Earlier this week, small-cap clinical-stage biotech company Alder Biopharmaceuticals (ALDR) reported compelling phase 2b study results that put it on a collision course for market share with the much larger Eli Lilly & Co. (LLY 0.73%). Can this upstart outmaneuver Eli Lilly and capture a share of this $6 billion market? Let's take a closer look. 

Head to head
Alder Biopharma reported that administering one single infusion of its ALD403 significantly reduced the number of monthly migraine days reported by chronic migraine patients, defined as experiencing 15 or more migraines per month.

Specifically, patients receiving a 100 mg or 300 mg dose of ALD403 reported a 31% and 33% reduction in migraine days per month over a 12-week period, respectively. That performance matched up nicely against the 21% of patients in the placebo arm of the study who reported a similar reduction in migraine days per month.

Alder Biopharmaceuticals data backs up efficacy reported last year from a phase 2 trial showing that 16% of episodic migraine patients, or those with between five and 14 migraine days per month, had a 100% response rate to ALD403.

These results are undeniably impressive, but investors might want to manage their expectations, because Eli Lilly is developing its own LY2951742 migraine drug that works similarly to ALD403. Last year, Eli Lilly also reported compelling midstage trial results.

Specifically, 33.3% of patients receiving LY2951742 twice per month saw a 100% drop in reported migraine headache days per month over a 12-week period. Overall, there was an average 62.5% decline in migraine headache days per month for Eli Lilly's drug, compared with an average 42.3% decrease reported within the placebo group. Eli Lilly also reported positive efficacy for a once-monthly 120 mg dose of LY2951742 last June.


Building similar mousetraps
Both companies are speeding their migraine drugs into late-stage studies, but picking a winner at this stage is made more difficult by the fact that Alder Biopharmaceuticals and Eli Lilly's drugs work similarly.

ALD403 and LY2951742 are monoclonal antibodies that target calcitonin gene-related peptide (CGRP), a small protein associated with the transmission of and sensitivity to migraine pain. Since ALD403 and LY2951742 both put the brakes on CGRP activity to halt migraines, it's not too surprising that both drugs posted solid efficacy in their respective mid-stage clinical trials.

If efficacy for these drugs holds up in each of these companies' phase 3 trials, then market share could be determined by safety. So far, both drugs appear to be safe. Alder Biopharmaceuticals reports that ALD403's safety profile is similar to placebo and in Eli Lilly's twice-monthly phase 2 trial, adverse events were manageable and consisted of injection site pain, upper respiratory infection, and abdominal pain. However, one-month dosing should improve upon that safety profile. 

Looking ahead
Alder Biopharmaceuticals started enrolling patients in one phase 3 trial that's expected to wrap up in the first half of next year, and a second phase 3 trial should begin enrolling patients soon. Meanwhile, Eli Lilly has six LY2951742 phase 3 trials under way and also expects data in 2017. Among its six trials, studies evaluating Eli Lilly's LY2951742 as a therapy for cluster headaches may be most intriguing. There are no currently approved treatments for cluster headaches, and they're a relatively rare form of headache, affecting less than 200,000 people. Because of the need for new treatment options in this patient population, the FDA granted LY2951742 fast-track designation for that indication, which could help Eli Lilly get its drug on the market first.

However, a first-to-market advantage in cluster headaches may not give Eli Lilly that much of an advantage in the much larger migraine market. If efficacy and safety between these two drugs match up similarly, then ALD403's once-quarterly dosing could be the defining advantage that allows it to capture the biggest share of this lucrative market.