Imported cancer drugs withdrawn due to carcinogenic concerns. Experts: Market withdrawals are all "life-saving"

Economic Observer Reporter Liu Xiaono

On March 9, a globally innovative imported drug was announced to be withdrawn from the market.

This drug, named Hydrochloride Taselisib Tablets (hereinafter referred to as “Taselisib”), was developed by a company under the French pharmaceutical company Ipsen, and was introduced to China by Hutchison China MediTech (00013.HK/HCM.NASDAQ) in 2021. In March 2025, Taselisib was conditionally approved for marketing in China for the treatment of eligible lymphoma patients.

The reason for the global withdrawal from the market is that Taselisib may induce secondary hematological malignancies.

Dr. Yi Shuhua, chief physician at the Blood Disease Hospital of the Chinese Academy of Medical Sciences and a researcher of drugs targeting the same pathway, told Economic Observer that there is currently a lack of effective medications and more difficulty in treating secondary hematological malignancies potentially induced by Taselisib.

Several interviewees pointed out that risks such as tumorigenesis from the drug need to be identified through long-term observation and follow-up. Allowing Taselisib to be conditionally marketed was also to provide severely ill patients with no available medications access to a new treatment plan that is fundamentally confirmed to be effective, but this carries some risks regarding efficacy and safety.

Taselisib had filled several clinical gaps. In 2020, when it was approved in the U.S., it became the first drug targeting epithelioid sarcoma globally; it is also the first drug applicable to tumors with EZH2 gene mutations.

On March 9, Economic Observer inquired with Hutchison China MediTech about the scale of affected patients. Hutchison replied, “The specific number of participating patients and the scale of use after marketing will be subject to regulatory records and company announcement information. The sales of this product in 2025 are limited, and the patient base is relatively small.”

After Taselisib was announced to be withdrawn from the market, the National Healthcare Security Administration also announced that it would be removed from the commercial insurance innovative drug directory.

Secondary tumors are harder to treat

According to Ipsen’s announcement, this withdrawal is based on new data from an ongoing Phase Ib/III clinical trial of Taselisib combined with other medications. The Independent Data Monitoring Committee (IDMC) suggested that based on adverse events related to secondary hematological malignancies, the risks of this treatment regimen may outweigh its potential benefits.

Yi Shuhua told Economic Observer that the risk of secondary tumors is a relatively tricky issue in cancer treatment: “If one tumor isn’t treated, another tumor might arise. One wave hasn’t settled, another wave rises.”

Currently, Ipsen has not disclosed specific new data. Yi Shuhua pointed out that previous research data had mentioned the possibility of Taselisib inducing secondary hematological malignancies:

According to the U.S. version of Taselisib’s instructions, among 758 adult clinical trial participants receiving monotherapy with Taselisib 800mg twice daily, 1.7% of patients experienced myelodysplastic syndromes, acute myeloid leukemia, or B-cell acute lymphoblastic leukemia. Additionally, one pediatric patient developed T-cell lymphoblastic lymphoma.

“This emergency withdrawal may be due to an increased probability as the sample size expands and follow-up duration lengthens. But without disclosing specific data, we don’t know how high the current incidence rate is or how strong the correlation is,” Yi Shuhua said. “Moreover, the two tumors, secondary myelodysplastic syndromes and acute myeloid leukemia, lack effective medications, making treatment more challenging.”

Liu Changnian, a partner at Longpan Investment who primarily invests in new oncology drugs, has over 20 years of drug development experience in the U.S. and previously served as the Executive Deputy Director of the Tianjin Cancer Institute. He believes that from a drug development perspective, although the severe adverse reaction of inducing hematological tumors may not exclude issues with the compound itself, the safety issues of Taselisib could be “bad news” for the development of other drugs targeting the same EZH2 pathway.

In mainland China, the only approved drug targeting the same pathway as Taselisib is the self-developed Zemeituzumab Tablets by Heng Rui Medicine (600276)(600276.SH/01276.HK), which is conditionally approved for marketing in August 2025. Additionally, Pfizer, Synlogic, and Haihe Medicine also have drugs targeting the same pathway undergoing Phase III or II clinical trials.

Yi Shuhua mentioned that adverse reactions of drugs targeting the same pathway are similar, and they may have similar potential risks; however, the strength of tumorigenicity may differ due to targeting different sites.

He also pointed out that in the aforementioned clinical trial, Taselisib was used in combination with two other drugs. “Currently, we cannot ascertain whether the risk of secondary tumors is due to Taselisib or the synergistic effect of the drug combination. However, future drug development targeting the same pathway will likely be more cautious regarding this combination approach. I believe other drugs targeting the same pathway can still be developed.”

Once filled clinical gaps

The indications for which Taselisib was approved all target relatively rare diseases, and these disease groups are small, making drug development difficult. New drugs are significant for these patients.

When Taselisib was launched in the U.S. in January 2020, it was classified as an orphan drug, with the first indication being epithelioid sarcoma, which is the first new drug targeting this condition globally.

Epithelioid sarcoma is considered a rare disease in countries such as the U.S. and China. According to the treatment guidelines released by the National Health Commission in 2025, the incidence of epithelioid sarcoma accounts for less than 1% of all soft tissue sarcomas. This means that even in China, there may only be several hundred to a thousand patients with epithelioid sarcoma.

The aforementioned guidelines indicated that Taselisib has limited efficacy for such patients. In a clinical trial involving 62 patients, the objective response rate (ORR, which refers to the proportion of patients responding effectively to a treatment) was 15%, but 67% of patients did not experience further deterioration of their condition.

Taselisib’s second indication is follicular lymphoma (FL). It performed better in this area, with two clinical trials in the U.S. including 42 patients with EZH2 mutated FL and 53 patients with EZH2 wild-type FL, achieving objective response rates of 69% and 34%, respectively.

Yi Shuhua told Economic Observer: “There are almost no other approved new drugs for follicular lymphoma besides CD20 monoclonal antibodies, and small molecule targeted new drugs are relatively scarce. Taselisib, as a small molecule targeted drug, is quite effective, and the Phase II bridging study conducted in China achieved good efficacy, similar to global research results.”

This patient group is also small, with Taselisib approved in China for the treatment of adult patients with third-line EZH2 mutation-positive relapsed or refractory follicular lymphoma. According to Hutchison’s 2025 mid-term report, about 9,000 new cases of follicular lymphoma are added each year in China, with approximately one-third ultimately requiring third-line therapy, and the frequency of EZH2 mutations is about 25%.

Market entry and withdrawal are both “lifesaving”

Based on clinical needs, Taselisib has been on a regulatory “green channel.”

In 2020 in the U.S., Taselisib was launched through the FDA’s accelerated approval process. In 2022, it was approved for use in the Boao Lecheng International Medical Tourism Pilot Zone in Hainan according to the standards for urgently needed imported drugs.

In March 2023 and May 2024, Taselisib was successively approved in Macau and Hong Kong. Subsequently, Taselisib’s application for market entry was included in the priority review procedure of the National Medical Products Administration of China and received conditional approval for marketing in March 2025.

China’s conditional approval system is similar to the FDA’s accelerated approval system, both allowing companies to apply using alternative clinical endpoints to expedite approval, but drugs must continue clinical trials after being marketed to confirm relevant clinical benefits for formal approval; otherwise, the drug may be withdrawn.

“It’s like ‘getting on the bus first and buying the ticket later’; it’s a temporary permit,” said Zhu Tongyu, the Vice President of Shanghai Medical College at Fudan University. He has closely followed the impact of the conditional marketing approval system for new drugs.

Zhu Tongyu told Economic Observer that drugs approved for conditional marketing mainly target diseases that pose a serious threat to life and have no effective treatment methods, such as advanced tumors. For these diseases, if early clinical data can predict clinical value, marketing approval can be granted early.

However, the gradually emerging tumorigenicity of Taselisib after its market entry has reversed the assessment of the risk-benefit ratio. “Some drugs induce tumor occurrence very slowly, and it may require long-term observation to discover, unlike toxicity reactions such as nausea and vomiting that appear quickly,” Liu Changnian said.

On March 9, Hutchison announced that it had immediately implemented lock-up measures for the product, suspending all sales and shipments, and notified medical institutions to stop prescriptions and pharmacies to halt sales. All ongoing clinical trials of Taselisib have also been stopped; existing patients are advised to consult their attending physicians immediately to discuss treatment options.

“Conditional marketing is to save lives. The early approval of these drugs is to allow patients to access new medications as soon as possible. The market withdrawal is a normal result of the closed-loop operation of the conditional marketing approval system and is also for saving lives; it does not indicate a failure or crisis in the innovative drug industry. This precisely demonstrates that strict regulation, transparent data, and controllable risks are a responsible approach for patients,” Zhu Tongyu said.

Tens of millions in sunk costs

According to data from MoSheng Pharmaceuticals, the listed price of Taselisib in various provinces is 32,260 yuan per box. One box can be used for one month, with an annual treatment cost of approximately 387,000 yuan.

Several interviewees assessed that due to the high cost of the drug and the small number of patients, the direct impact of this market withdrawal on the patient population would not be too large. Hutchison also told Economic Observer that the product’s sales in 2025 are limited, and the patient base is relatively small.

According to Hutchison’s 2025 annual report, the sales of Taselisib in 2024 and 2025 are expected to be $900,000 and $2.5 million (approximately 23.5 million yuan cumulatively). Meanwhile, Hutchison’s total revenue in 2025 is projected to be $548.5 million (approximately 3.791 billion yuan), with Taselisib contributing only about 0.45% of its revenue. Hutchison also stated that its market withdrawal is not expected to affect the company’s financial guidance.

However, Hutchison’s investment in Taselisib has likely become a sunk cost. The 2024 and 2025 annual reports show that Hutchison has already paid Ipsen’s subsidiary $25 million in upfront payments and at least $15 million in milestone payments, with all clinical development costs in China borne by Hutchison.

Regarding whether Hutchison might request a return or refund from Ipsen in the future, Hutchison responded to Economic Observer: “The company is maintaining close cooperation with Ipsen to jointly handle the relevant matters of this market withdrawal, including product recall, patient follow-up support, and subsequent arrangements. We respect the commercial agreements between both parties and will negotiate related matters rationally and properly according to contractual terms and industry practices. As for future cooperation, we have a good foundation for collaboration with Ipsen in the oncology field, and both sides have maintained an open and constructive communication attitude. Any further progress will be timely communicated to the market through official channels in accordance with regulatory requirements and information disclosure principles.”

The market withdrawal due to safety concerns shortly after the innovative drug began to scale up may have been an unforeseen black swan event for both parties.

On March 6, Hutchison also stated at its annual performance communication meeting that Taselisib was included in the first batch of commercial insurance innovative drug directories, providing future growth opportunities in the commercial insurance field; the market entry of Taselisib allowed Hutchison to enter the hematological oncology field, establishing collaborations with opinion leaders in the field and forming a core team with professional hematological oncology knowledge. Hutchison has several other drugs in the hematological oncology field, and the company’s goal is to create a leading hematological oncology product pipeline in China.

Some interviewees pointed out that the lesson from this market withdrawal event is that whether drugs approved for conditional marketing should be included in the medical insurance or commercial insurance directory is still a question worth considering.

The first commercial insurance innovative drug directory in China, announced in December 2025, is highly competitive, with only 19 drugs included out of 121 generic names that passed the preliminary review during the application stage, including Taselisib. The directory is positioned as “highly innovative, with significant clinical value and substantial patient benefits that exceed basic medical insurance coverage.”

“Drugs approved conditionally still need to be observed for long-term efficacy and safety before formal approval can be made. I believe that whether a drug is included in basic medical insurance or a commercial insurance directory, it should be a drug that has been formally approved as safe and effective by regulatory authorities, rather than one that has been conditionally approved and remains uncertain about its safety and efficacy,” Liu Changnian said.

Yi Shuhua, on the other hand, believes that whether to include drugs in medical insurance or commercial insurance directories should depend on patient needs, which is not closely related to the adverse reactions of the drug. Many drugs that have been on the market for years may also have adverse reactions that were previously undiscovered as the sample size expands over time.