Apotex/Apobiologix: Success in Canada, but Are They Shelving Biosimilars in the US?

Apotex has recently made news in Canada, introducing biosimilars and obtaining marketshare there. However, the story of Apotex and its Apobiologix biosimilar subsidiary in the US is less positive.

Apobiologix

As we’ve listed in our updated table, Apotex had originally filed for approval for its pegfilgrastim biosimilar with the FDA in late 2014 and its filgrastim biosimilar in early 2015. In 2019, no announcement has been made with regard to the filing status of either biosimilar.

In April 2018, we spoke with Apobiologix executives, who told us that the company “were still in discussions with the FDA” about the path forward for its G-CSF biosimilars. Unfortunately, this statement has not changed at all on its website. If there were discussions, they didn’t go far. And so the mystery continues.

There is some support for the view that the parent company is seeking to shed the Apobiologix subsidiary, and has been actively seeking a buyer for some time. This would make sense to a degree, as any of its newly approved biosimilars would be facing a difficult crawl to US marketshare, being the third or fourth filgrastim or pegfilgrastim biosimilar to launch.  Realizing that its marketshare potential would be substantially limited, why spend the additional developmental dollars?

In April 2018, Canada had granted the company approval to market its pegfilgrastim biosimilar (Lapelga™), and in Canada’s provincial systems, it has become a dominant player. Filgrastim was approved in Canada in 2016 (and in the EU in 2014).

According to its website, Apobiologix had been developing the following products for the US market:

  • Epoetin alfa (reference drug, Epogen®), in Phase 3
  • Darbepoetin alfa (Aranesp®), in preclinical study
  • Bevacizumab (Avastin®), in Phase 1
  • Rituximab (Rituxan®), in Phase 1
  • Trastuzumab (Herceptin®), in preclinical study

Although the pipeline lists the epoetin, bevacizumab, and rituximab biosimilars in clinical trials, no mention of any of these specific investigations can be found on www.clinicaltrials.gov, under Apotex or Apobiologix as a sponsor. A request for comment from Apobiologix was not answered by the time of this publication.

If this is the case, it is less the FDA than the parent drug maker who has lost faith in their biosimilars’ potential in the US. We can ill afford fewer active players in this market.

Pfizer Gets Green Light From the FDA on Epogen® Biosimilar

It has taken a long time, but Pfizer finally earned approval from the U.S. Food and Drug Administration (FDA) on the first biosimilar version of Epogen®. The drug, Retacrit® (epoetin alfa-epbx), had originally been submitted for approval in December 2014. Its much stalled road to approval is finally at an end.

After an initial rejection, the FDA’s Advisory Committee voted overwhelmingly (14–1) in May 2017 to give the product a green light. However, the FDA changed the traffic light to red, issued a second complete response letter in June 2017, citing issues with its manufacturing plant in McPherson, Kansas (a plant Pfizer inherited with its acquisition of Hospira).

Retacrit is approved for the treatment of anemia caused by chemotherapy or chronic kidney disease, for use in patients taking zidovudine for the treatment of HIV infection, and to reduce the need for red-cell blood transfusions before, during, or after surgery.

This is the 10th biosimilar approved by the FDA, and Pfizer is expected to shortly launch only the fourth biosimilar agent. Epogen’s patent has long expired, and it was one of the first biosimilars approved in Europe (in 2007). Retacrit has been marketed in the EU for over 10 years. It is one of four biosimilar epoetin products available overseas.

In other biosimilar news… Mylan’s earnings call on May 9 produced little clarity on the fate of its upcoming FDA decision on its pegfilgrastim biosimilar. Although CEO Heather Bresch believes that its product will represent one of its most important launches of the year, she could not shed any light on partner Biocon’s response to the FDA’s critical review of its manufacturing facility. The PDUFA date is June 4; a positive decision means that Mylan/Biocon will have beaten the competition to the market for this important biosimilar product.

More Clinical Study Evidence That Biosimilar Switching Carries a Low Risk

A literature review published this past weekend in Drugs reaffirms what most parties interested in biosimilars suspect—that switching from a reference product to biosimilar is not a significant clinical concern. Biosimilar switching was not generally associated with poorer outcomes.

The study evaluated the results of 90 clinical studies comprising more than 14,000 patients with 14 diseases or conditions. The authors from Novartis (and its Sandoz subsidiary), the Oregon Medical Research Center, Rocky Mountain Cancer Centers, IBD Center of Humanitas Clinical and Research Hospital (Milan), and Avalere Health stated that “the great majority of the publications did not report differences in immunogenicity, safety, or efficacy [as a result of biosimilar switching]. The nature and intensity of safety signals reported after switching from reference medicines to biosimilars were the same as those already known from continued use of the reference medicines alone.” In addition, they reported, “Three large multiple switch studies with different biosimilars did not show differences in efficacy or safety after multiple switches between reference medicine and biosimilar.”

In this evaluation, the biosimilars tested included those for infliximab, epoetin, filgrastim, growth hormone (which has not been considered a biosimilar in the Ubiosimilar switchingS), etanercept, and adalimumab. Infliximab was the subject of the majority of the clinical studies.

Of the 90 studies, two were outliers, suggesting potential safety issues associated with biosimilar switching. One was described as a 2016 retrospective study of a claims database from Turkey, which found a much higher discontinuation rate with the infliximab biosimilar compared with originator product in patients with rheumatoid arthritis.

The authors correctly note that the vast majority of the studies reviewed involved a single biosimilar switch, and that multiple switches may result in additional safety signals. However, they also point out that “patients have already been exposed to de facto multiple switches for many originator biologics when product quality attributes changed after one or more manufacturing process modifications were introduced.”

The question arises as to whether multiple switch studies are truly necessary outside of the requirement to prove interchangeability between a biosimilar and a reference product. There is a practical reason for doing so—the possibility (actually, the likelihood) of a patient enrolling in a new health plan one year, which covers the biosimilar but not the reference product. If the patient’s health plan changes once again one or two years later, that person may well be required to switch back to the reference product or yet another biosimilar.

This will heighten the importance of collecting real-world evidence and accumulating more experience outside of the clinical trial environment in terms of switching. Efforts such as those at the Biologics and Biosimilars Collective Intelligence Consortium should fill this gap over the next several years.

 

FDA Stuns With Rejection of Pfizer’s Retacrit

Following a 14-1 vote by its Oncology Drug Advisory Committee last month to recommend approval for Pfizer’s biosimilar version of Epogen®, the Food and Drug Administration (FDA) on June 22 sent the drug maker a complete response letter outlining its decision to reject the product.

It is unusual for the FDA to decide against a clear majority recommendation by its Advisory Committee, but the agency pointed to potential manufacturing issues at one of Pfizer’s facilities. Pfizer stated, “This [complete response letter] relates to matters noted in a Warning Letter issued on February 14, 2017 following a routine [FDA] inspection of the company’s facility in McPherson, Kansas in 2016. This facility was lisfdated as the potential manufacturing site in the BLA for the proposed epoetin alfa biosimilar. The issues noted in the Warning Letter do not relate specifically to the manufacture of epoetin alfa.” Although Pfizer responded to that notification by submitting a corrective and preventative action plan the following month, apparently, the FDA is not yet confident in the drug maker’s plan. According to Pfizer’s statement, the agency did not request that additional clinical data be submitted.

The FDA had cited this particular plant for several issues regarding the presence of foreign matter in medications being produced there. In its Warning Letter, the agency suggested there was “a significant loss of control in your manufacturing process” that represents a “severe risk of harm to patients.” The plant was one that Pfizer acquired in its purchase of Hospira in 2015.

This is Pfizer’s second rejection for Retacrit™, a product that was developed and brought to market in Europe by Hospira. Pfizer had resubmitted the 351(k) application in 2016.

The manufacturer stated that it is seeking to clear up any remaining issues at the plant cited by FDA. However, it is not clear whether Pfizer will have to resubmit its application entirely, as the rejection does not seem to be related to safety or efficacy issues involving the agent.

Pfizer’s Epogen® Biosimilar Gets FDA Advisory Committee Backing

Pfizer purchased Hospira in 2015, and one of its prizes was a biosimilar version of Epogen® and Procrit® that was already being reviewed by the Food and Drug Administration (FDA). The FDA rejected that 351(k) application and issued a complete response letter. Pfizer’s Hospira unit resubmitted its application for its Retacrit™ version of epoetin alpha in 2016. They received good news this week from the agency.

According to the FDA’s staffers’ summary released ahead of the May 25th Oncology Advisory Committee review, Retacrit fulfilled the requirements for biosimilarity. Today, the Advisory Committee added further support to this conclusion by voting 14-1 to recommend approval for all extrapolated indications, despite some safety concerns expressed by committee members.

According to the staff review, “The totality of analytical data support the determination that ‘Epoetin Hospira’ is highly similar to US-licensed Epogen/Procrit notwithstanding minor differences in clinically inactive components.” Nor were any clinically meaningful differences in immunogenicity risk found. The FDA staff review documents also concluded that Retacrit’s biosimilarity evidence supports extrapolation across its intended indications.

Last month, the Food and Drug Administration removed the Risk Evaluation and Mitigation Strategy (REMS) on the originator product, indicating that it is no longer necessary to “ensure that the benefits of Epogen/Procrit and Aranesp® outweigh the risks of shortened overall survival and/or increased risk of tumor progression or recurrence, for the treatment of anemia associated with myelosuppressive chemotherapy.” The originator agent has been linked with cardiovascular safety concerns, which has affected utilization of epoetin alpha over the years.

The first epoetin biosimilars were approved for use in Europe in 2007; a tremendous amount of real-world data have accumulated on their use. However, the FDA Oncology Advisory Committee cannot consider this in their decision.

Members of the FDA Committee expressed “residual concerns with immunogenicity and safety.” For example, patients with chronic kidney disease who require hemodialysis may have a reduced response to Retacrit.

The rather unique “dual” originator products (Epogen/Procrit) resulted from a duel in the 1990s between Amgen and Johnson & Johnson. Amgen originally manufactured the product in the late 1980s and licensed it to J&J’s Ortho Biotech unit. A stormy relationship developed, with lawsuits passed back and forth. The result was a licensing agreement that the drug would be manufactured under license (sounds a bit like a biosimilar, doesn’t it?) by each company for different indications.

Real-World Evidence Shows Biosimilar Epoetin Outcomes as Good as the Originator

The erythropoiesis-stimulating agents (ESAs) are among the first biosimilars approved for use in Europe, a decade ago. As more real-world evidence accumulates on the comparable outcomes of several classes of biosimilars, support increases for their utilization abroad. This past week, researchers from Rome, using a real-time patient registry, have confirmed the safety and efficacy of biosimilar versions of erythropoiesis-stimulating agents (ESAs) compared with the originator product (epoetin-alpha).

Dr. Francesco Trotta, Department of Epidemiology, Lazio Regional Health Service, Rome, led a team of investigators who evaluated the use of ESAs in nearly 13,500 patients with chronic kidney disease or undergoing treatment for cancer in a region of Italy (total population, 6 million) over a 3-year period, assuming a 6-month course of the agents. They assessed all-cause mortality and need for blood transfusion and the incidence of major cardiovascular events and blood dyscrasia, which comprised a composite endpoint of effectiveness and safety.

The results of this study were published in BMJ Open. In comparing 3 ESA biosimilars (Abseamed®, Binocrit®, and Retacrit®) to the epoetin alpha originator drug (Eprex®), the researchers found that in patients with chronic kidney disease, the risk estimates for the effectiveness and safety measures were not significantly different. Using a composite outcome, the biosimilars demonstrated an adjusted hazard ratio of 1.02 compared with Eprex. The biosimilars were also compared with other ESAs, including darbapoetin alpha, epoetin beta, epoetin theta, and methoxypolyethyleneglycol-epoetin beta. Though not considered biosimilars to these agents, the epoetin alpha biosimilars recorded an adjusted hazard ratio of 1.09 compared with these other ESAs. For patients receiving oncology treatment, the biosimilars demonstrated a better hazard ratio for the all-cause mortality outcome (adjusted HR, 0.82), which was on the “margin of statistical significance.” In terms of the composite outcome, the biosimilars exhibited a slightly improved adjusted hazard ratio (0.91). Subgroup analysis revealed some minor differences in outcomes, but none that would alter a patient’s clinical approach.

The authors concluded, “In both settings, our findings are suggestive of no difference between biosimilars and originators on relevant effectiveness and safety outcomes measured during the follow-up period.”

These results should not be surprising based on the success (and proliferation) of the ESA class since 2007. The fact that a US version of epoetin alpha has not yet been approved is surprising: Pfizer’s Retacrit was submitted in 2014, with hopes of being the first biosimilar on the market, but a complete response letter from the FDA the following year short circuited this plan. No other epoetin biosimilar is on record as being filed for approval with the FDA at this time.