin shortage was pretty tough. As a single doctor, privately owned practice, we did not have a large surplus on our shelves,” Dr. Oberthaler said. “We had to creatively schedule our patients so that no drug would go to waste and no half-used vials were thrown out.”

Because carboplatin is the first-line treatment agent for osteosarcomas, those patients with that type of cancer were prioritized. But she was faced with constant decisions about which patients could tolerate medication substitutions or decreased frequency of treatments.

“We did have to switch some other patients with different cancers to either doxorubicin, mitoxantrone, or Palladia—depending on their cancers, what chemotherapeutics they'd had before, and what their families desired,” Dr. Oberthaler added.

Both Drs. Hamilton and Oberthaler say because of the increased demand when a cancer drug was back ordered, the price became drastically higher than when it was more readily available. Dr. Oberthaler recalled paying 10-20 times more per vial than what it cost just weeks prior.

For example, in January, a standard vial of carboplatin was being sold for $25-$35. In July, if Dr. Oberthaler could find it, that same size vial was being sold for $500-550.

“As a business owner, it was important to me to honor the estimates we'd given to families at the beginning of their pet's therapy, but that was certainly tough when it was so much more expensive on our end,” she said.

To prevent running out of medication for her ;osteosarcoma patients, Dr. Oberthaler called every human cancer center in her area to see if they had any cancer drugs that she could buy or any short-dated product that they couldn't use on their patients. Her search was futile.

Dr. Hamilton said his previous practice stayed ahead of the curve pretty well, but multiple times they had to delay treatment with melanoma vaccines or with carboplatin. When he would get carboplatin, it was from having relationships with pharmaceutical representatives and immediately getting back to them when they said they had a few vials to sell.

“Probably the only thing that’s going to change this, unfortunately, is the government,” Dr. Hamilton said. “So put pressure on your congressmen to really work with pharmaceutical companies to have more redundancies instead of relying on one or two manufacturing plants.”

Patients with limited options

Dr. Hamilton can’t definitively say if patients suffered because of this shortage. If a patient is supposed to be getting a specific treatment and receives a substitute, “you can assume they might’ve lived longer if we’d had the correct medication,” Dr. Hamilton said.

When he’s told clients about delaying or adjusting a patient’s treatment because of the shortage, “they don’t take that well. They don’t get angry at the drug companies, they get angry at the person telling them.”

In comparison, Dr. Oberthaler has found her clients to be “incredibly understanding.”

“They know we are trying our best on our end to scramble and find carboplatin for their pets,” she said. “I also think the fact that people with certain cancers cannot get life-saving drugs for themselves has really put things into perspective for everyone.”

Dr. Oberthaler said that this is not the first time an important chemotherapy medication has been tough to obtain. She recalled weathering many shortages with asparaginase, vincristine, and vinblastine.

“Even veterinary-specific therapeutics like Palladia and Oncept—the melanoma vaccine—have been tough to get for periods,” she added. “We are used to this and we know how to handle it and more importantly how to counsel our patients' families through it, because it can be incredibly stressful from our client's perspective.

A version of this story appears in the November 2023 print issue of JAVMA