UPDATE: Jan. 30, 2019: Amgen on Tuesday disclosed fourth quarter sales numbers showing Aimovig earned the biotech $95 million in the three months from October through December, above Wall Street expectations.
Executives characterized payer coverage as "pretty good," noting the share of paid Aimovig prescriptions rose to 50% from 35% in the third quarter.
- Amgen and Novartis' early lead in commercializing a new type of preventive migraine therapy could be put to the test this year, as rivals Teva and Eli Lilly seek to make inroads with recently approved competitors that work in a similar fashion to Amgen and Novartis' drug.
- Concern over the impact of that competition could be seen in a hit to Amgen's stock price Friday after Reuters reported recent changes made by CVS to its formulary that prefer Teva's Ajovy and Eli Lilly's Emgality over Amgen and Novartis' Aimovig.
- While some Wall Street analysts downplayed the impact of the CVS decision, coverage decisions by payers look set to play a major role in how the market for these drugs — known as CGRP inhibitors — unfolds. Success is particularly important for Amgen, which faces significant challenges to its portfolio of older biologic blockbusters.
Amgen and Novartis were first to market with Aimovig (erenumab), beating both Teva and Eli Lilly in securing approval for a CGRP inhibitor. The drugs inhibit the calcitonin gene-related peptide, or CGRP, pathway, which is involved in the underlying mechanisms triggering migraine development.
Several therapies are already approved to prevent migraine, such as Allergan's Botox (onabotulinumtoxinA), yet CGRP inhibitors are seen as potentially more effective and convenient for certain patients.
Aimovig's early-mover advantage has translated into a strong lead in prescription uptake, with the drug holding a roughly 70% share of total prescriptions written for CGRP inhibitors.
But Teva and Lilly will test how durable that lead is, launching last year their rival drugs with limited-duration programs that offer patients access to free drug samples.
All three therapies are priced at $575 per month, or $6,900 a year, indicating the emphasis placed by their makers on securing favorable coverage nods from payers.
On the face of it, CVS' decision appears bad news for Amgen, potentially shifting patients toward Ajovy and Emgality.
"We currently have two CGRP inhibitors, Ajovy and Emgality, on our commercial formulary, which are available to members who have tried other preventive migraine treatments without success," a CVS spokesperson confirmed to BioPharma Dive.
The formulary decision appeared to have come late last year, but its impact will be increasingly felt as 2019 progresses.
The coming quarters are particularly important as the drugmakers seek to switch patients from free drug programs to paid prescriptions. As those programs end, favorable payer coverage — with lower copays or coinsurance rates — could play an important role.
Still, analysts at Piper Jaffray cautioned that the impact to Amgen of CVS' decision could be modest at most.
"Aimovig is not blocked," wrote Piper Jaffray analyst Christopher Raymond in a Jan. 25 note to investors. "Moreover, management indicates this formulary covers only roughly 30% of CVS' covered lives."
In the three months from October to December, roughly 55% of Aimovig prescriptions were approved by payers without need for resubmission, better than both Ajovy and Emgality, data cited by Piper showed.
Piper Jaffray predicts sales of Aimovig to total $50 million in the fourth quarter of 2018 and to fall just shy of $400 million in 2019.
While Aimovig may be disadvantaged in CVS-managed commercial plans, it does enjoy preferred status elsewhere.
Cigna, which recently acquired pharmacy benefit manager Express Scripts, lists Aimovig and Emgality preferentially on its National Preferred Formulary, but doesn't explicitly exclude Ajovy, a spokesperson for Cigna confirmed to BioPharma Dive.
A Cigna-covered patient could have some coverage for treatment with Teva's drug, but would likely pay a higher copay or percentage of the cost, the spokesperson added.
Whether CVS' decision ends up affecting Aimovig won't be apparent for some time, but worries over Amgen's growth prospects look here to stay.
A downgrade of Amgen's stock by Evercore ISI, motivated in part by encroaching biosimilar competition to the biotech's top drugs, spurred a further 4% drop in the company's stock Monday.